Science News: Holy ice cap. Tell me more about that ice-encased mountain range of East Antarctica
A pure gee-whiz piece of Earth science writing this morning leaves the mind spinning. At Science News, Alexandra Witze relates the mystery and hypotheses swirling among the few geologists who think hard about the most remote mountain range in the world. It’s remote because first one must get to the ice desert that is East Antarctica, and then see nothing. The Gamburtsev Mountain are underfoot, thousands of feet down, in the ice.
The story jangles the imagination. And Alex is a wonderful reporter, but I sure want to know more. Such as, how high are the mountains? If global warming is all and more it’s cracked up to be and in a few centuries or millennia the ice leaves and there are still geologists in the world to make measurements, how high might they rise, aided by glacial rebound? Have they been under ice for 300 million years, as she suggests? Or just glaciated part of that time? I did look up a map of Pangaea and see that the old supercontinent’s Antarctic portion was indeed pretty far south, but had it a mountain-burying ice sheet even then?
But one learns plenty. Such as that, cold enough, glacier ice does not so much grind across and erode mountains as it freezes fast – essentially extending the mountains by adding a mineral layer of solid H20. So, one gathers, the plastic flow of glaciers may not extend all the way to the ice-rock interface, but be a gradient of deformation that extends well into the ice column before displaying drastic shear motion? The result is these mountains are not just under ice, they may have been preserved long after most of their cohort from Silurian times have eroded down to a cratonic plain. They are cryonically preserved!
And the only way to get samples, it says here, is to go to a bay on the coast of the great white continent and find ancient riverbeds where, long ago, rivers carried boulders from the range.
I wanna know more. But without this, I’d not known a thing.
This is the second post today on a pub and writer with which I have had personal engagement. Disclosure: Science News employs me occasionally for a story. One that I’m working on right now, and that is blistering my brain, is based on some hints and clues and papers that Witze had accumulated in her doubtlessly immense ball of string – and that she had not the time to get to.
I am quite sure that no matter where this Antarctic story had run, or by whom, I’d have reacted about the same way.
Image source Penn State U ;
- Charlie Petit
October 21st, 2010 at 12:00 pm
Thanks Charlie; the check is in the mail.
This was actually a difficult story as the two main points had been reported before. The fact that the Gamburtsevs are extremely rugged came out last year when the first mapping results from IPY were announced — see for instance http://news.bbc.co.uk/2/hi/science/nature/7908824.stm. And the key paper reporting that glaciers can actually protect peaks from erosion came out last month (Thomson et al in Nature). This particular paper in Geophysical Research Letters happened to combine two things I found fascinating and hadn’t reported on for Science News. Nevertheless there was the struggle to make it sound new.
You can geek out on the Gamburtsevs with this paper: http://www.nature.com/nature/journal/v459/n7247/full/nature08024.html
At their highest point they are roughly 2400m above sea level, but still buried under hundreds of meters of ice. Topographical relief from valley floor to peak is on the order of 700-800m.
The history of glaciation in the area is pretty much a giant question mark prior to 34 million years ago which is when the Antarctic ice sheet we see today got going. Cole’s team says there may have been small-scale mountain glaciers that came and went over the past 300 million years or so. But they really don’t know.