Eastern Sayan and the death of ancient species
14.08.2019

Scientists at the TSU Faculty of Geology and Geography and their colleagues from the Institute of Geology and Mineralogy Siberian Branch of the Russian Academy of Sciences (SB RAS) and the Geological Institute of the Komi federal research center will conduct a joint expedition to Mongolia. In the southern spurs of the Eastern Sayan Mountains, researchers will take samples of ancient igneous rocks, which recorded the history of the Earth and the climatic changes that occurred on the planet in the distant past. Examination of the samples will help to determine which critical climatic events led to the mass extinction of animals more than 400 million years ago.

Many data indicate a direct relationship between the sudden change in the environment and magmatic processes, including the eruption of ancient supervolcanoes. For four of the five largest extinctions, such a relationship has already been proven. For the fifth, which happened at the end of the Ordovician period, when 85% of all living things died, the exact reason has not yet been established. TSU geologists and colleagues from other research centers are finding out whether there is a relationship between the formation of large igneous provinces and the climate catastrophe on Earth about 440 million years ago. The scientists want to extract the necessary information from zircons - one of the very first minerals formed on our planet.

- The objects of interest to us are in the south of the Great Lakes basin and Prikhubsugul, in the southern spurs of the Eastern Sayan Mountains, - says Alexey Semiryakov, expedition member and member of the TSU Laboratory of Geochronology and Geodynamics. We plan to bring rock samples back with us from various massifs and complexes, including samples of more than 10 kilograms, to extract geochronometer minerals and date them using equipment from the Laboratory of Geochronology and Geodynamics.

Geologists will “read” the information using a unique facility for conducting radioisotope dating. This is the most accurate method for determining the age of objects in hundreds of millions and even billions of years. In addition to absolute age, the analysis will identify isotopic changes and geochemical anomalies that carry information about the climate effects of the past.

- Large-scale emissions of magma and greenhouse gases led to critical climate changes - acid rains, sea-level changes, global warming, and ice ages, - says Richard Ernst, research advisor of the TSU Laboratory of Geochronology and Geodynamics. The analysis of the samples will give us information about the environmental conditions in the critical era and will help to determine the size of the erupted provinces that were involved in the mass extinction during the Ordovician period. To get the full picture, we will research samples taken by geologists during expeditions in Mongolia and Tuva, in North and Central Asia.