No abstract

_ _________________________________________ Introduction.______________________________________ Precambrian rocks._________________________________ Paleozoic rocks_____________________________________ Daylight Formation.____________________________ Age and correlation.________________________ Corkscrew Quartzite.___________________________ Age and correlation.________________________ Carrara Formation____________________________ Nopah Formation_____________________________ Pogonip Group,________________________________ Eureka Quartzite.______________________________ Ely Springs Dolomite.__________________________ Roberts Mountains Formation.__________________ Lone Mountain Dolomite..______________________ Other Paleozoic rocks.__________________________ Cenozoic rocks and volcanism________________________ Monolithologic. breccia._________________________ Titus Canyon Formation of Stock and Bode (1935)_ Bullfrog Hills caldera and associated rocks__. ______ Description of the volcanic rocks.___________ Ash flows__________________________________ Air-fall tuffs__________________________ Rhyolite flows and intrusives_________________ Basalt flows and intrusives___________________ Latite flows and intrusives.__________________ 11 11 11 Cenozoic rocks and volcanism Continued Bullfrog Hills caldera and associated rocks Con. Chemical composition of the rocks ____________ Older gravels_________________________________ Recent alluvium.

No abstract

This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards and stratigraphic nomenclature. Appendix A A1 Appendix B B1 Favorable Criteria Permissive Host Lithology; High-level calc-alkaline intrusions and intruded rocks. Associated Volcanic/Intrusive Rocks; Quartz diorite to monzogranite and syenite with evidence of several phases of intrusion, one of which is a porphyry commonly with a microaplitic groundmass. Alteration; Potassic, sericitic, and argillic. Also, sodic-calcic, propylitic, and, occassionally, advanced-argillic alteration are reported. Geochemical Signature; An association of Cu with Mo, gold (Au), silver (Ag), W, boron (B), and (or) strontium (Sr) near the center of the deposit with possible lead (Pb), Zn, Au, As, antimony (Sb), selenium (Se), manganese (Mn), and barium (Ba) in distal areas. Associated Deposit Types; Lead-zinc skarn, polymetallic replacement, copper skarn, replacement manganese deposits, porphyry copper-molybdenum, porphyry copper-gold. Occurrences of Pb, Zn, and Cu within the Tonopah quadrangle are listed in table 5. Additional Geologic Features; Stockworks of quartz veinlets are strongly favorable for this deposit type.

No abstract