Abstract The two lower members of the Springer Formation are well exposed in the vicinity of City Lake, located northwest of Ardmore, Oklahoma. The upper member of the Springer Formation and the lower member of the Golf Course Formation are well exposed along Phillips Creek, northwest of Springer, Oklahoma (Fig. 1). Detailed directions to these localities are given in the text.

Abstract A seismic profile from the Ardmore basin illustrates a positive flower structure and demonstrates important criteria for identifying convergent (or transpressional) wrench faults with seismic control. Positive flower structures are linear antiforms that are cut longitudinally along their apex by the upward-diverging strands of a wrench fault. Some of the fault strands have important reverse separations. These flower structures are to be distinguished from the negative flower structures discussed elsewhere in this atlas (Harding, 1983). Negative flower structures are complex, linear synforms displaced by inward-dipping strands of a wrench fault that have mostly normal separations. In the discussion that follows, we first briefly outline the setting and the geologic history of the region in which the profile was taken. Then the general characteristics of positive flower structures and the flower structure features observed on the Ardmore basin profile are described. Lastly, the controls and mechanisms for the development of positive flower structures are discussed. The Ardmore basin lies in the foreland of the Ouachita fold and thrust belt and within the splays of the Washita Valley wrench system. The Ardmore basin underwent initial subsidence in the latest Precambrian through Middle Cambrian as part of the southern Oklahoma aulacogen (Figure 1; Hoffman et al, 1974). The aulacogen was oriented transverse to the early Paleozoic continental margin (approximated by the Ouachita geosyncline on Figure 1) and became narrower toward the northwest. In the Late Cambrian through Pennsylvanian, basin subsidence took the form of a broad syncline.

Abstract During Pennsylvanian time, the Ardmore basin was the site of almost continuous deposition in long, narrow, and oftendeep basins lying in close proximity to structurally and topographically high islands. These islands and sea-mount archipelagoes formed and were rejuvenated during the several orogenic pulsations that mark the Pennsylvanian Period in southern Oklahoma as one of extreme unrest. As the islands were upfolded, they were truncated, and some of them buried—partly in their own detritus. The base of the Pennsylvanian is drawn at the base of the Rod Club sand. The underlying Goddard shale, which was formerly included in the Springeran Series, is now considered to be Chesterian in age. The Springeran Series as defined herein is apparently restricted to the Ardmore-Anadarko basin with only a very thin wedge, if any, within the western McAlester basin. It consists of shales with sandstone members, in many places oil bearing, which are “regionally persistent but locally very erratic” (phrase from Hubbard and Thompson, 1926, p. 457). The Morrowan Series began with a very widespread “transgression” of marine sands that covered the peneplained surface of most of Oklahoma north of the Wichita Mountains-Criner Hills axis, and extended northwest into southwestern Kansas and the Texas Panhandle. This was followed by marine shales and then limestones. Local uplifting (Wichita orogeny) began in the Criner Hills and elsewhere, possibly during late Springeran time, and increased in magnitude inthe Morrowan Epoch, producing coarse conglomerates east of the Criner Hills. It culminated in early Atokan time in intricate folding and faulting. These folds lie en echelon , with their axes about 10° from the major tectonic trend. Many of the upfolded insular structures that now contain vast amounts of oil were first formed duringthis period of unrest. Concomitant erosion of these islands stripped as much as 8,000-13,000 feet of sediments from many of them before their burial in late Desmoinesian time. The Atokan Series began with the deposition of thick conglomerates in the vicinity of the Criner Hills. Marine shales, sands, and some limestones make up the rest of the unit. Near the end of the epoch the Ouachita orogeny intensely compressed the Ouachita geosyncline to the east, raising the Ouachita Mountains into fairly high relief. The Desmoinesian rocks of the Ardmore basin tell the erosional story of that land mass. Great wedges of chert conglomerates, sands, and deltaic sediments extend northwestward into the Ardmore basin, where they intertongue with swamp and marine strata. The marine sands contain tremendous quantities of oil, in structurally high positions. Around the island uplifts a considerable accumulation of locally derived detritus was deposited. The presently exposed Arbuckle Mountains were strongly uplifted in late Desmoniesian time (first major phase of the Arbuckle orogeny), shedding detritus into adjacent submerged areas. An interval without severe tectonism resulted in slow subsidence of most of the region in Missourian time, with an influx of transgressive marine shales, sands, and limestones, interbedded with a few tongues of continental sediments.Bythe end of Missourian time most of the structural islands were completely buried. The end of this epoch was marked by the culmination of the Arbuckle orogeny, with great uplift in the Arbuckle Mountain area and intense compression ofthe Ardmore basin, continuing into Virgilian time. Close folding accompanied by major faulting occurred at this time. The Virgilian Series consists largely of terrestrial and shallow-water conglomerates and red shales that were deposited in the low areas surrounding the eroding mountain ranges that were formed during the Arbuckle orogeny. By the endofVirgilian time, both the erosional and the depositional surfaces were nearly flat.

Abstract During Pennsylvanian time, the Ardmore basin was the site of almost continuous deposition in long, narrow, and often deep basins lying in close proximity to structurally and topographically high islands. These islands and sea-mount archipelagoes formed and were rejuvenated during the several orogenic pulsations that mark the Pennsylvanian Period in southern Oklahoma as one of extreme unrest. As the islands were upfolded, they were truncated, and some of them buried—partly in their own detritus. The base of the Pennsylvanian is drawn at the base of the Rod Club sand. The underlying Goddard shale, which was formerly included in the Springeran Series, is now considered to be Chesterian in age. The Springeran Series as defined herein is apparently restricted to the Ardmore-Anadarko basin with only a very thin wedge, if any, within the western McAlester basin. It consists of shales with sandstone members, in many places oil bearing, which are “regionally persistent but locally very erratic” (phrase from Hubbard and Thompson, 1926, p. 457). The Morrowan Series began with a very widespread “transgression” of marine sands that covered the peneplained surface of most of Oklahoma north of the Wichita Mountains-Criner Hills axis, and extended northwest into southwestern Kansas and the Texas Panhandle. This was followed by marine shales and then limestones. Local uplifting (Wichita orogeny) began in the Criner Hills and elsewhere, possibly during late Springeran time, and increased in magnitude in the Morrowan Epoch, producing coarse conglomerates east of the Criner Hills, It culminated in early Atokan time in intricate folding and faulting. These folds lie en echelon , with their axes about 10° from the major tectonic trend. Many of the upfolded insular structures that now contain vast amounts of oil were first formed during this period of unrest. Concomitant erosion of these islands stripped as much as 8,000-13,000 feet of sediments from many of them before their burial in late Desmoinesian time. The Atokan Series began with the deposition of thick conglomerates in the vicinity of the Criner Hills. Marine shales, sands, and some limestones make up the rest of the unit. Near the end of the epoch the Ouachita orogeny intensely compressed the Ouachita geosyncline to the east, raising the Ouachita Mountains into fairly high relief. The Desmoinesian rocks of the Ardmore basin tell the erosional story of that land mass. Great wedges of chert conglomerates, sands, and deltaic sediments extend northwestward into the Ardmore basin, where they intertongue with swamp and marine strata. The marine sands contain tremendous quantities of oil, in structurally high positions. Around the island uplifts a considerable accumulation of locally derived detritus was deposited. The presently exposed Arbuckle Mountains were strongly uplifted in late Desmoinesian time (first major phase of the Arbuckle orogeny), shedding detritus into adjacent submerged areas. An interval without severe tectonism resulted in slow subsidence of most of the region in Missourian time, with an influx of transgressive marine shales, sands, and limestones, interbedded with a few tongues of continental sediments. By the end of Missourian time most of the structural islands were completely buried. The end of this epoch was marked by the culmination of the Arbuckle orogeny, with great uplift in the Arbuckle Mountain area and intense compression of the Ardmore basin, continuing into Virgilian time. Close folding accompanied by major faulting occurred at this time. The Virgilian Series consists largely of terrestrial and shallow-water conglomerates and red shales that were deposited in the low areas surrounding the eroding mountain ranges that were formed during the Arbuckle orogeny. By the end of Virgilian time, both the erosional and the depositional surfaces were nearly flat.

Abstract Middle Ordovician strata of the Arbuckle and Ouachita Mountains record markedly different depositional settings (Figs. 1, 2). Three localities in the Arbuckles and one in the Ouachitas demonstrate both the vertical sequences of Lithofacies within each area and the contrasts in Lithofacies and biofacies between the two areas. Localities 1 through 3 (Fig. 1) are in the Arbuckle Mountain region. Locality 1 (Fig. 3) is in the northeastern part of the Arbuckles. It consists of a roadcut exposure along the west side of Oklahoma 99, about 3.5 mi (5.6 km) south of Fittstown, SW¼Sec.12, T.1N., R.6E., Pontotoc County. It is readily accessible and requires no permission to visit. Locality 2 (Fig. 3) is a long roadcut along the west side of the southbound lanes of I-35 on the south flank of the Arbuckle Mountains. It is in the SW¼Sec.25, T.2S., R1E., Carter County, is readily accessible, and requires no permission to visit. Locality 3 (Fig. 3) is at the north end of Criner Hills. It is a small quarry situated in the SW¼SE¼- Sec.9, T.5S., R.1E., Carter County, readily accessible from I-35 and U.S. 70 by well-maintained gravel roads. The quarry is on private land. Permission for access can be obtained from the landowner, Ronald Burns of Ardmore, Oklahoma (405- 657-8262). Locality 4 (Figs. 1,3) is at the western edge of the Ouachita Mountains. It is the Stringtown Quarry at the north end of Black Knob Ridge, directly north of the town of Stringtown, and situated in the center of

Abstract The Altus field, Jackson county, Oklahoma, is about 3.75 mi. long, and averages 1.5 mi. in width. The field was discovered in 1934. The cumulative production to February 1, 1956, was 3 > 773 > I 8o barrels of oil. The daily average production in February 1956, was 349 barrels of oil from 197 wells. The average gravity of the oil is 48°. Production is obtained from four main granite wash units of the Pontotoc group (Wolfcampian) encountered between the depths of 1,200 and 1,600 feet. A fault terminates the field at the east side. The Altus structure was a positive element until Hennessey (Clear Fork) time.

Abstract The Southwest Lone Grove field, located about 14 miles southwest of Ardmore, was discovered in 1944. The field is located on the Wichita Mountains-Criner Hills anticlinorium, and is an example of a field whose existence is in part due to a normal fault which furnished one of the necessary components of the structural trap. Production is mainly from lenticular sandstones of Missouri and Des Moines age. There is also included an electric log cross section from the Brock field of Carter County to the Southwest Lone Grove field, and a discussion of the correlation of the formations.