Petrographic analysis and interpretation of the Whiskey Creek Pass Ls Member, Minturn and Madera Fm, Sangre de Cristo range, south-central Colorado
- Univ. of Akron, OH (United States). Geology Dept.
The Minturn and Madera formations of the Sangre de Cristo Mountains are laterally equivalent facies made up of interbedded carbonates and terrigenous clastic material deposited in the central Colorado trough during the mid Pennsylvanian period. To date, the Whiskey Creek Pass Ls Member (WCPLs) of the upper Minturn and Madera Fm. is the only marker unit of south-central Colorado that has been lithostratigraphically correlated for more than a few miles. This correlation is largely the result of the relative abundance of pure oolitic constituents within the WCPLs. As of yet, there has been no significant petrographic study of the lithologic character of the WCPLs. The WCPLs is well exposed in south-central Colorado containing overturned beds that dip approximately 70[degree] to the west. Six stratigraphic sections were measured and described from three separate localities: four sections were measured and described from three separate localities: four sections were measured on the north ridge of Trinchera Peak, one section at La Veta Pass, and one on Forbes Ranch near Fort Garland. Petrographic analysis shows that similar bioclastic constituents including brachiopods, echinoderms, mollusks, and foraminifera are found within all sections. These fossils are usually found in thin bands surrounded by oolitic and/or sandy limestone layers. Both radial and tangential ooids are evident but many are poorly preserved due to internal replacement by sparite. Oolitic nuclei are commonly composed of quartz, feldspar or bioclasts. Sparite or microspar is the main cementing agent. Diagenetic features such as compaction, syntaxial overgrowths, and replacement are common. Preliminary analysis suggests deposition occurred in a shallow marine environment close to an area of relatively high relief. Oolitic shoals and marginal lagoons predominate with siliclastic material suggesting proximal or distal localities of deposition for various units.
- OSTI ID:
- 6924661
- Report Number(s):
- CONF-9404217-; CODEN: GAAPBC
- Journal Information:
- Geological Society of America, Abstracts with Programs; (United States), Vol. 26:5; Conference: 27. annual conference of the North-Central Section of the Geological Society of America (GSA), Kalamazoo, MI (United States), 28-29 Apr 1994; ISSN 0016-7592
- Country of Publication:
- United States
- Language:
- English
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