Towards understanding the structural evolution of the Verkhoyansk fold-and-thrust belt (Russia)

The Verkhoyansk fold-and-thrust belt is located in far-east Russia and formed during the Mesozoic as a result of accretion of several continental terranes to the Siberian platform. The fold-and-thrust belt consists of imbricated thrust sheets of sedimentary sequences deposited onto the Verkhoyansk continental margin, which represented the eastern boundary of the Siberian platform. These thrust sheets are composed of a stratigraphic succession of Mesoproterozoic to Cretaceous continental, shallow- to deep-marine and syn-tectonic deposits. Several microcontinents were formed during a long-lasting phase of rifting from the Neoproterozoic to the Devonian. Tectonic inversion and subduction of formerly developed oceans lead to the amalgamation of these continental terranes during the Mesozoic.

This seed grant aims to initiate a scientific collaboration between the Geological Institute of the ETH in Zürich and the Institute of Earth Sciences of the St. Petersburg University with the ultimate goal of submitting a proposal to the Swiss National Science Foundation. The long-term goals of the SNSF project are resolving i) the large-scale tectonic history related to the separation of several terranes from the North Asian Craton since Neoproterozoic times and their amalgamation during Jurassic to Cretaceous times, and ii) the structural evolution of the Verkhoyansk fold-and-thrust belt that was formed from Late Jurassic to early Late Cretaceous times, including major structural variations dividing it into a West and a South sector. In this sense, the Leading House project allows for initial fieldwork in the Verkhoyansk and the possibility of testing our hypothesis on selected key samples collected during this field trip.

To achieve the targeted goals, we conduct provenance analysis and low-temperature thermo- and geochronology on selected Neoproterozoic to Cenozoic sandstone samples from the Verkhoyansk fold-and-thrust belt. This analytical work will be used to constrain the large-scale and long-term geo-tectonic history of the passive margin and amalgamated terranes and the timing of uplift of the Verkhoyansk range (low-temperature geochronology). The project includes a field trip to the Verkhoyansk to collect samples. Provenance analysis and low-temperature geochronology will be conducted at the Department of Earth Science at the ETH, including MSc students from either institution.

The implication of both partners is crucial for the success of the project. The Russian team consists of Prof. Dr. Andrei Khudoley and Dr. Sergey Malyshev, both from the Institute of Earth Sciences at the St. Petersburg University, who provide extensive experience in conducting fieldwork in the Verkhoyansk and invaluable scientific expertise of the regional geology. The Swiss team includes Dr. Jonas Ruh and Dr. Giuditta Fellin, both working at the Department of Earth Sciences at the ETH Zürich. The main PI of this project, Jonas Ruh, contributes as a specialist in structural geology with expertise in paleostress reconstructions. Giuditta Fellin is the manager of the sedimentology laboratory at the Geological Institute with expertise in provenance analysis and low-temperature thermochronology. The project aims towards establishing a long-term collaboration between the two partners and a vivid exchange of Master and PhD students for future field and laboratory work.

Participants:

ETH Zurich:

St. Petersburg University: