Mummy Range Project

Missouri State University Department of Geography, Geology, and Planning

Proterozoic Geology of the Mummy Range,

North-Central Colorado

Since 1987, Tom Moeglin and Tom Plymate have spent most of each summer in northern Colorado mapping the complex Proterozoic igneous and metamorphic geology exposed in the Comanche Peak Wilderness Area north of Rocky Mountain National Park. During this time we have collected over five hundred rock samples, including over twenty-five bulk samples for radiometric dating. We have made over 300 thin sections, and we have had whole-rock chemical analyses performed on 140 of these samples. Preliminary versions of our map, along with preliminary interpretations of our structural, petrographic, geochemical, and geochronologic data, have been presented at the 1992 and 1994 meetings of the Rocky Mountain Section of the Geological Society of America and at the 1999 GSA annual meeting in Denver. A full-length journal article on the geochemistry and geochronology of the six different granitoid rock units exposed in this area is currently in preparation for Geological Society of America Bulletin.

Photo of Tom & Lynda Plymate at Browns Lake, Colorado, August 1997

Tom and Lynda Plymate at Brown's Lake

Photo of Tom Moeglin at Mummy Pass, Colorado, July 1994

"Mountain Man Moeglin" crossing Mummy Pass

References

Moeglin, T.D. and Plymate, T.G., 1992, Precambrian Structural Geology of the Northern Mummy Range, North-central Colorado (abs.), Geological Society of America Abstracts with Programs, v. 24, n. 6, p. 53.

Plymate, T.G., Moeglin, T.D., Sabin, T.G., and Van Schmus, W.R., 1994, U-Pb Zircon Geochronology of Proterozoic Granitoids Exposed in the Northern Mummy Range, North-central Colorado (abs.), Geological Society of America Abstracts with Programs, v. 26.

Homburg, R.L., *Moeglin, T.D., and Plymate, T.G., 1999, Shear-sense Indicators Supporting Southeast-side-up Movement for the Skin Gulch Shear Zone, Northern Mummy Range, North-central Colorado (abs.), Geological Society of America Abstracts with Programs, v. 31(7), p. 205.

Plymate, T.G. and Moeglin, T.D., 2000, Proterozoic Granitoids of the Northern Mummy Range, North-central Colorado: Discrimination and Tectonic Interpretation Based on Field, Petrographic, and Geochemical Evidence (abs.), Geological Society of America Abstracts with Programs, v. 32(7), p. A-453.

Plymate, T.G., Moeglin, T.D., and Van Schmus, W.R., Proterozoic Granitoids of the Northern Mummy Range, North-central Colorado: Characterization, Discrimination, and Tectonic Interpretation Based on Geochemical, Petrographic, and U-Pb Zircon Geochemical Evidence, submitted 5/2002 to Geological Society of America Bulletin (currently in review).

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