Geology of Hutchinson County by Wes Phillips


Geology


Hutchinson County lies within the enormous Panhandle Field that extends into Oklahoma and Kansas. Locally, the field is called the Panhandle West Field and is continuous with the Panhandle and Panhandle East Fields to the east and the Hugoton Field to the north. The Panhandle / Hugoton trend covers approximately 86,000 square miles and is the largest gas producing area in North America. The field is a structural trap that is draped over fractured Precambrian basement rocks of the Amarillo Uplift. Discovered in 1918, the Panhandle Field has produced large quantities of oil and gas (1.1 billion barrels of oil, 6 trillion cubic feet casinghead gas, 30 trillion cubic feet of gas).

     The Permian (Leonardian) Red Cave Formation is an important gas reservoir in the area. Historically, the Red Cave has often been overlooked as an oil and gas reservoir, due to its generally poor reservoir quality. It consists of interbedded redbeds and carbonate / evaporite deposits which produce primarily gas in the vicinity of the parks. The Red Cave is found at depths of 1172' - 1542' and averages 250 feet in thickness. Both the upper and lower sands are productive, although the upper sands have higher porosities and permeabilities and account for most of the gas production from this formation.

     The Permian (Wolfcampian) Chase Group, Brown Dolomite is the most prolific oil and gas producer in the Lake Meredith area as well as in the entire Panhandle Field. The Brown Dolomite ranges from 1702 feet to 2170 feet in depth and averages 267 feet in thickness. The porosity is moderate to high (12 - 16%) with some fractures and vug enhancement. Through 1985 the Brown Dolomite has produced over 31 trillion cubic feet of gas.

     The Permian (Wolfcampian) Moore County Limestone is found from 2045 feet in depth to 2430 with an average thickness of 122 feet and also contributes to the gas production in the area. The lithology of the Moore County Lime is highly variable and thins toward the ancestral Amarillo Uplift.

     One of the deepest productive formations, the Permian/Pennsylvanian Granite Wash, found at depths of 1946 to 2412 feet consists of coarse feldspathic sandstones with highly variable reservoir quality. The Granite Wash averages 70 feet thick.

     There are several zones below the Granite Wash that have been penetrated that are locally known as the “A”, “B”, and “C” intervals. These zones are locally important because they produce oil and casinghead gas. The “A” zone has been described as a chalky lime, the “B” zone is a sandy lime, and the “C” zone, also known as Antelope Creek, is a limy wash or a clean quartzitic wash interbedded with lime. Drill depths for these units range from approximately 2850 - 3030 feet below the surface.

     In the vicinity of Lake Meredith, Permian-aged rocks directly overlie the Precambrian granitic core of the Amarillo Uplift. In the southwestern portion of the county, the granite is within 1930 feet of the surface.

Surface Geology


The principal feature of the Texas Panhandle is the wide area of breaks flanking the Canadian River. The river begins in the Foothills of the Rocky Mountains in Northern New Mexico and flows generally eastward until it joins the Arkansas River in Eastern Oklahoma. Any waters which reach the Arkansas from the Canadian in the Texas Panhandle are carried with the waters of that stream until the Arkansas joins the Mississippi at the boundary line between Arkansas and Mississippi.

     During the Rocky Mountain uplift, stream erosion increased, and huge channels distributed the outwash onto the present Great Plains, forming the Ogallala Formation which is Pliocene and Miocene in age. Fossils of the period have been preserved in Hutchinson County including horses, camels, rhinos, giant Bison, and several sorts of elephant. By Pleistocene times, many of these became extinct, but Mammoths and Mastodons as well as Bison were still common.

     In addition to these younger formations, rocks of Permian and Triassic age outcrop in Hutchinson County. There are also reports of some outcrops of Cretaceous formations in Western Hutchinson County, but these appear to be remnants of Cretaceous sediments which have been deposited in areas where they later dropped below the surrounding formations and were thus preserved.

     When the Alibates Dolomite was being formed around 250 million years ago Hutchinson County was covered by a shallow sea. During the Permian period, uplift and subsidence kept our area at or below sea level much of the time, though red sandstones indicate a period where wave actions produced a seashore environment. At times it must have been somewhat like Padre Island is today, with salty sediments and gypsum being deposited in shallow lagoons protected from the ocean by barrier islands.

     Alibates flint is a secondary mineral within the dolomite, and was very likely formed by silica-laden water percolating downward into the limestone and replacing the Calcium Carbonate. Though no outcrops of Alibates flint have been found in Hutchinson County, it is likely that some will eventually be identified. The flint does, however, occur in the gravels, and may be found throughout the county in gravel deposits.


Additional Resources

Geology of the Texas Panhandle