Geology of the Mike Gold-Copper Deposit, Eureka County, Nevada

Abstract Mike is a subhorizontal, sedimentary rock-hosted gold and copper deposit located in the Maggie Creek subdistrict within the greater southern Carlin trend, approximately two miles north of Newmont Mining's Gold Quarry mine, Eureka County Nevada (Fig. 1). Mike forms the northernmost of a belt of deposits including Gold Quarry and Tusc, that occur alongthe southwestern margin of the Carlin tectonic window and are controlled by the northwest trending Good Hope fault. On a district scale, the Carlin tectonic window forms a fault -bounded, anticlinorium of autochthonous lower Paleozoic sedimentary carbonate rocks, flanked by siliciclastic and carbonate-clastic rocks of the Roberts Mountains allochthon (Fig. 2). The Good Hope fault is a N45 o- 55 ow striking, high-angle reverse fault that bounds the southwestern margin of the window (Rota, 1987,1991,1993,1995~ Cole, 1995). The vast majority of gold mineralization within the Maggie Creek subdistrict occurs at intersections of the Good Hope fault with a series of northeast striking, high angle eros~ faults (Fig. 3). Mike is a buried deposit, covered by 450 to 800 feet of post-mineral, Tertiary Carlin Formation. The geology of the deposit is interpreted from 57 drill holes that range from 150 to 1000 foot spacings. Within the deposit, the Good Hope fault juxtaposes upper Silurian Roberts Mountains Formation in the hanging wall against parallochthonous, late Devonian siliciclastic rocks of the Rodeo Creek unit. While drilling indicates that disseminated gold and oxide copper mineralization straddles the fault zone, the bulk of mill-grade oxidized gold mineralization