319 ABSTRACT The Long Mountain Granite, a member of the Cam- brian Wichita Granite Group, is exposed in the western Wichita Mountains. The rock is red at the surface and grades into a dark gray to green that has been exposed by quarrying operations. The Long Mountain Granite is a granophyric, fluorite-bearing alkali-feldspar gran- ite with hedenbergite as the dominant mafic phase. The red and gray-green granites have similar geochemical signatures. Hematite in the red granite occurs as frac- ture fill, grain boundary coatings and as elongated crys- tals along cleavage and exsolution planes in alkali feld- spars. The iron in the hematite appears to be sourced from the oxidation of magnetite and ilmenite and the breakdown of mafic minerals. Anisotropy of magnetic susceptibility analysis shows that the gray-green granite contains a primary magnetic fabric that is consistent with the sill-like em- placement of Wichita Group granites. Paleomagnetic analysis of the gray-green granite yields a magnetiza- tion with easterly declinations and steep down inclina- tions that is interpreted as a primary or early Cambrian thermal remanent magnetization residing in magnetite. The pole (8.8°S, 134.7°E) is consistent with several oth- er paleomagnetic poles of similar age. The red granite has lower magnetic susceptibility and magnetic intensi- ties than the gray-green granite. The magnetization has southeasterly declinations and shallow inclinations with a Permian paleopole and is interpreted as a chemical remanent magnetization (CRM) residing in hematite. The CRM was caused by low-temperature weathering fluids while the granite was exposed near the surface in the late Paleozoic. INTRODUCTION Granitoid rocks throughout the world have a wide range of colors, including red. The origin of the hematite, which commonly occurs as inclusions in feldspars, has been the subject of research for decades. Some investi- gators have proposed a primary magmatic origin for the hematite, although this has usually been dismissed on the grounds that other minerals do not contain hematite (e.g., Ernst, 1960). Others have suggested solid-state exsolution from iron-bearing feldspar minerals, precipitation during deuteric feldspar recrystallization reactions (e.g., Putnis et al., 2007), or general hydrothermal activity (e.g., Wenner and Taylor, 1976) as possible origins of the oxide inclu- sions. Hematite can hold a magnetic remanence and can be used to constrain the timing of diagenetic events (e.g., El- more et al., 1998). Paleomagnetic analysis of the hematite in red granites should, therefore, be capable of determining the timing of the alteration of the rock which can help to assess the origin of the coloration. Long Mountain, a large granite inselberg located in the western Wichita Mountains, Oklahoma (Figure 1), is Petrology and paleomagnetism of the Long Mountain Granite, Wichita Mountains, Oklahoma Matthew Hamilton 1 , R. D. Elmore 2 , Barry Weaver 3 , and Shannon Dulin 4 1 919 23rd Street SE, Norman, Oklahoma 73071. mhamilton9875@gmail.com. 2 ConocoPhillips School of Geology and Geophysics, Mewbourne College of Earth and Energy, The University of Oklahoma, Norman, Oklahoma 73019. delmore@ou.edu. ph. (405) 325-4493. Corresponding author. 3 ConocoPhillips School of Geology and Geophysics, Mewbourne College of Earth and Energy, The University of Oklahoma, Norman, Oklahoma 73019. bweaver@ou.edu. 4 ConocoPhillips School of Geology and Geophysics, Mewbourne College of Earth and Energy, The University of Oklahoma, Norman, Oklahoma 73019. sdulin@ou.edu. Synder US 62 US 183 OK 54 Long Mountain 5 km Figure 1. Map showing the location of the Long Mountain Granite west of Snyder, Oklahoma.