Name applied as an informal term to one of two major bodies of mafic rock south of the Mullen Creek-Nash Fork shear zone. Is located in southeast part, T14N, R78W, south of Albany, Albany Co, WY in the Northern Rocky Mountain region. Is a large circular intrusive covering about 21 sq mi. Neither source of geographic name nor type locality stated. Geologic map. Tables showing modal analyses and composition. Includes troctolite, olivine gabbro, olivine norite, gabbro, and norite. Two zones mapped--1) olive-bearing and 2) gabbroic. Has an east-west trending magnetite-rich zone about 1 mi long and 1/4 mi wide near southeast border. The magnetite is disseminated and is concentrated in small stringers and pods. Cuts quartz diorite to west, and hornblende gneiss and quartz biotite andesine gneiss on the east. Is cut by coarse-grained granite on north and by felsic dikes on west. Metamorphosed especially along south border of complex. Has a fresh nature and thus may be younger than the other mafic rocks of this area. Of Precambrian age.

Source: GNU records (USGS DDS-6; Denver GNULEX).

Called "Lake Owens mafic complex," "Lake Owens Complex" in Medicine Bow Mountains, WY, Northern Rocky Mountain region, south of the Cheyenne belt, the suture zone separating the Archean Wyoming province to north from accreted island-arc terranes to south. Is a small cup-shaped intrusion with an exposed width of about 9 km and an exposed thickness of 4.5 km. Consists of gabbro, norite, troctolite, and anorthosite in a sequence showing rhythmic, cryptic, and size-graded layering, probably due to primary flow. Is least altered of the mafic intrusions of southeast WY. Similar mineralogically to Mullin Creek mafic complex. May represent the lower crustal zone of a continental-margin magmatic arc complex. Intrudes a volcanogenic gneiss terrain. Borders a quartz diorite intrusion to the south, east, and west, and granite with a 1.46 m.y. K-Ar age to north. Structural relations suggest it was intruded by the 1.781 +/-0.006 by quartz diorite that borders it. Probably was part of a larger layered complex that intruded the volcanic pile in Precambrian time.

Source: GNU records (USGS DDS-6; Denver GNULEX).