The Response of Miocene Shelf-Deltaic Systems to the Propagation of the Sakhalin Strike-Slip Zone

By

M. Brettle, S. Flint (University of Liverpool, U.K.), and J. Bessa (Sakhalin Energy)

Ascertaining the timing and extent of tectonic deformation is a major uncertainty when assessing the relationship between strike-slip tectonics and accommodation history. This is particularly true for the offshore Eastern area of Sakhalin; where strike-slip deformation was concomitant with the formation of the Miocene-Amur delta system that prograded orthogonal to the main strike-slip trend. Two distinct phases of strike-slip deformation affected Sakhalin; an early phase initiated south of Sakhalin during the Oligocene and a later phase propagated through the island during the Miocene. The Miocene phase rotated and uplifted blocks within the strike-slip zone, causing the progressive emergence of Sakhalin. In this zone, palaeo-Amur transportation/dispersal pathways were modified in response to the formation of strike-slip generated topography, whereas areas marginal to the strike-slip zone were less influenced by strike-slip tectonics. These areas marginal to the strike-slip system comprise deltaic-shelfal deposits that are currently the focus of offshore exploration and field development on the East Sakhalin shelf. This paper presents a tectono-stratigraphic synthesis of the East Sakhalin shelf, and contrasts the tectonic elements, basin-fill geometries and stratigraphy of offshore and onshore areas.We show that in order to assess the effect of modulations in accommodation and sediment supply on the East Sakhalin Shelf it is essential to ascertain the combined effects of changes to the palaeo-Amur, shelf-depositional systems and the tectonic regime. 

AAPG Search and Discovery Article #90008©2002 AAPG Pacific Section/SPE Western Region Joint Conference of Geoscientists and Petroleum Engineers, Anchorage, Alaska, May 18–23, 2002.