Abstract

Analyses of composite color images of ERTS-1 data for an area covering the major portions of Eureka and Lander Counties, Nevada, reveal a number of lineaments not previously mapped either by aerial or field studies. An iso-lineament intersection map prepared from the imagery displays a northwest concentrated band of lineament intersection density that corresponds with a northwest alignment of domes of Paleozoic sedimentary rocks associated with the Roberts Mountains thrust fault. Within the band, a strong correlation exists between areas of intersection concentration and domal windows associated with major areas of mineralization and igneous intrusives. The band also coincides closely with a prominent north-northwest trending. zone of aeromagnetic anomalies.

Stress analyses of the ERTS lineaments, aeromagnetic linears, and domal structures suggest that the doming of Paleozoic sedimentary rocks associated with the thrust may be related to the emplacement of magnetic anomaly source material along zones of weakness related to a deep-seated fracture zone trending in a northwest direction. Further, it is suggested that the preferred areas of igneous activity are related to weakness zones developed at deep-seated fracture zone intersections.