- GeoRef, Copyright 2004, American Geological Institute. Reference includes data from Bibliography and Index of North American Geology, U. S. Geological Survey, Reston, VA, United States
This structural analysis is based on study of 1,100 foliation attitudes from an area of about 20 sq mi on the lower north flank of the Sierra Madre Mts., Wyo. Equal-area projections of foliation attitudes, with field observations, suggest that the structure of the gneiss in the north is a northerly plunging synform, antedating intrusion by amphibolite. The synform has been transposed, in part, by penetrative action. Pi diagrams and maps are included.