Abstract

A stratabound tungsten (scheelite) occurrence is exposed in Proterozoic (1650–1720 Ma) metamorphic terrane near Santa Fe, New Mexico, and may be the first volcanogenic-exhalative tungsten deposit recognized in the United States. The tungsten-bearing horizon is composed of disseminated scheelite within epidote-actinolite rock, exhibits pronounced mineralogic zoning and anomalous metal contents, and is localized along the contact between sulfide-bearing felsic tuffs and cherts and barren basalts and mafic sediments. It is interpreted as a syngenetic tungsten deposit exhaled as a chemical sediment at the close of a volcanic cycle and subsequently metamorphosed to lower amphibolite facies and deformed. We suggest that other tungsten deposits in Precambrian terrane in the western United States may also be volcanogenic-exhalative. Application of this model to exploration could lead to additional discoveries.

This content is PDF only. Please click on the PDF icon to access.

First Page Preview

First page PDF preview
You do not currently have access to this article.