Tectonic of the Laptev Sea Region in North-Eastern Siberia

THEME 3: Plate Boundary Problems in the Laptev Sea Area Summary: Seismic reconnaissance lines were surveyed on the wide, virtually unexplored shelf of the Laptev Sea between the New Siberian Islands and the Taimyr Peninsula.The most prominent ritt basin is the Ust' Lena rift with a minimum width of 300 km E-W at latitude 75 "N.It is bounded to the Laptev horst in the east by a westerly dipping major listric fault, the MV Lazarev fault.The 100 to 150 km wide Laptev horst is subdivided into three parts by minor rift basins.Another rift graben, the Anisin basin, is separated from the Kotel'nyi horst by a deep fault, the IB Kapitan Dranitsin fault.The onset of the rift is inferred to have been in the Late Cretaceous and the main extension took place from the Paleocene to the Oligocene.