Death Valley geology
The geology of Death Valley is in the national park Death Valley (Death Valley) be traced.
The national park covers an area of 8,367 km², mostly in California ( USA ), but also to a small extent in Nevada . The stratigraphic sequence of the rock layers and the tectonic structure of the area reflect the long, varied and complex geological development history of the region.
The oldest rocks in the area are metamorphic rocks and granites of the middle and late Proterozoic , which are overlaid in a discordant manner (with a regional gap) by predominantly marine sediments (Pahrump group). In the uppermost layers of the Pahrump group there are indications of glacier deposits, which can possibly be assigned to a late Precambrian ice age ( see also Snowball Earth ).
When the supercontinent Rodinia broke up , narrow inlets first penetrated the continental crust. The edges of this rift zone sank until the continental crust broke and the Pacific began to open. A wedge of clastic sediments gathered at the base of the sunken shelf edges and buried the region's first complex fossils . A carbonate platform that existed for the next 300 million years in the Paleozoic was deposited about 550 million years ago .
The passive continental margin turned into an active margin in the early and middle Mesozoic Era when the Pacific Farallon plate pushed under the North American plate ( subduction ). A long epoch of volcanism and mountain formation ( orogenesis ) followed along the North American west coast. In the area of Death Valley, the erosion of the raised rock layers, which lasted for many millions of years, produced a relatively unstructured plain.
The renewed thinning of the crust beneath western North America began about 16 million years ago, presumably as a result of the upwelling of magmas above the Farallon Plate, which the North American continent crossed. This process continues to the present day and not only created the tectonic clumps and trenches of the Basin and Range Province, but also released lava . Two or three million years ago, the thinning process also reached what is now the national park, tearing it apart, creating Death Valley, Panamint Valley and the surrounding mountain ranges. These valleys were partially filled with sediments and, during the wet ice ages , also with lakes. The largest of these lakes is Lake Manly . 10,500 years ago, the lakes were increasingly cut off by the meltwater of the glaciers in the Sierra Nevada , whereupon they dried up and only salts and minerals remained. Today's desert landscape emerged after the lakes dried up.
Tectonic and sedimentary development in the Precambrian
The Protozeroic Complex
Little is known about the original composition of the oldest rocks in the area, as they later underwent a strong rock transformation (metamorphosis) under the pressure of overlying layers and the heat of the earth's interior. From the original quartz and feldspar-rich sediments and igneous rocks, dark gray, almost unmarked mica schist and gneiss formed . Radiometric measurements showed a metamorphic age of over 1700 million years and thus date them to the end of the Paleoproterozoic .
1400 million years ago a large granite mass ( intrusion ) penetrated this crystalline complex , which is now located in the Panamint Mountains . In addition, are dykes of pegmatite and granite intrusions are far apart on the Death Valley side facing the Black Mountains to see ( open-minded ), and in the Talc and Ibex Hills.
Then the metamorphosed rocks (probably together with the overlying sediments of a shallow sea) were lifted and the region was eroded for 500 million years. This created an extensive gap in the layers ( discordance ) in which the rock removed and no new sediments were deposited.
The Pahrump Group
The Pahrump Group is several hundred meters thick and was deposited over the Proterozoic erosional discordance between 1300 and 800 million years ago. It consists of (from bottom to top):
- Crystal Springs Formation
- Beck Spring Dolomite
- Kingston Peak Formation
Outcrops from this group can now be seen in a highly metamorphosed belt stretching from the Panamint Mountains to the eastern part of the Kingston Range, including an area near Ashford Mill.
The arkose - conglomerates and shales of the lower Crystal Spring Formation emerged from muddy deposits that were transported by rivers from the highlands approach. Later, a shallow sea penetrated the land ( transgression ) and left behind thick layers of lime mud with numerous algae colonies, which are known as algae mats or stromatolites . This became the dolomites and limestones in the central part of the Crystal Spring Formation. The upper part consists of siltstone and sandstone , which buried the older layers under them. Extensive diabase - transitions then penetrated layer parallel above and below the carbonate rocks a (this form of intrusions is as storage gallery or Sill hereinafter). The heat of the lower Sill, which has an area of several hundred square kilometers, converted the carbonates into economically usable talc through thermal decomposition .
The region of Death Valley was then raised again above sea level, which led to the re-deposition of terrestrial sediments. After sinking again, a series of carbonate banks formed, which were again covered with stromatolites, today's Beck Spring Dolomites. The rocks of the Beck Spring Formation and the underlying Crystal Spring Formation later broke into individual clods and were again exposed to erosion in the late Proterozoic. The large basins between the higher-lying areas were covered with conglomerates (rounded boulders and pebbles in a sandy-muddy base), which are now known as the Kingston Peak Formation. This formation is particularly prominent near Wildrose, Harrisburg Flats, and Butte Valley.
Part of the Kingston Peak Formation is similar because of poor sorting of its components a glacier - glacial therefore considered diamictite . In other parts there are large, isolated boulders that are embedded in very different types of fine-grained sedimentary rocks, such as sandstone or siltstone. These are blocks that were transported on the underside of floating glaciers and, after thawing , fell into the unconsolidated sediments on the lake or sea floor (English: dropstone ). Similar deposits from the same period (700 to 800 million years ago) can be found worldwide. Geologists therefore suspect that the world was hit by a severe ice age at that time , perhaps the most severe in geological history. The youngest rocks in the Pahrump Group consist of basaltic lava .
The supercontinent Rodinia breaks up and the Pacific opens up
Thinning of the crust and first fracture cracks
While the earth was still in a severe ice age, the then supercontinent Rodinia began to break up. The responsible rift system probably consisted of three individual rift breaks that united in a common center (triplet structure, or triple junction ). The two arms from which the Pacific Ocean would later develop widened more and more and became deeper and deeper. The third arm, the Amargosa Rift, "fell asleep again", as often happens with triplet structures, and could not divide the continent any further. The first formation that the advancing sea deposited over the sinking and thinning continental crust in the Death Valley area was the Noonday Dolomites. They arose from carbonate banks covered with algae. Today they are up to 300 m thick and often form bright yellow-gray cliffs. The carbonate banks were soon covered with thin layers of silt and limestone mud that became the hard silt and limestone of the Ibex Formation. Good outcrop of both the Noonday and the overlying Ibex Formation can be seen east of Ashford Mill.
Below the Noonday Formation there is a discordance that affects increasingly older rocks from south to north (angular discordance). In the northernmost part, the Pahrump Group was finally completely eroded and the Noonday Formation there lies directly on the Proterozoic Crystalline Complex.
Formation of a passive continental margin
As the Pacific opened wider and wider in the Late Proterozoic and Early Paleozoic Era, the continental crust completely shattered and a true ocean basin developed in the west. A flat coastline with an extensive shelf edge , and without volcanoes, which resembled today's Atlantic coast of the USA , lay east of today's Las Vegas . All previously formed formations have now been cut in two along a steep front. A wedge of clastic sediment collected at the foot of the two submarine edges, and the formation of two opposing shelf edges began.
The following formations developed from the sediments that accumulated in this wedge (from older to younger):
- Johnnie Formation (multi-colored slate )
- Stirling Quartzite
- Wood Canyon formation
- Zabriskie Quartzite
The Stirling, Wood Canyon and Zabriskie units together are around 1,800 meters thick and consist of strongly consolidated sandstones and conglomerates. Before they were tipped into their current position, the four formations were a five-kilometer-thick package of mud and sand that slowly accumulated on the near-shore ocean floor.
The sandy Wood Canyon Formation contains the first known complex fossils of the Death Valley region. The earliest (extremely rare) living beings can be found far west of the Death Valley area, namely in calcareous claystones that were deposited off the coast at the same time as the Stirling quartzites. The development of living things accelerated at the time of the Wood Canyon Formation. Here creatures of the Ediacara fauna , trilobites , archaeocyathids as well as a myriad of worm tubes and mysterious traces, as well as burial tunnels of primitive echinoderms were discovered . The first animals with permanent shells appear in the late sediments of the Wood Canyon Formation. With this they open the first rich fossil period, the Cambrian ( see also Cambrian Explosion ). Good outcrops of these three formations are exposed on the north face of Tucki Mountain in the northern Panamint Mountains .
The back road to Aguereberry Point successively crosses the schistous Johnnie Formation, the white Stirling Quartzites and the dark quartz rocks of the Wood Canyon Formation. At the lookout point itself, the bright band of the Zabriskie Formation slopes down to Death Valley. Parts of this sequence also emerge between Death Valley Buttes and Daylight Pass, in Upper Echo Canyon, and west of Mare Spring in Titus Canyon.
A carbonate shelf is created
The sandy mud layers were covered by a carbonate platform around 550 million years ago that was to exist for the next 300 million years. The sediments accumulated on the slowly sinking shelf throughout the remainder of the Paleozoic Era and into the early Mesozoic Era. The erosion had flattened the neighboring parts of the mainland to such an extent that the rivers could no longer wash large amounts of sand and silt. At that time, the Death Valley area was ten to twenty degrees from the Paleozoic Equator . The combination of a warm, sunny climate and clear, cloudy water now promoted the rich production of biogenic carbonates. However, the sedimentation of carbonate-rich layers was repeatedly interrupted by periods of land uplift. This resulted in (in the order of deposit):
- Carrara formation
- Bonanza King Formation
- Nopah formation
- Pogonip Group
These sediments solidified into limestone and dolomite after they were buried and compacted under further sediments. The most powerful of these units is the dolomitic Bonanza King Formation, which forms the dark and light striped slopes of Pyramid Peak, as well as the gorges of Titus and Grotto Canyon.
In an intermediate period in the Middle Ordovician (around 450 million years ago) a quartz-rich sand layer covered a large part of the mainland after the above units were deposited. This sand hardened to sandstone and later metamorphosed into the 120 m thick Eureka quartzite. This large white intermediate layer of Ordovician rock protrudes near the racing track at the summit of Pyramid Peak and high on the east side of Tucki Mountain. No American source is known for the Eureka sand, which once covered a 390,000 km² wide belt from California to Alberta ( Canada ). It may have been washed south by ocean currents along the coast of an eroding sandstone terrain in Canada.
Then the deposition of carbonate sediments started again and continued into the Triassic . Four formations emerged during this time (from old to young):
- Ely Springs Dolomite
- Hidden Valley Dolomite
- Lost Burro Formation
- Tin Mountain Limestone
Another disruption occurred within the Carboniferous and Permian (geology) when sporadic swellings of mud were washed south into the Death Valley area during the erosion of the highlands of northern and central Nevada 350 to 250 million years ago.
Although the geographic details changed during this enormous period of time, the northeastern coastline generally ran from Arizona up to Utah . A marine carbonate platform more than 160 km wide extended west to the edge of reefs off the coast. Lime sludge and sand that had been removed from the reefs and platform by the storm collected on the calmer seabed at a water depth of around 30 m. The carbonates of Death Valley seem to represent all three educational environments that result from the temporal development of a reef rim: the basin down the slope in front of the reef, the reef itself and the platform behind the reef.
In total, the eight formations and one group are 6,100 m thick. They are preserved under much of the Cottonwood, Funeral, Grapevine and Panamint mountain ranges. Good outcrops can be seen in the southern Funeral Mountains outside the park and in the Butte Valley inside the park. The Eureka quartzite appears as a relatively thin, almost white band with the gray Pogonip Group below and the almost black Ely Springs dolomite above. All layers are often displaced by faults.
The passive continental margin changes to an active margin
In the Middle Mesozoic , the relative movement of the Pacific plate versus the North American plate was reversed. The western edge of the continent was now increasingly pressed against the oceanic plate, until the latter finally began to sink along a deep sea channel under the continent ( subduction ). At the formerly passive continental margin, the rocks were raised to form mountains along the entire length of the shallow marine shelf under the increasing compression. The submerged oceanic crust was melted in the heat of the Upper Mantle . The resulting volcanic magmas rose, broke through the overlying continental crust, and fed a chain of volcanoes parallel to the deep sea channel. Lava flows hundreds of meters thick formed, and the coastline shifted more than 300 km to the west.
This is how the Sierra Arc, also known as the Mesozoic Magmatic Cordilleras Arc, was created. Large amounts of granitic magma ( plutons ) rose in the vicinity of Death Valley, such as the Sierra Nevada batholith to the west. The lateral pressure narrowed the continental shelf, and older layers were eventually pushed over even younger units due to severe tectonic faults.
The plutons that can be seen from the undeveloped roads on the western edge of the national park come from the Jura and the Chalk . One of these relatively small granite plutons invaded 67 to 87 million years ago and created one of the more profitable deposits of precious metal in the area. This led to the establishment of the city and the mines of Skidoo . Compared to the larger gold fields in California, west of the Sierra Nevada, the local gold deposits were relatively insignificant.
In Death Valley there are more solidified magma intrusions beneath the Owlshead Mountains and at the western end of the Panamint Mountains . Thrusts can be seen at Schwaub Peak in the southern part of the Funeral Mountains.
This long period of uplift and erosion created regional discordance. Sediments removed from the Death Valley area were carried east and west by wind and water. The eastern sediments eventually ended up in Colorado and are now famous for their dinosaur fossils. Apart from some (possibly Jurassic) volcanic rocks around Butte Valley, no sedimentation took place in the Death Valley area from the Jurassic period to the Eocene . Large parts of the previously deposited formations may have been eroded by currents and contributed to the sedimentation in the Cretaceous Inlet, which at that time traversed North America lengthways in the east.
Tectonic and sedimentary development in the Tertiary and Quaternary
Formation of an alluvial plain
After 150 million years of volcanism, plutonism, metamorphism, and thrusting had passed, the early Tertiary (65 to 30 million years ago) was a period of calm. Neither volcanic nor sedimentary rocks are known from this period in the Death Valley area. The erosion created a relatively unstructured level over many millions of years. The sedimentation only started again 35 million years ago in the Oligocene , in the form of an alluvial plain. Sluggish currents meandered across the plain, leaving behind rubble, sand and mud. Outcrops of the resulting conglomerates, sand and mudstones of the Titus Canyon Formation can be seen in road sections at Daylight Pass, which becomes Nevada State Route 374 near the pass.
Renewed crust thinning, trenches and clumps ( basin and range )
Around 16 million years ago ( Miocene ), a large part of the North American plate began to expand laterally as it was literally being pulled apart. This process continues to this day. The reasons for the thinning are still controversial, but according to the increasingly popular “slab gap” hypothesis (slab column hypothesis), the former spreading zone of the Farallon plate is still active today, although it has already been crossed and subducted by the North American continent. However, the result is a large and still growing region with a relatively thin continental crust.
While deep rocks can expand plastically under lateral pull, like wet putty, the rocks break closer to the surface along faults . The sunken clods form the floors of tectonic trenches , which are mostly represented as topographical depressions ( basins ). The remaining clods ( clumps ) then emerge as smaller mountain ranges ( ranges ) that run parallel to each other on both sides of the trench. English-speaking geologists therefore call this region Basin and Range . Usually the number of clumps and trenches is limited, but there are dozens of such structures here, all roughly in a north-south direction. From the east of the Sierra Nevada through almost all of Nevada and into western Utah and southern Idaho , one eyrie-and-ditch structure lies behind the other.
The rocks of the later Panamint Range were probably once stored above the rocks that are now exposed in the Black Mountains and Cottonwood Mountains. Over the course of many millions of years, the Black Mountains area rose relative to its surroundings and the overlying rocks slid westward along shallow faults. Around six million years ago, the rocks of the Cottonwood Mountains also slid to the northwest from the Panamint Range. There is also evidence that the rocks of the Grapevine Mountains may have slipped from the Funeral Mountains. However, some geologists believe that the rocks in today's mountain ranges were not originally on top of each other, but rather next to each other. The widening trenches and eyries began to pull the area of Death Valley apart about three million years ago in the Pliocene , and about two million years ago the Death Valley and Panamint Valley finally sank as well.
This is complicated by the right-lateral movement along slip faults (English: strike-slip faults ). These are faults in which the neighboring rock blocks in the fault zone push each other sideways, so that a hypothetical observer standing on one of the two blocks would see the other block moving to the right. They were likely caused by tension forces associated with the northwestern movement of the Pacific plate along the San Andreas Fault to the west of the region. Very often, however, such faults have not only a lateral, but also a vertical movement component, so that they simultaneously represent leaf displacements and faults.
The left- lateral leaf displacement along the Garlock Fault south of the park is also responsible for the particularly wide extent and the strong subsidence of Death Valley . (The Garlock Fault separates the Sierra Nevada from the Mojave Desert .) This particular fault pulls the Panamint Range westward, causing the Death Valley Rift at the base of the Black Mountains to sink even further along the Furnace Creek Fault. In this way, the lowest topographical point on the dry mainland in the western hemisphere was created at Badwater.
Volcanism and the filling of the valley
Magmatic activity also occurred in connection with crustal expansion from 12 million years ago to 4 million years ago. Magmatic intrusions (plutons) solidified in the subsurface, and extrusive volcanic rocks formed on the surface. Basaltic magmas rose to the surface on fault lines and led to the eruption of cinder cones , such as the Split Cinder Cone , as well as lava flows. On other occasions, the magma beneath the surface overheated the groundwater until it exploded, creating craters and tuff rings such as the 2000-year-old Ubehebe Crater in the north of the park ( see also Maar ).
Some lakes were formed before the area was expanded. The most important of these was Furnace Creek Lake, which existed in a dry climate five to nine million years ago (though not as dry as it is today). The resulting Furnace Creek formation consists of sediments on the lake bed, which are composed of salty mud, gravel from the neighboring mountains and ash from the volcanoes of the Black Mountains that were active at the time. Today they can be seen in the Badlands at Zabriskie Point .
The sediments that formed after the formation of the Death Valley and Panamint Valley trenches from the material that was eroded in the surrounding eyries still accumulate in these valleys today. The amount of deposited sediments is roughly proportional to the subsidence, which means that the altitude of the valley floor has remained roughly the same over time.
About two to three million years ago, in the Pleistocene , continental ice sheets expanded from the polar regions to lower latitudes (but always remained far north of the Death Valley region) and triggered a series of ice ages . Alpine glaciers formed in the neighboring Sierra Nevada. Even if these glaciers did not penetrate into Death Valley, the colder and more humid climate meant that rivers flowed through the valleys of the region all year round. Since most of the valleys were created by faults and not river erosion, they often have no drains, so that they may fill with water until it overflows into the next valley. As a result, during the rainy climates of the Ice Ages, eastern California, all of Nevada, and western Utah were covered by great lakes separated by elongated islands (today's mountain ranges).
Lake Manly , the lake that filled Death Valley 10,500 years ago, was the last in a series of lakes supplied by the Amargosa River and the Mojave River , and perhaps the Owens River . It was also the lowest point in the Great Basin catchment area . At the height of the Great Ice Age around 22,000 years ago, Lake Manly was 187 m deep, 15-16 km wide and 145 km long. But the salt pans at the bottom of the valley were formed from the 10 m deep Recent Lake, which only dried up a few thousand years ago and was probably formed by the so-called "Little Ice Age". The Devil's Golf Course forms a small part of this salt pan, the Badwater Basin another. The Panamint Valley had its own lake, which geologists call Lake Panamint. Old, weak shorelines of Lake Manly can be seen on a former island in the lake called Shoreline Butte.
As the flanking mountain ranges rose, so did the gradient of the rivers. These faster streams are dry for most of the year, but have nonetheless cut real river valleys, canyons, and canyons into the rocks facing Death Valley and Panamint Valley. In this dry environment, alluvial cones form at the estuaries . Very large alluvial cones united along the Panamint Range to form so-called bajadas (alluvial plains). Due to the greater elevation, however, much smaller alluvial cones formed along the Black Mountains, as old cones are buried under the so-called playa sediments ( salt plains ) before they can grow. At the mouth of such streams one can often find slot canyons with V-shaped canyons. In view of this shape, they are also called "wine glass canyons".
Table of formations
| system | series | formation | Petrology and thickness | characteristic fossils |
|---|---|---|---|---|
| quaternary | Holocene | Gravel; Sand and salt at the bottom of the salt flats , less than 30 m thick | ||
| Pleistocene | Gravel; Sand and salt under the bottom of the salt flat , maybe 600 m thick | |||
| dead conglomerate | cemented gravel with embedded basaltic lava, gravel penetrated with calcite (Mexican onyx ); maybe 300 m thick | Diatoms , pollen | ||
| Tertiary | Pliocene | Furnace Creek Formation | cemented gravel, silt and salty deposits in the salt flats; various salts (especially borates ); more than 1500 m thick | barely |
| Miocene | Artist Drive Formation | cemented gravel, deposits in the salt clay plain, a lot of volcanic rubble; maybe 1500 m thick | barely | |
| Oligocene | Titus Canyon formation | cemented gravel, debris from streams; 900 m thick | Vertebrates , titanotheres , etc. | |
| Eocene and Paleocene | Granite and volcanic rock penetrate; no known sediment deposits | |||
| Chalk and Jurassic | not represented as the area eroded | |||
| Triad | Butte Valley Formation of Johnson (1957) | Metasediments and volcanic rocks; 2500 m thick | Ammonites , soft-shelled brachiopods , Belemnites and Hexakorallen | |
| Pennsylvania and Permian | Formations on the east side of Tucki Mountain | Conglomerate, limestone and some slate. The conglomerate contains limestone, the limestone and slate contain spherical silica . Thickness uncertain due to faults, estimated more than 900 m, surface eroded | Fusulinide , v. a. Fusulinella | |
| Carbon | Mississippium and Pennsylvania | Rest spring shale | mainly slate, some limestone; spherical silica; Thickness uncertain due to faults, estimated 230 m | |
| Mississippium | Tin Mountain Limestone and Younger Limestone | Tin Mountain: black limestone, layers thinner below than above (300 m thick) nameless formation: roughly the same amount of limestone and silica (221 m thick) |
various arm pods , corals , hair stars | |
| Devon | middle and upper Devonian | Lost Burro Formation | Limestone in light and dark, 0.3 - 3 m thick layers create a striped effect on the mountain. Two quartz layers at the lower end (each about 1 m thick), various sandstone layers above (240 - 300 m thick). The top 60 m is made of limestone and quartz. The total thickness is uncertain due to faulting, estimated 600 m. | Armfeet, v. a. Spirifer , Cyrtospirifer , Productilla , Carmarotoechia and Atrypa . In addition, stromal pores . |
| Silurian and Devonian | Silurian and Lower Devonian | Hidden Valley Dolomite | fine dolomite in thick layers, mainly light. Thickness 90 - 430 m. | Hair stars, also large types. Favorites. |
| Ordovician | upper ordovician | Ely Springs Dolomite | massive, black dolomite; 120 - 240 m thick | Streptelasmatid corals ( Grewingkia , Bighornia ) and pods |
| middle and upper (?) Ordovician | Eureka Quartzite | solid quartz, with thinner layers above and below; 105 m thick | ||
| lower and middle Ordovician | Pogonip Group | Dolomite with some limestone below and slate in the middle; 460 m thick | large snails in the upper part ( Pallisera and Maclurites , related to Receptaculites ), below Protopliomerops , Kirkella and Orthidae pods | |
| Cambrian | upper Cambrian | Nopah formation | Slate with many fossils in the lower 30 m, the upper consists of alternating light and dark layers of dolomite (each 30 m thick); a total of 365 - 457 m thick. | in the upper part snails, below remains of trilobites (including Elburgis , Pseudagnostus , Horriagnostris , Elvinia , Apsotreta ). |
| middle and upper Cambrian | Bonanza King Formation | mainly thick layers of dry, massive, dark dolomite, thin limestone layer (150 m thick) 300 m below the top, two brown slate layers. Total thickness uncertain due to faults, estimated 900 m in the Paramint Range and 600 m in the Funeral Mountains | The shale layer in the middle contains linguid armpods and remains of trilobites (including Ehmaniella ). | |
| lower and middle Cambrian | Carrara formation | alternating slate and silt with limestone in between, clastic formations below, carbonates above. Thickness about 300 m, but variable due to shear. | numerous remains of trilobites (Olenellus) | |
| lower Cambrian | Zabriskie Quartzite | Quartz, mainly solid dry granulate from shear, 15 - 60 cm thick layers; 45 m thick in total, but variable due to shear | ||
| lower Cambrian | Wood Canyon formation | 500 m of quartz below, 75 m of slate above, 120 m of dolomite and quartz above | a few Olenellus trilobites and archaeocyathids | |
| Stirling Quartzite | quartz layers between 30 cm and 240 m thick, interrupted by 150 m red slate; maximum thickness around 600 m | |||
| Johnnie formation | mainly slate, partly olive brown, partly red; below 120 m dolomite and dry quartz with silica conglomerate; locally light dolomite; more than 1200 m thick | |||
| Precambrian | Noonday Dolomite | indefinite dolomite in the southern Panamint Range , cream-colored below, gray above, 240 m thick; further north a lot of limestone, brown and white and some limestone conglomerate, about 300 m thick | ||
| Discordance | ||||
| Kingston Peak Formation | mainly conglomerate, quartz and slate, some limestone and dry dolomite in the middle; at least 900 m thick; Assignment uncertain | |||
| Beck Spring Dolomite | not listed; Outcrops in the west; blue-gray dolomite, around 152 m thick; insecure identification | |||
| Pahrump Series | Crystal Spring Formation | only recognized in Galena Canyon and south; Conglomerate covered with quartz that turns into red slate, with dolomite, diabase and silica on top; Talc deposits on the border of diabase and dolomite; a total of around 600 m thick | ||
| Discordance | ||||
| Crystalline Base Rocks | Metasediments with granite inclusions |
Table of salts
| mineral | chemical structure | known or probable occurrence |
|---|---|---|
| Halite | NaCl | as rock salt, a basic component of chlorides and salty sulphates and carbonate deposits |
| Sylvin | KCl | with rock salt |
| Nahcolith | NaH [CO 3 ] | not yet identified, possibly in winter as efflorescence, trona or sodium carbonate in the carbonate of the Cottonball Basin |
| Trona | Na 3 (HCO 3 ) (CO 3 ) • 2H 2 O | Carbonate of the Cottonball Basin, especially in marshes |
| Thermonatrite | Na 2 [CO 3 ] • H 2 O | questionable in the floodplains of the Badwater Basin, expected in the marshes of the carbonate in the Cottonball Basin |
| Soda ( sodium hydrogen carbonate , baking soda ) | Na 2 [CO 3 ] • 10H 2 O | not yet identified, but v. a. expected in winter after rain or high runs in the Carbonate Marshes in the Cottonball Basin |
| Pirssonite | Na 2 Ca [CO 3 ] 2 • 2H 2 O | not yet identified, expected in areas where gaylussite is dehydrated |
| Gaylussite | Na 2 Ca [CO 3 ] 2 • 5H 2 O | in the carbonate and floodplains of the Badwater Basin |
| Calcite | Ca [CO 3 ] | as clastic pebbles in sediments under the salt pan and as sharp crystals in the clay of the carbonate and sediments under the sulfate |
| Magnesite ( magnesium carbonate ) | Mg [CO 3 ] | in artificially evaporated lye of Death Valley, not yet identified in the salt pan, possibly in the carbonate of the Cottonball Basin |
| dolomite | CaMg [CO 3 ] 2 | identified only as debris mineral, expected in carbonate |
| Northupit or Tychit | Na 3 Mg [Cl | (CO 3 ) 2 ] or Na 6 Mg 2 [SO 4 | (CO 3 ) 4 ] | an isotropic mineral with an index of refraction in the range of northupite and tychite; in salty facies of sulfate in the Cottonball Basin |
| Burkeit | Na 6 [CO 3 | (SO 4 ) 2 ] | Sulphate of the Cottonball Basin |
| Thenardite | Na 2 [SO 4 ] | in all zones of the Cottonball Basin and in the sulphate marshes of the Middle and Badwaters Basin |
| Mirabilite | Na 2 [SO 4 ] • 10H 2 O | in the floodplains of the Cottonball Basin immediately after winter storms |
| Glauberite | Na 2 Ca [SO 4 ] 2 | in floodplains except in the middle Badwater Basin, in the sulphate of the Cottonball Basin |
| Anhydrite | Ca [SO 4 ] | covers massive gypsum 2 km north of Badwater, possibly also as efflorescence of the dry season in floodplains |
| Bassanite | Ca [SO 4 ] • ½H 2 O | covered massive gypsum on the west side of the Badwater Basin and as dry season efflorescence in floodplains |
| plaster | Ca [SO 4 ] • 2H 2 O | in sulphate caliche, v. a. in the Middle and Badwater Basin, in sulphate marshes and as massive deposits in sulphate |
| Hexahydrite | Mg [SO 4 ] • 6H 2 O | not yet identified, expected as dehydration product of epsomite in chloride in floodplains |
| Epsomit | Mg [SO 4 ] • 7H 2 O | not yet identified, probably as efflorescence in floodplains after storms and floods |
| Stupid | Na 2 Mg [SO 4 ] 2 • 4H 2 O | possibly as efflorescence in floodplains in the chloride |
| Polyhalite | K 2 Ca 2 Mg [SO 4 ] 4 • 2H 2 O | possibly in floodplains in the chloride |
| Barite | Ba [SO 4 ] | not yet identified, but probably in carbonate and as clastic pebbles in sediments under the salt pan |
| Celestine | Sr [SO 4 ] | with solid plaster |
| Schairerit | Na 21 [F | Cl | (SO 4 ) 7 ] | not yet identified, expected in Cottonball Basin and on the east side of the Middle Basin |
| Sulfohalite | Na 6 [F | Cl | (SO 4 ) 2 ] | not yet identified, expected in Cottonball Basin and on the east side of the Middle Basin |
| Kernite | Na 2 [B 4 O 6 (OH) 2 ] • 3H 2 O | possibly in the Middle Basin above the sulphate and chloride salt layers |
| Tincalconite | Na 6 [B 4 O 5 (OH) 4 ] 3 • 8H 2 O | possibly as a dehydration product of borax |
| borax | Na 2 [B 4 O 5 (OH) 4 ] • 8H 2 O | Floodplains and marshes in the Cottonball Basin |
| Inyoit | Ca [B 3 O 3 (OH) 5 ] • 4H 2 O | possibly in floodplains of the Badwater Basin, but occurrence uncertain despite X-ray examination |
| Meyerhofferit | Ca [B 3 O 3 (OH) 5 ] • H 2 O | in all zones of the Badwater Basin and in raw siltstone salt in the Cottonball Basin |
| Colemanite | Ca [B 3 O 4 (OH) 3 ] • H 2 O | possibly in the floodplains of the Badwater Basin, but occurrence uncertain despite X-ray examination |
| Ulexite | NaCa [B 5 O 6 (OH) 6] • 5H 2 O | in the floodplains of the Cottonball Basin, also known as the "cotton ball" |
| Probertit | NaCa [B 5 O 7 (OH) 4 ] • 3H 2 O | a fibrous borate with a higher refractive index than ulexite, in dry areas of the Cottonball Basin after hot, dry times and as the surface of soft siltstone salt |
| Nitronatrite ( Nitratin ) | Na [NO 3 ] | weak but positive chemical tests |
swell
This article is based on the article en: Geology of the Death Valley area .
Individual evidence
- ^ Ann G. Harris, Esther Tuttle, Sherwood D. Tuttle: Geology of National Parks. 5th edition. Hunt Publishing, Dubuque, IA, Kendall 1997, p. 630.
- ↑ a b c Harris et al: Geology of National Parks. 1997, p. 631.
- ^ A b Harris et al.: Geology of National Parks. 1997, p. 611.
- ↑ a b c Harris et al: Geology of National Parks. 1997, p. 632.
- ↑ a b A Mudflat to Remember , Death Valley National Park through time, USGS
- ↑ a b c d e Harris et al: Geology of National Parks. 1997, p. 634.
- ^ The Earliest Animal , Death Valley National Park through time, USGS
- ↑ a b c Death Valley- Caribbean-style , Death Valley National Park through time, USGS
- ^ The Earth Shook, The Sea Withdrew , Death Valley National Park through time, USGS
- ↑ a b Granite ( Memento of the original from August 11, 2006 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. . Death Valley National Park through time, USGS
- ^ Quiet to Chaos , Death Valley National Park through time, USGS
- ↑ Forces Driving Mountain Building in Death Valley ( Memento of the original from August 14, 2006 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , Death Valley National Park through time, USGS
- ↑ Recent Geologic Changes ( Memento of the original from August 14, 2006 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. , Death Valley National Park through time, USGS
- ↑ Eugene P. Kiver, David V. Harris: Geology of US Parklands. 5th edition. New York, John Wiley & Sons, 1999, pp. 278-279.
- ^ Harris et al: Geology of National Parks. 1997, p. 616.
- ^ Robert P. Sharp, Allen F. Glazner: Geology Underfoot in Death Valley and Owens Valley. Mountain Press Publishing, Missoula, MT 1997, pp. 41-53.
- ↑ CB Hunt, DR Mabey: General geology of Death Valley, California. ( Memento of the original from April 25, 2006 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. US Geological Survey Professional Paper 494, 1966.
literature
- Ann G. Harris, Esther Tuttle, Sherwood D. Tuttle: Geology of National Parks: Fifth Edition. Hunt Publishing, Kendall, Iowa 1997, ISBN 0-7872-5353-7 .
- Eugene P. Kiver, David V. Harris: Geology of US Parklands: Fifth Edition. John Wiley & Sons, New York 1999, ISBN 0-471-33218-6 .
- Robert P. Sharp, Allen F. Glazner: Geology Underfoot in Death Valley and Owens Valley. Mountain Press Publishing Company, Missoula 1997, ISBN 0-87842-362-1 .
- Patrick Stäheli: California I - South and East; Basin and Range, Transverse and Peninsular Ranges, Death Valley, Mojave Desert, Geology and Excursions. Schweizerbart science publishers, Stuttgart 2013, ISBN 978-3-443-15096-9 .
Web links
- USGS: Death Valley National Park through time
- USGS Death Valley geology field trip
- USGS / NPS: Rock Formations exposed in the Death Valley area
- Proceedings on Conference on Status of Geologic Research and Mapping, Death Valley National Park (PDF) (1.61 MB)
- Tertiary Extensional Features, Death Valley, Eastern California (PDF; 1.2 MB)