Monthly archives of “July 2015

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(Both) Battles of Breitenfeld

It is a macabre thought that in these days of GIS and databases, someone could probably come up with a map of Europe – colour-coded by the amount of human lives lost in battles over the past score of centuries or so. I wonder what it might tell us.

Leipzig is one of those German cities that was basically off-limits when I first traveled to Europe. It was deep in East Germany. Finally having made it – I wondered what it was I ought to do there. My hotel was isolated in what might be described as a sterile industrial suburb, several kilometers to the north of the centre. A bit of Googling came up with the ‘Battle of Breitenfeld’ – in fact, two battles, fought during the Thirty Years War, about 7 km to the north of the city. That meant it couldn’t be too far. The Thirty Years War is something I know little about, except that it was religious (Protestants vs Catholics), fought in the 17th century, and it was nasty. Something like one-third of the German population died – the First and Second World Wars never came close to that. There was also a sort of incredulity from childhood that a war could go on for thirty years (it’s not so hard to believe now – it’s been 24 years since Iraq was first invaded, and no signs of anything stopping there).

A little more Googling came up with some maps, showing where the various forces were deployed in relation to the local villages. Google Earth showed the villages were still there, I could over-lay the battle-maps, and my GPS could take me to the area. The battles weren’t actually fought in Breitenfeld, but between smaller villages to its north,

I wandered off along a small road, past houses and corner-stores, and eventually found myself in the countryside. It was almost flat, open-fields with crops, and a few patches of trees. Eventually I came to an autobahn over-pass. Some concrete steps took me up to thee level of the autobahn, which was (except for what appeared to be a mine-dump some kilometres away), the highest point in the landscape. Sitting here, I could look out over the field that was the site of the Second Battle of Breitenfeld (1642).

Second Battle site 92615

Scene of the Second Battle of Breitenfeld. The village of Podelwitz lies at the end of the road at upper left. I’m sitting on an autobahn embankment, Leipzig is behind me.

It was here, on one day, that about 14,000 soldiers were killed or wounded. It’s likely that in those days, it was pretty much the same outcome. What struck me about the location was the ordinariness of it all. There was nothing spectacular or strategic about the place – it was just a flat open area where two armies could easily line up and proceed to systematically dismember each other. This was the first time that ‘chain-shot’ – two cannon balls linked by a chain and blasted into a formation of soldiers, was used on land. Hardly surprisingly, – one regiment fled the carnage and was subsequently accused of cowardice. When this group made it back to the Czech republic (!) the officers were beheaded and the troops decimated – one in ten were hung. That would have been a long walk for those condemned men. Food along the way would have been free though- any village they passed through would have been ransacked.

Descending from the autobahn I trudged on a few more kilometres to a small road-crossing Here, just before the village of Podelwitz, I turned right and wandered along a virtually deserted country lane. Another autobahn arced around in on the skyline, along with a few signs of the village of Gobschelwitz.

After several hundred metres, beside me was the field where the First Battle of Breitenfeld took place in 1631. According to Wikipedia, more than 13,000 soldiers were killed here in six hours – not including those wounded. Again, another banal location, some quiet villages in the distance, and no memorial (there is one several kilometres away) – a nameless field. Somewhere here will be a big hole where the remains of the equally nameless cannon—fodder would have been dumped.

First battle site 92634

Scene of the First Battle of Breitenfeld. It was fought on this field, between the two villages on the sky-line.

So here was a second battle – probably overlapping (if there was a GIS map, it would be red spot… ) with the other –  27,000 casualties at least. Why the hell Breitenfeld? It says something about the German culture, or perhaps more about my own – that there aren’t memorials to these battles everywhere. As far as I could tell, there was absolutely no sign commemorating this battle, or its victims. As I tried to take it all in as a solitary cyclist, a young man, slowly came towards me along the lane. A local villager no doubt, he and I were the only people in sight. He ignored me and continued on his way. I headed back along the lane, this time detouring to check out the village of Podelwitz (pop <500), it has a church that pre-dates the battles (see featured image). I passed a few people but finally I remembered the atmosphere from an earlier trip to this part of Germany. It’s one of those places where, even if by some chance, you ever make eye contact with someone, no-one ever, ever responds to your greeting. I even came across a man taking his cat for a walk on a leash. A ‘Guten tag!’ from me drew stares of outright malevolence from both man and cat.

Perhaps thirty years of butchery and a couple of world wars will do that.

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Where was the Murihiku in the Jurassic?

A few years ago I used to teach American classes that came to the University of Queensland. One evening my Stanford class had just arrived and I wandered over to their college accommodation to say Hello. I came across an odd sight – a knot of students surrounding what turned out to be a young woman who was so green, I thought she was photosynthesising. She was one of their number – and had been bet $US100 she couldn’t eat a bubble-pack of Vegemite (one of those little packs you get at hotel breakfasts that the average Aussie kid would smear five of on to a slice of toast).

Vegemite used to feature in the odd lecture I would give on New Zealand geology. As an analogy I would say to think of slice of toast – this is New Zealand’s Gondwana-core, firmly attached to Australia, Antarctica and the rest of Gondwana. On this, smear some Peanut Butter, Vegemite (cue a chorus of UUGGH!!! from Americans here), some slices of beetroot, and so-on. These are the ‘terranes’ that flank the core. They are slices of rock with different histories that have come from ‘somewhere else’.

One such terrane is the Murihiku – it includes a slice of sediments through Southland, including the Catlins area (see the Featured Image) and the Jurassic fossil forests at Curio Bay, and, after being separated by the Alpine Fault, reappears in the western North Island. There are many plant fossils in Murihiku – so the question is, where were they when they were growing?

Paleolatitude can be determined from a rock’s remnant magnetic field – something that can get ‘baked in’ when it is formed. Because of this, we know the latitude of any point on Gondwana fairly accurately and it turns out that the Gondwana-core of New Zealand was around 70-75 ° in the Jurassic. That’s polar – but where was the Murihiku and its plants? Unfortunately there is a problem with using the paleomagnetic method in New Zealand – there was a strong ‘overprint’ in the Cretaceous, making results from older rocks suspect. A more modern technique involves precisely dating mineral grains such as zircons and mica .  A river catchment, supplying sediment to a basin (like the Murihiku) will have a particular ‘fingerprint’ of detrital mineral ages. The combination of dates in a sediment can be used to narrow-down its source.

This technique has been used to suggest that the Torlesse Terrane – lying ‘outboard’ of the Murihiku, and forming much of Canterbury and the Southern Alps, formed off the New England Fold-Belt of northeastern Australia (Adams et al. 1998). This would have been in latitudes of about 60-65° – high, but not polar. As far as I know, no-one has used this technique for the Murihiku yet. But there is a suspicion that terranes were moving counter-clockwise around the Pacific in the New Zealand sector. In that case, the Murihiku may also have accumulated somewhere off Australia.

Another possibility to work out paleolatitude is to use the plant fossils. The Jurassic vegetation and paleolatitude of the Northern Hemisphere is particularly well-known. Someone who has given this a great deal of thought is Andrew Rees – an American paleobotanist. He found that different plant genera tended to have a particular latitudinal range over which they were restricted, or at least more prominent – a ‘centroid’.  Rees and co-authors Ziegler and Valdes, used multivariate statistics on a huge database of fossil distribution to work out the basic relative latitudinal order of these centroids – a ‘floral gradient’, for several key Jurassic plant genera. They found that Ginkgo, and some related genera along with broad-leaved conifers, were typical of high-latitude and polar regions. Scale-leaved conifers and some cycad-like plants were more typical for equatorial latitudes. The really novel idea in their work was that each genus along the gradient could be assigned a ‘score’. The average score for all genera in a fossil assemblage correlated with the latitude. This provided a method to work out paleolatitude in places where  it was unclear, such as the Murihiku. I gave this method a go for the Murihiku Group (Pole 2009) and came up with a broad mid-latitude result (c. 40-70°), consistent with a slightly more equatorial location than New Zealand’s Gondwana-core (an error in the paper said the addition of Hausmannia would raise the average score slightly, meaning a move away from the pole – it should read toward it).

This result can be compared with those based on marine faunas. Stevens (1971) noted that in the Northern Hemisphere Jurassic, a high-latitude ‘Boreal’ realm could be distinguished. The absence of an ‘anti-Boreal’ realm in New Zealand, suggested it lay away from the pole. However, a more recent work Damborenea 1993) has argued that a high-latitude (>60°) Boreal counterpart – the Austral Realm, can be identified, and the Murihiku was located within it.

Combined with the plant data, these latter faunal results suggest that the Jurassic Murihiku accumulated near the Polar Circle (66°), but whether above or below it is so-far, unclear.

Oh, the young woman from Stanford finished the Vegemite, without barfing, and at least some of the dosh was paid-out.

References

Adams, C. J., H. J. Campbell, I. J. Graham and N. Mortimer (1998). Torlesse, Waipapa and Caples suspect terranes of New Zealand: Integrated studies of their geological history in relation to neighbouring terranes. Episodes 21: 235-240.

Damborenea, S. E. (1993). Early Jurassic South American pectinaceans and circum-Pacific paleobiogeography. Palaeogeography, Palaeoclimatology, Palaeoecology 100: 109-123.

Pole, M. (2009). “Vegetation and climate of the New Zealand Jurassic.” GFF 131: 105 – 111.

Rees, P. M., A. M. Ziegler and P. J. Valdes (2000). Jurassic phytogeography and climates: new data and  model comparisons.  Warm climates in earth History. B. T. Huber, K. G. Macleod and S. L. Wing. Cambridge, Cambridge University Press: 297-318.

Stevens, G. R. (1971). Relationship of isotopic temperatures and faunal realms to Jurassic-Cretaceous Paleogeography, particularly of the south-west Pacific. Journal of the Royal Society of New Zealand 1: 145-158.

Coniopteris fossil fern from New Zealand Jurassic
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Globalisation in the Jurassic – the fossil fern Coniopteris in New Zealand

One of the plant fossils that turns up in New Zealand’s Jurassic rocks is a delicate-looking fern frond called Coniopteris (Arber, 1917; Edwards, 1934; see featured image). The well-known Jurassic fossil forest at Curio Bay (Pole 1999) would have had Coniopteris growing in it. And, oddly enough, it’s in the same family as one of New Zealand’s living tree-ferns (Dicksonia) – that grow around Curio Bay today.

A Coniopteris fossil fern from the Jurassic of southern New Zealand.

A Coniopteris fossil fern from the Jurassic of southern New Zealand.

Only one species of Coniopteris fossil has been found in New Zealand – but one that appears to have been truly global in distribution (C. hymenophylloides). It has, for example, also been found in England. How could this be? Back in the Jurassic period, New Zealand was not the isolated landmass it is today – but was part of Gondwana. As long as you carefully avoided the dinosaurs, you could have walked to Australia or Antarctica and from there on to much of the rest of the world. One might suspect, given these connections, that much of New Zealand’s fauna and flora would have been shared with other parts of the world. Of course, just because there are land connections, doesn’t mean the life will be the same – climatic barriers exist. As one moved north or south, it might be expected that eventually the climate became too hot or cold, or perhaps too dry, for a particular species to survive. And there’s the thing – the temperature of the Jurassic world was very moderate. There were no polar ice caps – meaning that as you moved north or south from the equator temperatures would have changed much more slowly than today. Probably there were no, or only very light frosts in the more polar regions. These far more equable conditions would have meant much broader vegetation belts than today.

Just how Coniopteris managed to spread all over the world, is anyone’s’ guess. But it seems to have managed this rather quickly. In some parts of the world, paleobotanists take the appearance of Coniopteris fossil as an indication of the start of the Jurassic. In older, Triassic rocks, there are no, or usually no, Coniopteris. Following a massive global extinction at the end of the Triassic, Coniopteris spread rapidly around the world.

That only one species of Coniopteris is known from New Zealand is rather telling – in other parts of the world there were more. For example, in the Jurassic of south-eastern Siberia, nine species of Coniopteris have been reported (Lebedev 1965). This suggests that conditions were particularly good for it there, but not so good in New Zealand. It’s another scrap of evidence for New Zealand lying at relatively high latitudes in the Jurassic – despite the lack of polar ice caps, conditions were still less-optimal than more equatorial regions.

But what happened to such a hardy plant? It turns out that, by convention, the name Coniopteris is only applied to Mesozoic (Triassic, Jurassic, Cretaceous) fossils. Unless you know this paleobotanical idiosyncrasy, it becomes just another thing on the list of what was killed off at the great Cretaceous-Paleogene extinction. So it raises the question – did Coniopteris go extinct at all? That doesn’t seem so easy to answer – but there are those tree ferns still growing around Curio Bay….

References

Arber, E.A.N., 1917: The earlier Mesozoic floras of New Zealand. New Zealand Geological Survey Palaeontological Bulletin 6, 1–80.

Edwards, W.N., 1934: Jurassic plants from New Zealand. Annals and Magazine of Natural History 10, 81– 109.

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