Wednesday, 30 September 2015

Argentinian Fieldwork

So a few weeks after getting back from Argentina, and catching up on lots of work (including SVP preparation), I finally am getting around to writing about what we got up to out there.

Anjali Goswami, my UCL supervisor, has spent a long time searching for new field sites to add to the India fieldsite she has been working on for the last decade (or more). As such she has been looking for locations in Gondwana (the old southern continental land mass of Antarctica, South America, Australia, Africa and India), particularly sites that have never been searched for microfossils. Microfossils are the little fossils that are often overlooked when people are hunting for dinosaurs, but can be anything from dinosaurs teeth, down to any microscopic remains. Anjali however, is interested in the mammals, particularly with work from Thomas Halliday who finished his PhD at UCL (and continues as a postdoc) on Palaeocene mammals, suggesting that the placental mammals (what we are, compared to marsupials - e.g. kangaroos, and montoremes e.g. platypuses) originated just before the K-Pg mass extinction (the one that killed all the non-avian dinosaurs). As such the time just before and after the mass extinction are incredibly important in understanding mammalian evolution. Argentina is a well known locale for its dinosaurs. Patagonia in the south, is home to loads of different dinosaurs from large theropods, to some of the largest sauropods that ever lived. However, in the north of Argentina there are also dinosaurs, and some of the beds extend into neighbouring countries as well as covering the really important K-Pg boundary (although damned if we saw it). Enough of my rambling prelude though...

So we flew into Salta in NW Argentina, Anjali, Thomas and myself where we met our Argentinian collaborators, Agustín Scanferla and his friend and technician Javier Guillermo Ochoa. After a night in Salta acclimatising to the altitude (with the help of some wine and empanadas), we drove up to Parque Nacional Los Cordones (The National Park of the Cactuses/Cacti) where we would be based.

Wiggly road from the "lowlands" into the mountains.
The drive up was a long winding road, ascending from 2000m up to 3500m (see above). I sometimes have issues with being stuck in a car for long period of times, and with the altitude must say I was feeling a bit rough. It was on this drive I tried coca leaves for the first time. I know what you are thinking, yes it is what cocaine is made from, but chewing the leaves is a traditional remedy for altitude sickness. They taste just like tea (or at least to my uncultured non-tea drinking taste buds) and actually made me feel sicker, so I disposed of mine pretty promptly. Finally we stopped ascending and got to the national park, where you drive into it along the line of an old Incan road (now under tarmac).

The Incas could build straight roads!
The Argentinians have been very successful at developing little stopping points in the area that allow tourists to have a wander around and read some of the old myths about cactuses the Incans had (something to do with protecting a young eloping couple from angry parents).

Whilst Anjali isn't exactly tall, the cactus sure is!
Having had a quick drive down the road past where we were staying, we drove back as the sun was setting and the moon rising. It was also the first time we got to see the reason this area was a desert. Every night the clouds roll in but get stuck (more or less) at the edge of the basin creating the appearance of a wall of clouds.

Moon rise, sunset, and a wall of clouds arriving.
The accommodation was pretty basic, but can't complain too much as it had walls, hot water/shower and central heating. And occasionally electricity/wifi although that was all dependent on a very temperamental generator. I am thankful for it as we did see temperatures dropping below freezing most nights even if it was in the 20+C region most days.

The least flattering picture of Thomas I took in the field, but shows our adobe brick home, with a mud roof covered by tin held down by big stones.
Our first day out in the field we headed to a site previously described to us by a field geologist up the side of a mountain. Most of the morning was spent climbing up and down finding very little (we were one peak adrift of the site as we prospected). My best find until getting to the actual location was a stromatolite - layers of mud held in place by algal mats that build up over time.

Stromatolite in section. The layers showing how they build up are clear.
It is worth pointing out that the region is truly gorgeous in terms of scenery, with the rock layers fluctuating in colours from whites, to reds, to greys and purples. Truly an amazing place.

The vertical rock beds, showing the different colour layers. Somewhere over there is fossils.
We spent the early afternoon at the site and found many fossils, but were unable to extract much due to the hardness of the rock (and not wanting to climb a generator 1.5km horizontally before 1km vertically). As such we collected some scree from the exposure to test how it will prepare under acid digestion.
From left to right Agustín, Javier, Anjali, Thomas. Up the hill (mountain) on day one.
The next day we did a major prospect and found nothing. This was to set the trend for the trip as we alternated days of no fossils and fossils for most of the first week. Just the occasional trace fossils. The Palaeocene seemed strangely devoid of macro fossils, but this is likely due to the environment of the basin which was forming as the Andes started to rise. It wasn't until the 3rd day we came across fossils in a location we didn't know about with Thomas finding a mammal tooth, and me being competitive climbed up a silly slope in the area and found a vertebrae and some other small bone of a mammal whilst the rest had taken a break. There were also a few teeth in amongst some of the small conglomerates (old river channels with rocks/pebbles instead of just sand).

Mammal vertebra in-situ
Over the duration of the trip it would become a recurring theme that it felt like the landscape didn't want you there. Many of the locations were giant sandstones with no fossils, and were covered in bucket loads of cactuses and thorny bushes. If you weren't careful you could easily sit on them as some cactuses were tiny (as Thomas and I can attest).
Spines, spines, and red rocks
If that wasn't bad enough, we realised we were in cougar/mountain lion territory with sittings of footprints, followed by Javier finding a panther hairball (as indicated by the size of it). Whilst in another place, location way up a mountain, I came across a lovely little cave filled with bones (I assume guanaco), so promptly made a hasty retreat from the area.

Puma hairball
Puma cave
I am going to blame that and the crazy amount of time climbing up and down mountains (and so watching your footing rather than looking for rocks) for our lack of finds as much as the locations. This can be attested to by poor Thomas who, whilst following Agustín up a hill (who successfully, and unintentionally, destroyed all the footholds by climbing up) slid down about 5m of hill before he managed to stop himself falling much further.

However, after much failing in one region to find anything, we spent some time in the Cretaceous where I found my first bits of Argentinian dinosaur bones. The first bits were scrappy, but due to the same bed being exposed for some way, I found much more as I followed it along, including a small vertebra.
My first Argentinian bits of dinosaur bone.
On the walk back to the car that day, I was trying to find my way to a GPS point on the top of the hill and apparently forgot that we were in the southern hemisphere so went the wrong way. In my typical lucky/persistent way I happen to stumble across a bunch of bones eroding out of a single location including some unusual shaped ones. Probably bits of girdle from a sauropod, but unfortunately they weren't very extensive, and the bits of rib and long bone were no better. However it was a start!

Chunk of dinosaur bone
The next day we were in a new location, once again expecting no fossils, as we were still alternating days on and off for fossils and we'd found dinosaurs the day before. After an adventurous drive we stopped at the intersection of hills and badlands. Thomas and I went up one hill, Anjali another, and Agustín and Javier into the badlands. Having climbed one hill, Thomas and I were on our way back when I spotted an eroded slab with a fossil on it. We believe it's a tooth, but still none the wiser until it gets prepped.

View from the top of the hill. Note the clouds rolling in.
However, whilst smacking more rocks to see what else we could find we heard Agustín and Javier shout in excitement. They said they'd found a skull. After some discussion, we believe it is indeed a skull, but heaven knows what. It is only the back of the skull if it is, and with the bone almost matching the colour of the rock extracting it was difficult for Javier. We spent another day and a bit there, searching the badlands and finding no more, but up on the hill some more fish bits, including a bit of skull (and maybe a mammal tooth...), as well as finding lots of locations for future exploration. We built/rebuilt the road so we could drive in and get the specimen out. It also turns out that it hand't rained in over a year, but between our 2 days of visiting the location, it did rain!

My nerdy photo of a fossil fish scale, with lichen growing on it, taken with an iPhone through a hand lens.
The final day in the area, we returned to the area where I'd found dinosaur bones to do a thorough exploration. Everyone found some more small bits of dinosaurs, but typically I waited until the last hour as we were returning to the car to stumble across a large bonebed full bones of all sizes (although to be determined if they are just bits of big dinosaur bones or actually small bones), plus a few teeth. There is even an almost complete dinosaur rib that dives into the hill, but that was left there for now. Almost certainly part of a sauropod, but we did find a theropod tooth.

That evening, after a bit of a rush due to my find, we left our field station, and headed down to the south to a town called Cafayate (although one of the things I learnt is that Argentinians, at least those from Buenos Aires, pronounce the y like a sh sound) where we stayed in a hotel for the night. We then headed to a previously published ancient lake full of fish and frogs. So we sat and split lots of slabs of rock. We found a few partial frogs, before Thomas found something that might be the biggest tadpoles at the site. Whilst packing up were were working to sort the good from bad (ie the keepers vs those we were leaving), and there was a nice pelvis on one rock I was keen to extract. I hit the rock and one of the layers popped apart, exposing a beautiful frog fossil, preserved down to the individual bones in the phalanges in the hand and foot. It was probably the find I loved most, despite always loving dinosaurs more than amphibians,

The fossil frog, part and counter part. The left specimen has the head facing down. Big man thumbs for scale?
Myself looking very proud of my frog
With that being the last find of the trip, that rounds up our reconnaissance of the area having found some new areas with fossils, seen lots of new areas to recon, and set the ground work for what will be a hopefully incredibly productive location for Anjali and her field crews for many more years (and grant money is already being applied for so there can be a return).

If you are still reading, I did a things I've learnt from the field in my last blog on the matter, which I will add some new things to here:

  1. Altitude is hard. Don't get tired because getting your breath back is far harder than taking it easier the whole time.
  2. Coca leaves taste like tea. Basically you chew leaves, get a buzz, don't feel altitude, and in my case feel sick. Everyone has a different experience though.
  3. Walking sticks can be useful. Everyone else used them and raved about them. I however, did not, and this links to point 4.
  4. Walking sticks have downsides... Climbing steep slopes with them becomes a pain unless you are Agustín and climb like a mountain goat. How I envy him. I am very much a scrambler requiring 2 hands as well to climb things.
  5. Pumas are everywhere but remain hidden. Same goes for snakes.
  6. People look ridiculous wrapping fossils whilst wearing gloves.
  7. Argentina does good steak, wine and cheese (as if people didn't already know).
  8. Despite this I still lose weight in the field even after getting fit for the altitude first,
  9. The scenery in Argentina is the most spectacular anywhere I've ever been. I'd go back just for that!
  10. I remain lucky (or have some crazy 6th sense) at finding fossils. Long may it last as it means I get taken to go hunting for more!