Field trip no. 26 from “Geologic Excursions to the Rocky Mountains and Beyond,” field trip guidebook of the 1996 Annual Meeting of the Geological Society of America. Precambrian Tectonics and Metallogeny of the Hartville Uplift Wyoming. (SP-44 has the complete set.) 28 pages. Digital PDF download. OF-96-04-26D
From the Summary and Introduction:
The Hartville uplift is located on the southeast margin of the Archean Wyoming craton and exposes Late Archean granite and gneiss and Late Archean or Early Proterozoic supracrustal rocks that were deformed during three, and possibly four, major compressional events in Early Proterozoic time, extending from ~2.1 to 1.76 Ga. The recognized events are (1) inversion of the supracrustal succession (D 1 ), at least in parts of the uplift, as a result of probable fold nappe formation; (2) folding of rocks on east-west axes (D 2)in southern part of uplift; folds are open to tight, generally plunge westward, and verge southward; (3) west-vergent folding on northeast-trending axes and associated thick-skinned thrusting (dominant deformation, D3) in central and northern parts of uplift, with concomitant prograde metamorphism; and (4) local recumbent folds in southernmost part of uplift. … The purpose of this report is to describe the general geology of the Precambrian rocks in the Hartville uplift, with emphasis on the structure, and to relate these structures insofar as possible to specific compressional events along the southern and southeastern margins of the Wyoming craton.