"The area under study is located along the southeast flank of the Wind River Range in Fremont County, Wyoming, Beds overlying the Madison Group are measured and described in six locations within this area. These locations are: Worth Fork Popo Agie River, Sink’s Canyon, Crooked Creek, Canyon Creek, Little Popo Agie River, and Cherry Creek.
Laboratory studies are used as an aid in correlating the sandstone and dolomite sequences described In the six sections. These studies include sieve and heavy mineral analyses and thin section examination.
Sorting factors, obtained from the sieve analyses, and heavy mineral suites indicate that the Darwin Sandstone which occurs at North Fork Popo Agie River also is present to the southeast at Crooked Creek and Canyon Creek. The heavy mineral suite of a sandstone in Sink’s Canyon differs markedly from those from sands in the other locations. A younger age is postulated for the Sink’s Canyon sandstone.
Thin-bedded dolomites overlying the Madison Group in Sink’s Canyon, Little Popo Agie River, and Cherry Creek are correlated with the upper thin-bedded limestones included in the Sacajawea Formation at its type area, Bull Lake Creek. Fossils from Sink’s Canyon and Cherry Creek aid in this correlation.
It is postulated that during late Chesterian time a shallow sea existed in western Wyoming. Beds of the Sacajawea Formation were laid down in this body of water. With retreat of the sea northward at the end of the Mississippian Period red beds from a southern source began to accumulate over the beds of the Sacajawea Formation. Erosion of local highs re-exposed the Madison Limestone in certain areas. With the start of the Pennsylvanian Period the Darwin Sandstone began to accumulate from the northeast on an erosion surface of either the Madison Limestone or the Sacajawea Formation, depending on the extent of prior erosion. The Darwin Sandstone lenses out in the southeast portion of the Wind River Range. Isolated lenses of Darwin Sandstone occur south of North Fork Popo Agie River where it rests on an eroded Madison surface. Elsewhere in this area the sand was probably mixed with red shale from the south. Thus, the Darwin Sandstone is generally equivalent in age to the sandy red shale found along the southeast flank of the Wind River Range"--Abstract, pages ii-iii.
Kennedy, Richard R. (Richard Ray)
Rupert, Gerald B., 1930-2016
Spreng, Alfred C., 1923-2012
Fisher, Emory D.
Geosciences and Geological and Petroleum Engineering
M.S. in Geology
Missouri School of Mines and Metallurgy
vii, 62 pages
Southeast Wind River Mountains, Wyoming
© 1963 Denny N. Bearce, All rights reserved.
Thesis - Open Access
Print OCLC #
Link to Catalog Record
Bearce, Denny N., "The Sacajawea formation and the Darwin sandstone in the Southeast Wind River Mountains, Wyoming" (1963). Masters Theses. 2888.