Eastern Mojave Vegetation	Eastern Mojave Geology -- A Botanist's View
	Tom Schweich

Topics in this Article:
Rock Units
Geomorphology
Economic Geology
Literature Cited

Try as I might, I am unable to ignore the substrate for the plants I study. Over the years, notes about rock units, sand dunes, and mines have accumulated at such a rate as to present the alarming possibility that I might be nearly as interested in the geology as the botany. My intention for this page is to present those notes as a very brief review of the geology immediate to Lobo Point and the Mid Hills.

Literature Cited:
- Reynolds, Robert E. and Jennifer Reynolds, 1995.
- Theodore, Ted G., ed., 2007.

Locations: Lobo Point. Mid Hills.

Introduction

These notes comprise readily accessible data about the rock units, the common geomorphic features and the economic geology of the eastern Mojave. There are many other sources of information. The Reynolds and Reynolds (1995) volume and the web sites prepared by the U. S. G. S. are also excellent starting places for additional information.

Both the National Park Service and the United States Geological Survey have web pages about the geology of Mojave National Preserve. You can find them at:

Geology of Mojave National Preserve, by the National Park Service, and
Geology and Mineral Resources of the East Mojave National Scenic Area, San Bernardino County, California

Other articles: Vegetation of the Mid Hills about geology

This article is one of three geology articles on my web site. The other two pages are: Death Valley Geology and Inyo-White Geology.

Geologic Time Scale.

The University of California Museum of Paleontology has a excellent Geologic Time Scale.

Rock Units

In this chapter, rock units are presented in time sequence from oldest rocks to youngest rocks.

Precambrian

Precambrian metamorphic gneiss and schist crop out just north of the North Wild Horse Mesa and Lobo Point.

Hadean

Archaean

Large volumes of continental crust were produced over a short period of time in the Archean, when the planet was probably too hot for modern plate tectonics to operate. Under the higher thermal gradient of the Archean, it is likely that metamorphism of subducted oceanic crust proceeded via a different P-T path than followed by present day subducted oceanic crust. In particular, the higher temperatures at shallower depths quickly dehydrated subducting oceanic crust metamorphosing it through the lower pressure greenschist to amphibolite to granulite facies, as opposed to the higher-pressure blueschist to eclogite facies of modern day subduction.

Literature Cited:
- Bjørnerud, M. G., and H Austrheim., 2004.

Other articles: Glossary eclogite facies
Eclogite P-T Pathways

Bjørnerud and Austrheim (2004) studied an outcrop of partly eclogitized mafic granulite facies in Holsnøy, western Norway, in which reaction process to eclogite from granulite was limited by the availability of water. Such dehydrated but uneclogitized mafic crust could have been very strong and too buoyant to sink into the mantle, and it may have formed the substrate for the first continental lithosphere.

Literature Cited:
- Melezhik, Victor A., Anthony E. Fallick, Eero J. Hanski, Lee R. Kump, Aivo Lepland, Anthony R. Prave, and Harald Strauss, 2005.

… emergence of the aerobic biosphere during the Archean-Proterozoic transition …

Proterozoic Eon

The period of Earth's history that began 2.5 billion years ago and ended 542.0 million years ago is known as the Proterozoic, which is subdivided into three eras: the Paleoproterozoic (2.5 to 1.6 billion years ago), Mesoproterozoic (1.6 to 1 billion years ago), and Neoproterozoic (1 billion to 542.0 million years ago).

Paleoproterozoic Era

Spans the time period from 2,500 to 1,600 million years ago (2.5–1.6 Ga), is the first of the three sub-divisions (eras) of the Proterozoic Eon. It was during this era that the continents first stabilized.

Paleontological evidence suggests that the Earth's rotational rate during this era resulted in 20 hour days ~1.8 billion years ago, implying a total of ~450 days per year.

Mesoproterozoic

The Mesoproterozoic Era is a geologic era that occurred from 1,600 to 1,000 million years ago. The Mesoproterozoic was the first period of Earth's history of which a fairly definitive geological record survives. Continents existed during the preceding era (the Paleoproterozoic), but little is known about them. The continental masses of the Mesoproterozoic were more or less the same ones that exist today

Neoproterozoic

The Neoproterozoic Era is the unit of geologic time from 1,000 to 541 million years ago.

It is the last era of the Precambrian Supereon and the Proterozoic Eon; it is subdivided into the Tonian, Cryogenian, and Ediacaran Periods. It is preceded by the Mesoproterozoic era and succeeded by the Paleozoic era.

The most severe glaciation known in the geologic record occurred during the Cryogenian, when ice sheets reached the equator and formed a possible "Snowball Earth".

The earliest fossils of multicellular life are found in the Ediacaran, including the Ediacarans, which were the earliest animals.

According to Rino and co-workers, the sum of the continental crust formed in the Pan-African orogeny and the Grenville orogeny makes the Neoproterozoic the period of Earth's history that has produced most continental crust

Literature Cited:
- Corsetti, Frank A., and James W. Hagadorn, 2003.
Generalized tectonic setting of the Precambrian-Cambrian margin of North America.

The succession of Precambrian-Cambrian rock units from the southeast near Las Vegas to the northwest in the Inyo-White mountain ranges show facies changes from continental deposits through shallow water or continental margin deposits in the death Valley area to deep water deposits in the Inyo-White Mountains.

Literature Cited:
- Fedo, C.M., and Cooper, J.D., 1990.

Locations: Marble Mountains.

In the Mojave this succession was studied by Fedo and Cooper (1990).

Literature Cited:
- Diehl, P. E., 1979.

Locations: Marble Mountains.

Other articles: Glossary aulacogen

Locations: Pahrump.

Pahrump Group

Crystal Spring Formation

Beck Spring Dolomite

Kingston Peak Formation

Paleozoic

Locations: New York Mountains. Providence Mountains.

The Paleozoic is represented by the shales and limestones of the Providence and New York Mountains.

Literature Cited:
- DeCourten, Frank L., 1979.

Prospect Mountain Quartzite

This is an abandoned term in most of the Mojave Desert. This sequence of quartzite is now attributed to, in ascending order, the Johnnie, Stirling, Wood Canyon and Zabriskie Formations (DeCourten, 1979)

Literature Cited:
- DeCourten, Frank L., 1979.

Other articles: Summit Spring Road at Latham Sh

Locations: Latham's Cabin.

Latham Shale

The Latham Shale is a Lower Cambrian, fossiliferous, greenish-gray platy shale, ranging between 55 and 75 feet in thickness. With a type locality of Latham's Cabin, northern Providence Mountains, the Latham Shale is common in the Providence and Marble Mountains, and east-central Mojave Desert. It is considered a part of the Carrara Formation (DeCourten, 1979).

Literature Cited:
- Hazzard, John C., 1954.

Hazzard (1954) describes the Latham Shale as a fossiliferous greenish gray platy shale which weathers to platy and paper-thin fragments. Thin, buff-weathering sandy limestone layers are present.

Locations: Summit Spring.
Julie looks for trilobite fossils in the Latham Shale.

The Latham Shale is exposed at several places around the periphery of the Providence Mountains. One of the most accessible locations is found near Summit Spring at the north end of the Providence Mountains.

Literature Cited:
- DeCourten, Frank L., 1979.

Locations: Chambless. Marble Mountains.

Chambless Limestone

The Chambless limestone is a Lower Cambrian massive to thick-bedded, light to gray limestone with abundant oncolites, including a platy, fossiliferous zone yeilding brachiopods and trilobites. It commonly about 200 feet thick. The type locality is 2 miles north of Chambless in an old quarry in the Marble Mountains. The Chambless Limestone is found in the Providence and Marble Mountains, and is considered a part of the Carrara Formation (DeCourten, 1979).

Literature Cited:
- Hazzard, John C., 1954.

Hazzard (1954) describes the Chambless Limestone as a massive weathering, light to dark limestone in beds 1 to 10 feet thick, with algal nodules throughout. Locally a 10 to 15-foot zone of platy, fossiliferous limestone occurs a little above the middle.

Literature Cited:
- DeCourten, Frank L., 1979.

Locations: Cadiz. Marble Mountains.

Cadiz Formation

The Cadiz Formation is a Lower and Middle Cambrian sequence of shale, arenaceous limestone, nodular limestone, and argillaceous limestone; commonly fossiliferous and locally cross-bedded, from 400 to 600 feet thick. The type locality is in the Marble Mountains, 3 miles north of Cadiz. The Cadiz Formation is well exposed in the east-central Mojave Desert region, particularly in the Providence - Marble Mountains area. Some authors now consider the Cadiz Formation to be part of the Carrara Formation (DeCourten, 1979).

Literature Cited:
- Hazzard, John C., 1954.

Hazzard (1954) describes the Cadiz Formation as a buff and gray muddy limestone, purplish and reddish shale; greenish gray shale, and platy quartzite.

Literature Cited:
- DeCourten, Frank L., 1979.

Other articles: FAQ F205774

Locations: Providence Mountains.

Bonanza King Formation

The Bonanza King Formation is a Middle and Upper Cambrian, non-fossiliferous, light gray domomite and dolomitic limestone commonly displaying algal laminae and containing chert nodules. It is 1900 to 2000 feet thick. The type locality is the east flank of the Providence Mountains. The distribution of the Bonanza King Formation includes the Providence Mountains and several adjacent ranges of the eastern Mojave desert, also much of the southwestern Basin and Range province in California (DeCourten, 1979).

Literature Cited:
- Hazzard, John C., 1954.

In the Providence Mountains, the Bonanza king Formation has been divided into three units. The lower unit is a dark smoky gray dolomite and partially dolomitized limestone, locally cherty and sandy with intraformational pebble and cobble conglomerates, in individual beds 6 inches to 3 feet thick (Hazzard, 1954).

Literature Cited:
- Hazzard, John C., 1954.

Silver King Dolomite

The Silver King dolomite is the middle unit of the Bonanza King Formation and is a very dark smoky gray to nearly black dolomite (Hazzard, 1954).

The upper unit of the Bonanza King Formation is a light creamy gray dolomite.

Literature Cited:
- Cooper, John D., 1987.
- Hewett, D. F., 1931.

Other articles: Potosi Mountain Road 40000

Locations: Goodsprings. Sheep Mountain.

Goodsprings Dolomite

The Goodsprings dolomite was named and described by Hewett (1931), who assigned a Cambrian-Devonian age based on sparse fossils and stratigraphic position between known Cambrian and Devonian strata. In its type section at Sheep Mountain, the Goodsprings is 2,475 ft (750 m) thick and lies between the Middle Cambrian Bright Angel Shale (= Carrara Formation) and the Middle Devonian Sultan Formation (Cooper, 1987).

Locations: Kokoweef Peak.
Kokoweef Peak forms the backdrop for a discussion of the regional significance of the Aztec Sandstone

The peak of Kokoweef Peak is formed of Goodsprings Dolomite. The outcrop is bounded by the Clark Mountain Fault and extends to the southeast into the Ivanpah Valley. Flanking the north and west of Kokoweef Peak is a series of progressively younger rocks, beginning with the Sultan Limestone and ending with the Aztec Sandstone.

Literature Cited:
- Hazzard, John C., 1954.

The Goodsprings Dolomite is not identified in the Providence Mountains by Hazzard (1954). Instead he describes 750 feet of dolomite, containing an unconformity, that has been formerly named the Cornfield Springs Formation. On the basis of the materials I have, it appears that relationship between the Bonanza King and Goodsprings Formations is unclear and requires additional work.

Literature Cited:
- DeCourten, Frank L., 1979.

Locations: Sultan Mine.

Sultan Limestone

The Sultan limestone is a Middle Devonian massive, finely crystalline limestone, crystalline dolomite, thin bedded bleached linestone, and chert. It is locally fossiliferous. The type locality is near the Sultan Mine, Goodsprings District, Nevada. The Sultan limestone is common in many eastern Mojave Desert ranges; Providence Mountains -- Devil's Playground area (DeCourten, 1979).

Literature Cited:
- DeCourten, Frank L., 1979.

Locations: Ironside Mine.

Ironside(?) dolomite

The Ironside Dolomite member of the Sultan limestone is a Middle and Upper Devonian dark gray to black dolomite, up to 150 feet thick, and sparsely fossiliferous. The type area is near the Ironside mine, west side of the Spring Mountains, Goodsprings quadrangle, Nevada. The Ironside dolomite is common wherever the Sultan limestone is present in the eastern Mojave Desert region; Providence Mountains (DeCourten, 1979).

Literature Cited:
- DeCourten, Frank L., 1979.

Locations: Valentine Mine.

Valentine limestone

The Valentine Limestone Member of the Sultan Limestone is a Devonian dolomite, limestone, and dolomitic limestone, up to 700 feet in total thickness. The type locality is east of the Valentine mine, Clark County, Nevada. The Valentine Limestone is recognized wherever the Sultan Limestone is present in the east-central Mojave Desert, in the Providence -- Marble Mountains region (DeCourten, 1979).

Literature Cited:
- DeCourten, Frank L., 1979.

Locations: Crystal Pass.

Crystal Pass Limestone

The Crystal Pass Limestone member of the Sultan Limestone is a thick-bedded light gray limestone with subordinate dolomite and white to brown dolomitic limestone; up to 300 feet thick. The type locality is in the Crystal Pass area, Clark County, Nevada. The Crystal Pass Limestone is found in the east-central Mojave Desert region; Providence and Old Dad Mountains (DeCourten, 1979).

Literature Cited:
- Trexler, James H., Jr., Patricia H. Cashman, Walter S. Snyder, and Vladimir I. Davidov, 2004.

Other articles: Interstate 80 Antler and Sonoma orogenies

I think somewhere about here, the latest Devonian -- Early Mississippian Antler orogeny fits in.

Literature Cited:
- DeCourten, Frank L., 1979.

Other articles: Field Notes 20010422100

Locations: Monte Cristo Mine. Old Dad Mountain.

Monte Cristo Formation

Approximate Location of the Monte Cristo Mine.

The Monte Cristo Formation is a Mississippian fossiliferous cherty crystalline limestone, crystalline dolomite, massive limestone, and vitreous, cross-bedded quartzite. The type locality is near the Monte Cristo Mine, in the Goodsprings Mining district of southern Nevada. In the eastern Mojave, the Monte Cristo Formation is found in the Providence Mountains, and the Devil's Playground area (DeCourten, 1979).

Literature Cited:
- Hazzard, John C., 1954.

The lowest unit of the Monte Cristo Formation is a white to brownish-weathering vitreous quartzite and sandstone with local cross-bedding (Hazzard, 1954).

Literature Cited:
- Brown, Howard, 2003.

Other articles: Kelbaker Road near Amboy Limestone Quarry Field Notes 22-Apr-08
Snowcap Limestone Mine

Omya (California) operates the Amboy Limestone quarry located 6 miles east of Amboy, California, in the southern Bristol Mountains. The Amboy Limestone deposit, a very high purity, high brightness (white) crystalline limestone deposit is of such high purity it is suitable for pharmaceutical and food grade limestone applications, and can be utilized in products for human consumption. The limstone is mined from an extensive dip slope of Mississippian age Monte Cristo Limestone, Bullion Member, up to 300 feet thick, and 1500 feet long. Current mine life is 55 years, plus reclamation phases for a total operation life of 70 years. The current Phase 1 quarry development occurs in an area of about 10 acres. The ultimate quary will cover approximately 50 acres.

Literature Cited:
- DeCourten, Frank L., 1979.

Locations: Dawn Mine.

Dawn limestone

The Dawn Limestone Member of the Monte Cristo Formation is a Lower Mississippian fossiliferous, dark blue-gray, massive to thick-bedded limestone and crystalline dolomite with locally abundant lenses of chert, 100-300 feet thick. The type locality is near the Dawn Mine, in the Goodsprings Mining District of southern Nevada. The Dawn Limestone is found in the Providence - New York Mountains area (DeCourten, 1979).

Literature Cited:
- Hazzard, John C., 1954.

Hazzard (1954) describes the Dawn Limestone as a light and dark limestone in massive beds up to 20 feet thick separated by platy beds. The upper part is characterized by much chert in irregular discontinuous beds up to 3 inches in thickness.

Locations: Pahranagat Range.

The Dawn Limestone, as exposed in the Arrow Canyon Range, plays a part in understanding significant changes in carbon and oxygen isotope of the Lower Mississippian. Deposited in the foreland basin on the craton-side of the Antler orogenic system, Saltzman (2002) compared carbon and oxygen isotopes in the Dawn Limestone with those found in Limestone X from the Pahranagat and and the Henderson Canyon Formation (limestone) from southeast Idaho in an attempt to understand the cause of increased ¹³C. While Saltzman was able to show synchronicity in the isotope changes, his data does not show whether the cause was burial of organic carbon in deep-marine basins associated with subsidence during the Antler orogeny, or eustatic lowering of sea level due to glaciation.

Literature Cited:
- DeCourten, Frank L., 1979.

Other articles: Glossary crinoid

Locations: Anchor Mine.

Anchor Limestone

The Anchor Limestone Member (of the Monte Cristo Limestone) is a Mississippian pale gray, platy, crinoidal limestone containing irregular-shaped brown chert nodules, which ranges from 100 to 150 feet in thickness in the eastern Mojave Desert. The type locality is the Anchor Mine, Goodsprings quadrangle, Nevada. In the Mojave Desert, the Anchor Limestone is found in the Providence Mountains (DeCourten, 1979).

Literature Cited:
- Hazzard, John C., 1954.

Hazzard (1954) describes the Anchor Limestone as a light gray, platy-weathering crinoidal limestone with much brown chert in irregular nodules and sheets along bedding planes.

Literature Cited:
- DeCourten, Frank L., 1979.

Locations: Bullion Mine.

Bullion Limestone

Also known as the Bullion Dolomite Member (of the Monte Cristo Formation) is a Lower Mississippian massive, commonly cliff-forming, coarsely crustalline crinoidal dolomite. The type locality is near the Bullion Mine, in the Goodsprings Quadrangle of southern Nevada. The Bullion Limestone is common in the east-centeral Mojave, particularly in the Providence Mountains - Devil's Playground area (DeCourten, 1979).

Literature Cited:
- Hazzard, John C., 1954.

Hazzard (1954) describes the Bullion Limestone as a light gray to cream-colored crinoidal imestone with very obscure bedding; commonly cliff forming.

Literature Cited:
- DeCourten, Frank L., 1979.

Locations: Yellowpine Mine.

Yellowpine limestone

The Yellowpine Limestone member (of the Monte Cristo Limestone) is an Upper Missippian dark gray limestone, massive to thin-bedded, fossiliferous; 75-125 feet thick in the Providence Mountains. The type locality is near the Yellowpine Mine, Goodsprings region, Nevada. The Yellowpine Limestone is found in the Providence Mountains region, of the east-central Mojave (DeCourten, 1979).

Literature Cited:
- Hazzard, John C., 1954.

Hazzard (1954) describes the Yellowpine Limestone as a very dark gray limestone, generally massive but locally thinly bedded.

Literature Cited:
- DeCourten, Frank L., 1979.

Other articles: Glossary coral

Locations: Bird Spring Range.

Bird Spring Formation

Solitary horn coral found in Bonanza King Canyon.

The Bird Spring Formation is up to 2400 feet of Mississippian to Permian locally fossiliferous limestone and dolomitic limestone with subordinate units of sandy limestone, chert and shale. The type locality is in the Bird Spring Range of southern Nevada. The Bird Spring Formation is found in the Mojave Desert region from the Old Dad Mountains to Nevada. It is also widely distributed throughout the southern Great Basin (DeCourten, 1979).

Literature Cited:
- Hazzard, John C., 1954.

The lower unit of the Bird Spring Formation in the Providence Mountains is a very dark to light creamy gray limestone, that is locally domomitized. The lower half of the unit comprises massive weathering beds up to 30 feet in thickness separated by platy, commonly cherty and fossiliferous layers. Minor amounts of sandstone, sandy limestone, and shale occur. The outcrop surface commonly develops a cliff-bench slope (Hazzard, 1954).

Literature Cited:
- Hazzard, John C., 1954.

In the Providence Mountains, the upper unit contains both sandstone and limestone. At the base is 20-foot some of locally cross-bedded sandy limestone and limy sandstone with black chert pebbles. About 75 feet above is a massive 70-foot light gray limestone. As a unit the lower 750 feet of beds consists of dark and light limestone in beds up to 10 feet thick. Platy to shaly, in part sandy, fossiliferous, chert rich zones separate some of the massive beds. The upper 1380 feet of the section is medium to light gray, sparingly fossiliferous limestone in beds up to 5 feet thick. Minor chert and sandstone occur (Hazzard, 1954).

Literature Cited:
- Trexler, James H., Jr., Patricia H. Cashman, Walter S. Snyder, and Vladimir I. Davidov, 2004.

Other articles: Interstate 80 Antler and Sonoma orogenies Trexler, et al (2004)

Somewhere around here the Late Permian -- earliest Triassic Sonoma orogeny fits in.

Mesozoic

At the beginning of the Mesozoic, the continents of the Earth formed a supercontinent called Pangea. The western or northwestern coast of the supercontinent was the Panthalassa Ocean.

Literature Cited:
- DeCourten, Frank L., 1979.

Other articles: Field Notes 20010421030 20040523050

Locations: Aztec Tank. Mescal Range.

Aztec Sandstone

Field discussion about dinosaur tracks in California.

Location of Aztec Tank, type locality of Aztec Sandstone.

Aztec Tank, type locality of Aztec Sandstone

Location of Aztec Tank

The Jurassic Aztec Sandstone is a massive to cross-bedded, buff colored orthoquartzite, that is commonly metamorphosed. The type locality is Aztec Tank, near the Contact Mine in the Goodsprings quadrangle of Nevada. The Aztec Sandstone is present in many ranges of the eastern Mojave including the Providence Mountains. An outcrop of the Aztec Sandstone in the Mescal Range contains the only known dinosaur tracks in California.

Tower of granite in the Mid Hills.

The Mesozoic era is represented in the Mid Hills by the Mid Hills adamellite and other granitic intrusive rocks.

Locations: Little Thorne Mountains. Lobo Point.

Washes at Lobo Point contain grus from the Mesozoic granite of Little Thorn Mountains to the north.

Literature Cited:
- Reynolds, Robert E. and Jennifer Reynolds, 1995.

Other articles: Glossary adamellite breccia gneiss
Tectonic breccia.

This outcrop of tectonic breccia alongside Wild Horse Canyon Road contains Mid Hills adamellite with tumbled blocks of Precambrian gneiss (Reynolds and Reynolds, 1995).

Cenozoic

Tertiary

The Sevier Thrust Belt is found in southeastern California, southeastern Nevada, western Utah, southwestern Wyoming, eastern Idaho, and western Montana,

Literature Cited:
- Friedrich, Anke M., and John M. Bartley, 2003.

Locations: Wah Wah Mountains.

In Utah the Sevier Thrust Belt is found in the Wah Wah Mountains.

Miocene

Literature Cited:
- McCurry, Michael O, 1985.
- McCurry, Michael, 1988.

Other articles: Black Canyon Road in Round Valley

Rocks at Lobo Point and North Wild Horse Mesa are Miocene rhyolitic pyroclastic flows interbedded with lacustrine sedimentary rocks (McCurry, 1985).

Other articles: U. S. Interstate 40 at Kingman

Peach Spring Tuff

Literature Cited:
- Glazner, Allen F., Jane E. Nielson, Keith A. Howard, and David M. Miller, 1986.

Other articles: Glossary welded_tuff

A single welded rhyolite tuff containing conspicuous chatoyant sanidine phenocrysts occurs in the Tertiary section in many mountain ranges in western Arizona and the Mojave Desert. The tuff is exposed is continuously in a region stretching from Barstow, California to the Colorado Plateau at Peach Springs, Arizona. In most ranges it is the only welded tuff in the Tertiary section. These scattered outcrops represent part of a single enormous early Miocene outflow sheet (Glazner et al., 1986)

Literature Cited:
- Goldfarb, R., D. M. Miller, R. W. Simpson, D. B. Hoover, and P. Moyle, 1986.
- Miller, D. M., J. G. Frisken, R. C. Jachens, and D. D. Gese, 1986.

The tuff was originally recognized over an area of about 500 km² between Kingman and Peach Springs, where it was named. Mapping in the Colorado River trough extended the correlation westward into tilted Miocene sections on both sides of the Colorado River. In the eastern Mojave Desert, the tuff has been found in the Providence Mountains (Goldfarb et al., 1986), the Mid Hills at Wild Horse Mesa and Pinto Mountain, and the New York Mountains (Miller et al., 1986). Petrographically identical tuff occurs in most of the desert ranges of the central Mojave Desert, such as the Bristol Mountains, Bullion Mountains, Cady Mountains, and Old Dad Mountains.

Other articles: Field Notes 19-Apr-08 Glossary desert_pavement
Desert pavement

Correlation of the tuff makes it a exceptionally valuable stratigraphic and tectonic marker horizon because of (1) its presence in otherwise difficult-to-correlate local stratigraphic sections, (2) its deposition during a time of regional extension, and (3) its wide geographic distribution across Neogene tectonic-province boundaries.

Literature Cited:
- Wells., Ray E., and John W. Hillhouse, 1989.

Other articles: U. S. Highway 66 Peach Springs

Locations: Peach Springs.

The Peach Springs Tuff and its Mojave Desert equivalent are characterized by discrepant K-Ar ages. Ages determined on sanidine, the mineral most often used for dating, range from 16.2 to 20.0 Ma; the mean is 18.2 Ma.

The tuff lacks a known source; however, trends in outcrop thickness suggest the source was somewhere in the Colorado River trough area, near the southern tip of Nevada.

Literature Cited:
- Aguirre-Diaz, Gerardo J., and Guillermo Labarthe-Hernandez, 2003.

Other articles: Glossary ignimbrite

Approximately coeval with the welded tuffs of the eastern Mojave Desert are the ignimbrites of the Sierra Madre Occidental. Peculiar to these ignimbrites is eruption from large fissures rather than calderas as we look for in the Mojave Desert. As described by Aguirre-Diaz and Labarthe-Hernandez (2003), the fissures have the same general trend of Basin and Range faults. The authors propose a model in which batholith-sized magma chambers reached shallow crustal levels and erupted their contents when they reached Basin and Range normal faults.

Other articles: Jeep Trail outcrop of PST Field Notes 23 Apr 2010
Outcrop of Peach Spring Tuff

Outcrop at Columbus/Gem mine, in Daggett Ridge.

Other articles: Stoddard Valley Road at Stop M-12 Field Notes 24 Apr 2010 24 Apr 2010

Locations: Daggett Ridge.
Field Trip Stop M-12

Field Trip Stop M-12

Other articles: Field Notes 23 Apr 2011
Field discussion about Peach Spring Tuff in the Alvord Mountain area.

Other articles: Cedar Canyon Road Pinto Mountain Field Notes 20010915030
Purple Bird's-Beak (Cordylanthus parviflorus)

Winkler Formation

Literature Cited:
- Reynolds, Robert E. and Jennifer Reynolds, 1995.

Other articles: Frasera albomarginata Introduction

Locations: Pinto Mountain. Providence Mountains.

Winkler's Cabin.

Reynolds et al (1995) described the lacustrine sedimentary rocks that are found at Wild Horse Mesa. These happen to be the same rocks in which Frasera albomarginata grows. They are thin-bedded fine grained limestone and dolomite formed in Tertiary non-marine lake beds. They conformably overlay the Peach Springs Tuff and are in turn conformably overlain by the Wild Horse Mesa Tuff, constraining their age to between 18.5 and 17.8 Ma. Similar rocks are exposed at Pinto Mountain (10 miles north, where F. albomarginata is also found) and at Hackberry Mountain (14 miles east). Reynolds et al (1995) informally name the rocks "Winkler Formation" in honor of the long-term caretaker of a nearby cabin which served as temporary shelter to many travelers to the northern Providence Mountains.

Other articles: Cedar Canyon Road 30000 FAQ Lobo Point

Locations: Pinto Mountain.
Winkler Formation at Pinto Mountain.

Figure 3-__. Wild Horse Mesa Tuff (Hole-in-the-Wall Tuff), Winkler Formation, and Peach Springs Tuff as exposed on the south side of Pinto Mountain.

Locations: Hackberry Mountain.
Winkler Formation at Hackberry Mountain.

Figure 3-_ shows the Winkler Formation as exposed on the east side of Hackberry Mountain. The people in the photograph are with the field trip of the 1995 Desert Research Symposium, sponsored by the San Bernardino County Museum and the California Desert Studies Symposium.

Locations: Pinto Mountain.
Peach Springs Tuff, Winkler Formation, and Wild Horse Mesa Tuff on the south side of Pinto Mountain.

View of Winkler Formation on the south side of Pinto Mountain. The lower unit on the left is Peach Springs Tuff. The middle unit, just right of center, is Winkler Formation. The volcanic unit in the upper right is Wild Horse Mesa Tuff.

Other articles: Cedar Canyon Road 22000

Locations: Cedar Canyon. Pinto Mountain.
Winkler Formation, with Cedar Canyon in the background.

View of an outcrop of the Winkler Formation on the south side of Pinto Mountain, with Cedar Canyon Road in the background. The dark ledge in the lower right corner of the photograph is the top of the Winkler Formation. The Winkler Formation also crops out as the light-colored rocks in the middle distance. The rocks above the Winkler Formation are the Wild Horse Mesa Tuff.

Other articles: Frasera albomarginata Introduction
Winkler Formation on the south side of Pinto Mountain

Another view of the same outcrop. The Winkler Formation is seen in the lower left. The Wild Horse Mesa Tuff is above.

A few stakes marking location of some Frasera albomarginata can be seen in the lower right corner.

Locations: Wild Horse Mesa.
Winkler formation on the north face of Wild Horse Mesa.

The exposures of Winkler formation on the north face of Wild Horse Mesa are not quite as dramatic as those on Pinto Mountain. Nevertheless, the white rocks across the center of the photograph are Winkler Formation.

Literature Cited:
- Perry, Loren E, 1977.

Locations: Lobo Point.

Lobo Point is also well known to rock hounds for its "opalite" silicified lake bed deposits (Perry, 1977). The lake bed deposits may correlate with the Winkler Formation, as found on the north slope of Wild Horse Mesa.

Wild Horse Mesa Tuff

Literature Cited:
- McCurry, Michael, Daniel R. Lux, and Kevin L. Mickus, 1995.

See McCurry et al (1995).

Geomorphology

Pediments

Other articles: Glossary pediment

Locations: Cima Dome. Joshua Tree National Park.

Pediments and pediment passes such as found in Joshua Tree National Park, Cima Dome, and pediment passes in the Sacaton Mountains, Arizona, are common in arid regions.

Aridity limits weathering rates and vegetation, and promotes bare-bedrock uplands. It also provides the conditions for weakly consolidated soils, high infiltration capacities, and localized storm footprints that favor diffusive smoothing by fluvial processes.

Literature Cited:
- Strudley, Mark W., A. Brad Murray, and P. K. Haff, 2006.

Strudley, Murray, and Haff (2006) presented a new, parsimonius explnation for the origin and maintenance of pediments, piedmont junctions, and tors, which emerge spontaneously in a numerical model coupling bedrock weathering and sediment transport.

They identify a negative feedback between bedrock weathering and regolith thickness: if regolith thins (thickens) by sediment transport, the regolith production rate will increase (decrease), maintaining an equilibrium regolith thickness on the piedmont.

High infiltration capacities and the instability of ephemeral channel banks in arid and semiarid environments suppress fluvial incision and promote the smoothness of pediments.

A positive feedback between bedrock weathering and regolith thickness causes tor growth: if regolith thins locally below a critical value, regolith production slows while surrounding areas continue to weather and erode more rapidly.

They suggest that many pedimented and tor-studded landscapes may therefore be a consequence of intrinsic sediment transport-weathering feedbacks mediated by climatic and tectonic conditions, not by lithologic templates.

Sand Dunes

Locations: Kelso Dunes.

Kelso Dunes

Locations: Kelso Dunes.
Kelso Dunes as seen from Kelbaker Road north of Kelso.

Locations: Kelso Dunes.
Matt near the top of the Kelso Dunes.

The Cronese “Cat”

Literature Cited:
- Evans, James R., 1962.

Other articles: Interstate 15 54000

Locations: Cronese Basin.

The Cronese "Cat"

The sand dunes in the Cronese ("Cat") Mountains were studied by Evans (1962). These sand dunes can be seen from the Basin Road exit of Interstate 15, 45 miles east of Barstow, and 18 miles west of Baker. Evans describes the Cronese mountains as a finger-like projection that nearly joins with the Soda Mountains and separates the adjacent Cronese Valley into east and west, but interconnecting, playas. Each playa contains a dry lake. The sand-filled Cronese Valley as a whole is an integrated part of the Mojave River system and has been since late Pleistocene (Tioga) time. Beach sand deposited during the high-water stand of old Lake Cronese (Little Lake Mojave) is a source material for the climbing and falling dunes.

Evans (1962) notes that prevailing westerly winds, at times reaching a velocity of about 100 miles per hour, have driven available sand in the west Cronese playa upon the northwest slope of Cronese ("Cat") Mountain over the ridge (locally as much as 900 feet above the playa), and down the southwest slope to form falling dunes.

Locally, climbing or falling dunes have been worked into unusual postures. It is for a relatively large falling dune much resembling the outline of a cat that Cronese Mountain and Cronese Valley may have been named (Evans, 1962).

Evans (1962) studied six sand dunes, three climbing and three falling, in detail. Windward dune-covered slopes average about 9° and leeward dune covered slopes about 24°. The sand is composed largely of frosted quartz grains, with smaller amounts of feldspar and broken bivalve and gastropod shells. The climbing dunes are composed of medium-sized grains that become less coarse upslope, whereas the falling dunes are composed of small-sized grains that remain in constant in size throughout their downslope extent.

Literature Cited:
- Criswell, D. R., J. F. Lindsay, and D. L. Reasoner, 1975.
- Lindsay, J. F., D. R. Criswell, T. L. Criswell, and B. S. Criswell, 1976.
- Trexler, Dennis T., and Wilton N. Melhorn, 1986.

Other articles: FAQ Singing Sands

Locations: Big Dune. Crescent Dunes. Eureka Sand Dunes. Kelso Dunes.

Singing and Booming Sand Dunes

There are a number of dune fields in various parts of the world that emit sound when disturbed. Sounds produced by desert dunes have been variously described as roaring, squeaking, singing, and musical. The production of sand in desert dunes is not as common as the squeaking of beach sands. Shearing between adjacent layers of moving sand appears to cause the sounds; although, the cause is by no means settled. Lindsay et al. (1976) reported that only 27 areas in the world were known to exhibit the booming sound phenomenon. Criswell et al. (1975) reported their extensive investigation of sound production at Sand Mountain, Nevada. Trexler and Melhorn (1986) extended Lindsay's list by several additional sites in the southwestern United States. Overall, they reported booming or singing at Big Dune, Crescent Dunes, and Sand Mountain in Nevada, as well as the Eureka Dunes and Kelso Dunes in California.

Stabilized Dunes

Other articles: California Highway 167 near US Hwy 395 near Mono Dunes Field Notes 5-Jun-05 on CA Hwy 167 5-Jun-05 near Mono Dunes
Stabilized dunes along California Highway 167
Sand dunes near Mono Lake.

Sand dunes can also be stabilized by vegetation growing on them. While a little far afield from the Eastern Mojave, some examples of stabilized dunes can be seen along California Hoghway 167, just north of Mono Lake.

Desert Pavement

Literature Cited:
- Valentine, Greg A., and Charles D. Harrington, 2006.

Other articles: U. S. Highway 95 near Lathrop Wells Volcano

Locations: Lathrop Wells Volcano. Red Cone.

Valentine and Harrington (2006) studied desert pavements at Lathrop Wells and Red Cone volcanoes. The Lathrop Wells Volcano is 75-80 ka, whereas the age of nearby Red Cone is older, about 1 ma. Well-defined age data and knowledge of the volcanological characteristics of parent materials, lead to two main conclusions. First, pavements are most likely to develop where parent clasts are within the range of several millimeters to a few centimers in size. The low end of this range is determined by the ability of clasts to be mobilized by the strongest winds in an area, and the high end is determined by the ability of the clasts to form a tight-fitting mosaic that acts as a natural sieve to promote silt accumulation compared to sand.

This conclusion would seem to apply to clasts formed from all types of parent materials, not just volcanic scoria.

Second, the authors were able to recognize different levels of desert pavement maturity at the two volcanoes which contributed similar parent materials for pavement development.

This suggests that desert pavement development at the two volcanoes was reset by latest Pleistocene vegetation advances, and that further quantitative studies of such features on volcanoes may provide additional insights into desert geomorphic processes.

Desert Varnish

Other articles: California Highway 127 near Salt Spring Hills CA Hwy 178 near Salsberry Pass Halloran Springs Road at Halloran Wash

Desert varnish forms a dark coating up to 0.10 mm thick on the exposed surfaces of many stones and outcrops in southern California deserts. Engel and Sharp (1958) made wet chemical analyses were of varnish, the underlying weathered rind, and fresh rock for a rhyolite and two andesites. The principal elements in varnish are O, H, Si, Al, Fe, and Mn, and the last two give the deposit its distinctive physical characteristics. H₂O, Fe₂O₃, and especially MnO show the greatest enrichment. Field observations and a number of partial analyses indicate that the best varnishes are on fine-grained rocks relatively rich in Fe and Mn.

Locations: Halloran Springs. Salsberry Pass. Salt Spring Hills.

Spectrographic analyses were made of 22 varnishes, 14 rocks, 8 soils, and 5 samples of air-borne material. In the varnishes Ti, Ba, and Sr are by far the most abundant trace elements, followed by Cu, Ni, Zr, Pb, V, Co, La, Y, B, Cr, Sc, and Yb. Cd, W, Ag, Nb, Sn, Ga, Mo, Be, and Zn were recorded in some but not all varnishes. The trace-element content of all varnishes is similar, and the variations recorded are related to differences in the local geology. Most trace elements are considerably enriched in varnish—Cu and Co especially, and Ni, Pb, Ba, Cr, Yb, B, Y, Sr, and V.

The chemical data suggest that (1) varnish on stones seated in soil or colluvium is derived largely from that material, (2) varnish on large bedrock exposures come from weathered parts of the rock, (3) air-borne material is probably a minor contributor.

The formation of desert varnish is primarily a weathering process involving the solution, transportation, and deposition of Mn and Fe in particular and a host of trace elements. Most of these elements are derived from local sources, and the small amount of movement required can occur by transport in solution or possibly by ionic diffusion through moisture films. Dew may be as important a source of moisture as rain. Organic agents, such as bacteria, may cause deposition of varnish, but this has not yet been demonstrated. In the desert, evaporation and the catalytic action of MnO₂ should be capable of performing the task (Engel and Sharp, 1958).

The rate of varnish formation varies widely with local conditions. Hundreds and thousands of years may be required to form a dark coating in some situations, but at one locality in the Mojave Desert a good varnish formed on the surface stones of an alluvial deposit in 25 years. Although the widespread evidence of varnish deterioration may be due to climatological change, conditions in some parts of this desert area are currently favorable to varnish formation (Engel and Sharp, 1958).

Economic Geology

Locations: Blue Rock Mine. Macedonia Canyon.

Blue Rock Mine

Locations: Blue Rock Mine.
Blue Rock Mine.

I met Bill Brown, owner of the Blue Rock Mine, one afternoon in about 1985. He told me the Blue Rock Mine was his, and that he mined "pods" of scheelite (tungsten ore) even though there was substantial copper mineralization on his property. He also said he lived in Los Angeles, and drove out to his mine on the weekends. He kept his trailer and "jeep" at the Cima Store.

I haven't seen Bill since, the roof is torn off of his cabin and the trailer at Cima Store looks to be abandoned.

Locations: Columbia Mine.
Columbia Mine as seen from the ridge above.

Columbia Mine

Columbia Mine as seen from the ridge above.

The Columbia mine lies at the head of a valley that drains northwest from the north end of the Providence Mountains, 6 miles southwest of Dawes. The workings include a shaft 380 feet deep which is inclined 49°, from which there are drifts southwest at 100, 200, and 300 eet. These drifts explore the footwall vein. A crosscut from the south side of the ridge and connected drift explore the hanging-wall vein (fig. 50). A crosscut from this drift meets the shaft at the 100 foot level. Water stands in the shaft 120 feet below the surface.

Other articles: Glossary breccia gneiss
The Columbia Mine …

The veins lie in fine-grained gneiss that is made up of layers of quartz and orthoclase separated by thin layers and films of chlorite. The general trend of the foliation of the gneiss is southwest and the dip southeast. The hanging-wall vein is a zone of sheared gneiss from 1 to 6 feet wide in which there are sporadic lenses of quartz as much as 2 feet wide. Unlike the white quartz that makes up the veins in the monzonite in the New York Mountains and eastward, the quartz of this vein is dense and dark gray. Polishing and etching reveal that the quartz has replaced the enclosing has been minutely brecciated and recemented several times. The only sulphide minerals observed were pyrite and blende, which also have been crushed.

Literature Cited:
- Hewett, D. Foster, 1956.
Chemical storage at the Columbia Mine.

The records of the early production, when the shaft was sunk and the levels run on the footwall vein, are not at hand. At that time, 1900-1905, there was a 5-stamp mill on the property. During recent years, 57 tons of selected ore that was mined and shipped yielded 0.28 ounce of gold and 35 ounces of silver to the ton (Hewett, 1956, p. 133-134).

Sec. 3, T11N, R14E (WSGH, 1953). Noted to have produced silver in 1926 in USBM Mineral Resources. Hewett's No. 115. (Eric 48:303,311; Tucker 21:340; 30:275; 31:348; 43:447, pl.7).

Giant Ledge Mine

Literature Cited:
- Wells, Michael L., Mengesha A. Beyene, Terry L. Spell, Joseph L. Kula, David M. Miller, and Kathleen A. Zanetti, 2005.

Other articles: Caruthers Canyon Road at the Giant Ledge Mine Frasera albomarginata Introduction

Locations: Caruthers Canyon. Giant Ledge Mine.

Caruthers Canyon as seen from New York Mountain Road.

Giant Ledge Mine, Caruthers Canyon, New York Mountains.

The Giant Ledge Mine in Caruthers Canyon, New York Mountains, is one of the larger mines in the area. This is also a location for Frasera albomarginata.

The Giant Ledge mine (no. 118, pl.2) lies at the head of (Caruthers Canyon which) drains southward from the south side of the New York Mountains. It includes two tunnels, the lower extending 610 feet northwest to a caved area; another, 300 feet higher, includes 500 feet of drifts and crosscuts. The upper tunnel explores a quartz vein 10-15 feet wide that strikes N.25!W. and dips steeply southwest. The lower tunnel cuts several quartz veins that strike N. 30!-50!W. and dip steeply southwest. The width of the veins ranges from 2 to 9 feet. Probably the widest vein in the tunnel is the same as that explored in the upper tunnel, but this has not been proven by underground work.

Literature Cited:
- Hewett, D. Foster, 1956.

These veins are nearly pure quartz, but several contain small amounts of pyrite; traces of galena and flourite were recognized in one vein. The enclosing rock is the intrusive quartz monzonite that underlies a large part of the New York Mountains. The quartz vein in the upper tunnel lies parallel to the contact of the monzonite and the Goodsprings dolomite, 600 feet east. Probably the veins were explored for their gold content, but the amount produced is not known. (Hewett, 1956, p. 142)

Literature Cited:
- Haskell, Barry, 1959.

Workings at the Giant Ledge Mine consist of a 1,200-foot crosscut, shallow shafts, and open cuts along a massive quartz vein about 75 feet thick near the limestone-quartz monzonite contact. Scheelite, huebnerite, galena, chalcopyrite, pyrite, sphalerite, bornite, malachite, and azurite were found in samples in the tailing dump. Though the mine is inactive, considerable interest has been shown by promoters in the use of geological information to ascertain the mine's true value. (Haskell, 1959, p. 87)

Locations: Golden Quail Claims.

Golden Quail Claims

Mine shaft.

Within an area 1,500 feet in diameter in the low hills that lie 2 miles west of bench mark 5118 near the southern edge of New York Mountains There are eight shafts and short tunnels (no. 110, pl. 2). The principal works is a shaft 250 feet deep with about 500 feet of drifts, which, to judge from the materials on the dump, explores the Cedar Canyon fault along which flows of Tertiary age on the south lie in contact with the Goodsprings dolomite and monzonite on the north. This shaft is dismantled but the dump yields blocks of nearly solid sulfides, largely pyrite with a little chalcopyrite, galena, and blende in a chloritic gangue.

Literature Cited:
- Hewett, D. Foster, 1956.

Another shaft, 800 feet north, is about 200 feet deep. The dump shows quartz with sparse stains of copper and quartz schist. Nothing could be learned concerning the record of operations at these mines. (Hewett, 1956, p. 142)

This area was visited April 15, 1981. Stopped for a few minutes at the small hills just west of the main road out of Caruthers Canyon. The small hill closest to the road is made up of a granitic rock, a mica schist and a carbonate rock. Hewett (1956, see quote above) notes that the granitic rock is Teutonia quartz monzonite as is much of the rock in the southern New York Mountains. The schist includes a black mica schist, a thinly banded gneiss and a few outcrops of metaconglomerate. The carbonate rock is identified by Hewett as Goodsprings dolomite. There are numerous workings on this hill. In one prospect, on the northeast side of the hill, horizontal slickensides were observed in the quartz monzonite. A shaft is directly south of the small knoll. Depth is greater than 100 feet. When approached, an owl was sitting on the timbers at the top of the shaft. The owl flew down the shaft. Four nestling owl chicks were found on a ledge about 6 feet down the shaft.

A number of core holes were drilled in this area, probably during 1980. All core holes are numbered 80-1, 80-2, etc.. There are at least 8 holes. Most are drilled at 90° and average about 200 feet deep.

This area was visited again on April 4, 1985. First, explored small hill north of the road. It is composed mostly of a warm gray limestone which is sometimes lighter in color and sandy. It appears to be partially recrystallized. No recognizable macro fossils were found but there were some slender rod-like objects up to 8mm in length (Rock Sample No. 10911-3). On top of the hill, the limestone is very much recrystallized and has reddish zones suggestive of cinnabar deposited during low temperature hydrothermal alteration.

On the northwest side of the hill is a contact with granite. The contact appears intrusive. There were no signs of faulting. A search for contact metamorphic minerals such as garnet and epidote was fruitless. There were many quartz dikes in the granite but none in the limestone.

The first hill south of the road was then explored. This is the second time this hill has been examined. Slickensides in quartz monzonite were located again. The fault trace strikes N 53° E and dips 50° south. The slickensides indicate nearly horizontal, trending up about 5° to the east. This suggest strike-slip movement.

Signs in this area bear the name of the Golden Quail Mining Company or the Golden Quail claims.

The open pit of the Golden Quail Mine.

The main shaft has been bulldozed over. The surface of the land has been lowered about 15 feet and bedrock exposed. The location of the shaft is still visible because of soil subsidence. There has been more core drilling since 1981. Markings on the stakes indicate that one hole was drilled to at least 638 feet. All cores have been removed from the area, but rock cuttings are a black mica schist (Rock Sample No. 10931).

Other articles: Glossary welded_tuff
Sketch map.

Surrounding hills are mostly Precambrian schist and gneiss. Some are capped by limestone. The contacts are presumably depositional, but were not explored. Small hills farther south are covered by Tertiary welded tuffs.

Silver Buddy Mine

Ore bin and equipment dump at the Silver Buddy Mine.

The Silver Buddy Mine is west of Wild Horse Canyon Road. The area is now enclosed in a wilderness so you have to walk about 2 easy miles up the former road.

Debris around the Silver Buddy Mine.

There was a large trailer at this site, but it has apparently been removed. This trailer and associated debris remains behind.

Prospect trenches at the Silver Buddy Mine.

In prospecting for valuable ore, it appears that the miners used a caterpillar tractor to dig 4 trenches in the hillside in an attempt to expose the ore-bearing veins.

Aerial photograph of prospect trenches at the Silver Buddy Mine.

No attempt was made to cover the trenches, and the miners have left 4 huge gashes in the earth that won't heal within a human life time. This portion of a Digital Orthophoto Quadrangle was obtained from the Microsoft TerraServer.

Literature Cited

A list of all literature cited by this web site can be found in the Bibliography.

Aguirre-Diaz, Gerardo J., and Guillermo Labarthe-Hernandez. 2003. Fissure ignimbrites: Fissure-source origin for voluminous ignimbrites of the Sierra Madre Occidental and its relationship with Basin and Range faulting. Geology. 31(9):773-776.

Bjørnerud, M. G., and H Austrheim. 2004. Inhibited eclogite formation: The key to the rapid growth of strong and buoyant Archean continental crust. Geology. 32(9):765-768.

Brown, Howard. 2003. Geology, genesis and mining of pharmaceutical and food grade calcium carbonate at the Amboy Limestone Quarry. pp. 49-56 in Reynolds, Robert E.. Land of Lost Lakes, the 2003 Desert Research Symposium. April 2003. {TAS}

Cooper, John D. 1987. Lower Paleozoic craton-margin section, northern Potosi Valley, southern Spring Moutains, Clark County, Nevada. pp. pp. 61-66 in Hill, Mason. Centennial field guide.

Corsetti, Frank A., and James W. Hagadorn. 2003. The Precambrian-Cambrian transition in the southern Great Basin, USA. The Sedimentary Record. 1(1).

Criswell, D. R., J. F. Lindsay, and D. L. Reasoner. 1975. Seismic and acoustic emissions of a booming dune. Journal of Geophysical Research. 80(35):4963-4974. Washington DC: American Geophysical Union, December 10, 1975. {TAS}

DeCourten, Frank L. 1979. Rock Units in the Mojave Desert Province. California Geology.

Diehl, P. E. 1979. The stratigraphy, depositional environment, and quantitative petrography of the Precambrian-Cambrian Wood Canyon Wood Canyon Formation, Death Valley region, California. [Ph.D Thesis]. University Park: Pennsylvania State University.

Evans, James R. 1962. Falling and climbing sand dunes in the Cronese ("Cat") Mountain area, San Bernardino County, California. Journal of Geology. 70: 107-113. {TAS}

Fedo, C.M., and Cooper, J.D. 1990. Braided fluvial to marine transition; the basal Lower Cambrian Wood Canyon Formation, southern Marble Mountains, Mojave Desert, California. Journal of Sedimentary Petrology. 60: 220-234.

Friedrich, Anke M., and John M. Bartley. 2003. Three-dimensional structural reconstruction of a thrust system overprinted by postorogenic extension, Wah Wah thrust zone, southwestern Utah. GSA Bulletin. 115(12):1473-1491. {TAS-pdf}

Glazner, Allen F., Jane E. Nielson, Keith A. Howard, and David M. Miller. 1986. Correlation of the Peach Springs Tuff, a large-volume ignimbrite sheet in California and Arizona. Geology. 14: 840-843. {TAS-PDF}

Goldfarb, R., D. M. Miller, R. W. Simpson, D. B. Hoover, and P. Moyle. 1986. Mineral resources of the Providence Mountains Wilderness Study Area, San Bernardino County, California. U. S. Geological Survey Bulletin 1712D.

Haskell, Barry. 1959. The Geology of a portion of the New York Mountains and Lanfair Valley. Unpublished M. A. thesis..

Hazzard, John C. 1954. Rocks and structure of the northern Providence Mountains, San Bernardino County, California. pp. 27-35 in Jahns, R. H., ed., 1954. Geology of Southern California. Bulletin 170.. {TAS}

Hewett, D. F. 1931. Geology and ore deposits of the Goodsprings quadrangle, Nevada. U. S. Geological Survey Professional Paper 162..

Hewett, D. Foster. 1956. Geology and Mineral Resources of the Ivanpah Quadrangle, California and Nevada. U. S. Geological Survey Professional Paper 275.. {TAS} 172 pp.

Lindsay, J. F., D. R. Criswell, T. L. Criswell, and B. S. Criswell. 1976. Sound-producing dune and beach sands. Geological Society of America Bulletin. 87(3):463-473. Boulder, CO: Geological Society of America (GSA), March 1976.

McCurry, Michael O. 1985. The Petrology of the Woods Mountains Volcanic Center, San Bernardino County, California. Ph. D. Dissertation, University of California, Los Angeles..

McCurry, Michael. 1988. Geology and Petrology of the Woods Mountains Volcanic Center, Southeastern California: Implications for the Genesis of Peralkaline Rhyolite Ash Flow Tuffs. Journal of Geophysical Research. 93(B12):14,835-14,855.

McCurry, Michael, Daniel R. Lux, and Kevin L. Mickus. 1995. Neogene structural evolution of the Woods Mountains Volcanic Center, East Mojave National Scenic Area. Ancient Surfaces of the East Mojave Desert: A volume and field trip guide prepared in conjunction with the 1995 Desert Research Symposium. San Bernardino County Museum Association Quarterly. 42(3).

Melezhik, Victor A., Anthony E. Fallick, Eero J. Hanski, Lee R. Kump, Aivo Lepland, Anthony R. Prave, and Harald Strauss. 2005. Emergence of the aerobic biosphere during the Archean-Proterozoic transition: Challenges of future research. GSA Today. 15(11):4-11. {TAS-pdf}

Miller, D. M., J. G. Frisken, R. C. Jachens, and D. D. Gese. 1986. Mineral resources of the Castle Peaks Wilderness Study Area, San Bernardino County, California. U. S. Geological Survey Bulletin B-1713-A.

Perry, Loren E. 1977. Opalite in the Providence Mountains, a visit to Mid Hills and Hole-in-the-Wall. Lapidary Journal. 31(7):1586-1590.

Reynolds, Robert E. and Jennifer Reynolds. 1995. Ancient Surfaces of the East Mojave Desert: A volume and field trip guide prepared in conjunction with the 1995 Desert Research Symposium,. San Bernardino County Museum Association Quarterly. 42(3). {TAS}

Strudley, Mark W., A. Brad Murray, and P. K. Haff. 2006. Emergence of pediments, tors, and piedmont junctions from a bedrock weathering-regolith thickness feedback. Geology. 34(10):805-808. {TAS-pdf}

Theodore, Ted G., ed. 2007. Geology and Mineral Resources of the East Mojave National Scenic Area, San Bernardino County, California. U. S. Geological Survey Bulletin 2160. Menlo Park, CA: U. S. Geological Survey, 2007. {TAS-pdf} Date retrieved: 28 Feb 2018, https://pubs.usgs.gov/bul/b2160/pdf/B2160v9.pdf

Trexler, James H., Jr., Patricia H. Cashman, Walter S. Snyder, and Vladimir I. Davidov. 2004. Late Paleozoic tectonism in Nevada: Timing, kinematics, and tectonic significance. GSA Bulletin. 116(5/6):525-538. {TAS-pdf}

Trexler, Dennis T., and Wilton N. Melhorn. 1986. Singing and booming land dunes of California and Nevada. California Geology. 39(7):147-152. San Francisco, CA: California Division of Mines and Geology, July 1986. {TAS}

Valentine, Greg A., and Charles D. Harrington. 2006. Clast size controls and longevity of Pleistocene desert pavements at Lathrop Wells and Red Cone volcanoes, southern Nevada. Geology. 34(7):533-536. {TAS-pdf}

Wells, Michael L., Mengesha A. Beyene, Terry L. Spell, Joseph L. Kula, David M. Miller, and Kathleen A. Zanetti. 2005. The Pinto shear zone; a Laramide synconvergent extensional shear zone in the Mojave Desert region of the southwestern United States. Journal of Structural Geology. 27(9):1697-1720. {TAS-pdf}

Wells., Ray E., and John W. Hillhouse. 1989. Paleomagnetism and tectonic rotation of the lower Miocene Peach Springs Tuff: Colorado Pleateau, Arizona, to Barstow, California. GSA Bulletin. 101: 846-863. {TAS-pdf}

If you have a question or a comment you may write to me at: tas4@schweich.com I sometimes post interesting questions in my FAQ, but I never disclose your full name or address.

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Date and time this article was prepared: 12/22/2019 10:09:20 AM