near Panther Creek; US Point, looking south one can see a pre- 183 south of Roosevelt; existing drainage network of small, previ- Meers area. ously carved in , tributary canyons Good exposures: Mt. that disappear to the south under a layer Sheridan of younger conglomerate. These OK 115 crossing Medi- features are currently being uncovered. cine Creek. – gray rock hh Along US 62 west of Lawton, and around that can be scratched the intersection with OK 54, small granitic knobs stick up through Permian shale on Limestone, with with a knife and reacts calcite veins. Penny to acid; calcite crystals the south side of the highway. They con- shown for scale. mostly too fine to be nect with the larger granitic topography, as seen with naked eye. shown in the photo on the reverse. Trace of the as it cuts NW across the Part of stratigraphic Arbuckle Group. Slick Hills. hh Particularly striking is the SW corner of Good exposures: Along OK 58 through the Slick neotectonic scientists. Now this fault seems to State Park, which is dedi- Hills; Dolese Brothers Porter Hill Quarry. be relatively quiet, but it is being monitored by cated to rock climbing. the Geological Survey. PALEOTOPOGRAPHY Most of the topographic forms Good exposures: A good public exposure is on seen in the Wichitas, whether un- OK 58 where an E–W section line road crosses derlain by igneous rocks or lime- OK 58, one mile north of the road to Meers and stones, were carved in the Early the location of Ann’s Diner. Here, the modern Permian 290–280 million years Meers Fault scarp makes a small upward WNW– ago then buried in later Permian ESE bump in the present topography. At this in- red shales and conglomerates. tersection, if one stops on the section line road and looks northwest, one can see a notch on All the igneous hills and lime- the skyline formed by the fault. This scarp was stone hills seen are sticking up well studied in the 1980s by the OGS and USGS. out of the shale (see figure at Diagrammatic earth cross-section showing the rock structures of the right), showing that the hilly eastern Wichitas. Text by Dr. M. Charles Gilbert and mountainous topography Professor Emeritus, Mewbourne College of Earth extends beneath the shales and is therefore MEERS FAULT and Energy, University of Oklahoma Cover photo: Mount Scott older than the shales. Because this can be seen For more information on the Wichitas, visit: everywhere, only a few illustrative locations are This is a great example of a Holocene (modern) highlighted. geologic fault apparently tracing out the loca- http://www.ogs.ou.edu Good exposures: tion of a much larger, older fault. Oklahoma Geological Survey 100 E. Boyd, Rm. N-131 hh Along OK 58 in the Slick Hills, just north of During the Pennsylvanian uplift, the Meers Fault Norman, OK 73019; 405/325-3031 the Kimbell Ranch headquarters, a knob of acted as a thrust lifting the area south of the Permian red conglomerate sits on top of fault 1 ½ miles higher than the Slick Hills side. Mewbourne College of Earth and Energy older limestone at the floor of Blue Creek However, about 1100 years ago, part of this The University of Oklahoma fault moved up about 10–15 feet on the north The University of Oklahoma is an equal opportunity employer. Canyon, showing the valley existed before This publication, printed by the Oklahoma Geological Survey, Nor- the conglomerate. side, creating a small scarp in the present topog- man, Oklahoma, is issued by the Survey as authorized by Title 70, raphy and probably generating a large earth- Oklahoma Statutes 1981, Section 3310, and Title 74, Oklahoma hh On OK 49 extended, in the Refuge, 1 mile Statutes 1981, Sections 231—238. 1,500 copies have been pre- past the Mount Scott turnoff, near Quetone quake. For this reason, the Meers is famous to pared at a cost of $170 to the taxpayers of the State of Oklahoma. INTRODUCTION African or the Rio Grande ROCK TYPES Rift. These rocks are a record – equivalent to granite in composition The Wichita extend about 60 miles of that part of Oklahoma’s and mineralogy but texturally different because WNW from out to the town of Granite. geologic history. Good exam- magma flowed out on the surface and cooled They cover a good part of Fort Sill, all of the ples of these rocks are readily quickly. Usually buff, pink, or red. Individual Wildlife Refuge, the Slick seen in the Wildlife Refuge. crystals of feldspar and quartz can be seen by Hills (where all the wind towers are), Great the naked eye. Plains State Park, State Park The other major rock type is Good exposures: Medicine Bluffs, Fort Sill; and many areas in between. These mountains the limestone forming the West end of Mt. Scott picnic area; East side of are a beautiful illustration of a “fossil” moun- Slick Hills. These sedimentary OK 58, southern Slick Hills. tain range, one that existed 290–280 million rocks formed 500–480 mil- years ago. This range was buried in the red lion years ago when the sea Granite – red/pink rock form- shales making up the plains and is now being flooded the rifted zone and ing most mountains; easily seen uncovered. So parts of the range are still buried View of Baldy Point , Quartz Mountain State Park, shows the Cambrian the rest of the surrounding crystals of feldspar, quartz and beneath the present surface. What a geologic basement rocks of the mountains and the overlying Permian strata. continent. The , dark clusters of mica, hornblende, story can be seen and is displayed! sedimentary limestones. The igneous rocks, such called the Arbuckle Group and/or magnetite. Mount Scott as , and , were formed because the same rock units are exposed in the Granite is most widespread and GEOLOGIC HISTORY from molten magmas 540–525 million years ago. along I-35, were formed fine-grained. from the shells of many tiny marine animals. These magmas came up from below and filled Quanah Good exposures: Mount Scott There are two groups of rocks making up the The limestones sit on the igneous rocks but in a continental rift, a place where the crust was Granite. Granite (fine-grained): Top of Wichitas: the older igneous, and the younger being partially pulled apart, as in the present East once also covered Mount Scott and all the igne- Mount Scott; Lake Elmer Thomas ous rocks of the Wichitas. A major fault, the dam; and Lake Tom Steed dam. Meers Fault, separates the Slick Hills from the Quanah Granite (coarser-grained): Quanah rest of the Wichitas. Parker Lake dam; Camp Boulder; Elk Mountain. Lugert Granite (fine-grained): Quartz Mountain The uplifts that brought the igneous part of Lodge area. the rift to the surface occurred 320–300 mil- Reformatory Granite (coarser- lion years ago when South America and North grained): Quartz Mountain Park; America collided, resulting in crustal deforma- Willis Quarry in Granite, OK and tion in the Appalachians and in the Ouachitas of many public monuments in Okla- Arkansas and SE Oklahoma. This plate tectonic homa. collisional process also deformed the old and buried rift zone, causing the uplift of the Wichita Gabbro – dark gray rock form- Mountains and Arbuckle Mountains. ing most of the mountains in the Reformatory Roosevelt area (Glen Mountains), Then deep erosion of these uplifted blocks took Granite. the Central Lowland in the Wild- off most of the overlying sedimentary rocks and life Refuge, the heavily treed slopes on the exposed much of the older igneous rocks. The north sides of Mt. Sheridan, Mount Scott, and paleotopography of this erosional remnant is along OK 115 between the Refuge and Meers. what we see today in the Wichitas. The Wichita Good exposures: Glen Mountains Layered landforms were preserved for us by being Complex (laminated plagioclase, a calcic buried in the sediments eroding off the higher feldspar, reflective pyroxene, and magnetite); lands to the east 280–270 million years ago. along the E–W Refuge road (OK 49, extended)