Laptev Rift System Composite Tectono-Sedimentary Element, East Siberian Arctic

The Laptev Sea in the East Siberian Arctic is characterized by a system of extensional structures known as the Laptev Rift System (LRS), developed at the continental prolongation of an active divergent plate boundary – the Gakkel spreading ridge. The LRS hosts as much as 13–14 km of siliciclastic sedimentary strata of supposedly Late Cretaceous–Recent age. The strata accumulated atop stretched and thinned continental crust that before the rifting onset was a complex tectonic juncture of Late Paleozoic–Early Mesozoic Taimyr and Late Mesozoic Verkhoyansk fold-and-thrust belts formed along the edges of the Siberian palaeocontinent. In the context of this volume, the LRS is described as a composite tectono-sedimentary element that includes sedimentary rocks accumulated during pre-rift and synrift phases. The latter includes at least two synrift sedimentary cycles separated by a sedimentary succession formed during a stalled rift phase. In the absence of deep exploration wells, many aspects of the LRS geology and its petroleum prospects remain poorly constrained.