Preliminary geologic map of the Farrier Quadrangle, Clark and Lincoln Counties, Nevada

Abstract

Altitude, height (h), and thickness (t) of alluvial units on the map are given in feet and inches in order for reader to directly correlate such figures with the topographic contours reading in feet; in text all measurements are in metric units as is standard except references to topographic contours are listed in feet and meters. (2) Localities described in text are indexed to the borders of the quadrangle and to the railroad site of Farrier, except that an unofficial place name, Farrier narrows, is used in reference to the conspicuous canyon of Meadow Valley Wash from 2.5 to 4.0 km north of Farrier. The structural and sedimentary basin of Meadow Valley Wash is herein informally called the Glendale basin for the small town of Glendale at the southern end of the basin in the adjacent Moapa East quadrangle. Recent terrace alluvium (Holocene) Mostly tan silt and sand, but some mainstream gray gravel exposed in low mainstream terraces; tan sandy gravel in low sidestream terraces. Unit is subdivided into mainstream (Meadow Valley Wash, Qrm) and sidestream (Farrier Wash and other sidestream) deposits. Exposed mainstream alluvium is mostly a silt and tine sand, pluvial deposit; in many places covered by or mixed with much reworked eolian sand; dark-gray mainstream gravel is not well exposed, except in the southeastern corner where the gravel is exposed in a large, low terrace (Qrmg); elsewhere, gravel probably more widely underlies the silt and sand. The recent mainstream alluvium forms terraces about 3 m high, and is inset below the young alluvial terrace (Qym) of Meadow Valley Wash ; sidestream terraces are lower but likewise inset. Depositional surface of mainstream terrace is intact, meander channel and bar and swale features are well preserved; no obvious carbonate-enriched soil or associated pavement is recognized Qrm Recent mainstream alluvium Mainstream-terrace alluvium of Meadow Valley Wash. Predominantly silt, sand, and mud and locally some intertongued gravel lenses; the fine-grained sediments were deposited either as a normal overbank, flood-plain deposit of a perennial Meadow Valley Wash, or as a special, climatic-controlled, pluvial, paludal deposit; distinction between these two processes for Meadow Valley Wash has not been studied Qrmg Recent gravel-facies of mainstream alluvium Locally exposed deposit containing abundant, well-sorted, dark-gray, coarse, mainstream gravel; mapped in southeastern corner of quadrangle Qrf Recent alluvium of Farrier Wash Tan and light-gray terrace sand and gravel of Farrier Wash Qrs Recent sidestream alluvium Tan and light gray sidestream-terrace sand and gravel Young terrace alluvium Gate Pleistocene) Tan to gray, silty to sandy gravel, and silt and sand, poorly bedded, moderately sorted; gravel mostly clast supported. Subdivided into mainstream (Meadow Valley Wash) and sidestream (Farrier Wash and other sidestream) deposits, of which the mainstream deposit commonly consists of dark-gray gravel overlain by overbank or pluvial silt, all inset in the erosional valley of Mea...

The mystery of the pre–Grand Canyon Colorado River—Results from the Muddy Creek Formation

“…The contrasting, strongly upward-coarsening capping beds of the upper Muddy Creek Formation have been recognized across the study area and are generally early Pliocene in age (Schmidt, 1994;Williams, 1996;Pederson et al, 2001). In the western study basins, these capping beds reflect a climatedriven change to the strong progradation of piedmont gravel from local mountainsides into the basins .…”

“…At the east end of the study transect, part of this capping unit has been identified as Virgin River gravel entering the Mesquite Basin from the Colorado Plateau (Billingsley, 1995;Billingsley and Bohannon, 1995;Williams, 1996). The early Pliocene change from Muddy Creek deposition to incision of the basin fill is marked by the first of a series of inset piedmont gravels and Virgin River gravels in the Mesquite Basin (Schmidt, 1994;Williams, 1996).…”

“…The Muddy Creek Formation contains laterally gradational facies that are interpreted to range from evaporate-and travertine-rich lake deposits lower in the stratigraphy and to the south and west to pebbly fluvial gravel as the unit coarsens upward and to the east (Longwell, 1946;Bohannon, 1984;Kowallis and Everett, 1986;Dicke, 1990;Schmidt, 1994;Billingsley, 1995;Schmidt et al, 1996;Williams, 1996;Pederson et al, 2000). In the westernmost basins, the upward transition from saline-lacustrine deposits to the overlying subaerial, siliciclastic-rich deposits of the middle Muddy Creek is abrupt, suggesting basin interconnection and the introduction of extrabasinal sediment at this time (Pederson et al, 2000).…”

Hydrology and water quality of the Beaver Dam Wash area, Washington County, Utah, Lincoln County, Nevada, and Mohave County, Arizona

“…Recharge to the Muddy Creek Formation from stream infiltration along Beaver Dam Wash was estimated to be about 11,000 acre-ft in 1993. Recharge from stream infiltration probably occurs in Beaver Dam Wash where alluvial channel-fill deposits are in contact with coarse, post-Muddy Creek Tertiary gravel similar to the regrade gravel of Moapa, which overlies the fine-grained Muddy Creek Formation about 40 mi west of Beaver Dam Wash (Schmidt, 1994). These outcrops of gravel were observed at several locations upstream from Beaver Dam, Arizona, and generally coincide with areas where losses of streamflow were observed during seepage studies.…”

“…As much as 200 ft of the upper part of the formation is exposed in these quadrangles; it is light reddish-brown gray and white, slope-forming, finegrained, thin-to thick-bedded, calcareous, gypsiferous, siltstone, sandstone, and calcrete (Billingsley, 1995, p. 11). Billingsley (1995) and Billingsley and Bohannon (1995) do not follow Schmidt (1994) in mapping aggradational and regrade gravels of Tertiary age above the formation; they define conglomeratic gravels of ancestral Beaver Dam Wash and the Virgin River in the upper part of the formation, which may correspond to the post-Muddy Creek Formation gravels defined by Schmidt (1994). Kowallis and Everett (1986, p. 70-75) studied gently northwest-dipping exposures of the Muddy Creek Formation just west of Mesquite, Nevada, about 7 mi southwest of the southern end of the Beaver Dam Wash study area.…”