RSF №16-17-10231

Project "The precise chronology of the Permian-Triassic biotic and abiotic events in Siberia: the traps volcanism as a trigger of the regional and global extinction"

The problem of catastrophic extinction of marine and continental biota perhaps is one of the most important and exceedingly debating problems, which attracts the attention of the broad science community as well as public. This is definitely related to the problem of recent global warming, that some geologists considered as analogues to the climate around Permian-Triassic transition. Dispute the fact that enormous information regarding extinction problem is accumulated, many critical aspects that might clarify at least problem in general are still unresolved. In particular, there is no answer on the main question, what was causing the extinction at this time? We still do not know undoubtedly, which main event or combination of events triggered such as fundamental changes of biota, climate and evolution of the Earth? There are several dozen of hypothesis and models describing the causes of this extinction, but none of the concept/model have been commonly accepted yet. The majority of the specialists tend to accept the model that proposes the Siberian trap volcanism and the products of the explosion and interaction with surrounding traps rocks (coal, evaporates and sulfates) were the main source of the rapid growth of CO2 and sulfides amount in the atmosphere and in the oceans. The problem of the age of

Siberian traps volcanism is the most critical for the clarification the Permian-Triassic global extinction. If the main mass of the traps preceding the extinction, then the trap volcanism might be the main trigger of the all climatic, geochemical and biotic changes at the P-T boundary. If the traps are post extinction in age, then we have to look for different forces of the extinction. The marine and continental sediments in Siberia are the obvious target of our study and the geochronology is its major component.

Multidisciplinary approach that will integrate sedimentologic, stratigraphic, geochronologic, paleontologic, geochemical and paleomagnetic methods is going to be used in our project. For the first time the most precise and reliable CA-IDTIMS method of the geochronologic dating across Permian-Triassic boundary in Siberia will be applied to all samples with datable zircon, particularly samples from Babyi Kamen' section where excellent sinsedimentary zircons were already recovered. The geochemical studies will be focused on the development of chemostratigraphic data with the goal to precisely define the Permian Triassic boundary in continental and marine sections. We will perform the paleomagnetic study in continental successions in Kuznets Basin and in Southern Verkhoyanie marine sections with the goal to recognize the paleomagnetic inversions within the Permian-Triassic transition. All compiled and taxonomically interpreted data and new results will be involved in the statistical and computer analyses (CONOP, PAST, Unitary Association, available free on internet) for the development reliable succession of biotic events and biodiversity within the continental and marine Permian-Triassic transition in Siberia.

This will help to understand the objective and more complete picture of evolutionary events during this time in Siberia and correlate these events globally. Once we will calibrate the faunistic succession numerically we will be able directly correlate with Permian-Triassic deposits in the regions were radiometric ages already obtained, i.e. Australia South China and South Africa. The integrated data and analyses in our project will let us to better understand the main features of the evolution of the Earth in general and the biosphere in particular in continental and marine successions; will clarify our understanding of probably cause of Permian-Triassic extinction and particular the role of Siberian traps; recognize the casualties between extinction and volcanic, eustatic, climatic and other possible events.