Preliminary geologic map of the Frisco Quadrangle, Beaver County, Utah

Abstract

Unconsolidated talus, stream, and floodplain deposits in the mountains^ and Lake Bonneville deposits and semi-consolidated pediment gravel, fanglomerate, and other basin-fill deposits in the valleys. Total thickness locally may exceed 1,000 m Qt TUFA OF WAH WAR SPRINGS (HOLOCENE AND PLEISTOCENE) Low mounds of gray, porous, calcareous tufa, possibly deposited when the spring water was somewhat hotter than at present* A maximum of 40 m thick Td DIABASE PLUG AND DIKE (PLIOCENE?) Suspected plug in SW 1/4 sec. 15, T. 29 S., R. 13 W. consists of light-brownish-gray, aphanitic rock now reduced to a thick rubble. Dike rock has slightly sugary texture and small phenocrysts of labradorite and chloritized augite BASALT OF BRIMSTONE RESERVOIR AREA (PLIOCENE?) Tb Flow member Black to medium-gray, fine-grained, locally vesicular or amygdular lava flows. Contains small phenocrysts of augite, hornblende, and andesine (or labradorite) in a felted matrix of plagioclase feldspar, glass, and magnetite. May approach augite andesite in composition. Age may be as young as early Pleistocene. Locally is more than 500 m thick Tbt Basaltic conglomerate and tuff member Nonresistant unit containing cobbles and boulders of basalt and all older rocks, including quartzite and limestone, in a matrix of calcareous volcanic ash. In areas where it is not capped by flow member, the weathered surface is commonly littered by a residuum of boulders and cobbles of vesicular basalt. Maximum thickness of about

Gem-Quality Red Beryl from the Wah Wah Mountains, Utah

“…raphy. On the basis of the work of various investigators (Miller, 1966;Rowley et al, 1978;Lemmon and Morris, 1979;Weaver, 1980;Christiansen, 1980;Abbott et al, 1981;Steven and Morris, 1983)) the geologic history of the southern Wah Wah Mountains can be briefly summarized as follows.…”

Mineral resource potential of the Richfield 1° x 2° quadrangle, west-central Utah

“…A tract nearly 30 km across, west and northwest of Milford, Utah, contains many mineralized areas associated with calc-alkalic igneous intrusions of quartz diorite, granodiorite, quartz monzonite, and granite (Whelan, 1973;Morris, 1979a and1979b;Hintze and others, 1981;Lemmon and Morris, 1984). These mineralized areas have supplied the great majority of mineral products produced so far in the Richfield quadrangle.…”

Map showing outcrops of Pre-Quaternary ash-flow tuffs and volcaniclastic rocks, Basin and Range Province, Utah

“…Formation as much as 1,000 ft thick. Lemmon and Morris, 1979a, 1979bRowley and others, 1979;Steven and Morris, 1983;Steven, Rowley, Hintze, and others, 1978;Stringham, 1967;Whelan, 1973 Anderson and Rowley, 1975;Steven, 1978, 1979; Cook, 1957;Mackin, 1960;Mackin and others, 1976;Mackin andRowley, 1975, 1976 Rhyodacitic to quartz latitic ash-flow tuff. Maximum exposed thickness 260 ft, but as much as 1,640 ft thick in subsurface of Dugway Valley where unit is interbedded with tuffaceous lake beds (Lindsey, 1979).…”