12 - Geology of the shelves surrounding the New Siberian Islands from seismic images: Laptev Sea and East Siberian Sea, Russian Arctic

Abstract

The major structural elements of the Laptev Sea Rift include the Ust'Lena Rift, the Laptev Horst, the Anisin and Neben Basins, the Kotel'nyi Horst and the New Siberian Basin. The most prominent rift basin is the >300 km wide Ust'Lena Rift with a sedimentary infill ranging from 3,000 m to 13,000 m. The Anisin and Neben Basins, and the New Siberian Basin are complex half-grabens. The major west-dipping MV Lazarev Fault separating the Ust'Lena Rift from the Laptev Horst is considered as a hinge zone which developed by linkage of several smaller half-grabens. The sediment-starved Laptev Horst consists of several tilted blocks. The Laptev Sea Rift was primarily formed in interaction with the opening of the Eurasia Basin by seafloor spreading. Simple-shear mechanism with ductile stretching beneath a deep detachment can best accommodate the structural elements of the complex Laptev Sea Rift, which terminates to the north at a major transform zone, the Severnyi Transfer. No conclusive evidence was found in the seismic data for a continuation of the Laptev Sea Rift into the East Siberia Sea. The surveyed part of the East Siberian shelf is best described as a relative stable epicontinental platform that subsided and sediments were deposited since probably Late Cretaceous time.