Influence of Late Jurassic Inversion Structures on Sedimentary Basin Uplift, Chukchi Shelf, Offshore Alaska (thesis)

Abstract

This thesis examines the existence of a reactivated fault interpreted to be an inversion structure associated with a Jurassic tectonic event in the Chukchi Shelf off the NW coast of Alaska. Brookian, Jurassic, Ellesmerian, and Franklinian stratigraphic horizons were interpreted in a sequence stratigraphic framework along several thousand kilometers of 2D seismic lines along the Chukchi Platform and Hanna Trough, as well as all faults related to the tectonic history of the study area. Seismic interpretation was based off of a tie to the Klondike test well in the Chukchi Sea.

Using isopach and structure contour maps, as well as mapped horizons along the 2D seismic data, structural and stratigraphic history was determined. Through this seismic interpretation, events such as basin thickening and crustal shortening that had previously been documented as tectonic history of the study are were in in conjunction with what was found in this study. Evidence of normal faulting as well as reverse faulting based off both offset of a seismic horizon in a normal sense and in a reverse sense based on the presence of sedimentary uplift supports the presence of an inversion structure. This indicates that during a regional extensional Jurassic event, a local contractional event occurred, causing shortening in all horizons older than 131 million years old.