Tag Archives: extinction

Descending into Natural Trap Cave – A Scientist’s Day in the Office

By Alan Cooper and Laura Weyrich

Caving (rappelling), fossil finds, bone grinding, DNA sampling and fieldwork all in a day’s work.  Here Alan Cooper descends into the Natural Trap Cave, Wyoming to collect unique animal fossils for sampling, to be subsequently analysed at ACAD.

What happens at Camp, stays at Camp… or does it?

by Tim Rabanus-Wallace

Tim presents a snapshot of life on the Dawson Field Camp during the July 2014 Yukon field expedition, introduces you to the crew, and talks about some of the considerations that go into ancient DNA fieldwork.

Digging up frozen bones in gold mines

by Julien Soubrier

As part of our research on the evolution of flora and megafauna throughout the climate variations of the late Pleistocene (~10 to 100 thousand years ago), we had the opportunity to collect frozen bone remains directly from the permafrost in Canada. Three of us traveled to the gold rush city of Dawson in the Yukon, where a few families are still mining for gold in the frozen soil. To reach the gold-rich layers, miners are using high-pressure water to accelerate the natural thawing of the permafrost, uncovering numerous bone remains in the process. Most of these bones are from large mammals who were grazing in the steppes of the Berigian region a few millennia ago: mammoths, horses, bison…

Placer mining. Recycled water is pumped into the mine face at high pressure, melting the ice and revealing the gold-bearing gravels. After a claim is worked in the way, miners reform the land using excavators, allowing local plants to recolonise, and the environment to rapidly recover.   Yukon_C_2014Sml

Above: Placer mining. Recycled water is pumped into the mine face at high pressure, melting the ice and revealing the gold-bearing gravels. After a claim is worked in the way, miners reform the land using excavators, allowing local plants to recolonise, and the environment to rapidly recover.

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Natural Trap Cave: First instalment of year 1 of the field project.

by Alan Cooper

Having rigged the cave on the first day, I guess it was appropriate that I was the one to take the first descent into the chasm below. It’s caving lore something along the lines of the Captain going down with his ship – if you rigged it, you should be first to ‘test’ it out! Backing over the ledge and unlocking my brakebar, I descended about 3 m against a series of ledges – before dropping into open space. Looking around I could see several enormous nests, around a metre wide and made of big branches – eagles had obviously lived under the overhang of the cave entrance for many years, presumably until the grid was placed over the entrance. I’ve not seen eagle nests up close before and it was impressed how large they were. Pack rats were also nesting around these ledges – 100ft over space, and we saw several snake skeletons down in the cave attesting to the effective security systems surrounding their home! Continue reading

How do you get 10 scientists (safely) down a 100 ft vertical shaft?

By Alan Cooper

Natural Trap Cave (NTC) has an impressive entrance pitch – which is concealed immediately below a large innocuous looking slab of limestone, in the middle of a gently sloping ridge overlooking Bighorn Lake on the border between Wyoming and Montana. As you walk across the slab you can see why anything with hooves, or running at speed, would have had no time to react when the cave entrance came into view – suddenly all the edges slope inwards steeply, and you’re looking straight down a hole, about 30ft wide, 100ft onto rocks at the bottom of a large chamber. As a result, over the last 100,000 years or so, a very large accumulation of skeletons has built up in the sediments below – standard herbivores such as bison, horse, and mountain sheep but also large numbers of carnivores including American Lion and cheetah-like cat (really a puma on steroids), many wolves, and even giant short-faced bears  and mammoths. Continue reading