Miocene leaf fossil from Blue Lake, St Bathans, New Zealand
comment 0

Blue Lake, St Bathans – the most biodiverse Miocene fossil plant locality

The biodiversity of Blue Lake, at St Bathans, New Zealand, is precisely zero. It is an artificial lake partly filling a hole blasted out in the search for gold in the 19th century. The hole is directly in front of one of St Bathan’s and New Zealand’s gems – the Vulcan Hotel. If you ran out the front door and forgot to stop at the cliff marking the edge of the old workings – you would land in one of the most biodiverse fossil plant sites anywhere on the planet.

Blue Lake, St Bathans, New Zealand

Blue Lake, St Bathans, New Zealand

The gold miners were sluicing quartz-rich gravel and sands. But in among those are thinner beds and lenses of mud. These are often full of plant fossils of Miocene age – say around 17-18 million years. Sometimes these are amazingly-preserved whole leaves – the featured image and one below show fossil leaves that have been floated out of the mudstone and then set in glycerine jelly between sheets of plastic. But often the fossils are just a hash of leaf fragments. This looks like a handful of compost at first, but it’s this hash, plus the extremely good preservation of that hash – that can make just a single handful of mud rich with fossils.

On the slope marking the edge of the Blue Lake digging and in front of the Vulcan Hotel there used to be a pine tree. It was my marker to locate a lens of mud remarkable by itself for its fossil plant content. In a few handfuls of mud from that lens were seven genera of conifers and at least 48 flowering plants. The conifers included some of our familiar New Zealand trees – like matai (Prumnopitys) and rimu (Dacrydium). But there were also surprises. There was Acmopyle – unique as a ‘hairy’-leaved conifer, and only growing in Fiji and New Caledonia now. Also Retrophyllum, a conifer with a distinctive paired arrangement of leaves along its shoot, but now found only in New Caledonia, Melanesia and South America.

Miocene leaf fossil from Blue Lake, St Bathans, New Zealand

Miocene leaf fossil from Blue Lake, St Bathans, New Zealand

And that little lens was just the start of it. Blue Lake has many such lenses, and over the hill is a ‘sister-lake’ – one of the local names being ‘Grey Lake’. It has a similar kind of geology. The sands and mud exposed in these lakes were deposited in an ancient river flowing along what geologist Barry Douglas (1986)  has called the ‘St Bathans PaleoValley’. It came from uplands in the west, to the coast somewhere to the east. In both Blue and Grey Lake muds I’ve now recorded a total of 13 conifers, 144 flowering-plant types and a further two cycad-like ones. To put this biodiversity in context, As a comparison, today there are around 215 species of tree in the entire New Zealand region (including the subtropical Kermadec Island; McGlone et al., 2010) and nine genera of conifers. So in an area of just a few hectares – there are more fossil conifer types than in all of New Zealand today. This is one of the most biodiverse, and perhaps the most, Miocene plant fossil localities anywhere.

What caused this high biodiversity? It was certainly warmer – the climate was warm temperate or even subtropical. Average temperatures would have been at least 6-7 degrees warmer than today. But perhaps more importantly, the cooler temperatures would have been much warmer. The harsh frosts and snow that St Bathans gets now, would have been entirely unknown. The kinds of rainforest plant fossils found at Blue Lake prove that rainfall too, would have been higher and more consistent, quite unlike the low and drought-ridden climate that the area has now. On top of that, Douglas considered that the ancient river was ‘braided’. This is a type of river that has many channels, and switches between  them from time to time. This process keeps vegetation in various stages of ‘succession’, allowing many species a chance to find their niche.

Vulcan Hotel, St Bathans, New Zealand

Vulcan Hotel, St Bathans, New Zealand in the snow. There would have been no snow, or even frosts, during the Miocene when biodiverse rainforest grew here.

The Miocene plant fossils of Blue and Grey Lakes are a treasure -trove and much remains yet to be understood. Many of the fragmentary plant fossils are still unidentified. They are clearly not plants living in New Zealand today – but where will similar plants turn-up? New Caledonia? Patagonia? Madagascar? And just what were the plant communities that lived in the St Bathans Paleovalley? How many new fossils wait to be found?

And that first lens of mud? The one beside the pine tree? Pine trees are an introduced, often invasive conifer in New Zealand. Their spread across parts of New Zealand is causing problems (they shade out smaller natives, acidify the soil and are a fire hazard) and so the Department of Conservation is doing their best to control the pines. That pine, one of the few trees in an otherwise naturally vegetation-free spot, was removed, and along with it, much of that biodiverse fossil lens. In fact, with the pine tree gone and the disturbance that created, I’ve had trouble re-locating it.

Something very ironic there!

References

Links will take you to a site to download pdfs of the papers.

Douglas, B. J. 1986. Lignite resources of Central Otago. New Zealand Energy Research and Development Committee Publication P104: Volume one, Volume 2.

Pocknall, D.T., 1982. Pollen and spores from Blue Lake, St Bathans (H41) and Harliwichs Lignite Pit, Roxburgh (G43), Central Otago, New Zealand. Palynology Section, NZGS, Lower Hutt.

Pole, M.S., 1992. Early Miocene flora of the Manuherikia Group, New Zealand. 2. Conifers. Journal of the Royal Society of New Zealand 22, 287-302.

Pole, M.S., 1997. Miocene conifers from the Manuherikia Group, New Zealand. Journal of the Royal Society of New Zealand 27, 355-370.

McGlone, M. S., S. J. Richardson, et al. 2010. Comparative biogeography of New Zealand trees: species richness, height, leaf traits and range sizes. New Zealand Journal of Ecology 34: 1-15.

Pole, M., 2007. Conifer and cycad distribution in the Miocene of southern New Zealand. Australian Journal of Botany 55, 143-164.

Pole, M., 2008. Dispersed leaf cuticle from the Early Miocene of southern New Zealand. Palaeontologia Electronica 11 (3) 15A:, 1-117.

Pole, M., 2014. The Miocene climate in New Zealand: Estimates from paleobotanical data. Palaeontologia Electronica 17, 1-79, palaeo-electronica.org/content/2014/2780-miocene-climate-of-new-zealand.

 

Fossil pea pod (legume) from the Miocene of New Zealand
comment 0

Giant Pea Pod fossils in New Zealand’s Miocene

Pea pod fossils in New Zealand were first found by Aline Holden, a pioneer of New Zealand plant fossil research. She found the first ones at Bannockburn in 1981, while working on her PhD, and then found more in the Nevis Valley.

In 1987, my PhD professor, J.D. Campbell and his wife, Anne, dropped in unexpectedly in Alexandra (my home). They were on their way to the Nevis Valley and wanted to know if I would come too. The Nevis Valley has a well-known oil shale deposit, and this includes fossil leaves and scattered fish bones of Miocene age (c. 18-17 million years). Once in the area, ‘JDC’ focussed on shale near the track, while I set off to explore up a shrubby side valley. I was on the way back when I spotted a likely outcrop up on the valley side. It was solid gold – to a fossil plant person that it is. Technically it was mudstone, but stuffed full of not only fossil leaves, but pea pods as well. I worked out as large a chunk as I could, strapped it to my pack frame, and then staggered back to the car with it.

Back in the lab, chipping away the overlying mudstone, revealed fossil pods (legumes) up to 130 mm long, and with 14 peas (seeds).

Fossil pea pod (legume) from the Miocene of Nevis Valley, New Zealand

Fossil pea pod (legume) from the Miocene of Nevis Valley, New Zealand (length c. 130 mm)

Today New Zealand has just four groups of peas (the legume family). There’s kowhai (Sophora), Kakabeak (Clianthus), the scree pea (Montigena) and the many brooms (Carmichaelia). All of these are part of the legume family that have classic ‘pea flowers’. One of the technical terms for this group is (or was) the Papilionoideae (think of the French word for butterfly – ‘papillion’).

But traditionally, there are also two other large groups of legumes. One is the Caesalpinioideae – with quite showy flowers (think Bauhinia), then the Mimosoideae. These have very reduced flowers, looking a bit like pom-poms (think of the wattles/Acacia).

Fossil pea pod (legume) from the Miocene of Bannockburn, New Zealand

Fossil pea pod (legume) from the Miocene of Bannockburn, New Zealand

The lucky find in the Nevis that day was not just the large fossil pea pods, some with the seeds (peas) in them, but some scattered leaves that were surely produced by the same plant. Based on the combination of evidence, the legume expert Dr Les Pedley, suggested most likely identification of the fossils was Serianthes. This plant is now found in New Caledonia, Fiji, and French Polynesia.

Fossil legume leaflet from the Miocene of Bannockburn, New Zealand

Fossil legume leaflet from the Miocene of Bannockburn, New Zealand

Serianthes is one of the Mimosoideae group. The Mimosoideae was already known in New Zealand based on fossil pollen, although in those cases, Acacia was considered the more likely parent plant (Pocknall and Mildenahll 1984; Mildenhall and Pocknall 1989).

Together, the pods, leaves and pollen make a nice addition to what used to grow in New Zealand. But what do these fossil mean? Based on where Serianthes grows today, the average annual temperature may have been more than 20 C. That’s about twice what it is now. Also a suspicion that the vegetation it was growing in was relatively dry.

I seem to spend half my life staggering kilometres with a pile of rock, either on my back or worse, carrying it in my arms. But in this case, it was well worth it.

References

Links will take you to my academia.edu site where you can download a pdf.

Mildenhall, D.C., Pocknall, D.T., 1989. Miocene-Pleistocene spores and pollen from Central Otago, South Island, New Zealand. New Zealand Geological Survey Palaeontological Bulletin 59, 1-128.

Pocknall, D.T., Mildenhall, D.C., 1984. Late Oligocene -Early Miocene spores and pollen from Southland, New Zealand. New Zealand Geological Survey Paleontological Bulletin 51, 1-66.

Pole, M.S., 1992. Fossils of Leguminosae from the Miocene Manuherikia Group of New Zealand, in: Herendeen, P.S., Dilcher, D.L. (Eds.), Advances in Legume Systematics: Part 4. The Fossil Record. The Royal Botanic Gardens, Kew, pp. 251-258.

Pole, M.S., Holden, A.M., Campbell, J.D., 1989. Fossil legumes from the Manuherikia Group (Miocene), Central Otago, New Zealand. Journal of the Royal Society of New Zealand 19, 225-228.

Araucaria fossil shoot from Miocene of New Zealand.
comments 2

Hoop Pine fossils – dry rainforest in New Zealand’s Miocene

In a little patch of shale, continually flaking onto the road near Bannockburn (central South Island, New Zealand), there are the unmistakable fossils like Australian ‘hoop pine’ shoots. Hoop pines are members of the tree family which includes ‘monkey puzzles’, ‘bunyas’ and the ‘Norfolk Island Pines’. The Latin name is Araucaria – New Zealand has none of these in its native flora today, but it does have the kauri (it’s another genus, Agathis, but in the same family).

A long fossil Araucaria shoot from the Miocene of Bannockburn, New Zealand. Shoot is c. 6 mm wide.

A long fossil Araucaria shoot from the Miocene of Bannockburn, New Zealand. Shoot is c. 6 mm wide.

Around 17 million years ago (Miocene period) the shale would have been accumulating in a standing body of water, probably a flood-basin lake. Plant fossils would have been washed into it after they blew off a tree into a river, which then flowed into the body of water. The pine shoots are made of long, overlapping scale-like leaves, that together make a tail-like structure, maybe 4-6 mm in diameter. Along with the shoots there are also occasional  seed cone-scales and rare pollen cones. The cone-scales have delicate wings, just like modern hoop-pines, but these have often been lost in the fossil.  These additional plant fossils all help to show that the original tree was something much closer to the Australian ‘hoop pines’, the Norfolk Island pine’ and some New Caledonian species of Araucaria, than to other species in the family.

A fragment of a branch of fossil Araucaria shoots from the Miocene of Bannockburn, New Zealand

A fragment of a branch of fossil Araucaria shoots from the Miocene of Bannockburn, New Zealand

Back in the days of the dinosaurs (Cretaceous, c. 75 million years ago) the hoop pine family was common in New Zealand. They were an important component of the wet coal-swamps. But at the same time the dinosaurs vanished, so did those trees. From that time on, fossils of Araucaria are rare in New Zealand, with the layer of shale near Bannockburn an exception.

A fossil Araucaria seed-cone scale from the Miocene of Bannockburn, New Zealand (c. 20 mm high)

A fossil Araucaria seed-cone scale from the Miocene of Bannockburn, New Zealand (c. 20 mm high)

What do these fossils mean? Probably warmer times than today, but perhaps more intriguingly, the Australian hoop pine is a key plant in what are called ‘dry rainforests’. This term sounds a bit contradictory, but it refers to forest where rainfall is relatively low, but where fire does not normally occur. Unlike wetter, more normal rainforests, the low rainfall helps keep the forest canopy more open. Without so much shade, the greater amount of light reaching the forest floor is probably a reason why the hoop pines live in them. It’s certainly a very different habitat than the coal swamps where their relatives lived in along side dinosaurs.

The Bannockburn fossil ‘hoop pines’ (using the term broadly to refer to a group pf species) are evidence of forest (the area was virtually treeless when Europeans arrived in the 19th century),  warmer conditions than in southern New Zealand today (and more like southeastern Queensland), but with some sort of degree of ‘dryness’ – probably seasonally low rainfall.

Small-stuff, but it’s bits of evidence like this that climatologists can use to figure out exactly how our climate system changes.

 

References

Links will take you to my Academia.edu page where you can download a pdf.

Pole, M.S., 1992. Early Miocene flora of the Manuherikia Group, New Zealand. 2. Conifers. Journal of the Royal Society of New Zealand 22, 287-302. (describes the Araucaria shoot, seed-cone and pollen cone fossils from Bannockburn)

Pole, M.S., 1993. Early Miocene flora of the Manuherikia Group, New Zealand. 10. Paleoecology and stratigraphy. Journal of the Royal Society of New Zealand 23, 393-426. (proposes the dry rainforest interpretation for the shale at Bannockburn)

Pole, M., 2008. The record of Araucariaceae macrofossils in New Zealand. Alcheringa 32, 405–426. (describes cuticle from the Araucaria fossils at Bannockburn)

Palaeontologia Electronica 17, Issue2;27A; 79p;palaeo-electronica.org/content/2014/780-miocene-climate-of-new-zealand (detailed evaluation of New Zealand’s climate at the time of the Bannockburn shale and its Araucaria fossils)

<a

Webb, L.J., 1959. A physiognomic classification of Australian rainforests. Journal of Ecology 47, 551-570. (defines ‘dry rainforest’ in Australia and Araucaria as one of their keys)

 

comments 2

How Tall were the trees in New Zealand’s Jurassic Fossil Forest at Curio Bay?

At Curio Bay near the southernmost point of New Zealand’’s South Island, you can walk around the remains of a Jurassic fossil forest. Tree stumps are still in their growth position, and fossilised logs criss-cross through the sandstone overlying them. So can we add these pieces of information together – and see what the Curio Bay fossil forest looked like when it was alive? In fact, was it actually a forest?

The view over the Jurassic Curio Bay fossil forest from the viewing platform. Fossil logs can be seen criss-crossing the tidal platform among hundreds of fossil stumps.

The view over the Jurassic Curio Bay fossil forest from the viewing platform. Fossil logs can be seen criss-crossing the tidal platform among hundreds of fossil stumps.

In 1982 I wrote a report on the Curio Bay fossil forest as part of my study at Otago University. Something I was keen to do was to produce a forest profile – a cross section of the vegetation as it would have looked when it was growing. At that time, I used a fairly simple approach. I measured the locations of stumps along a transect, then, simply sketch in trunks based on the lengths of appropriately sized fossil logs, then sketch in a canopy.

An early attempt at a reconstructed profile of the Jurassic Curio Bay fossil forest. This is from my 1982 report on the forest, and simply rotates known fossil logs to the vertical, and 'attaches' them to mapped tree stumps.

An early attempt at a reconstructed profile of the Jurassic Curio Bay fossil forest. This is from my 1982 report on the forest, and simply rotates known fossil logs to the vertical, and ‘attaches’ them to mapped tree stumps.

However, in that same year, a paper was published by paleobotanist Tim Jefferson, documenting a series of Cretaceous fossil forests in Antarctica. The general style of sedimentation, Jefferson’s (1982) similar goal to bring a fossil forest alive, meant that as I continued work on Curio Bay, his paper had a strong influence on me.

The focus of Jefferson’s paper was on the information the fossil tree rings can give. The important issue was trying to understand how forests grew in a polar environments. Almost as an afterthought, Jefferson provided a 3D reconstruction of a portion of his Cretaceous Antarctic forest. It showed rather widely-separated trees, more like a woodland than a forest. Oddly, the trees he drew were very short – only 4-5 m tall. The only details Jefferson gave was to say that the tree heights were “estimated from trunk breadth: height ratios in LaMarche et al. (1979)”.

While the rest of Jeffersons paper was stimulating, his reconstructed forest image bothered me. For one thing, Jefferson had illustrated a vertical fossil tree trunk about 5 m high. Surely the forest would be much higher than a preserved trunk?

In the mid 1990s I was putting my work on the Curio Bay fossil forest together for a proper paper. I wrote to LaMarche and obtained a copy of their paper, which deals with tree ring chronologies of living trees. As a tree-ring study, this covers the old trees and often from stressed environments. The reason for Jefferson’s oddly short trees became clear – he had reconstructed them based on the dimensions of aged or relatively stunted modern trees. But Jefferson’s work had hinted at a much more rigorous approach – a mathematical relationship between the diameter of a tree trunk, and the height of the tree.

In 1994 a timely paper on another fossil forest came out – this time for one in the Miocene of Germany. Mosbrugger et al. (1994) used quite a different calculation to predict the tree height, and when I applied it to Jefferson’s Antarctic tree stumps, it effectively doubled his height predictions. This looked much more realistic. However, even Mossbrugger et al.’s equation was apparently based on ‘champion trees’. As trees age, they trunks grow wider, but upward growth tends to level off. So this equation might still be underestimating height.

Fossil logs and tree stumps at the Jurassic Curio Bay fossil forest - looking back towards the viewing platform.

Fossil logs and tree stumps at the Jurassic Curio Bay fossil forest – looking back towards the viewing platform.

At this point I decided to get some of my own measurements, and therefore spent some time in the rainforest of Queensland’s Bunya Mountains. This was courtesy of Don Butler, a botanist who was studying the area for his PhD. The Bunyas are one of the few areas where two species of Araucaria grow together. The Bunya Araucarias appear to be regenerating continuously below the forest canopy. There meant there was a wide rang of tree sizes, from saplings up to ‘champions’. This, plus the fact that Araucarias, or something close to them, formed some of the trees in the Curio Bay fossil forest, meant I figured this was a perfect place to get a range of data. Armed with a tape measure and an inclinometer, I measured as many of the two species as I could.

The key observation was that young trees, many of them the size of trunks in the Curio Bay forest, were tall and skinny. Growing up within the forest, they were forced to strive for light, but because they were sheltered from wind by surrounding trees, they could get away with being so skinny.

When I plotted up the data from the Bunya Mountains, they gave a curve about twice as high as Mosbrugger et al’s curve. But then I found measurements by other botanists – for living Araucarias from New Guinea (Paijmans, 1970; Gray 1975), and these produced an even higher curve. So, the Bunya tree diameter-height curve was not exceptional.

A comparison of three different ‘curves’ of tree trunk diameter versus tree height. The Mosbrugger et al. (1994), Bunya Mountains (the ‘low’ curve in Pole 1999) and New Guinea curve (from data in Pajmans 1070 and Gray 1975).

Based on the Bunya curve as a minimum, the Jurassic Curio Bay vegetation was clearly a forest, albeit with a reasonably low c. 10 m canopy, with some c.30 m emergent trees poking through it (Pole 1999). The minimum predicted tree heights are consistent with the dimensions of some of the fossil logs scattered over the forest. The log lengths are a little less than the Bunya curve, but represent trees that would have been taller. However, there are logs with dimensions above the Bunya curve – indicating that the New Guinea curve might be more appropriate, and emergent trees may have reached around 35 m high.

The dimensions of actual logs in the sediment overlying the Curio Bay fossil forest (red dots) compared with the Mosbrugger et al. (1994) and Bunya Mountain tree trunk diameter versus height curves.

The dimensions of actual logs in the sediment overlying the Curio Bay fossil forest (red dots) compared with the Mosbrugger et al. (1994) and Bunya Mountain tree trunk diameter versus height curves.

I never got to meet Tim Jefferson – he was killed in an avalanche in Peru on Sept 12, 1983 (Jefferson and Taylor 1983). I arrived in the UK just over a year later, and spent the winter of 1984-85 in Cambridge. While I was there I took the opportunity to read through his thesis at the British Antarctic Survey. Jefferson was clearly a smart researcher and admired by his colleagues. He has since had a genus of fossil wood named after him, Jeffersonioxylon (del Fueyo, et al. 1995) and there is even a Timothy Jefferson Field Research Fund.

A reconstructed profile of the Jurassic Curio Bay fossil forest, adapted from Pole (1999) and based on the Bunya Mountains tree trunk diameter versus height curve. Using the New Guinea tree curve would 'stretch' the profile upwards such that the tallest trees were around 35 m.

A reconstructed profile of the Jurassic Curio Bay fossil forest, adapted from Pole (1999) and based on the Bunya Mountains tree trunk diameter versus height curve. Using the New Guinea tree curve would ‘stretch’ the profile upwards such that the tallest trees were around 35 m.

But there is an epilogue to this. Just after my paper was published, I became aware of another work – specifically on ‘Predicting the Height of Fossil Plant Remains’ by Karl Niklas. For whatever reason, this paper (Niklas 1994) hadn’t reached either my radar when I submitted my manuscript. (Mosbrugger and Niklas would have submitted their papers at about the same time). Niklas, who specialises in plant structure, had, after extensive work, already come up with a tree diameter -height equation that pretty much exactly describes the Bunya curve.

So a hat-tilt to Karl Niklas.

References (clickable links will take you to a pdf)

del Fueyo, G. M., E. L. Taylor, T. N. Taylor, and N. R. Cúneo. 1995. Triassic wood from the Gordon Valley, central Transantarctic Mountains, Antarctica IAWA Journal. 16, 111-126

Gray, B., 1975. Size composition and regeneration of Araucaria stands in New Guinea. J. Ecol. 63, 273–289.

Jefferson, T.H., 1982. Fossil forests from the Lower Cretaceous of Alexander Island, Antarctica. Palaeontology 25, 681-708.

LaMarche, V. C., Holmes, R.L., Dunwiddie, P.W. and Drew, I.G.. 1979. Tree ring chronologies of the southern hemisphere. 1 .Argentina. 2. Chile. 3. New Zealand. 4. Australia. 5. South Africa. Chronology series V, Laboratory of Tree Ring Research, University of Arizona. Tucson, Arizona.

Mosbrugger, V., Gee, C.T., Belz, G., Ashraf, A.R., 1994. Three dimensional reconstruction of an in situ Miocene peat forest from the Lower Rhine Embayment, northwestern Germany— new methods in palaeovegetation analysis. Palaeogeogr., Palaeoclimatol., Palaeoecol. 110, 295–317.

Niklas K,J. 1994. Predicting the height of fossil plant remains: an allometric approach to an old problem. American Journal of Botany 81: 1235–1242

Paijmans, K., 1970. An analysis of four tropical rainforest sites in New Guinea. J. Ecol. 58, 77–101

Pole, M.S., 2001. Repeated flood events and fossil forests at Curio Bay (Middle Jurassic), New Zealand. Sedimentary Geology 144, 223-242.

Pole, M.S., 1999. Structure of a near-polar latitude forest from the New Zealand Jurassic. Palaeogeography, Palaeoclimatology, Palaeoecology 147, 121-139.

Pole, M., 2004. Early-Middle Jurassic stratigraphy of the Fortrose-Chaslands region, southernmost South Island, New Zealand. New Zealand Journal of Geology & Geophysics 47, 129-139.

Pole, M., 2009. Vegetation and climate of the New Zealand Jurassic. GFF 131, 105 – 111.

comments 6

When Frequent-Flying Becomes Insane-Flying

I loved my Singapore Airlines ‘Elite Gold’ card. Suddenly, International airports transitioned from being places where food and drink were wildly overpriced, to …. free. When I stuffed-up and missed flights, or political rules changed and I couldn’t board an aircraft – instead of costing hundreds of dollars, the issues were quietly and politely taken care of. I’ve spent several nights in the KrisFlyer Lounge at Changi Airport, helping myself to pumpkin soup and red wine in the evenings and muesli and yoghurt in the morning. And of course, free wifi.

I’m a product of my culture and my times. In New Zealand there is an expectation that you travel abroad at some point. The joke is that one can get their BSc, PhD, and their O.E. (Overseas Experience). For most kiwi travellers this translates into a year or two working and travelling abroad. I did an O.E. but many more trips as well. As a traveller I’ve accumulated nearly 80 countries. Country-totals are a kind of currency travellers use, something that gives them a bit of street-cred. But I’ll be the first to say that most of those countries in my list have been grossly superficial visits. Many have been just single, brief trips, but others I have been to multiple times.

Coming home – flying over the Southern Alps

Somewhere, we kiwis believe, there is a point to our travel. It’s to make us better people, appreciate our own country more, that sort of stuff. But is there a down-side? Somewhere I read a comment that slipped into my subconscious, as good propaganda does, that air-travel was an insignificant contributor to global warming. Blame it on heavy industry and power-generation, don’t worry about your air-miles. With an answer that I wanted to believe in, I didnt worry.

Cruising Amazon for Kindle-content last year, I happened upon a thought-provoking book, “Beyond Flying” (edited by Chris Watson). It means exactly what the title implies – it’s an analysis of how bad flying really is (it’s really bad) and explores the implications of a post-flight world. More specifically, each chapter is written from someone who has voluntarily given up flying. It was in this book (Chris Brazier’s chapter) that I came across the flight amount category of ‘Insane’. I took that to be somewhere above ‘Frequent’. The lower border of the ‘Insane Flying’ category is not defined, but the chapter hints at it by citing UK Dept of Transport figures that only 4% (of one of the richest nations on Earth) took four or more flights per year. This was a pretty clear indication that I’m in it.

Not far from home – Lake Wakatipu in the distance.

As two of the contributors (Anirvan Chatterjee and Barnali Ghosh) in ‘Beyond Flying’ point out, you can be the greenest person you know (walk/cycle to work, recycle, don’t use air conditioners) but as soon as you make one long-haul jet flight, you’ve just blown it. You may as well have been a daily car-user. And that hurts.

‘Beyond Flying’ builds on George Monbiot’s earlier, and thoroughly researched book ‘Heat’, so I tracked down a copy of it too (in a second-hand shop in Brisbane, though since then, a Kindle version has appeared). ‘Heat’ is an analysis of how humans might replace fossil-fuels with other ones. Monbiot came up with various technological answers for various activities. He found, in other words, ways to make the books balance. But when it came to flying (jet-flight), his answer was simple and unequivocal – Don’t.

Don’t fly. Stop-it. Just Say No. Jet flight is a totally extravagant, unsustainable activity.

This, of course, set off a howl of inner indignation in me.

‘But – I’m a New Zealander! I live in the most isolated country on Earth. I have to fly to see the world.’

Now the folks who wrote “Beyond Flying” knew that me and my fellow kiwi travellers would react like this. So they pointedly included a couple of other Australasians who have given up flying. Now those people are commendable, and I take my hat off to them. But really? This means the end of international travel, bar finding a boat to get me out of this place? Even one of ‘Beyond Flying’’s contributors (Nic Seton) gave up trying to get a boat between Australia and Asia and finally took a flight.

I’m not a Brit who can courageously forego flying and instead, take the bike to Paris for the hols, or even to Singapore via the Hindu Kush if they felt like it. No, I’m a bloody kiwi. Isn’t there a way-out? Can’t we be exempted from this?

My pathology is an unfortunate combination of a mania for collecting, added to finding it hard to throw anything out and, worse – wanting to catalogue what I accumulate. This odd way that my brain works told me it was time to work out, just how many flights were made in racking-up those 80-odd countries. And, and from there, the point of the exercise, work out what my personal impact, in terms of carbon dioxide emissions, was on the planet.

So I started with boarding passes. Not having thrown any out of curse, I dug up little stacks of these all over the place. I know there will be more to find – they will be slotted in the pages of whatever book I was reading on the flight (How many books do I have? Let me check my database….. 856), but beyond a few I’ve given to employers, I will have most, somewhere. Then I scanned them all – all 359 of them, and entered them into a database. It’s then that I realised airlines seem to have had an infuriating aversion to including a year on a boarding pass. This seems to have changed in recent years, but I have a whole bunch with just days and months. Most boarding passes are at least on solid card, but a few of them are on paper – currently very blank paper. These airlines, or rather, just one airline, has (commendably, maybe) cut costs and resource-use to a point where the ink rapidly fades and the information that was once on your pass, has vanished (Mr Branson, I’m looking at you).

So then I turned to the paper or email record of tickets, and travel-agent itineraries. These recorded flights that I currently don’t seem to have passes for, although some of them could be the faded ones. For other trips I made for which I still haven’t found any documentation, there are my diaries. After marrying the two lists on a relational database, followed by a bit of editing, I came up with a provisional, minimum figure. And it’s kind of astounding.

I seem to have made more than 500 flights.

This is a sobering figure. In ‘Beyond Flying’, John Stewart pointed out that only around 5% of the worlds population have ever actually flown and Chris Watson added that perhaps just 1% are responsible for 80% of all flights. I’d guess I am in that 1%.

For better or worse, many of those flights are ‘long-haul’, rather than a daily commute. These were getting me from New Zealand to somewhere on the other side of the planet. Some of them may as well be called a long-haul commute – for instance, I’ve done the Singapore-Brisbane run no less than 20 times and flown across ‘The Ditch” (The Tasman Sea) at least 50 times. But many flights just got me between islands (North and South New Zealand, or Tasmania and the Australian mainland) for which there is a good (if slow) option of a boat

Evening flight past the Kaikoura Mountains.

So how to take all this to the next level? It would be simple enough to add flight distances, and come up with a useless total in terms of the distance to the Moon perhaps. But what I want to know is something meaningful. Specifically, how much carbon dioxide has my travel, pumped into the atmosphere? This has become a hot topic (that’s too bad to be a pun, so it’s not) and there are several websites that purport to help you do this. I’ve chosen to go with one, because it documents the method behind its calculations – a good sign. Its the International Civil Aviation Organization (ICAO), which is an agency of the UN.

There are all sorts of complicating factors in trying to work out individual air traveler emissions. For instance, the length of the flight (longer ones involving lots of ’cruising’ are more economical), the type of plane typically used on certain routes, weather patterns (tail-winds are good), and so-on. The ICAO methodology at least makes an effort to confront these.

So I entered the various routes I have flown (Quick database check – I’ve flown more than 176) into the ICAO website, plugged the indicated carbon outputs into my database of actual flights – and got my answer.

My personal carbon dioxide contribution from jet travel comes to over 80 tonnes.

Ye Gods.

This is a provisional figure, but its going to be close enough to work with. To give it some sort of perspective, a flight from New York to London generates about 358 kg of carbon dioxide.

I’m a researcher who is familiar enough with the science and literature of climate change, and from that perspective, I realise my carbon emissions are part of the problem. Frankly, they’re appalling. Can I make up for what I have inflicted on the planet? Or better still, can I take care of future flying in ‘real-time’? In other words – have my cake and eat it too? Is it as simple as planting-trees? Apparently not. Mitigation of carbon emissions turns out to be a complicated subject but something I very much want to get straight in my own head. Future posts will explore this. I’m looking for a way out of course. An exemption. Straws to clutch at perhaps.

But Nature, of course, doesn’t negotiate.

comments 2

The Lost Forests of Southland, New Zealand

Forests that have disappeared so completely that you would hardly believe they really existed, have long fascinated me.  When I left my home in Alexandra for university in Dunedin, I took with me a facsimile map my mother had given me. It was a mid 19th century view of the Southland plains, the area sweeping north from Invercargill. I blue-tacked it in front of my desk, and framed it with two pot-plants, Zak, and Derek the Dicot. What intrigued me about this map, was that it showed huge patches of forest on the Southland plains, that have now vanished, mostly with barely a physical trace.

Unless you’re really, really into cows and very green grass (and I know a lot of our tourists do love this) the Southland Plains are a pretty boring place. It’s been entirely transformed by agriculture, particularly the dairy industry. It’s not a place that comes to mind for a couple of days hiking or biking.

But scattered all over Southland, on maps present and past, are place names ending in ‘Bush’. This is the kiwi word for ‘forest’. For instance, there’s ‘Long Bush’, ‘Makarewa Bush’, ‘Grove Bush’, ‘Ryal Bush’ and even the charming “Six Little Bushes”. There’s also a ‘Druid’s Grove’ and also place names that are simply botanical, recording (using a Maori word) a type of tree that was likely prominent in the area, like ‘Rimu’, ‘Matai’ and ‘Kamahi’. These places are typically little more than a loose collection of houses or farms, but what they mostly have in common, is that the bush the names refer to, has vanished.

I bear some collective responsibility for this. My mother grew up in the tiny farming area of Rimu-Long Bush where her grandfather had been a pit saw-miller (a photo showed him standing in the unenviable position as the saw-man at the bottom of the pit). She remembers, at about age six, being taken to the nearby forest by her mother and uncle and being “overwhelmed” by the size of the forest trees. When she tried to relocate them a decade or so later, they had all gone.

I can’t now locate that map that sat in front of me for two years in room 613 (Men’s tower) at Unicol. It’s around somewhere, no-doubt slotted between something else. But come the Internet Age and digital copies of these things tend to turn up out-there somewhere. I think it may have been the ‘Sketch Map of the Province of Southland’ compiled by the Chief Surveyor, John H. Baker, up to 1865. There is a digital copy of this map on the Auckland Council Libraries website (‘Sir George Grey Special Collections, Auckland Libraries, NZ Map 3817‘).

‘Sketch Map of the Province of Southland’ compiled by the Chief Surveyor, John H. Baker, up to 1865. There is from a digital copy of this map on the Auckland Council Libraries website ('Sir George Grey Special Collections, Auckland Libraries, NZ Map 3817'). It shows patches of forest (blue-green) where almost none remain today.

‘Sketch Map of the Province of Southland’ compiled by the Chief Surveyor, John H. Baker, up to 1865. There is from a digital copy of this map on the Auckland Council Libraries website (‘Sir George Grey Special Collections, Auckland Libraries, NZ Map 3817’). It shows patches of forest (blue-green) where almost none remain today.

While searching that web site, I found an even more detailed map (covering a slightly smaller area) – ‘Map of the southern portion of the Province of Southland’ also produced by J.H. Baker in 1865 (‘Sir George Grey Special Collections, Auckland Libraries, NZ Map 3816 and 3842‘).

This is a cadastral map – showing the surveyed boundaries of plots of land. It’s accuracy is amazing – using GIS techniques, it can be laid over the modern New Zealand 1:50,000 topographical maps almost exactly. At first glance, the surveyed small land plots seem to have been placed with total disregard for the forest, bisecting them everywhere. But only at first glance. A second look shows that it was the forest that was a major controlling factor. The plots were surveyed such that almost everyone (bar those in totally open areas) had about half their land in forest. This meant that everyone had a wood resource to use, and, of course, everyone could do their little bit to get rid of it. The orientation of roads and fence-lines that we see today, are ghosts, in a funny perpendicular sort of way, of those long-vanished patches of bush.

A section of an 1865 cadastral map showing forest/bush patches in the area around Invercargill (Sir George Grey Special Collections, Auckland Libraries, NZ Map 3842)

A section of an 1865 cadastral map showing forest/bush patches in the area around Invercargill (Sir George Grey Special Collections, Auckland Libraries, NZ Map 3842)

Southland’s patches of bush beg the question – why the patches? This patchwork is somehow unique. Why wasn’t it wall-to-wall forest, such as the vast Catlins area just to the east? It’s likely that fire had much to do with it. Before humans arrived in New Zealand, most of the land that was below the tree-line was probably covered in forest. With humans came fire, and the driest parts of the country, such as Central Otago, to the north of Southland, had their forests incinerated very quickly. It makes some intuitive sense that nor-wester gales would have driven fires from this broadly flammable interior region to the wetter southern areas, where there were more subtle controls on what did and didn’t burn. The Southland Plains also have many outcrops of lignite, which are known to have smoldered for many years, and may have provided repeated ignition pints. There are also lots of wetlands, swampy ground, and of course rivers, where forest would have only colonised with difficulty.

The question of ‘why the patches of bush in Southland’ is a good one for future academic research. But in fact, the whole landscape ecology is crying out for study. For example, the forest types are not controlled by volcanism, like much of the North Island, by slips and flooding braided rivers, like Westland, or by montane cold, like much of the rest. Southland’s forests show what grows without much of this extreme disturbance. There is now a growing public perception that these forests even existed, and an interest in understanding just what made them up. Paul Star’s article ‘Towards an environmental history of Seaward Forest’ is one such contribution. Star’s research stimulated an exhibition at the Eastern Southland Gallery, where 12 artists produced works on the topic. I didn’t see this, but I’d love to get a hold of the catalogue.

A section of an 1865 cadastral map showing forest/bush patches in the area around Waimatuku (Sir George Grey Special Collections, Auckland Libraries, NZ Map 3842).

A section of an 1865 cadastral map showing forest/bush patches in the area around Waimatuku (Sir George Grey Special Collections, Auckland Libraries, NZ Map 3842).

Tramping in New Zealand has become virtually synonymous with negotiating high-country. That’s because that’s where our ‘wilderness’ and large areas of forest are left. We’ve whacked all the lowland stuff. For better or worse, this country now plays on its Middle Earth image. But it’s largely the dramatic. However, the subdued landscape with scattered patches of forest, also evoke a very Tolkinesque feeling. In fact, what could look more like some parts of Middle-Earth than that 1865 cadastral map – absent the cadastral lines of course? Imagine Southland’s tourism industry if more of that had survived? It would be a different kind of experience than completing a mountain trail, getting that sense of satisfaction at having lugged a huge pack from A to B (sometimes the same point) and taking the zillionth photograph of a scenic view. Instead, there could be something we don’t presently have much of in New Zealand, but is far more a European phenomenon – a network of lowland pathways. People could plot out a relaxing route, from bush to bush, stopping off at village cafes, or for Devonshire teas at enterprising farms. Even a small patch of bush, enough to shelter a picnic table, would be enough for some of Southland’s little ‘Bush’ settlements to re-establish their namesake.

The bushes have mostly gone, but from the point of view of a walker or cyclist, it may not take that much effort to reconstruct the feeling of being in them. Southland has a huge network of sometimes rather wide ‘long paddocks’ (the strip of land between the road and farm. It also has the rivers, and at least technically, public access along them (in reality this is more complicated, as in Southland, the rivers have often meandered away from the surveyed public land). The planting of native trees on these, and in fact, all over New Zealand, is an accelerating phenomenon. For the feeling of a trail through a forest, these only have to be wide enough to cut out the view of the road, and muffle the sound of traffic. It would be a kind of ‘geoengineering’. But, with a bit of political will and some long-term thinking, I think wonders could be worked.

What strikes me most about that 1865 map, is not just the huge areas of forest that have totally vanished, but that there are a few tiny patches of bush, perhaps just a hectare and peripheral to a huge forest, that are still there. Thanks to the vision of a few generations of some Southland farmers, these tiny remnants remain. There are shades (pun unintended) here of Geoff Park’s book ‘Nga Uru Ora’ (a weird coincidence: a friend and I had just completed 10 days walking around Stewart Island. We were relaxing at a picnic table back near Half Moon Bay, discussing Nga Uru Ora, when Park’s son literally walked out of the bush beside us). So it’s something I’ve wanted to do for ages – now that I can see exactly where those patches of bush were, I want to go and have a look. I want to see what remains, get a feel for what vanished, and what might be done… I’ll get back with future blog-posts.

Looking back, I suspect that ‘Derek the Dicot’ who framed one side of that map, was probably a monocot. But like my copy of that map, he seems to have vanished.

comment 0

New Zealand’s Hawks Crag Breccia – prelude to the drift from Gondwana

The New Zealand road network has some seriously quirky idiosyncrasies – little things we locals take for granted, but can cause some alarm to the ever-increasing number of tourists. There are, for example, hundreds of ‘one lane’ bridges. And about these,  I was once asked, in total exasperation by an American “Why don’t you just build two-lane bridges?!” (I dunno, cause they cost twice as much?). But on encountering one of those one lane bridges up near Hokitika – that also include the railway line, he was speechless.

Another quirky New Zealand road is that which claws its way around Hawks Crag, a steep bluff above the Buller River. You’ll encounter it if you drive from Westport towards Murchison. It’s one-way, and, in contrast to one-way bridges, because of the curve, you can’t see if there is on-coming traffic. There are now traffic lights, but a sign asks you that if the lights aren’t working (they weren’t last time I drove it) to be-careful.

The one-way road clawing its way around Hawks Crag, above the Buller River in New Zealand.

The one-way road clawing its way around Hawks Crag, above the Buller River in New Zealand.

The bluff that the road cuts around is’Hawks Crag’, and the rock its self is a ‘breccia’, composed of angular rock fragments in a finer matrix. Hence the formation that the road cuts through is called the Hawks Crag Breccia. It’s one of the more intriguing units of New Zealand geology.

The origin of the Breccia is relatively clear – it is the accumulation of material on a ‘fan’ – along the edge of an actively-growing mountain (this type of rock is sometimes called a ‘fanglomerate’). The rocks have not traveled far -rivers have not rounded or sorted the boulders. Material simply poured off active fault scarps into a basin. However, for many years the age of the Hawks Crag Breccia was unclear. Partially this was due to the nature of the breccia itself. It is largely devoid of fossils. But there are a few mudstone beds that would have been flood basins or swamps, and these did prove to have fossil spores. But many of these fossils were new – they were found no-where else, and thus could not be correlated elsewhere. From a variety of reasons, an early conclusions was that the Breccia was Jurassic (Couper, 1953, 1960). However, this was a problem, as the fledgling science of radiometric dating rocks at the same time concluded that the boulders in the breccia, were Cretaceous (Aronson 1965). The age of the rocks in the breccia of course, cannot be younger than the breccia itself. Either the radiometric date, or the date based on fossils, had to be wrong.

Detailed view of the Hawks Crag Breccia - an unsorted pile of sharp-edged rocks.

Detailed view of the Hawks Crag Breccia – an unsorted pile of sharp-edged rocks.

Eventually 30 species of plant fossils were found in the Hawks Crag Breccia (Norris 1968) – and fortuitously, at the same time, a detailed study of similar fossils in the Cretaceous of Australia became available (Dettmann and Playford 1968). This led to confirmation of a  mid Cretaceous age (late Albian, c. 105 Ma) of the Hawks Crag Breccia (Norris and Waterhouse, 1970; Waterhouse and Norris 1972; Raine 1984). There was no longer a problem with the age of the boulders – they were formed slightly before they entered the breccia. Several plant species that grew at Hawks Crag were also in eastern Australia. In some respects this is not surprising, as at the time, not only were they closer, but you could have walked from this part of New Zealand to Australia, or even Antarctica.  New Zealand was peripheral to, and only just breaking away from, the continent of Gondwana.

The plant fossils of the Hawks Crag Breccia (Norris 1968) are a diverse mix of lycopods, ferns (including tree ferns), podocarp and araucarian conifers, as well as the pollen of an extinct conifer family, the Cheirolepidiaceae. In some respects, the particular pollen and spore fossils are reminiscent of the cool and wet New Zealand vegetation today – but with one major difference – there were no flowering plants. These arrived in New Zealand very shortly (a million or two years or so) after the Hawks Crag Breccia accumulated.

The Hawks Crag Breccia is now understood to be one rock type in a broader system – the Porari Group. For example, the very different Bullock Formation is made up largely of mudstone. This has been interpreted as a lake, or series of lakes, into which the Hawks Crag fans flowed (Laird 1995). The Porari Group is now scattered over about 320 km of the West Coast, as well as there being similar deposits east of the Alps (Laird 1995). One could thus think of a ‘Porari Landscape’ or even a ‘Porari Ecosystem’.

In the broader picture the deposition of the Hawks Crag Breccia, and the whole Porari Group, was related to the Rangitata Orogeny – the period of mountainous upheaval that preceded the New Zealand region breaking away from the rest of Gondwana (Carter et al. 1974; Waterhouse and Norris 1972; Adams and Nathan 1978). The Rangitata Orogeny is one of New Zealand’s major periods of geological change where the regime went from compressional to extensional and eventually led to New Zealand drifting into the Pacific (Laird and Bradshaw 2004).

Schematic diagram (simplified from Schulte et al., 2014) to show the the Porari Group (including the Hawks Crag Breccia) forming on the flanks of a Metamorphic Core Complex.

Schematic diagram (simplified from Schulte et al., 2014) to show the the Porari Group (including the Hawks Crag Breccia) forming on the flanks of a Metamorphic Core Complex.

In detail, the Hawks Crag Breccia can also be placed into a more recent concept – the Metamorphic Core Complex (Tulloch and Kimbrough, 1989; Schulte, et al., 2014). These form in extensional environments, and consist of a central core of deeper, older rock that rises to the surface and is typically intruded by granites, while breccia-filled half-graben valleys develop on the flanks.

I wonder how long it will be before some local-Councillor gets it into his or her head to blast away this quirky stretch of road, to enable more people to get through, faster? In the meantime, just keep driving carefully, watch out for on-coming traffic. and the odd person having a closer look at the Hawks Crag Breccia.

References (links will take you to a downloadable pdf)

Adams, C.J.D., Nathan, S., 1978. Cretaceous chronology of the Lower Buller Valley, South Island, New Zealand. New Zealand Journal of Geology and Geophysics 21, 455-462.

Aronson, J.L., 1965. Reconnaissance rubidium—strontium geochronology of New Zealand plutonic and metamorphic rocks. New Zealand Journal of Geology and Geophysics 8, 401-423.

Carter, R.M., Landis, C.A., Norris, R.J., Bishop, D.G., 1974. Suggestions towards a high-level nomenclature for New Zealand rocks. Journal of the Royal Society of New Zealand 4, 5-18.

Couper, R.A., 1953. Upper Mesozoic and Cainozoic spores and pollen grains from New Zealand. New Zealand Geological Survey Palaeontological Bulletin n.s. 22, 77.

Couper, R.A., 1960. New Zealand Mesozoic and Cainozoic plant microfossils. New Zealand Geological Survey Paleontological Bulletin 32, 88 pp.

Dettmann, M.E., Playford, G., 1968. Taxonomy of some Cretaceous spores and pollen grains from eastern Australia. Proceedings of the Royal Society of Victoria 81, 69-93.

Laird, M.G., 1995. Coarse-grained lacustrine fan-delta deposits (Pororari Group) of the northwestern South Island, New Zealan: evidence for Mid-Cretaceous rifting. Special Publication of the International Association of Sedimentologists 22, 197-217.

Laird, M.G., Bradshaw, J.D., 2004. The Break-up of a Long-term Relationship: the Cretaceous Separation of New Zealand from Gondwana. Gondwana Research 7, 273-286.

Norris, G., 1968. Plant microfossils from the Hawks Crag Breccia, south-west Nelson, New Zealand. New Zealand Journal of Geology and Geophysics 11, 312-344.

Norris, G., Waterhouse, J.B., 1970. Age of the Hawks Crag Breccia. Transactions of the Royal Society of New Zealand. Earth Sciences 7, 241-250.

Raine, J.I., 1984. Outline of a palynological zonation of Cretaceous to Paleogene terrestrial sediments in west coast region, south island, New Zealand. New Zealand Geological Survey Report 109, 1-82.

Schulte, D.O., Ring, U., Thomson, S.N., Glodny, J., Carrad, H., 2014. Two-stage development of the Paparoa Metamorphic Core Complex, West Coast, South Island, New Zealand: Hot continental extension precedes sea-floor spreading by ~25 m.y. Lithosphere 6, 177-194.

Tulloch, A.J., and Kimbrough, D.L., 1989, The Paparoa Metamorphic Core Complex, New Zealand: Cretaceous extension associated with fragmentation of the Pacific margin of Gondwana: Tectonics, 8, 1217–1234.

Waterhouse, J.B., Norris, G., 1972. Paleobotanical solution to a granite conundrum: Hawks Crag Breccia of New Zealand and the tectonic evolution of the southwest Pacific. Geoscience and Man 4, 1-15.

comment 0

The Lost Forest of the Ashley River, Canterbury, New Zealand

A gem in the heart of Christchurch is Riccarton Bush (sometimes called Deans Bush). It’s a patch of original kahikatea forest, just a few hundred meters from the Riccarton shopping center (See Molloy,1995, for pretty much all you need to know about the forest).

As anyone who flies in or out of Christchurch, or drives that dead-boring road to Timaru can see, the Canterbury Plains are as ecologically-devastated as an area can get. Not just flat, but the native vegetation has simply been replaced with something else. There was, and remain, patches of native forest on the Banks Peninsula high-ground, and likewise where the foothills meet the plains, such as Geraldine and Oxford (Clark 1926). But for the Plains, Riccarton Bush is pretty much it. It really is a miracle that this one little patch has been preserved. Added to the data collated by Molloy and Brown (1995) of relict living trees, old stumps and charcoals, it is clear that there were once at least patches of forest on the good alluvial soils.  Without Riccarton Bush, it would be so much harder to believe that forest once grew on the Canterbury Plains.

92050

The interior of Riccarton Bush.

Much of the ‘subfossil’ evidence for ancient forests comes from transient exposures in gravel pits or road works, but Benfield (2011)and Molloy (1995, Plate 9) illustrated stumps of a lost forest in a channel of the Ashley River. I don’t share Benfield’s views on 1080 poison, but his interest in the remains of the forest in the Ashley River fascinated me, and led me to have a look for myself.

As is so often the case (with me, anyway) I spent ages floundering around an overgrown, weedy area, along the river bank, then threading my way through a pile of blackberry (I made the most of this by eating lots and giving myself a stomach ache) before giving up, and finally finding some remains of the forest on the way back to the car.

IMG_0757

A single large conifer stump in the Ashley River.

What I came across was one large tree stump, projecting from flowing water up to my thighs (see the featured image). It is one of the podocarp conifers, probably totara, or perhaps kahikatea or matai, although I haven’t worked out which yet. There were a few smaller stumps, totally submerged, a little downstream. The broad location is c. 28 km north of the center of Christchurch, and more precisely, 600 m  upstream of the bridge over the Ashley River near the right bank. A radiocarbon date on an Ashley River stump (NZ 14C No 7680) reported in Molloy and Brown (1995) provided an age of c. 870 years before 1950.

The radiating roots of a submerged stump in the Ashley River are just visible - and another stump is just upstream.

The radiating roots of a submerged stump in the Ashley River are just visible – and another stump is just upstream.

Benfield’s (2011) personal experience shows that even this small group of stumps was more extensive up until a few years ago. Development has either destroyed or re-buried much of it. Forests such as the one in the Ashley or Riccarton, owe their existence to the dynamic nature of braided rivers – with periodic fresh alluvial deposits or old channels becoming available for a new cohort of seedlings. The abruptly changing channels can also be their demise, or leave them standing in water as a ‘swamp forest’. Travelers down the West Coast will be familiar with the sight of semi-submerged kahikatea forests, for instance at Lake Wahapo or Ship Creek. These postcard examples help give rise to the belief that kahikatea prefers to grow in standing water, and in high rainfall areas.

IMG_0140

Kahikatea trees in Lake Wahapo – with a c. 1m lower water level than normal.

However, it’s the Canterbury Plain evidence that helps confirm that kahikatea is also a tree of drier rainfall, provided the soils, and the groundwater table (Webb, 1995), suit. Ryan (1995) gives a figure of 668 mm as the average annual rainfall of the Christchurch Botanical Gardens – relatively low for New Zealand forests. These drier forests were most prone to being destroyed by fire once humans arrived on thee scene, thus distorting their apparent climatic preferences towards the wet end of the spectrum, Tellingly, Benfield (2011) observed that the Ashley River forest appeared to have been burnt.

A take-home message from this, is that the soils and the rainfall of the Canterbury Plains are fine for some of our native forests. Imagine a revived network of forest patches across the Plains – spaced within walking/cycling distance of Christchurch. Something to break that awful tedium of farms. It’s something I think about every time I drive past our ever increasing roadside plantings of natives. It can be done, and it just may have started.

References

Benfield, W.F. 2011. The Third Wave, Poisoning the Land. Tross Publishing, Wellington.

Clark, A.F. 1926. Canterbury’s native bush. TeKuraNgahere, New Zealand Journal of Forestry, 2, 15-22.

Molloy,  B. 1995. Riccarton Bush: Putaringamotu. The Riccarton Bush Trust, Christchurch.

Molloy, B. and Brown, L. 1995. Vegetation history. pp. 85-115 in: Molloy,  B. (Ed.) Riccarton Bush: Putaringamotu. The Riccarton Bush Trust, Christchurch.

Ryan, A. 1995. Climate & Weather. pp. 69-82 in: Molloy,  B. (Ed.) Riccarton Bush: Putaringamotu. The Riccarton Bush Trust, Christchurch.

Webb, T. 1995. Soils & Landforms.pp. 59-68  in: Molloy,  B. (Ed.) Riccarton Bush: Putaringamotu. The Riccarton Bush Trust, Christchurch.

comment 0

Phyllocladus fossils from the Miocene of New Zealand, and Cretaceous Protophyllocladus

A rare plant fossil in the Miocene Manuherikia Group of New Zealand, is Phyllocladus (the Celery Pine). This is a strange conifer which, instead of leaves, the adult plant has multi-veined flattened branches that are called phylloclades. With these phylloclades, the average person would scarcely believe Phyllocladus is a kind of conifer (very broadly, a pine). But it is common in some parts of New Zealand today (typically in ‘difficult’ places, cold, or with poor soils) and also in Tasmania and Malaysia.

Fossil pollen suggests Phyllocladus has been in New Zealand since the Eocene (Mildenhall 1980). There are somewhat similar, but older pollen records,  for example from New Zealand’s Late Cretaceous (Couper, 1953; Cookson & Pike, 1954) but these are likely to represent something distinct. Despite conifers being very diverse in the Miocene St Bathans Paleovalley sediments of the Manuherikia Group,  Phyllocladus appears to have been absent there (Pole 1992a, 1997, 2007). The climate may have been so warm, and the soils rich enough, to preclude it (Pole 2014). However, Phyllocladus is present in the Miocene Nevis Oil Shale (Pole 1992, see figured image), which was deposited in very different conditions (Douglas 1986). There are hints from the Nevis, including large fossil legumes (Pole et al. 1989, 1992b) that the climate may have had a distinct dry season. This may have favoured Phyllocladus. DNA evidence suggest the extant New Zealand species only radiated in the Late Cenozoic (Wagstaff, 2004), and there are certainly Phyllocladus fossils from this time (e.g. From Mataora, in the Coromandel. Pole and Moore, 2011).

Fossil Phyllocladus from Mataora, New Zealand.

Fossil Phyllocladus from Mataora, New Zealand.

Phylloclades appears to be a strategy to increase light-intercepting area beyond that of typical, simple, needle-like leaves ( e.g. Brodribb 2011). In essence, Phyllocladus is trying to become more like the broad leaves of typical flowing plants, in order to compete with them. Separate from that hypothesis, there seems to be an unstated assumption – that the world’s forests became darker, shadier places, with the evolution of broad-leaved flowering plants. But did they? Conifer forests can be damned dark under the canopy. An individual pine needle doesn’t create much shade, but a whole lot of them do.

Extant Phyllocladus IMG_0714

In one of the places I lived in for a few years in Brisbane, my neighbour on the opposite side of the street was Ray Specht. There was a big Eucalyptus tree growing between his house and mine. Ray happened to be one of the most influential people in Australian botany. For example, the various schemes of Australian vegetation classification mostly stem from him. On visiting Ray, the conversation would usually quickly go to the 1948 American-Australian Scientific Expedition to Arnhem Land, which was clearly a highlight of his life.   Ray would expound on the expedition until his wife would look up from her book and go “Oh Ray – shut up!”  Then, fascinating as the Expedition was, I could get him back to what I really wanted him to talk about – his views on how vegetation structure could be predicted from basic environmental properties.

One of Specht’s understandings was that the amount of shade under the canopy of a forest was fundamentally determined by the environment. Basically, closed canopy forests (like rainforests) are more open underneath the canopy, whereas open canopy forests (like Eucalyptus forests) have a denser zone of shrubs. Down near the ground, things even out. There are no doubt plenty of botanists who might take issue with the details, but I find it a valuable insight. At least in Specht’s view, given the right environmental conditions,  forests would have been just as dark and shady before flowering plants evolved, as after.

I’ve wondered if any other fossils might be helpful. In fact, there is a fossil plant with the intriguing name Protophyllocladus has long been known from Cretaceous rocks right across the Northern Hemisphere. In terms of gross morphology, it has phylloclades uncannily like Phyllocladus. However, their detailed structure,  and its affinities, have remained unclear up until very recently. But in 2014 the Russian scientists Natalya Nosova and Lena Golovneva from St Petersburg made a detailed study of the fossil epidermis of Protophyllocladus and compared it with Phyllocladus (Nosova and Golovneva 2014). They concluded Protophyllocladus was a conifer, and likely in the same family as Phyllocladus (the Podocarpaceae).  Protophyllocladus is much older than Phyllocladus, but it still comes from a time when flowering plant forests had spread across the Northern Hemisphere (see fig. 7 in Pole et al. 2016). In that respect, it is consistent with the idea that phylloclades evolved in response to the spread of flowering plants. If fossils of conifers with phylloclades turn up from pre-angiosperm times, then Spechts’ ideas should be looked at closely.

Extant Phyllocladus trichomanoides

Extant Phyllocladus trichomanoides

However, my feeling is that the epidermal morphology of Protophyllocladus is distinct from Phyllocladus or any of the extant related plants (the family Podocarpaceae). For instance the epidermal cells of Protophyllocladus  do not often occur in files. That is, I think the phylloclades of Protophyllocladus probably evolved quite independently of Phyllocladus.

Lightening, so it is said, never strikes the same place twice. But of course, we know this is wrong – lightening does hit some places multiple times and even the odd person has been struck more than once. I think of evolutionary developments as a bit like lightening striking a particular place (a new morphological feature evolves), but just occasionally, it strikes there again (and a similar feature evolves in another lineage. The technical term for this is ‘convergent evolution’. I suspect the phylloclades of Protophyllocladus and Phyllocladus are convergent evolution.

And that big Eucalyptus between my place and Ray Spechts’ ? According to him – it had been hit by lightening at least three times.

References

Links will take you to a site to download pdfs of the papers.

Brodribb, T.J., 2011. A functional analysis of podocarp ecology, in: Turner, B.L., Cernusak, L.A. (Eds.), Ecology of the Podocarpaceae in Tropical Forests, Smithsonian Contributions to Botany, No. 95. . Smithsonian Institution Scholarly Press, Washington, D.C., pp. 165-173.

Douglas, B. J. 1986. Lignite resources of Central Otago. New Zealand Energy Research and Development Committee Publication P104: Volume one, Volume 2.

Mildenhall, D.C., 1980. New Zealand Late Cretaceous and Cenozoic plant biogeography: a contribution. Palaeogeography, Palaeoclimatology, Palaeoecology 31, 197-233.

Nosova, N., Golovneva, L., 2014. The Mesozoic genus Protophyllocladus Berry (Pinopsida). Review of Palaeobotany and Palynology 210, 77–88.

Pole, M.S., 1992a. Early Miocene flora of the Manuherikia Group, New Zealand. 2. Conifers. Journal of the Royal Society of New Zealand 22, 287-302.

Pole, M.S., 1997. Miocene conifers from the Manuherikia Group, New Zealand. Journal of the Royal Society of New Zealand 27, 355-370.

Pole, M., 2007. Conifer and cycad distribution in the Miocene of southern New Zealand. Australian Journal of Botany 55, 143-164.

Pole, M., Moore, P.R., 2011. A late Miocene leaf assemblage from Mataora, Coromandel, New Zealand and its climatic implications. Alcheringa 35, 103-121.

Pole, M.S., 1992. Fossils of Leguminosae from the Miocene Manuherikia Group of New Zealand, in: Herendeen, P.S., Dilcher, D.L. (Eds.), Advances in Legume Systematics: Part 4. The Fossil Record. The Royal Botanic Gardens, Kew, pp. 251-258.

Pole, M.S., Holden, A.M., Campbell, J.D., 1989. Fossil legumes from the Manuherikia Group (Miocene), Central Otago, New Zealand. Journal of the Royal Society of New Zealand 19, 225-228.

Pole, M., Wang, Y., Bugdaeva, E.V., Dong, C., Tian, N., Li, L., Zhou, N., 2016. The rise and demise of Podozamites in east Asia—An extinct conifer life style, . Palaeogeography, Palaeoclimatology, Palaeoecology.

Wagstaff, S.J., 2004. Evolution and biogeography of the austral genus Phyllocladus (Podocarpaceae). Journal of Biogeography 31, 1569–1577.

comment 0

Aboriginal Paintings of the Kimberley- very old Pleistocene or not so old Holocene?

Many of the real advances in science seem to come from a sudden ‘insight’ ( think Archimedes and “Eureka!”) – and there is often no simple connection between collecting data and that ‘aha!’ moment.  The tedious data collection happens, but at some moment, the brain, perhaps quite subconsciously, puts two and two together, and comes up with something more than four. Grahame Walsh was a man who dedicated most of his life to studying the ancient rock paintings of Australia. After having spent about twenty years recording paintings in the Canarvon Gorge region of Queensland (and many other parts of the state), he also spent thirty working in the Kimberley – the remote, north-west corner of the continent.

The extraordinary Grahame Walsh - an authority on Australian rock paintings.

The extraordinary Grahame Walsh – an authority on Australian rock paintings.

The fundamental part of his research was a grueling regime of surveying. Scattered over the rock outcrops in the Kimberley there is a series of often very distinct painting styles. There are rock faces where there are layers of paintings, one over the other. Oddly, the older paintings are often better preserved than the younger, as they are ‘sealed’ by a layer of natural silica varnish.  These superimposed layers provide a kind of stratigraphy of painting styles, and persistent study by Walsh and others, worked out the relative order of these painting styles. But the big mystery, was not the relative but the absolute date. Just how old were they? Almost all of the sites with paintings do not have associated archaeological  material that can be easily  dated.

Thousands of years of overlapping rock paintings in Australia's Kimberley region. Instances like these provide a kind of 'stratigraphy' that allowed researchers such as Grahame Walsh, to work out the relative order of painting styles.

Thousands of years of overlapping rock paintings in Australia’s Kimberley region. Instances like these provide a kind of ‘stratigraphy’ that allowed researchers such as Grahame Walsh, to work out the relative order of painting styles.

Walsh came up with a compelling scenario. A part of the painting style sequence could be interpreted as passing from an earlier time of abundance, where the paintings emphasised personal adornment, with no indication of aggression or violence. These have been called the ‘Bradshaw’ style, although ‘Gwion’ is used by some researchers (see figure below and the featured image).  The paintings then become militaristic, including regimented ‘toy soldier’ like individuals, with weapons. Then there was an apparent long gap, where no paintings were made, but existing paintings were ‘sealed in’ with a layer of natural rock varnish. After an unknown period of time, painting began again, but in an entirely different style. These continued to be painted until the Europeans invaded.

An example of the Bradshaw style of Kimberley rock paintings. Nice the costume 'finery' and ornate hair styles.

An example of the Bradshaw style of Kimberley rock paintings. Nice the costume ‘finery’ and ornate hair styles.

To Walsh, it seemed like this particular sequence recorded first a time of resource abundance – essentially ‘good-times’, which then passed to scarcity, resulting in violence. Then there was a time gap – when environmental conditions may have been so bad, that no one was in the area at all. Finally, when conditions improved again, a new culture moved into the area with different ideas about what to paint. Walsh’s insight was to suspect that this sequence was the run-up to the peak of the Last Glacial Maximum (around 17,000-21,000 years ago), and then the return to good times in the post-glacial Holocene. At Glacial Maximum, there was so  much water tied up in the worlds ice caps, that parts of Australia became super dry and humans were probably driven out of some areas – hence a gap in painting.  It was so dry that constant dust storms were blowing – and these were the cause of  the rock varnish.

Confirming this scenario was the problem. Walsh collaborated with some other researchers who had developed specialised techniques to date minute pieces of material. Richard Roberts used a technique (Optically Stimulated Luminescence – OSL)  that determines how long ago quartz grains were exposed to sunlight. The brilliant part here is that mud wasps in the Kimberley build their nests in the same rock overhangs as the paintings. Mud containing quartz grains is collected bit by bit by the wasp- and it is exposed ti the sun. But when it gets packed away into a next, it is sealed in darkness.

The core of one mud wasp nest yielded an age of  around 17,500 years (Roberts et al. 1997). This implied that a possible Bradshaw figure was even older, and the stencil of a hand below that, older still. It meant that these were painted at, or even before the Last Glacial Maximum. It supported Walsh’s insight. This date makes the Bradshaw Paintings remarkably old – perhaps older than the famous paintings at Lascaux in France, which are about 18,000 years old.

An example of a typical rock outcrop with Bradshaw rock paintings. There may be hundreds of paintings in such a spot - but little or no trace of who painted them in the ground below.

An example of a typical rock outcrop with Bradshaw rock paintings. There may be hundreds of paintings in such a spot – but little or no trace of who painted them in the ground below.

Another researcher involved in the study of the paintings was Alan Watchman. One of his specialties is the carbon dating very small fragments, and as well, he has an interest in the kind of rock varnish that covers the older paintings. Watchman collaborated with Walsh to collect material from paintings that could be dated, for example, a beeswax resin component . However, when he published his results, in the same year as Roberts and co-authors work on the mud wasp nests (Watchman 1997; Watchman et al. 1997), Walsh was not included as a co-author, and Watchman came up with very different results. Watchman’s pioneering estimates for the age of some Bradshaw figures and some from an even older painting style, were in the range of (only) 3,000-4000 years.

An example of a much younger painting style than the Bradshaws.

An example of a much younger painting style than the Bradshaws.

Robert’s Pleistocene results came under intense scrutiny. For instance, Aubert (2012) focused on both the location of the wasp nests with relation to the paintings, and details of their sampling and, in a blow to Team-Walsh,  concluded that there was “no substantial evidence” for a Pleistocene age. On the other hand, Bednarik (2014) threw a life-line to Team-Walsh by arguing that the organic material within the paint residues  may have been “acquired subsequent to the time of rock art production”.  In other words, there was now a mechanism to account for the young dates obtained by Watchman, but still have old paintings.

However, at around this time another group of workers came up with a new scenario for the sequence of Kimberley paintings.  They basically agreed with Walsh about the climatic significance of a ‘gap’ – but they incorporated Watchman’s younger Holocene dates.  Based on a record of fossil pollen, charcoal and dust, McGowan et al. (2012) found evidence for an exceptionally dry phase in the Kimberley in the mid Holocene. Thus, they proposed that Walsh’s ‘gap’ was not at the height of the Last Glacial Maximum, but relates to a ‘mega drought’ that occurred around 6300-3400 years ago and which was triggered by changes in the El Niño Southern Oscillation. This paper got my attention, and it was what stimulated me to write this. Was Walsh’s claim of amazingly old paintings wrong after all?

Come 2016 and out came a new paper (Ross et al 2016) using the OSL technique on mudwasp nests. It was mostly  a new group of researchers and a far more rigorous procedure was used than the pioneering work of Roberts et al. The minimum age of one painting was established at 16,000 years old. Unfortunately that particular figure could not be clearly placed into one of Walsh’s painting styles. That is disappointing, but the important conclusion is that Pleistocene aged rock painting in the Kimberley has probably been solidly established. McGowan et al’s drought was surely real, but just not the cause of the gap in the painting sequence.

Science seems to jump forward with ‘insights’. They may or not actually be right, but they do tend to stimulate more research, and that’s a good thing. In any case, my money is on Walsh being on the mark.

References

Aubert, M., 2012. A review of rock art dating in the Kimberley, Western Australia. Journal  of Archaeological  Science 39, 573–577.

McGowan, H., Marx, S., Moss, P.T., Hammond, A., 2012. Evidence of ENSO mega-drought triggered collapse of prehistory Aboriginal society in northwest Australia. Geophysical Research Letters 39, L22702.

Morwood, M.J., Walsh, G.L., Watchman, A.L., 2010. AMS Radiocarbon Ages for Beeswax and Charcoal Pigments in North Kimberley Rock Art. Rock Art Research: The Journal of the Australian Rock Art Research Association (AURA) 27, 3-8

Roberts, R., Walsh, G., Murray, A., Olley, J., Jones, R., Morwood, M., Tuniz, C., Lawson, E., Macphail, M., Bowdery, D., Naumann, I., 1997. Luminescence dating of rock art and past environments using mud-wasp nests in northern Australia. Nature 387, 696-699.

Ross, J., Westaway, K., Travers, M., Morwood, M.J., Hayward, J., 2016. Into the Past: A Step Towards a Robust Kimberley Rock Art Chronology. PLoS ONE 11, e0161726. doi:0161710.0161371/journal.pone.0161726.

Walsh, G.L., 1994. Bradshaws: Ancient Rock Paintings of North-West Australia. The Bradshaw Foundation, Geneva.

Watchman, A.L., 1997. Dating the Kimberley rock paintings, in: Kenneally, K.F., Lewis, M.R., Donaldson, M., Clement, C. (Eds.), Aboriginal Rock Art of the Kimberley. The Kimberley Society, Perth, pp. 39-45.

Watchman, A.L., Walsh, G.L., Morwood, M.J., Tuniz, C., 1997. AMS radiocarbon dating age estimates for early rock paintings in the Kimberley, N. W. Australia: Preliminary results. Rock Art Research: The Journal of the Australian Rock Art Research Association (AURA) 14, 18–26.

comment 0

The Biggest Tree Stump in the Curio Bay Jurassic Forest

Back in the late 1980s I had the pleasure of meeting the English scientist David Bellamy. Bellamy was famous at the time as ‘The Botanic Man’, and he was in New Zealand to film for ‘Moa’s Ark’, a TV series and book about the development of New Zealand’s flora and fauna (including the extinct moa birds) over time. ‘Moa’s Ark’ describes the view that New Zealand broke away from the edge of Gondwana (in this case, Australia and Antarctica) and drifted into the Pacific with a compliment of life that was then preserved in isolation for many millions of years. I don’t subscribe to that view – but hats off to the series and the book (and the title!). They were an inspired bit of science communication.

Curio Bay is a petrified forest of Jurassic age, located in southernmost New Zealand. This was when New Zealand was firmly attached to Gondwana. You could have walked to what was going to become  Australia or Antarctica from Curio Bay at the time. If you wanted a place to start talking about the voyage of ‘Moa’s Ark’, you could hardly beat the real Gondwanan fossil forest at Curio Bay.

The largest tree stump in the Jurassic fossil forest at Curio Bay, New Zealand.

The largest tree stump in the Jurassic fossil forest at Curio Bay, New Zealand.

 

I ended up in contact with Bellamy because of my work on Curio Bay. I had mapped part of the forest, studied the rocks that encompass the fossil forest, and searched the coastline for many kilometers either side of it for additional clues.

Curio Bay seems to have been a first generation forest. There was a flood that deposited sediment over a large area, forming a ‘clean slate’ for a new forest to grow. When the forest was preserved – by another flood, silica from the sediment percolated the wood and preserved it. In many cases you can walk around the forest and can see at least some of the growth rings in the tree stumps. On this basis, most of the trees in the forest were rather young when they were preserved, say 50-60 years. There are a few that much older, perhaps around 200 years. These may have been the very first trees to colonise the new flood plain surface. Gradually, the space around them was filled in by more trees. The fact that there are growth rings at all, tells us that there was some kind of seasonality – perhaps temperature, or even light conditions (the forest grew much nearer the South Pole than it is today.

David Bellamy (arm outstretched) and his Moa's Ark crew beside the largest tree stump at the Jurassic fossil forest of Curio Bay, New Zealand (1989).

David Bellamy (arm outstretched) and his Moa’s Ark crew beside the largest tree stump at the Jurassic fossil forest of Curio Bay, New Zealand. (1989).

I showed David Bellamy and his crew around the fossil forest, taking them to what is the most prominent large fossil stump. The idea at the time was that Bellamy would be Robin Hood, in Sherwood Forest, England, and shooting off an arrow. The arrow was to fall, and bounce off one of the petrified logs at Curio Bay, and story would begin. When I pointed out the big stump, and its growth rings (see the featured image), Bellamy, a gifted communicator – placed the arrow head-down, its tip on one of the growth rings. “I wonder what story this might tell us?” he asked – and proceeded to run round and round the stump, like a record player (note to younger generations, these were devices to play music from flat disks. The typical speed was 33 rpm, or a faster 45 rpm). After a couple of revolutions, Bellamy announced: “Wrong speed!”, and ran round and round even faster.

“What story?” indeed. I’ve added to it, but Curio Bay and its fossil forest will have more to tell us yet.

References

*Clicking on these links will take you to my Academia.edu site, where you can download a pdf of the paper.

Pole, M.S., 2001. Repeated flood events and fossil forests at Curio Bay (Middle Jurassic), New Zealand. Sedimentary Geology 144, 223-242.

Pole, M.S., 1999. Structure of a near-polar latitude forest from the New Zealand Jurassic. Palaeogeography, Palaeoclimatology, Palaeoecology 147, 121-139.

Pole, M., 2004. Early-Middle Jurassic stratigraphy of the Fortrose-Chaslands region, southernmost South Island, New Zealand. New Zealand Journal of Geology & Geophysics 47, 129-139.

Pole, M., 2009. Vegetation and climate of the New Zealand Jurassic. GFF 131, 105 – 111.

 

 

 

Miocene Lauraceae leaf fossil
comment 0

The Amazing Miocene Fossil Leaf Pack of Mata Creek, New Zealand

I was crouched in a long boat somewhere up a rainforest-swathed river in Kalimatan, Borneo, when I saw it – a ‘living’ example of a fossil leaf pack I had once seen in New Zealand.

Our long boat is pulled up on the bank of a rainforested stream deep in Kalimantan (Indonesian Borneo) while others pass by.

Our long boat is pulled up on the bank of a rainforested stream deep in Kalimantan (Indonesian Borneo) while others pass by.

Several years before, I had been exploring down a little stream near St Bathans, New Zealand. I was looking for leaf fossils in sediments of an ancient river. The geological unit is a faulted mix of the St Bathans and Fiddlers Members (Douglas 1986) of the Manuherikia Group. This was deposited in the Miocene, about 20 million years ago, by rivers that meandered across a landscape that didn’t have the high topography of today,

In a low cut-bank of Mata Creek a layer had been exposed that looked like a stack of old newspapers charred by fire on their edges. Sandwiching this, above and below, was the more typical white sand laid down by the Fiddlers Member rivers.

A Miocene fossil 'leaf pack' - thousands of fossil leaves compacted together in the bank of Mata Creek, near St Bathans, New Zealand.

A Miocene fossil ‘leaf pack’ – thousands of fossil leaves compacted together in the bank of Mata Creek, near St Bathans, New Zealand.

The magic happened back in the lab. What looked like flakes of old newspaper, were in fact fossil leaves along with some small twigs. Long and gentle treatment with bleach turned the dark, opaque fragments into beautiful, golden and translucent specimens (see featured image). The stack of newspapers was in fact, a solid Miocene leaf pack – hundreds and hundreds of fossil leaves, all compressed together. Preservation was so good, that the outlines of epidermal cells could be seen under a microscope.

Many of these fossil leaves belong to the laurel family. They do not grow this far south in New Zealand today (it’s too cold), a good indication that in the Miocene, New Zealand was warmer than today. Some of the laurel leaves are ‘tripli-veined’, with three large veins radiating near the leaf base. This kind of laurel leaf is not found in New Zealand at all today, but is common in some other rainforests, in Australia for example.

The long boats of Kalimantan are ideal for navigating the little rivers or streams of the rainforest. They have a propeller that is barely submerged, making it possible to skim over shallows or submerged logs. They aren’t that conformable, and their engines usually aren’t muffled. After an hour or so of squatting on a wooden beam (or none at all), I was generally looking for any excuse to get out.

A leaf pack extending into the river on a point bar in Kalimantan.

A leaf pack extending into the river on a point bar in Kalimantan.

It was on one of these trips that I spotted a real, recently-made leaf pack. We were roaring along the discoloured water, almost covered by a canopy of rainforest trees, when I noticed a clear patch of the bank. Instead of being a densely vegetated green, it was dark grey, and had a layered appearance. We had the boat turned around and pulled up alongside.  It was a huge mass of leaves and twigs, separated by a smaller amount of silt. This was a perfect recent analogy of the fossil deposit that I had found in Mata Creek.

Close up view of a leaf pack on the point bar of a river in Kalimantan. A little below an to the left of the upper hand is a leaf very similar to the Miocene fossil shown in the featured image.

Close up view of a leaf pack on the point bar of a river in Kalimantan. A little below an to the left of the upper hand is a leaf very similar to the Miocene fossil shown in the featured image.

The best part was that I could now actually see – just where a leaf mat occurred in the river system, and how it had formed. The leaf mat was on a ‘point bar’. These are the inner parts of the meanders in a meandering river. While the outer part of the meander loop cuts into its bank,  the inner part grows by dropping sediment – and in this case, leaves.

Diagram illustrating where point bars (the yellow) occur in a meandering river. Arrows indicate the current direction. Fossil leaf mats can be deposited on these point bars.

Diagram illustrating where point bars (the yellow) occur in a meandering river. Arrows indicate the current direction. Fossil leaf mats can be deposited on these point bars.

Vast amounts of leaves are dropped into the river from the rainforest canopy. During floods, the leaves tend to get sorted from the silt because of their lower density and bigger size. When the currents drop, on the point bars, a layer of almost nothing but leaves can be deposited on ‘normal’ point bar sand.  Then, if the next flood doesn’t wash it away, it can be covered with a layer of sand – and a fossil leaf pack is in the making.

A view of another leaf mat, this one more clearly showing it has been covered by a layer of white sand.

A view of another leaf mat, this one more clearly showing it has been covered by a layer of white sand.

I’m a great fan of trying to see ‘living’ examples of what you come across in the geological record. In this case it made a welcome relief for a sore butt sitting in a Kalimantan long boat.

References

Links will take you to a site to download pdfs of the papers.

Douglas, B. J. 1986. Lignite resources of Central Otago. New Zealand Energy Research and Development Committee Publication P104: Volume one, Volume 2.

Pole, M.S., 1993. Early Miocene flora of the Manuherikia Group, New Zealand. 6. Lauraceae. Journal of the Royal Society of New Zealand 23, 303-312.

Self portrait of Kcenia Nechitailo, State Russian Museum in St Petersburg,
comments 3

St Petersburg – 200 years of Russian Chick Selfies

Women, so I’ve read (and seem to observe), are significantly more likely to take ‘selfies’ than men. It doesn’t seem to matter where I go now, but there are crowds, struggling under the weight of a selfie-stick, with some digital apparatus on the end of it.

In a previous incarnation, I was a photographer. This was back in the days when, after the fun part, I disappeared into a dark room, banged the ends of ten rolls of film, threaded each onto a reel, whacked them into two tanks with chemicals, and then started shaking them – five rolls in each hand.  From strips of negatives proof-sheets were printed, then some frames enlarged onto prints. If there were dust spots, sorry, I mean, when there were dust spots, I mixed up a little white paint and Indian ink to get the right shade of grey to paint them out. God – where did all that go?!

Digital has somehow profaned the whole thing. Not just photography itself, but it’s made it so much easier to turn the camera around. Framing and focusing was damned hard  on yourself. Selfies are just too-easy. But there was the time, and still is the medium, when how you presented yourself to posterity, took time and effort.

In the  State Russian Museum in St Petersburg,  I was lucky enough to come across an entire exhibition of self-portraits. Not digital, or photographs at all, but mostly paintings. The exhibition was called (it’s over now)  ‘My own self’.

Right near the entry was one of the oldest self-portraits. A picture of Ekaterina Chikacheva, painted in 1812, the same year as her untimely death, at about 25.

Self portrait of Ekaterina Chikacheva , 1812, State Russian Museum in St Petersburg,

Self portrait of Ekaterina Chikacheva, 1812, State Russian Museum in St Petersburg,

From there on, I wandered through several rooms, engrossed in dozens and dozens of self portraits. They probably covered every decade for more than two centuries. There were more than 200 self portraits in the exhibition – possibly one of the largest collection of painted selfies on the planet. Men, men, men – where were the women? I had to look hard – maybe six artists?  The male:female ratio must have been at least 40:1.

The exhibition of Self-Portraits 'My Own Self' at the State Russian Museum in St Petersburg,

The exhibition of Self-Portraits ‘My Own Self’ at the State Russian Museum in St Petersburg,

As time and the exhibition progressed, there did seem to be a few more women. And perhaps to make up for the few female artists, there were several works shown from some of them. For ex example several self-portraits of the wonderful Zinaida Serebriakova. The first in the series spanning 46 years was a pencil sketch,  drawn in about 1900, when she was just 17. The next was a painting from 1911.

Self portrait of , State Russian Museum in St Petersburg,

Self portrait of Zinaida Serebriakova, c. 1900, State Russian Museum in St Petersburg,

 

Self portrait of , State Russian Museum in St Petersburg,

Self portrait of Zinaida Serebriakova, 1911, State Russian Museum in St Petersburg,

Self portrait of Zinaida Serebriakova, 1946, State Russian Museum in St Petersburg,

Self portrait of Zinaida Serebriakova, 1946, State Russian Museum in St Petersburg,

There were also a couple from Valentina Markova, and one of my favourites – a selfie of the contemporary painter Kcenia Nechitailo, which I’ve used as the featured image.

Self portrait of Valentina Markova, c. 1930, State Russian Museum in St Petersburg,

Self portrait of Valentina Markova, c. 1930, State Russian Museum in St Petersburg,

Perhaps there is a simple explanation for the very few women in a huge exhibition of self-portraits – maybe women just didn’t have the same opportunities to paint as men. Overall, I guess not. But, I’m not sure that’s the answer. One of the few options for women of leisure, was painting. So did they tend not to paint themselves in the past? Or is the imbalance something to do with curation?

In any case – what a change! Digital media is one of the great equalisers. The massive difference in gender balance with digital selfies seems to show us a kind of underlying reality –  what people like to do, when they can….

Thoughts?