Study area is within Wichita Mountains, southwestern Oklahoma (S. Oklahoma folded belt province). /Wichita Granite Group provisionally revised, from consisting of 5 units (Mount Scott, Headquarters, Reformatory, Lugert, and Quanah) to 10 units (with the addition of Cache, Cooperton, Long Mountain, Medicine Park, and Saddle Mountain). Wichita igneous province divided into eastern and western provinces. Eastern province contains largest area of outcrop, but most of existing nomenclature originated in western part. In the eastern province, the Wichita Granite Group (revised) consists of: Mount Scott Granite, Saddle Mountain Formation, Medicine Park Formation, Cache Formation, and Quanah Granite. In the western province, the Wichita consists of: Mount Scott Granite, Headquarters Granite, Reformatory Granite, Long Mountain Formation, Cooperton Formation, and Lugert Granite. Wichita Granite Group is intrusive equivalent of /Carlton Rhyolite Group. Age of Wichita is Middle Cambrian (525 +/-25 m.y.). Report includes geochemistry, stratigraphic table, map showing distribution of units.
Name Medicine Park Formation informally used by Johnson and Denison (1973, Oklahoma Geol. Survey Special Pub. 73-2) for a granite that is finer grained than Mount Scott Granite, in the Medicine Park area (S. Oklahoma folded belt province). Unit has a distinct purplish cast. Appears to cut Mount Scott; relationship to Cache Formation and Quanah Granite is unclear.
[Derivation of name not stated, but probably named from Medicine Park.]
[Wichita Granite Group preempted by Wichita [Group] of Cummins (1890) in TX; conflicts with nomenclature guidelines stating a group name combines a geographic name with the term "group," and no lithic designation is included (ACSN, 1961, 1970; NACSN, 1983, 2005, 2021).]
Source: Modified from GNU records (USGS DDS-6; Denver GNULEX).
For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.
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