"Death Valley is the Grand Canyon put into a juicer and minced!"
Geologist, Author and Guide Wayne Ranney, 2016
Over the course of almost two billion years, the Death Valley region has experienced a long and varied series of geologic events with each progressively adding complexity to the former. They include the fragmentation of two supercontinents - Rodinia in the Late Proterozoic and Pangaea in the Mesozoic - at least four episodes of major volcanism, three or more intervals of marine deposition - one in the Late Proterozoic, another during the Paleozoic and a third during the early Mesozoic - at least four prolonged periods of large-scale tectonic deformation and two or more low-latitude, global glaciations in the Late Proterozoic.
Beginning in the late Mesozoic, tectonic compression led to severe and widespread crustal extension in the late Cenozoic across western North America's Basin and Range province including Death Valley. Extension is thought, in part, to have operated synchronously under the influence of two superimposed stress fields, one tectonically-controlled and the other gravity-induced.
Death Valley's landscape lies in contrast to the Grand Canyon in nearby northern Arizona. Their crystalline basements and sedimentary successions formed under closely related orogenic, rift-to-drift and Cordilleran miogeoclinal circumstances, but the Grand Canyon's rocks have remained uplifted, untilted and largely undeformed. If it wasn’t for the fortuitous erosive action of the Colorado River system, they would not have been exposed.
Death Valley, on the other hand, possesses a diverse, complicated and beguiling terrain with a distribution of rocks that are variably faulted, folded, deformed, mangled, chaotic and nothing less than a challenge to interpret. In addition to being relatively uneroded, unobstructed by vegetation and unmarred by glaciation, extension has provided a landscape that is well exposed and highly accessible.
Tortured South Wall of Titus Canyon in the Grapevine Mountains of Northeastern Death Valley With the exception of aptly-named Amargosa Chaos of southern Death Valley, perhaps nowhere else in the region better demonstrates the cumulative complexity of geological events experienced by the landscape than on a drive on Titus Canyon Road through east-west trending Titus Canyon in the Grapevines along northern Death Valley’s northeast border. Late Proterozoic through Quaternary strata are exposed in the range with lowermost representing siliciclastic rift strata acquired during the fragmentation of the supercontinent of Rodinia and overlying carbonates, sandstones and shales deposited on the early developing Laurentian passive margin sequence. Factor in compression related to the development of the Cordilleran fold and thrust belt in late Paleozoic and Mesozoic time and Basin and Range extension in late Cenozoic time. The result can be seen in folded shale and limestone beds of the widely-distributed Middle Cambrian Bonanza King Formation that form the south wall of Titus Canyon in the vicinity of the Leadfield Mine. Yet, the wall is even more tortured than it looks. The rocks are completely upside-down, so the oldest rock in the fold is in the core --which makes it an anticline. You can't tell that from the photo, but you can tell it by following the stratigraphy down the canyon. Therefore, it’s a synformal anticline. Think of it as an anticline (where the rock layers get younger away from the axial surface of the fold) that has been inverted, but it has the shape of a synform (with a trough-like shape). Multifolded stratigraphic layers such as this are typical of collisional environments. From the air, the upturned, upfolded (anticlinally), downfolded (synclinally) and recumbant folds (turned back on itself) of Titus Canyon make more sense. Visit Marli Miller (here) for a great perspective. Thanks for the help with the clarification, Marli! |
OUR PLAN
In mid-winter 2016, our intrepid party of four, under the guidance of geologist and author Wayne Ranney (here), explored Death Valley from its heights to its depths. Our plan was to investigate the geology, experience the region's otherworldly aura, beat the heat and precede the throngs that arrive to see the colorful wildflowers that typically appear in spring. We succeeded on all accounts and, to our delight, arrived in the midst of a once-in-a-decade spectacular "super-bloom" spawned by El Niño rains in October.
This is my first post of three on the geology of Death Valley. It begins with a compilation of some of the region's most vexing questions, many of which remain unanswered and hotly debated. It is followed by a discussion of the region's geographic and physiographic location in western North America. Part II presents a synopsis of Death Valley's geological evolution beginning with the acquisition its basement rocks in the Early Proterozoic. Part III offers a few examples of profound biologic resilience when confronted by Death Valley's environmental extremes and of the diverse human and mining history scattered about the region. Global co-ordinates have been added to each post that, when copied into a mapping program such as Google Earth, will allow you to "Go there."
WELCOME TO DEATH VALLEY
When conversing with individuals unfamiliar with its location - with the exception of geologists, residents of the Southwest and baby-boomers who watched Death Valley Days on television when they were kids - the most common questions are "Where is it?" and "Isn't it a desert?" The uninformed are gratified to learn that it is a desert but are surprised to discover that barely 10% of its surface is covered with sand. But, deserts are defined by lack of rainfall, not surface composition or elevation. And they're not all hot. In fact, the two largest deserts on Earth are located at each of the poles - sandless and frigid. In addition, they are astounded to hear that Death Valley is flanked by spectacular mountain ranges, some snow-capped and some that tower almost two miles above the desert floor, which is below sea level. Lets investigate the geography.
And where is it? Simply stated, Death Valley is the geological centerpiece of Death Valley National Park in southeastern California along the southwest Nevada state line. The north-south basin of Death Valley is divided into three contiguous subbasins that vary somewhat in structure and timing of formation while sharing a commonality of extensional tectonics, from north to south: Cottonball, Middle and Badwater. They lie between the lofty Panamint Range on the west and the Amargosa Mountain Range on the east. The range-basin-range triad possesses a roughly N-S trend, in keeping with the alternating landforms of the Basin and Range physiographic province in which it resides.
The 110 mile-long Amargosa Range consists of three sub-ranges, from north to south: the Grapevine, Funeral and Black Mountains with the Ibex Hills in the south. Northeast of the Blacks, across Grand View Valley, stretches the smaller Greenwater Range that, along with the Funeral Mountains, defines intervening Furnace Creek Wash, a small basin that preceded the formation of Death Valley proper. State Route 190 follows the wash down into the valley from Death Valley Junction and Las Vegas further east.
On Death Valley's west side are the Last Chance Mountains and the 100 mile-long Panamint Range. The latter consists of two sub-ranges: the Cottonwood and Panamint Mountains. The Owlshead Mountains are to the south. Beyond the Panamint Range to the west is Panamint Valley, and beyond that is Owens Valley - the westernmost valley in the Basin and Range province - and then the Sierra Nevada - the granitic mountainous spine of eastern California. On Death Valley's east side, beyond the Amargosa Range, lies the Amargosa Desert-Valley, and beyond that is Las Vegas Valley beyond the Spring Mountains.
VALLEY OF QUESTIONS
Death Valley's Early Proterozoic crystalline foundation formed during the assembly of the supercontinent of Rodinia on which are deposited Middle and Late Proterozoic shallow-marine, intracratonic basinal carbonate sequences of the Pahrump Group and latest Proterozoic to Early Cambrian sedimentary sequences on the newly-established passive margin of Laurentia. The Precambrian-Cambrian succession was acquired during Rodinia's dissassembly and is one of the best exposed in the world. It was deposited at a time of dramatic change in the biosphere that included putative "snowball earth" glaciations, fluctuating oceanographic and atmospheric chemistries, long-lived mantle convection patterns, and large-scale plate reconfigurations that led to eukaryote diversification prior to the Cambrian Explosion of animals.
• What is the theorized association between Rodinia's fragmentation, global climate deterioration and biological evolution?
• The Pahrump Group contains intervals of carbonate rock directly over suspected glaciogenic deposits. These "cap" carbonates are found globally during the late Proterozoic. The unusual and abrupt facies registers strong negative (depleted) carbon isotopic signatures often associated with extinction events. Most assign them an oceanographic origin with flooding of continental shelves and platforms as low-latitudinal ice sheets melted. Do glaciogenic deposits in Death Valley correlate to similar successions regionally and globally? Do they bear relationships to "snowball earth" glaciations, the Sturtian and Marinoan ice ages in particular?
• The Late Proterozoic world is also thought to have possessed a number of equatorial Death Valley "Pahrump-type" and Grand Canyon "Chuar-type" intracratonic marine basins. What have we learned from them regarding rifting, paleo-climate and biological evolution?
• Distinctive 'fingerprints' such as lithostratographic and geochemical similarities, paleontological correlates and detrital zircon geochronology are used to match rifted margins. What have we learned regarding the configuration of Rodinia? If the rift zone was positioned somewhere between the margins of SW Laurentia and perhaps Australia, Antarctica or Siberia, where was Death Valley in the big picture?
Crustal thickness in the Basin and Range province averages only 30 km compared to 50 km of the adjacent Colorado Plateau to the east. Yet, before its Cenozoic collapse its crust was actually thicker than the Colorado Plateau, since it was the site of the Sevier Mountains thrust belt acquired during Farallon plate compression. Death Valley's landscape is partially a consequence of widespread gravitational collapse of the Sevier-orogenic, over-thickened Cordilleran crust. It's also the result of the slab's demise beneath the western rim of North America, when an oceanic-oceanic transform plate boundary system "jumped" onto the continent and changed the structural fabric of the Southwest.
• How did the development of the Pacific-North American plate boundary effect the structure of Death Valley and the Basin and Range province in which it resides?
• Most rifts occur between diverging plates along mid-ocean ridges, such as the East Pacific Rise, while only a few are on land. Continental rifts, whether wide or narrow, form in extensional tectonic settings typified by crustal thinning, sedimentary basins, and thermal activity. Does Death Valley's extensional regime demonstrate these processes?
• Los Angeles resides on the Pacific plate, along with an "acquired" slice of coastal California and all of Baja California. If continental rifting continues, what is the future of the western continent? Will a new ocean basin form? Will Death Valley also "depart" from the North American plate or will it "remain" on the plate in the vicinity of a new passive margin, as it did when Rodinia was breaking apart?
• If the prevailing tectonic regime for Death Valley is strike-slip, how did the region extensionally "pull apart"?
• Furthermore, how did the mountain ranges ascend, if compression is generally required for uplift?
• Are the geodynamics ongoing? How do we know? What evidence of extension is there on the landscape that can be readily observed?
• Why does Death Valley possess such extremes not only in relief but temperature and aridity?
• For almost 150 years, the fact that topography in the Basin and Range province is controlled by normal faulting is recognized. But, what is the geometric behavior at depth of range-bounded faults as they dip beneath the intervening basins? Are some listric that dip steeply at the surface and abruptly flatten?
We frequently focus our attention on rapidly-moving, discrete faults where one or more continental plates interact such as the Pacific-North American plate boundary. Yet, a significant proportion of plate motion is also accommodated on complex, diffuse systems at hundreds to thousands of kilometers from interacting plate boundaries. Such is the case with the San Andreas fault system in coastal California, where of the 48-51 mm/yr of relative motion between the Pacific and North American plates, ~35 mm/yr is accommodated in a zone less than 100 kilometers wide or ~75%. The remainder of residual motion, some 15 mm/yr or ~25%, is distributed in a broad inland boundary of over a thousand kilometers wide in the Walker Lane belt, the Eastern California Shear Zone and the Basin and Range province.
• How does the migration of strain transfer extensionally to Death Valley?
• What is the relationship of Basin and Range volcanism to extensional tectonics? Is magmatism a passive response to crustal thinning or is asthenospheric upwelling (which accounts for the Basin and Range province's high thermal gradient, three times normal for continental areas) a trigger for extensional deformation?
• Do mantle processes such as a plume play an active role in promoting magmatism? Does a hot, buoyant mantle explain the province's high average elevation of 1,400 meters above sea level? Does that explain the magnitude of intraplate volcanism within the Basin and Range province? Where does Death Valley fit in?
• Why does the Basin and Range province consist of a broadly-distributed region of strain instead of one or two elongate rifts of typical continental rifts?
• Does extension of the Basin and Range's orogenic (Sevier-thickened) lithosphere differ from extension of cratonic lithosphere?
Death Valley is actually composed of three contiguous sub-basins, from north to south: Cottonball, Middle and Badwater. Their formative and structural histories differ, but they share a commonality of tectonic extension. The northern and southern sub-basins are parallel and trend roughly northwest, while the center sub-basin trends north to south. Faults in the north and south are strike slip, whereas those in the center are largely normal faults with oblique components.
• How did they evolve? Did they do so coevally?
• How can strike-slip and normal faulting co-exist in one fault system? Is there an interplay? What's a pull-apart basin? What's a rhombochasm?
• What is the relationship of Furnace Creek Basin to the adjoined younger and lower basin of Death Valley?
• A relatively small Holocene-age volcanic field called Ubehebe lies in northern Death Valley. The field's eruptive style is phreatomagmatic - amagmatic explosions of steam and ash rather than effusive emanations of lava. Whether subterranean or surficial, where did all that water come from? Does the eruption imply a wetter paleo-climate for the region or was the abundance of water related to an underground remnant of paleo-Lake Manly that once filled the entire valley?
• Mesozoic and Tertiary volcanic and intrusive rocks are found in Death Valley basin and some ranges. What's their genesis in regards to the region's evolutionary history?
• On a grander scale, the relationship and interplay of tectonics and magmatism in the Basin and Range province has been a topic of long-standing debate. Is there a relationship between extension and magmatism in the Basin and Range province and Death Valley? Does it play an active role in extension or is magmatism merely a passive component of the region's thinned lithosphere? Is it possible that the initial phase of passive rifting could trigger more dynamic asthenospheric ascention? Where does gravitational collapse fit in?
At one time, the Death Valley region was reputed to possess every mineral that put California on the map - gold, silver, copper and lead. But, it was unromantic borax - a whitish salt of boric acid - and everyday talc - a hydrated magnesium silicate - that propelled the region into prominence and led to Death Valley's long-term development. Borax, in particular, put Death Valley on the map, inspired a "white gold" rush and fostered the construction of a narrow gauge railroad, an elegant Spanish-style inn in the desert, a "castle" in a canyon, a radio and television western anthology series, a world famous National Park and a thriving tourist industry.
• Why were the minerals of borax and talc in such commercial demand? Are they still?
• Where are they found? How did they form and when?
• What were the unique challenges associated with mining in Death Valley and getting the deposits to market?
• From the days of the "single-blanket jackass prospector" and the thousands of shafts and tunnels that probe the subsurface - more in Death Valley National Park than any other - what put an end to the industry that made Death Valley so famous in spite of modern techniques of exploration and mining?
WHERE IS DEATH VALLEY?
The 140 mile-long, 5 to 20 mile-wide, generally north to south-trending trough is situated mostly in Inyo County in southeast California, astride the border of southwest Nevada. Its central depression reaches 282 feet below sea level and is bordered by mountains as high as 11,049 feet. The dominant orientation is north to south, but many adjacent valleys and mountain ranges trend northwest-southeast.
In 1933, President Herbert Hoover proclaimed the region a National Monument, along with a connected triangle of land athwart the Nevada state line. In 1984, a small detached unit in Nevada was set aside as a wildlife refuge for the endangered Devil's Hole pupfish. In 1994, the region was redesignated as Death Valley National park with over 3.4 million acres (5,307 square miles). It's the largest park in the contiguous 48 states with over 95% classified as "wilderness" - rugged, unsettled, undeveloped and undivided. Go there (36°27.70 N, 116°52.00 W) to the Death Valley Visitor Center at Furnace Creek Ranch.
In 1984, Death Valley became a UNESCO Biosphere Reserve, one of 699 internationally designated that are "reserved to protect biological and cultural diversity while promoting sustainable economic development." In 2013, the region was named an International Dark Sky Park and awarded a "Gold Tier" for the highest level of pristine nocturnal star-viewing away from urban light-pollution. The IDS in association with the National Park Service makes recommendations how dark skies can be protected such as advocating for ideal levels of outdoor light brightness, appropriate sky-shielding and hours of illumination.
BASIN AND RANGE - A GEOMORPHIC PROVINCE
Death Valley lies within the extreme western extent of the ~800,000 sq km Basin and Range physiographic province and within the southern extent of its Great Basin subprovince. Both regions are without counterpart in North America for the extreme extension across the landscape and their average ~1,200 meter-elevation above sea level. In the late Cenozoic, crustal and lithospheric mantle thinning has occurred over an unusually wide area.
Broad continental extension (as opposed to a narrow zone with a single downward-displaced block of crust) has given rise to the province's surface expression of alternating basins and ranges that extend over a region up to 1,000 km wide. The strain that created the extension is not uniformly distributed over the extended region. As a result, average extensions (and crustal thickness) of 50-100% can vary in areas from 100-400% and less than 10%. It is estimated that the Death Valley region, since the end of Mesozoic compressional thrust faulting, has undergone as much as 160 km of extension.
The province covers most of Nevada, portions of adjoining states and extends south into Arizona, west Texas and northwest Mexico where it engulfs the Sierra Madre Occidental Range. The province lies between the Cascade Ranges and Rockies in the north and the 600-km long granitic spine of the Sierra Nevada and Colorado Plateau in the middle and south.
Each region differs greatly in geology, age, topography, elevation, structure, hydrology, ecology, population density and human history but are related by tectonic processes that created them. Although uncertainty centers on the magnitude, style and timing of the Basin and Range formative event(s), the consensus is that it is the product of widespread, extreme extension, rather than from differential, fluvial erosional processes acting upon folded and faulted rocks in an arid climate or a compressional tectonic episode, as was once thought. It wasn't genetically linked to an extended crust until a faulting-extension connection was made.
WHAT IS DEATH VALLEY?
The province's name "basin and range" is based on geomorphology, which includes surface and sub-surface rocks, structural elements and evolutionary history. The landscape is typified by abrupt changes in elevation between rugged, longitudinal, asymmetric, tilted and fault-bound, uplifted blocks of crust that form mountain ranges called horsts (German for "heap") and broad, flat, sediment-filled, downdropped blocks of crust that form basins called grabens (German for "grave"). Death Valley typifies the province's corrugated landforms, and is its most famous, most visited and most studied region with the greatest extremes in landscape and climate.
Two kinds of extensional faults exist in the Basin and Range province: high-angle normal faults (that create the repetitive horsts and grabens and are responsible for the majority of horizontal extension) and low-angle normal detachments faults (with associated metamorphic core complexes). Both types of faults are related to the development of two superimposed stress fields in the province, one related to tectonics and the other to gravitational collapse.
In the late 1880's, geologist Clarence Dutton compared the Basin and Range's alternating topography to "an army of caterpillars crawling northward out of Mexico." The extremes in elevation posed a formidable impediment to westward travel for pioneers, prospectors and settlers in the 1800's and was one of the last regions to be settled in the United States.
The ~362,600 sq km Great Basin is the northern subprovince of the Basin and Range, where "The earth is splitting apart there" as well (author John McPhee). Thus, it also possesses the province's distinctive alternating landforms, but the appellation is misleading. Rather than defined by geomorphology, "great basin" is a hydrologic definition. Precipitation is not directed centrally into a massive catchment as implied but into range-flanked, below sea level, endorheic (Greek for "flow within") basins, over 200.
Each range-basin-range triplet is a closed-system, whose waters, scant and variable as they may be, have no outlet to the sea. Each range acts as a hydrologic drainage divide that runs down its axis. Water is directed from the ranges' relatively impermeable bedrock to broad basins where over 90% is lost due to evaporation and the rest enters playa or forms aquifers, dictated by regional structure and lithology. Aquifers are the principal source of ground water in over 120 alluvium-filled basins. Draped over this framework are erosionally-created features such as wine-glass canyons, triangular-shaped facets, spur benches, regularly-spaced catchments and omnipresent alluvial fans. Death Valley is representative of the province's geomorphology and the subprovince's hydrology.
VALLEY OF EXTREMES
As warm, moisture-laden air rises on the windward side of the mountains, it expands and loses heat and moisture in a process called adiabatic cooling. Descending drier air contracts on the leeward side and warms as its humidity plummets. In Death Valley's Badwater Basin, which reaches 282 feet below sea level, high pressure and dry conditions dominate due to the greater weight of the atmosphere above. By the time it reaches Death Valley's sunken floor, the super-heated air is dry as a bone.
Snowmelt, mountain runoff, springs and water seeps along the fronts and negligible rain within the basins either accumulates in ephemeral, hypersaline playa lakes, infrequently makes its way to adjoining basins, enters the subsurface recharging aquifers or most likely evapotranspirates into the atmosphere in the intense heat. Although scarce, when rain does occur, it can have a catastrophic effect on the landscape by breaking down rock and transporting it down mountain. Alluvial fans, extensive bajadas, debris flows and thousands of feet of sediment basin-fill are commonplace. In Utah, the Great Salt Lake is the Great Basin's largest internal "drain", while Death Valley is arguably its most famous and most studied landform with classic basin and range topography and with an internal hydrologic basin that covers some 8,700 square miles.
Death Valley lies within the northern arm of the Mojave Desert, North America's smallest, driest, most unspoiled and undivided North American desert with the greatest range of elevations. The Mojave is a rainshadow desert and serves as a transition zone between the hot Sonoran Desert to the south and cooler Great Basin Desert to the north. The Joshua Tree is considered the region's indicator species and occurs at elevations between 1,300 and 5,900 feet and defines the areal limits of Mojave's ecosystem.
DEATH VALLEY - A STRUCTURAL PROVINCE
In addition to occupying a locale within the Basin and Range and Great Basin, Death Valley is transitional between three partly overlapping seismic provinces - the Basin and Range, the Walker Lane Belt and the Eastern California Shear Zone. All three are actively deforming regions of extension and shear. Although some combine the latter two into a continuous zone, they are evolving components of the San Andreas fault system along the coast of California.
The arrival of the East Pacific Rise spreading center at the Farallon-North American plate subduction zone initiated extension about 27 million years ago and 17-18 million years ago at Death Valley. What is the relationship of Death Valley to the San Andreas system, and how did it come to form? Please visit post Part II for an explanation.
The Mohave Desert is also a structurally transitional region, in that it contains the Mohave block. The block is a wedge-shaped zone with clockwise rotation between the dextral San Andreas fault on the west and the sinistral strike-slip Garlock fault in the north. The Garlock separates the Mojave region from the Basin and Range province to the north and connects with the dextral Southern Death Valley fault zone. The entire region - the Basin and Range province, the Mojave block and Death Valley region prior to the Oligocene - was a tectonically quiescent, lithospherically unextended, externally-drained plateau. These aspects were reversed when the Farallon-North-American plate subduction zone encountered the Farallon-Pacific spreading ridge. Please visit post Part II for more info.
WHAT ISN'T DEATH VALLEY?Death Valley acquired its infamous moniker in 1849 when a member of "The Lost '49ers" - a group of pioneers and prospectors who made an ill-fated attempt to find a 500-mile short-cut to the California goldfields - looked back one last time and exclaimed, "Goodbye, Death Valley." The name stuck (to the dismay of at least one geologist I know). But don't be mislead....it's a complete misnomer. Death Valley isn't a valley, and it's far from dead - either biologically or geologically.
Geologically speaking, Death Valley is a basin not a valley. Valleys might look similar - regions of low relief and sediment-filled between topographic highs - but their genesis is erosional, produced by the carving action of rivers or gouging of glaciers. Basins - whether bowl-shaped or elongate and often below sea level - sport a tectonic origin. They can be very small (hundreds of meters) or very large (such as ocean basins), but the essential element is the prolonged tectonic creation of relief.
In Death Valley, extension has bestowed the basin with faults along its flanks, a flat or tilted, down-dropping floor that provides accommodation space for the deposition of thick sediment and parallel mountain ranges along the sides of the basin. The mountain ranges are more steeply sloped on their western flanks in contrast to the eastern flanks, which drops less precipitously to the neighboring basins. The architecture is perhaps visualized best on an elevation profile generated along a 77 km-long SW-NE geologic transect (red line) across the landscape of Death Valley through the ranges and basins that flank it.
As for the absence of life, Death Valley's Badwater Basin with the Western Hemisphere's lowest elevation, maximum temperatures and near greatest aridity is indeed desolate, salt-infused and lifeless (with the exception of ancient, halo-tolerant prokaryotic Archaea micro-organisms recently discovered). Factor in scorching summers and freezing winters. Everything changes with elevation with increasing water exposure as temperatures become cooler and more life-tolerant. In Death Valley, life is defined and confined by the availability of water.
HOT AND DRY BUT FAR FROM DEAD
Death Valley's lifeforms are specially adapted to cope with the region's extremes. Life and diversity appear within the Lower Sonoran ecosystem in the first 4,000 feet, where a host of specially evolved lifeforms have adapted to environmental extremes. Cacti, desert holly, scorpions, sidewinders, ravens, roadrunners, kit foxes and kangaroo rats thrive. From 4,000 to 8,500 feet, Upper Sonoran pinyon pine and juniper, and small mammals and reptiles persist. From 4,000 to 8,500 feet within the Transition Zone, sierra juniper, mountain mahogany, mule deer, bobcats, cougars and coyotes exist, and up to 9,000 feet in the Sub-Alpine Zone, where bristlecone pine, limber and bighorn sheep are found. These lifeforms defy our conventional images of Death Valley. Each has evolved creative solutions to the problems of survival.
DEATH VALLEY GEOLOGY CALLING: PART II - HOW DID IT FORM?
Late Cenozoic extensional forces wreaked havoc on the landscape of Death Valley. They uplfited, tilted, deformed, stretched and wrenched crustal blocks of Proterozoic through Cenozoic strata into elongate mountain ranges, while downdropping intervening blocks within basins that variably filled with range-derived colluvium and alluvium, long-gone Pleistocene lakes and saliferous playa.
The basins contain the deposits that put the region on the map, while the ranges contain the region's oldest rocks and tell the story of Death Valley's ancient past. An excursion would be incomplete without a visit to both. In my next post, I'll present a condensed synopsis of Death Valley's geologic evolution that spans nearly two billion years. Thank you for visiting!
SPECIAL THANKS
Immense gratitude is offered to geologist and author Wayne Ranney for his knowledge, expertise, unlimited enthusiasm, endless wit, exceptional car-camping cuisine, friendship and great companionship. Please visit Wayne here. Great appreciation is also extended to Marli Miller for her personal communications, thoughtful explanations and photographic contributions. A stop at Bennie Troxel's Museum Rock Trail in nearby Shoshone, California is highly recommended. His outdoor chronologic collection of large rocks tells the geologic story of the Death Valley region. And of course, there's Death Valley National Park. Go there!
Thanks, Wayne, for another great trip and for taking me to the next level! |
EXTREMELY HELPFUL BOOKS
• Ancient Landscapes of the Colorado Plateau by Ron Blakey and Wayne Ranney, 2008.
• A Trip Through Death Valley's Geologic Past by Kenneth E. Lengner, 2009.
• Death Valley's Titus Canyon and Leadfield Ghost Town by Ken Lengner and Bennie Troxel, Second Edition, 2008.
• Geology of the American Southwest by W. Scott Baldridge, 2004.
• Geology of Death Valley National Park by Marli B. Miller and Lauren A. Wright, Third Edition, 2015.
• Geology of the Great Basin by Bill Fiero, 1986.
• Geology Underfoot in Death Valley and Owens Valley by Robert P. Sharp and Allen F. Glazner, 2012.
• Geology Underfoot in Southern California by Robert P. Sharp and Allen F. Glazner, 2014.
• Hiking Death Valley by Michel Digonnet, 1972.
• Images of America - Death Valley by Robert P. Palazzo, 2008.
• Plate Tectonics by Wolfgang Frisch et al, 2011.
ON-LINE MAPS OF DEATH VALLEY
• Geologic Map of the Death Valley Ground-Water Model Area, Nevada and California by J.B. Workman et al, 2002.
• Death Valley National Park Map here
NOTABLE DEATH VALLEY FIELD GUIDES BOTH ON-LINE AND IN PRINT
• A Trip Through Death Valley's Geologic Past by Kenneth E. Lengner, 2009.
• Cal Poly Geology Club, Death Valley Field Trip – 2004 (On-line)
• Death Valley National Park Visitor Guide - Winter/Spring 2016
• Death Valley's Titus Canyon and Leadfield Ghost Town by Ken Lengner and Bennie Troxel, Second Edition, 2008.
• Field Trip Guide to Death Valley National Park, Geology of the National Parks, San Francisco State University, March 22-26, 2002 (On-line)
• Geology of Death Valley National Park by Marli B. Miller and Lauren A. Wright, Third Edition, 2015
• Hiking Death Valley by Michel Digonnet, 1972.
• Hofstra University, Field Trip Guidebook, Geology 143D - Geology of California/Nevada, Spring Semester April 11, 2009 (On-line)
• Proceedings of Conference on Status of Geologic Research and Mapping in Death Valley National Park, Las Vegas, Nevada, USGS, Open File Report 99-153, 1999 (On-Line)
• Quaternary and Late Pliocene Geology of the Death Valley Region: Recent Observations on Tectonics, Stratigraphy, and Lake Cycles, Guidebook for the 2001 Pacific Cell—Friends of the Pleistocene Fieldtrip (Online)
• Stanford Project on Deep-Water Depositional Systems, 23rd Annual Meeting and Field Workshop, Death Valley California, Field Guide: Upper Paleozoic Deep-Water Passive Margin Sequences of the Death Valley Region (On-line)
• Virtual Field Guide of the Death Valley Region, Geology Program, Department of Earth Sciences, Palomar College (On-line)
VERY INFORMATIVE PROFESSIONAL PAPERS
• Analogue Modelling of Continental Extension: A Review Focused on the Relations Between the Patterns of Deformation and the Presence of Magma by Giacomo Corti et al, Earth-Science Reviews 63, 2003.
• An Imbricate Midcrustal Suture Zone: The Mojave-Yavapai Province Boundary in Grand Canyon, Arizona by Mark E. Holland et al, GSA Bulletin, September/October 2015.
• A Positive Test of East Antarctica–Laurentia Juxtaposition Within the Rodinia Supercontinent by J. W. Goodge et al, Science, 2008.
• Assembly, Configuration, and Break-up History of Rodinia: A Synthesis by Z.X. Li et al, Precambrian Research, 2008.
• A USGS Study of Talc Deposits and Associated Amphibole Asbestos Within Mined Deposits of the Southern Death Valley Region, California by Bradley S. Van Gosen et al, USGS, 2004.
• Basin and Range Volcanism as a Passive Response to Extensional Tectonics by Keith Putirka and Bryant Platt, Geosphere, 2012.
• Cenozoic Extension and Magmatism in the North American Cordillera: The Role of Gravitational Collapse by Mian Liu, Tectonophysics 342, 2001.
• Detrital Zircon Provence, Geochronology and Revised Stratigraphy of the Mesoproterozoic and Neoproterozoic Pahrump (Super) Group, Death Valley Region, California by Robert Clyde Mahon, Thesis, Idaho State University, 2012.
• Evolution of Mountainous Topography in the Basin and Range Province by Michael A. Ellis et al, Basin Research, 1999.
• Extensional Tectonics in the Basin and Range Province and the Geology of the Grapevine Mountains, Death Valley Region, California and Nevada, Thesis by Nathan A. Niemi, CIT, 2002.
• Geochronologic and Stratigraphic Constraints on the Mesoproterozoic and Neoproterozoic Pahrump Group, Death Valley, California: A Record of the Assembly, Stability, and Breakup of Rodinia by Robert C. Mahon et al, GSA Bulletin, 2014.
• Geologic map of the Death Valley Ground-Water Model Area, Nevada and California by J.B. Workman et al, USGS 2381-A, 2002.
• Geomorphic Evidence for Late-Wisconsin and Holocene Tectonic Deformation, Death Valley, California by Roger L. Hooke, GSA Bulletin, 1972.
• Glacigenic and Related Strata of the Neoproterozoic Kingston Peak Formation in the Panamint Range, Death Valley Region, California, etc. by Ryan Peterson, Thesis, CIT, 2009.
• Gravitational collapse of the continental crust: definition, regimes and modes by P. Reya et al, Tectonophysics 342, 2001.
• Groundwater Geology and Hydrology of Death Valley National Park, California and Nevada by M.S. Bedinger and J.R.Harrill, Technical Report NPS/NRSS/WRD/NRTR—2012/652, 2012.
• Hydrogeology and Hydrologic Landscape Regions of Nevada by Douglas K. Maurer et al, USGS Report 2004-5131, 2004.
• Late Cenozoic Crustal Extension and Magmatism, Southern Death Valley Region, California by J.P. Calzia and O.T. Ramo, GSA Field Guide 2, 2000.
• Late Quaternary Tectonic Activity on the Death Valley and Furnace Creek Faults, Death Valley, California by Ralph E. Klinger and Lucille A. Piety, USGA, 2001.
• Nd Isotopic Composition of Cratonic Rocks in the Southern Death Valley Region: Evidence for a Substantial Archean Source Component in Mojavia by O.T. Remo and J.P. Calzia, Geology 26, 1998.
• Neoproterozoic Uinta Mountain Group of Northeastern Utah: Pre-Sturtian Geographic, Tectonic and Biologic Evolution by Carol M. Dehler et al, GSA Field Guide 6, 2005.
• Sliding Stones of Racetrack Playa, Death Valley, USA: The Roles of Rock Thermal Conductivity and Fluctuating Water Levels by Gunther Kletetschka et al, Geomorphology, 2013.
• Supercontinent Tectonics and Biogeochemical Cycle: A Matter of ‘Life and Death’ by M. Santosh, Geoscience Frontiers, 2010.
• Tectonic influences on the spatial and temporal evolution of the Walker Lane by James E. Faulds and Christopher D. Henry, Arizona Geological Society, Digest 22, 2008.
• Tectonic Model for the Proterozoic Growth of North America by Steven J. Whitmeyer and Karl E. Karlstrom, Geosphere, 2007.
• Tectonostratigraphic Evolution of the ~780–730 Ma Beck Spring Dolomite: Basin Formation in the Core of Rodinia by Emily F. Smith et al, Geological Society of London, 2015.
• Terrestrial Cosmogenic-Nuclide Dating of Alluvial Fans in Death Valley, California by Michael N. Machette et al, USGS, Professional Paper 1755, 2008.
• The Laurentian Record of Neoproterozoic Glaciation, Tectonism, and Eukaryotic Evolution in Death Valley, California by Francis A. Macdonald et al, GSA Bulletin, 2013.
• The Making and Unmaking of a Supercontinent: Rodinia Revisited Joseph G. Meert and Trond H. Torsvik, Tectonophysics, 375, 2003.
• The Relationship between the Neoproterozoic Noonday Dolomite and the Ibex Formation: New Observations and Their Bearing on "Snowball Earth" by Frank A. Corsetti and Alan J. Kaufman, Earth Science Reviews, 2005.
• Toward a Neoproterozoic Composite Carbon-isotope Record by Galven P. Halverson et al, GSA Bulletin, 2005.
• Two Diamictites, Two Cap Carbonates, Two Carbon 13 Excursions, Two Rifts: The Neoproterozoic Kingston Peak Formation, Death Valley, California by A.R. Prave, Geology, 1999.
• Two-stage Formation of Death Valley by Ian Norton, GSA Geosphere, 2011.
• U-Pb Geochronology of 1.1 Ga Diabase in the Southwestern United States: Testing Models for the Origin of a Post-Grenville Large Igneous Province by Ryan M. Bright et al, Lithosphere online, 2014.
• Variations Across and Along a Major Continental Rift: an Interdisciplinary Study of the Basin and Range Province, Western USA by Craig H. Jones et al, Tectonophysics 213, 1992.