Basin Lithofacies of Siliciclastics of Springer-Morrow Formations (Mississippian-Pennsylvanian), Panhandle and Anadarko Basin, Oklahoma
C. W. Keighin, R. M. Flores
Investigations of 6,500 ft of core and 100 thin sections from 30 drill holes from the Oklahoma Panhandle to the southwestern portion of the Anadarko basin, Oklahoma, have led to the recognition of three lithofacies of the Springer-Morrow Formations of Mississippian-Pennsylvanian age. Lithofacies include (1) fluvial-influenced coastal (FIC), (2) tidal-influenced shallow marine (TISM), and (3) mixed, which includes features of both FIC and TISM. FIC facies is restricted to downhole depths of 4,400 to 8,000 ft; TISM facies occurs between 4,000-ft and 18,000-ft downhole depths.
Thin-section study of sandstones indicates that quartzarenites are the most common rocks in both the FIC and the TISM facies. Subarkose sandstones are present in the FIC facies, and sublitharenites are present in the TISM facies. Calcite skeletal fragments of mainly brachiopods and crinoids were more abundant in the FIC facies than in the TISM facies. The mixed facies includes quartzarenites, subarkose sandstones, and sublitharenites. Iron-bearing carbonate cements are observed in rocks of all facies types. Porosity is typically less than 10% and has generally been reduced by iron-bearing carbonate cements; silica and/or clay cements are less common. Fracture porosity was identified in core samples but was rare in thin sections. No obvious relation exists between downhole depths and a ount of porosity. Dissolution porosity appears to be less common than primary porosity.
AAPG Search and Discovery Article #91038©1987 AAPG Annual Convention, Los Angeles, California, June 7-10, 1987.