Fieldwork in the Atacama Desert, Chile

Monday, 23 April 2012

Rock Bothering, Cider & Jenga (Slapton Field Course 13-20/04/2012)

So last week was spent demonstrating on a first year Environmental Sciences undergrad course to Slapton in Devon.

The week started off less than promisingly (well we'd started a field trip on a Friday the 13th so what did we expect) when we thought we’d lost a student at Reading services, after the initial panic when no one seemed to know who he was or have his number turned out he’d just swapped coaches without anyone noticing…obviously a popular guy.

My job for the week was to demonstrate on the geology-based activities which mostly meant I had to get students to be enthusiastic about rocks, even getting some students to actually look at them was challenging.
The first two mornings activities were spent topographically surveying the Slapton Ley beach barrier. The Ley itself is a freshwater lake with SSI status due to providing a unique habitat for many species of plants and animals, this body of water formed when sea levels rose at the end of the last ice age and created the shingle ridge. The students were looking at changes in sediment lithology and particle size up the beach profile and using resistivity and conductivity methods for the depths and composition of the water table. These surveys were to attempt to look at the future sustainability of the Ley as sea levels rise over the next century. By comparing the main sediment type (flint) to the known geology of the local area it was found that the main sediment source was an offshore flint bank.  This source is not being currently renewed and so as sea level rises, and the sediment source decreases, the barrier will not be replenished and so will retreat or be overtopped by the sea, destroying the Ley and the main transport route through the area. The geophysical results were a little more ambiguous, mostly due to the repeated failure of numerous pieces of equipment, but seemed to show that salt water was not permeating far through the barrier and so was not polluting the Ley, although this could too change as sea level rises. The highlight of these activities were the sampling methods the students came up with to ensure they collected a random sample of pebbles; these included one student sitting on the ground and reaching behind himself to pick up pebbles so he couldn’t bias the sample by seeing it and another group with 2 students standing on the spot with their eyes closed; one waving a stick around and the other telling him to stop so they’d collect whichever pebble the stick pointed at. I found out later one of the students had also managed to lose both his shoes to the sea while surveying too close and not looking out for waves.

Slapton Sands beach barrier and ley

One afternoon was spent doing lichen chronology (see Winchester & Chaujar, 2007 for an example) on gravestones around the local church. All the students had to do was pick a consistent gravestone lithology and a type of lichen that grew on those stones and compare lichen diameter to age of the gravestone to make a calibration curve. Unfortunately we had students that couldn’t tell the difference between granite and marble and in one case slate and wood (“This gravestone feels like it’s made out of wood”)! Most calibration curves turned out to be just a random scatter of points although I doubt this was the fault of the students as the method has so many variables and assumptions (e.g. gravestones may have been cleaned for a while delaying colonisation, different conditions of light and shelter in different parts of the graveyard, etc.) I don’t think it would have worked properly anyway. I think I prefer my contact with lichens to be limited to just scraping them off rocks to find a fresh surface to look at, although this seems to annoy the ecologists somewhat.

A major challenge was attempting to teach students with massive hangovers various geological techniques (logging, using compass-clino’s) on the beach while a dog was running around with a lump of quartz in its mouth, trying to give it to students and digging holes in the sand which was admittedly more interesting than what they were supposed to be doing.

One the same day as the dog we had a very impressive bus driver who managed to almost get the bus stuck in a very narrow village and had to reverse a mile backwards down a country lane, only demolishing one wall in the process while being heckled loudly by a local with a pony.

The last two teaching days were full days of geology. The first sedimentary; in the morning looking at a good outcrop of Permian desert sands with clear wadi (flash flood) deposits at Fairy Cove, Torbay. Here we had a succession with breccias, cross-bedding and dessication cracks and mud lenses from dried out puddles and streams, a lot of stuff for the students to look at to deduce processes and environment of deposition as the fast approaching  tide tried to cut us off. The afternoon was spent looking at Devonian reef limestones;  these were absolutely rammed full of fossils of corals, stromataporids, bryozoa and brachiopods up until a period of intense volcanic activity (shown by a thick ash bed) killed off the reef and the remainder of the succession is pretty sterile, summarised expertly by one student, “Basically the volcano just raped the ocean”. The second of these two days was spent up on Dartmoor looking at the granite and its effects on the surrounding country rocks with contact metamorphism (slates going into spotted slates with cordierite) and hydrothermal mineral precipitates (mostly unidentifiable brown stuff, presumably some form of iron oxide).  Was not expecting Environmental Sciences students to moan so much about having to walk up hills although I’ll let them off moaning about being caught in an ice storm (it was too bad to be just hail) where we couldn’t even see the other side of the valley, I ended up just laughing hysterically at them all huddling together as they had to face the hail to see the lecturer, which caused no end of dirty looks.

The last two days the students had to do independent group projects to create poster presentations, which basically meant we got a couple of days off, just checking up on them from time to time. In my case this meant walking up & down the beach for a morning and hiding in a bird hide when the weather got too bad laughing at the thought of the students still working out in the torrential rain. In spite of the weather some good projects & posters did come out of this, unfortunately I wasn’t allowed to give extra marks to a group that had taped rocks to and got lots of bad geology puns in their poster.

What was most annoying about the week was the lack of preparedness of many of the students, why anyone would think trainers, ugg boots, tight jeans, no waterproofs or (in one case up on Dartmoor) an umbrella would be a good idea for fieldwork? Although at the other end of the spectrum the girl who wore chest waders to the beach on a nice day was a bit extreme!

Spent every night in the local pub (The Queens Arms) drinking too much of the local cider (Devon Mist, very nice) and playing very intense drunken games of Jenga. Although on the last night of teaching we got a bit carried away on the tequila & vodka and didn’t all make it on time for breakfast and the morning’s activities.

Impossible Jenga

On the last night we had a good bonfire on the beach, was surprisingly tame although 2 students had to be repeatedly pulled away from the fire as they kept drunkenly falling/rolling way to close to it (one girl repeatedly shouting, ‘It’s OK, I used to be a Scout, we’re pyromaniacs”) and 3 guys had to be pulled out of the sea (one fully clothed), although this only added to the night.  There were some rough people on the coach the next morning, although for once I wasn’t one of them, must be growing up, or not.

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