Structure of the Wills Valley Anticline, Alabama

Delores M. Robinson¹, Marty G. Gates², and Andrew M. Goodliffe¹

¹University of Alabama, P.O. Box 870338, Tuscaloosa, Alabama  35487

²U.S. Army Corps of Engineers, 465 Stinson Ridge, Carrollton, Alabama  35447

ABSTRACT

The Wills Valley Anticline is located in the Alabama thrust belt in the southern Appalachian Mountains.  The importance of this structure is clear when the anticline is projected to the southwest under the Coastal Plain sediments.  These antiformal structures are common near the Appalachian foreland and could be present in the subsurface under the Coastal Plain sediments providing traps for hydrocarbons.  Thus, a study of the Wills Valley Anticline may provide an analog for subsurface geology under the Coastal Plain sediments.  This study integrates multi-channel seismic data, surface geology and well log data to develop a comprehensive understanding of the structure of the Wills Valley Anticline.

A velocity model was built from the well data from the SAGA Petroleum Incorporated Hudson 16-7 #1.  This was depth converted into a 24 km (14.9 mi) seismic profile which was then interpreted.  The interpreted cross section contains surface structural data and data derived from the seismic line.  Subsequently, the cross section was line length balanced to provide validity to the structural model.

Motion along the basal decollement in the Rome-Conasauga unit ramped upsection and produced a thrust fault.  This fault had multiple stages of motion and produced a composite fault propagation fold in the hanging-wall.  The Wills Valley Anticline combines a trishear fault propagation fold with two breakthrough constant thickness fault propagation folds.  The minimum amount of shortening through the anticline derived from the balanced cross section and restoration is 5.4%.

Robinson, D. M., M. G. Gates, and A. M. Goodliffe, 2009, Structure of the Wills Valley Anticline, Alabama:  Gulf Coast Association of Geological Societies Transactions, v. 59, p. 663-671.

AAPG Search and Discover Article #90093 © 2009 GCAGS 59th Annual Meeting, Shreveport, Louisiana