Geochemical prospecting studies in the Bullwhacker mine area, Eureka district, Nevada

Abstract

Investigation of the distribution of lead, zinc, and arsenic in soils of the Bullwhacker mine area, Eureka district, Nev., indicates dispersion patterns of these three metals in residual soils over near-surface ore at the Bullwhacker mine. Ore at greater depth in the shaft of the T. L. mine, however, is not reflected in lead, zinc, and arsenic contents of the soils. The dispersion patterns are secondary residual soil anomalies in the classification given by H. E. Hawkes. INTRODUCTION This study was undertaken to determine whether geo chemical prospecting methods which have proved valuable for finding ore in other districts can be successfully applied to exploration for new ore deposits in the Eureka district, Nevada. The ore deposits, which were mined as early as 1864 (Curtis, 1884, p. 3), have been valuable principally for their lead, silver, and gold. The Bullwhacker mine area is on Mineral Point in the northern part of the Fish Creek Range, approximately \% miles northwest of the town of Eureka, Eureka County, Nev. (fig. 33). This area was selected for investigation because the distribution of ore in the area is relatively well known from drilling and mining. James Prentice, under the supervision of T. S. Lovering, collected the samples for this study. All analyses were made by H. E. Crowe, of the U. S. Geological Survey. GEOLOGY The Bullwhacker mine area is underlain by a gently dipping sequence of sedimentary rocks of Cambrian and Ordovician age which have been intruded by a sill-like mass of quartz porphyry (fig. 34) A general description of the sedimentary rocks is given in table 1. A complete description of the sedimentary rocks in the vicinity of Eureka is given by Nolan and others (1956). The general northeast dip of the sediments is interrupted to the west and the south by poorly defined domal upwarps, and numerous faults of relatively small throw cut the tilted and domed beds. The quartz porphyry appears to be younger than the faults.