Cretaceous (Brookian) Deep-Water Deposits of the Alaskan North Slope: Evidence from 3D Seismic Data

Henry Posamentier

Henry Posamentier
Anadarko Petroleum Corp.

Tuesday, September 21st, 2004 – 11:30 AM MST
Telus Convention Centre


The Brookian section (Middle Cretaceous) of the north slope of Alaska is characterized by high-relief clinoforms prograding towards the northeast into a deep foreland basin. The paleo-water depth ranges from sea level at the topset beds to approximately 800 m at the basin floor. The shelf-edge staging area, where the deep-water sediments originated, appears to be mud dominated. The slope is characterized by numerous gullies and isolated slope channels. Several sand-prone leveed channels and associated frontal splays imbedded within an overall mud-prone section have been identified on the slope and across the basin floor using 3D seismic data using a variety of imaging techniques including amplitude extractions, opacity rendering, illumination, and horizon slicing. Successive channels and splays appear to be arranged in a compensating pattern.

In the study area, channels track down the slope and trend subparallel to the toe of slope. These slope-parallel fairways appear to generally correspond to paleobathymetric lows. Other depositional features observed in the deep-water environment include slumps and sediment waves. The sediment waves are characterized by a series of slope-parallel, sinuous-crested, low-amplitude ridges that are distributed from the lower slope across the basin floor. These also appear to be mud-prone features.


Henry W. Posamentier is the Chief Geologist – Technical, for Anadarko Petroleum Corporation. Prior to joining Anadarko in 2001, he was with Veritas Exploration Services (2000-2001), the Atlantic Richfield Co. (1991-2000), Exxon Production Research Co. and Esso Resources Canada, Ltd. (1979-1991), and at Rider University, Assistant Professor of Geology (1974-1979).

Dr. Posamentier's research interests have been in the fields of sequence stratigraphy and depositional systems analysis, where he has published widely. Most recently, he has employed an interdisciplinary approach using 3D seismic visualization integrated with borehole data to interpret depositional systems and develop basin fill histories, in particular with reference to deep-water depositional settings. His current responsibilities include co-ordinating Aanadarko's Technical Chiefs and ensuring integration of appropriate technologies into the exploration process. In 1971-1972, Dr. Posamentier was a Fulbright Fellow to Austria. He has served as an AAPG Distinguished Lecturer to the United States (1991-1992), an AAPG Distinguished Lecturer to the former Soviet Union (1996-1997), and an AAPG Distinguished Lecturer to the Middle East (1998-1999).