Gerald G. McCloskey¹, Christopher G. St. C. Kendall¹
(1) Department of Geological Sciences, University of South Carolina, Columbia, SC

Abstract: Sequence stratigraphy of the Lower Cretaceous strata of the Northeastern National Petroleum Reserve of Alaska (NPRA): a test case for age-dating sediments with sea level curves

A sequence stratigraphic framework for the Cretaceous sediments of the northeastern National Petroleum Reserve of Alaska (NPRA) was established using a public domain data set obtained from the United States Geological Survey (USGS), including nearly 200 2-D seismic lines and 29 geophysical well logs, and Seismic Micro-Technology Inc.'s (SMT) Kingdom Suite software. This data set provided an excellent opportunity to test the validity of age-dating sedimentary sequences using the sea level curve developed by Haq and others. The study area was relatively tectonically stable during the Cretaceous, with a slow and constant rate of subsidence, and a relatively steady flux of clastic sediments into the Colville Basin. Subsequent to establishing a sequence stratigraphic framework for the area, numerous and detailed chronostratigraphic charts were created to separate and analyze the changes in base level responsible for the sequences, relating them to delta migration, local tectonics and any eustatic signal preserved in the rock record. An overall second and third order eustatic signal appeared evident in the Cretaceous section but some of the higher-frequency (4th order?) sequences identified appeared to be more localized and therefore may be related to delta migration. Based on our initial observations, it seems likely that the sea level curve developed by Haq, et al, could be successfully used to preliminarily date some of these sequences.

AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana