Today John and I will join Phil, Eva, Dave and Derek on an overnight trip to Altan Ula, southeast of Bugin Tsav. This was the site of many important fossil discoveries made by the Polish-Mongolian expedition between 1965, 1971 and 1972.
While Phil, Eva and Derek look for historic quarries and more fossil localities, John and I will be collecting carbonate and dinosaur eggshell samples to be used for stable isotope geochemistry. The goal is to look for patterns in the carbon and oxygen isotope ratios in the samples that will provide clues as to the paleoclimate of the area.
The rocks and fossils at Bugin Tsav, Altan Ula and other localities in the western Gobi occur within the Nemegt Formation, approximately 70 million years old. The rocks were deposited by meandering rivers, lakes and sand dunes, a much different environment then today’s desert.
(In photo: A view across Altan Ula.)