Initiation of Salt Flow, East Texas Basin: ABSTRACT

Abstract

Salt structures constitute five domains subparallel to the basin margin and the Louann Salt updip limit: (1) thin ( 760 m thick); (4) pre-Gilmer salt diapirs (Oakwood and, possibly, Grand Saline); and (5) post-Gilmer salt diapirs in the basin center. This inward increase in shape maturity results from increasing salt thickness and distribution of post-Louann sedimentary facies. The Louann Salt (Middle Jurassic) was deposited in a broad continental basin on a post-rift unconformity surface. Domain 1 suggests that a critical salt thickness (~500 m) was necessary to initiate flow. In the Late Jurassic, an aggrading carbonate wedge uniformly loaded the underlying salt and formed the salt pillows of domain 2. Salt flow in the basin center had not begun by Gilmer time, probably due to a thinner overburden of basinal carbonate facies there. The Upper Jurassic-Lower Cretaceous Schuler-Hosston regressive terrigenous clastics prograded rapidly across the carbonate platform as coalescing fan deltas, filling the central basin. Salt anticlines of domain 3 grew by serial amplification of pre-Gilmer pillows to form ridges normal to dip direction fronting depocenters. Salt iapirs subsequently evolved from the distal anticlines. Salt anticlines have trapped 80% of petroleum produced from the west-center of the basin. Marine pre-Gilmer source rocks, early initiation of folding, and the large size of the anticlines have all contributed to petroleum accumulation. End_of_Article - Last_Page 585------------