Man! I’ve been really lucky in my fieldwork over the last year or two, getting to some really important cave sites in 2014/15. In my last post I briefly discussed the caves I’ve just visited in the South Island, but prior to that I had the chance to work in two *famous* caves (*in my world): Heshang (Translation: Monk) Cave, China, which is famous for its monstrous Holocene stalagmites (ca last 10,000 years; left) and Uamh an Tartair (Translation: Cave of the roaring), Scotland, which is famous for intricate fluorescent laminations in its stalagmites (fluorescence microscope image to the right).
Both sites are a pretty big deal in scientific terms, being the subject of important research into the East Asian monsoon (Heshang) and the north Atlantic oscillation (NAO). So both sites have strong links to hydrologic change, especially Heshang with its monsoonal climate.
I visited China in January 2013 and together with Chaoyong Hu (China University of Geosciences), JiaoYang Ruan (Le Laboratoire des Sciences du Climat et de l’Environnement [LSCE]) and Clement Bourdin (University of Birmingham, formerly LSCE), traveled into the heart of China. Heshang Cave, which is developed in Cambrian dolomite, sits in an elevated position above the Qing River (middle reaches of the Yangtze) and is easily accessed by boat.
Asides from the research, China is easily the most interesting place I’ve been to culturally, and also from a chemistry standpoint, in a sort of sadomasochistic way anyway… Sorry to say this, but my Chinese colleagues acknowledge it, it’s really quite shocking in terms of the state of the environment, particularly the air quality. I guess this is what happens when the world exports its manufacturing to a country without the same levels of environmental protection we’re used to in the West. It makes us all culpable – those cheap goods come at cost. Unfortunately, people in China are paying for it in terms of reduced life expectancy..
Seriously- look at it! A lot of this stuff is aerosols, including PM10 (fine particles, diameters < 10 microns, that can get into your lungs causing lung cancer and other respiratory illnesses). Nice! Anyway, back to the point of this post which is the research- so we crossed the Qing on a local ferry with Chaoyong and his students. Chaoyong has been monitoring Heshang Cave on a monthly basis continuously for over a decade. That’s pretty darn impressive given that it takes a whole day of travel by train and car to get there in 2014 (ten years ago transport was probably nowhere near as efficient either given the rapid expansion and industrialisation which occurred over the same period).
For my part, I trialed a new way to measure trace elements in cave dripwaters. Translation: I measured really low concentrations (parts per billion, ppb) of metals in the waters falling from the cave ceiling. These waters, falling in the same spot for 10,000 years are what make Heshang stalagmites on the order of 2 metres tall! This essentially involved putting a DGT sampler under a funnel which routed the drips onto the surface of the sampler. DGT stands for Diffusive Gradients in Thin Films (DGT) and basically, without getting all technical, DGT binds and concentrates metals in a resin. We measure the metals in the resin back in the lab to work out interesting stuff about the chemistry of different elements. For this work we were interested in the metals which come from the soil above the cave in association with dissolved organic matter. This is the same stuff that makes some rivers draining peat catchments look brown. Anyway, what do you know? It worked!
The results of the trial have formed the basis of a research paper which we just submitted together with Nik Lehto at the University of Lincoln (Canterbury, NZ), Rebecca Bartlett and Ian Fairchild (University of Birmingham). Nik is bit of a DGT guru (shouldn’t think he’d mind that description) and he’s helping me and my students with DGT- so thanks heaps Nik! As part of this work, Nik and I have developed a DGT prototype which Clement Bourdin and I trialed in Scotland late last year.
It was great to finally make it to Uamh an Tartair (Sutherland, Scotland), the location of fantastic studies by Andy Baker (UNSW) and his students over the years. The cave is located on the NW Atlantic seaboard and has a very strong influence from the NAO index (http://en.wikipedia.org/wiki/North_Atlantic_oscillation) which is all to do with how atmospheric pressure (at sea level) distributes itself across the East Atlantic. Differences in the strength of these persistent high (Iceland) and low (Azores) pressure cells drives pretty significant variations in the climate of Northern Europe. Think about the expansion of the Vikings, Cathedral building, wine growing in Northern England (!!), wars between the French and English, the crusades, more France vs. England argy-bargy, ice skating on the River Thames in London (!!), advances of glaciers in the alps destroying or displacing whole villages, the Spanish inquisition (nobody expects the Spanish inquisition).. ok maybe not Monty Python, but you get the picture. All of these historically significant events occurred during the last 1000 years. In some years the same regions experienced bitterly cold winters, or mild winters, warm and productive summers, or summers of hardship (check out this pretty interesting book on the subject http://books.google.co.nz/books/about/The_Little_Ice_Age.html?id=LwvkmXt5fQUC). Now I know environmental determinism isn’t too fashionable among historians (I should know- my sister and brother-in-law are medieval historians!), but it’s pretty clear that the NAO had a role to play in how civilisation played out over the last 1000 years, and has played out since the expansion of the first peoples from the “Fertile Crescent” around the start of our present inter glacial (around 10,000 years ago).. In Northern Europe it’s got a lot to do with how the Atlantic transports and redistributes heat towards the Arctic.. In the Southern Hemisphere, another ocean-driven process (El Nino Southern Oscillation [ENSO]) causes a similar oscillating East-West climatic see-saw. Anyway, I’m getting side-tracked..
Uamh an Tartair, or Cave of the Roaring, is approached from Loch Assynt, Sutherland Shire (http://en.wikipedia.org/wiki/Loch_Assynt). A hike of around 1.5 hours takes you up to the cave and on clear days like the ones we had, its elevated position affords fantastic views down to the Loch. We had a few friends to keep us company. They also made things interesting on the drives home through the thick fog coming off the Loch. Although called “Cave of the Roaring”, this has nothing to do with hairy ruminants, but rather the impressive sound of the Assynt stream amplified by the wide chamber at the entrance to the cave.
Uamh an Tartair is comparatively small, and compared to Nettlebed easily accessible. Indeed, compared to Nettlebed, dragging yourself through a few crawly squeezes in Tartair feels like luxury. In case your wondering why I drag myself through muddy, cold and wet places to take samples of water – I’ll tell you- it’s bloody brilliant fun and fascinating science. Ultimately, it’s all about trying to decipher the code encrypted into these carbonate deposits. Yup, subterranean Turing, that’s me! Hope to be able to share more specifics on this work when it’s published- I’m really excited about this stuff!
Will dig out the photos from Scotland when I can find the cable for my camera..In the meantime here are a few more photos from my China trip.
Thanks for reading if you made it this far.