--> ABSTRACT: Architecture, Stratigraphic Distribution and Origin of Eocene Deepwater Sandstone Wedges, Central Tertiary Basin, Spitsbergen, by R. Steel, P. Plink, and D. Mellere; #91021 (2010)

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Architecture, Stratigraphic Distribution and Origin of Eocene Deepwater Sandstone Wedges, Central Tertiary Basin, Spitsbergen

STEEL, RON,  PIRET PLINK, and DONATELLA MELLERE

Ten Eocene wedge-shaped, deepwater sandstone units have been mapped and characterized across the Central Tertiary Basin of Spitsbergen. The turbidite wedges overlap partly with each other, but step successively farther out across the basin in time, thus forming a diachronous deepwater sandstone tract in the foreland basin infill. The overlying succession of slope mudstones, deltaic sandstones and coastal plain deposits show that the basin was completely infilled during the uplift and eastward migration of the adjacent orogenic belt.

Individual turbidite wedges thin from 80m proximally to less than 10m out on the basin floor, and extend over a radial distance of only 3-10km. Their architecture varies significantly from the deeper to the shallower reaches of the asymmetric basin, but generally consists of an older progradational part that produces extensive sandy lobes, and a younger retrogradational part (laps back onto the muddy slope) dominated by well developed channel-levee systems.

The deepwater wedges are erosively associated (at proximal end) with mud-prone clinoform complexes (400m to 150m high) that represent shelf/slope progradation and broadly indicate depositional water depth for the associated turbidites. Although clinoform trajectories show the overall succession to be highly aggradational and dominated by relative sea level rise, facies evidence suggests that the turbidite wedges formed during brief intervals of stillstand or sea level fall, when deltas supplied sand directly to the (?collapsed) shelf edge.

AAPG Search and Discovery Article #91021©1997 AAPG Annual Convention, Dallas, Texas.