Post-Laramide and pre-Basin and Range deformation and
... a b s t r a c t At central-eastern Mexico, in the Mesa Central province, there are several ranges that were formed after the K/T Laramide compression but before the Basin and Range peak extensional episodes at middle–late Oligocene. Two important volcano-tectonic events happened during this time int ...
... a b s t r a c t At central-eastern Mexico, in the Mesa Central province, there are several ranges that were formed after the K/T Laramide compression but before the Basin and Range peak extensional episodes at middle–late Oligocene. Two important volcano-tectonic events happened during this time int ...
geologic map of the pocatello south quadrangle, bannock and
... member. Marble is thin-bedded to massive, tan to dark gray, typically composed of calcite but locally dolomite, and as much as 30 feet thick. Quartzite is interbedded with interlaminated metasiltstone and fine-grained quartzite, typical of the Papoose Creek Formation, in the lower 100-300 feet. Lowe ...
... member. Marble is thin-bedded to massive, tan to dark gray, typically composed of calcite but locally dolomite, and as much as 30 feet thick. Quartzite is interbedded with interlaminated metasiltstone and fine-grained quartzite, typical of the Papoose Creek Formation, in the lower 100-300 feet. Lowe ...
Synclinal-horst basins: examples from the southern Rio Grande rift
... Miocene RinconValley Formation and the Pliocene^lower Pleistocene Camp Rice Formation, as well as a few metres to tens of metres of middle Pleistocene to Holocene sediment overlying and locally inset against the Camp Rice Formation (Clemons, 1979). Both the Camp Rice and younger alluvium are exposed ...
... Miocene RinconValley Formation and the Pliocene^lower Pleistocene Camp Rice Formation, as well as a few metres to tens of metres of middle Pleistocene to Holocene sediment overlying and locally inset against the Camp Rice Formation (Clemons, 1979). Both the Camp Rice and younger alluvium are exposed ...
Cenozoic Stratigraphy and Tectonic Evolution of the Raft River
... fill is mainly the Salt Lake Formation of Miocene to Pliocene age, which consists of four members: (1) a lower tuffaceous member of shale, siltstone, and sandstone; (2) a wedge of talc-alkalic rhyolite flows with associated volcanic domes here named the Jim Sage Volcanic Member; (3) an upper tufface ...
... fill is mainly the Salt Lake Formation of Miocene to Pliocene age, which consists of four members: (1) a lower tuffaceous member of shale, siltstone, and sandstone; (2) a wedge of talc-alkalic rhyolite flows with associated volcanic domes here named the Jim Sage Volcanic Member; (3) an upper tufface ...
GEOMORPHOLOGY AND MOUNTAIN BUILDING
... over a hundred kilometres (fig. 6). But the thrusts did not make the mountains! After the thrusting of nappes there was a period of planation, with gentle surfaces cutting across rock structures (Demangeot, 1965). Regardless of arguments about the age and perfection of the planation surfaces, the ol ...
... over a hundred kilometres (fig. 6). But the thrusts did not make the mountains! After the thrusting of nappes there was a period of planation, with gentle surfaces cutting across rock structures (Demangeot, 1965). Regardless of arguments about the age and perfection of the planation surfaces, the ol ...
East Java: Cenozoic Basins, Volcanoes and Ancient Basement
... volcanic arc (named here the Southern Mountains Volcanic Arc) built on Mesozoic basement. Deposits include siliciclastic, volcaniclastic, volcanic and carbonate rocks which generally dip uniformly to the south. Present-day volcanic arc: active from the Late Miocene. Kendeng Zone: the main Eocene-Mio ...
... volcanic arc (named here the Southern Mountains Volcanic Arc) built on Mesozoic basement. Deposits include siliciclastic, volcaniclastic, volcanic and carbonate rocks which generally dip uniformly to the south. Present-day volcanic arc: active from the Late Miocene. Kendeng Zone: the main Eocene-Mio ...
Geological History of Canada - McGraw Hill Higher Education
... of low relief and great areal extent and age. Erosion and bevelling of the ancient rocks of the craton had created this peneplain by about 800 million years ago. The outer, gently sloping margins of the Shield are buried below younger sedimentary rocks, and the ancient peneplain surface now forms an ...
... of low relief and great areal extent and age. Erosion and bevelling of the ancient rocks of the craton had created this peneplain by about 800 million years ago. The outer, gently sloping margins of the Shield are buried below younger sedimentary rocks, and the ancient peneplain surface now forms an ...
1 I-68/I-70: A WINDOW TO THE APPALACHIANS by Dr. John J
... with some of the rocks exposed in Europe from northern Ireland through Scotland to Scandinavia. Over the next 100 million or so years, the combined efforts of weathering, mass wasting, and erosion wore the topography of the original Allegheny Mountains down to a flat, featureless plain nearly at sea ...
... with some of the rocks exposed in Europe from northern Ireland through Scotland to Scandinavia. Over the next 100 million or so years, the combined efforts of weathering, mass wasting, and erosion wore the topography of the original Allegheny Mountains down to a flat, featureless plain nearly at sea ...
Geology of the Eagle Mountains, Hudspeth County, Texas
... Eagle Mountains and the associated highlands, Devil Ridge and Indio Mountains, trending generally northwest to northnorthwest, are surrounded by "bolsons" or intermontane basins partly filled with alluvium and are an extension into southeastern Hudspeth County of the eastern part of a long, narrow, ...
... Eagle Mountains and the associated highlands, Devil Ridge and Indio Mountains, trending generally northwest to northnorthwest, are surrounded by "bolsons" or intermontane basins partly filled with alluvium and are an extension into southeastern Hudspeth County of the eastern part of a long, narrow, ...
Carrizo Plain Natural Area Two Self-Guided Geologic
... flow to the ocean, but rather to Soda Lake and nearby ponds, which usually dry out in the summer. Salts, dissolved from sediments and carried down into the plain, accumulate through evaporation. A lack of old shorelines or terraces suggests that, unlike other alkali lakes in the western states, Soda ...
... flow to the ocean, but rather to Soda Lake and nearby ponds, which usually dry out in the summer. Salts, dissolved from sediments and carried down into the plain, accumulate through evaporation. A lack of old shorelines or terraces suggests that, unlike other alkali lakes in the western states, Soda ...
Guide_CarbonerasFieldTrip
... Rocks of the Cabo de Gata calc-alkaline volcanic terrain cover much of the onshore area to the south-east of the CFZ, between Cabo de Gata and a few km north from Carboneras, and include a number of individual eruptive volcanic centres (e.g. Rodalquilar, Majada Redondo, Los Frailes). The ages of the ...
... Rocks of the Cabo de Gata calc-alkaline volcanic terrain cover much of the onshore area to the south-east of the CFZ, between Cabo de Gata and a few km north from Carboneras, and include a number of individual eruptive volcanic centres (e.g. Rodalquilar, Majada Redondo, Los Frailes). The ages of the ...
Chapter 30. The Sediments of the Continental Margin
... The continental rise exists only along Atlantic-type, passive margins (Figure 30.2a). It is expressed as a gradual decline in slope seaward of the continental slope. The continental rise blends into the deep abyssal plains, which are mainly composed of abyssal hills at an average depth of 2.5 miles ...
... The continental rise exists only along Atlantic-type, passive margins (Figure 30.2a). It is expressed as a gradual decline in slope seaward of the continental slope. The continental rise blends into the deep abyssal plains, which are mainly composed of abyssal hills at an average depth of 2.5 miles ...
the geology of the olifants river area, transvaal
... the Leolo" Mountains and most of that along the Drakensberg are inaccessible to wheeled transport. Some of the tracks leading to isolated farms and asbestos-mines are very dangerous. This area was first geologically surveyed by Hall (1914) between 1907 and 1911. The northeastern corner of the area w ...
... the Leolo" Mountains and most of that along the Drakensberg are inaccessible to wheeled transport. Some of the tracks leading to isolated farms and asbestos-mines are very dangerous. This area was first geologically surveyed by Hall (1914) between 1907 and 1911. The northeastern corner of the area w ...
Part 3
... years, several registrations have been made which indicate that in some areas at least, land uplift is not a reaction to relief of pressure following former loading by ice. These crustal movements are related to movements in the Earth's interior and are called neotectonics. Neotectonic movements inv ...
... years, several registrations have been made which indicate that in some areas at least, land uplift is not a reaction to relief of pressure following former loading by ice. These crustal movements are related to movements in the Earth's interior and are called neotectonics. Neotectonic movements inv ...
NWGS Swauk-Snoq
... the vicinity of Cle Elum, were deposited in separate basins. An alternative view is that sedimentation and volcanism since and including the Eocene are bounded by four major interregional and even more numerous regional unconformities (Cheney, 1994) (Figure 3). In this view, interregional and region ...
... the vicinity of Cle Elum, were deposited in separate basins. An alternative view is that sedimentation and volcanism since and including the Eocene are bounded by four major interregional and even more numerous regional unconformities (Cheney, 1994) (Figure 3). In this view, interregional and region ...
Field Geology: Northern Arizona
... Sedona, AZ. Time permitting, along the way examine exposures at Sunset Point where the Shylock Fault Zone which separates two Proterozoic metamorphic terranes and the related Transition Zone topography. The Bradshaw Mountains are visible to the west (~7000’ elev.) from the Sunset rest area. Stop nor ...
... Sedona, AZ. Time permitting, along the way examine exposures at Sunset Point where the Shylock Fault Zone which separates two Proterozoic metamorphic terranes and the related Transition Zone topography. The Bradshaw Mountains are visible to the west (~7000’ elev.) from the Sunset rest area. Stop nor ...
This field trip will emphasize the changing geographic
... Ocean Dallas is the story of rocks and fossils in what is now the Dallas-Fort Worth region, called the Metroplex by many of the people who live here. It explains the changing geographic arrangement of land and sea during the time interval from 96 Ma to 86 Ma (mega-annum, which means millions of year ...
... Ocean Dallas is the story of rocks and fossils in what is now the Dallas-Fort Worth region, called the Metroplex by many of the people who live here. It explains the changing geographic arrangement of land and sea during the time interval from 96 Ma to 86 Ma (mega-annum, which means millions of year ...
Chapter 11 SEDIMENTARY BASINS
... 5.1 Much effort has gone into developing ways of figuring out paths of dispersal of sedimentary material in basins. One of the standard ways is to measure paleocurrent directions recorded locally in the rocks. (A paleocurrent is just what the term implies: a current, of water or wind, that existed a ...
... 5.1 Much effort has gone into developing ways of figuring out paths of dispersal of sedimentary material in basins. One of the standard ways is to measure paleocurrent directions recorded locally in the rocks. (A paleocurrent is just what the term implies: a current, of water or wind, that existed a ...
The Recognition of Strike-Slip Fault Systems Using Imagery
... Overton Arm is a narrow north-south extension of Lake Mead, but once it crosses north of the southwestern strand of the Lake Mead Fault System, the lake assumes a rhomboid shape that trends to the northeast (Figure 8). The topographic low continues to the northeast beyond the lake to the Virgin Moun ...
... Overton Arm is a narrow north-south extension of Lake Mead, but once it crosses north of the southwestern strand of the Lake Mead Fault System, the lake assumes a rhomboid shape that trends to the northeast (Figure 8). The topographic low continues to the northeast beyond the lake to the Virgin Moun ...
Tertiary Igneous Rocks of Northeastern Cache Valley, Idaho
... periods are most readily recognized along the valley edges as valley aprons and at the mouths of the large streams draining into the valley where deltas are developed. ...
... periods are most readily recognized along the valley edges as valley aprons and at the mouths of the large streams draining into the valley where deltas are developed. ...
Lone Pine Area - Geologic Trips
... formed the backdrop for some 200 movies and many television programs. The rocks of the Alabama Hills are the same granitic and metamorphic rocks that occur in the Sierra Nevada. However, the granite in the Alabama Hills is not clean and fresh like the granite in the High Sierra, but is deeply weathe ...
... formed the backdrop for some 200 movies and many television programs. The rocks of the Alabama Hills are the same granitic and metamorphic rocks that occur in the Sierra Nevada. However, the granite in the Alabama Hills is not clean and fresh like the granite in the High Sierra, but is deeply weathe ...
Geologic Map of Paleozoic Rocks in the Mount Morrison Pendant
... northeast in west central Nevada and in the Saddlebag Lake, Northern Ritter Range and Log Cabin Mine pendants (Greene et al., 1997a). In general, the Mount Morrison pendant seems to have occupied a position at the base of the continental slope, where finegrained, siliceous, deep-water sediments were ...
... northeast in west central Nevada and in the Saddlebag Lake, Northern Ritter Range and Log Cabin Mine pendants (Greene et al., 1997a). In general, the Mount Morrison pendant seems to have occupied a position at the base of the continental slope, where finegrained, siliceous, deep-water sediments were ...
Sequoia and Kings Canyon
... From Junction View, you can see where the Middle and South Forks join to form the Kings River. These rivers are in the steep, rugged, V-shaped canyons that were cut during the Plio-Pleistocene uplift of the Sierra Nevada. The bottom of the canyon is 8,000 feet below the top of Spanish Mountain, whic ...
... From Junction View, you can see where the Middle and South Forks join to form the Kings River. These rivers are in the steep, rugged, V-shaped canyons that were cut during the Plio-Pleistocene uplift of the Sierra Nevada. The bottom of the canyon is 8,000 feet below the top of Spanish Mountain, whic ...
CENOZOIC HISTORY OF THE CHUYA DEPRESSION (Gorny Altai
... structure of the formation suggest its origin in a large limnic basin, and the presence of coarse-grained interbeds with angular fragments at the depression's periphery indicates the inception of the Kurai Range. The 50 m thick Kyzyl-Gir Formation is composed of yellow-brown and gray coarse-grained ...
... structure of the formation suggest its origin in a large limnic basin, and the presence of coarse-grained interbeds with angular fragments at the depression's periphery indicates the inception of the Kurai Range. The 50 m thick Kyzyl-Gir Formation is composed of yellow-brown and gray coarse-grained ...
Paleozoic stratigraphy, tectonics and metallogeny
... Kechika, Askin, Harvey and Seagull groups. TempelmanKluit (2012) concluded that many of these depositional sequences likely correlate with age-equivalent strata of the Cassiar terrane in northern British Columbia (Cassiar Mountains) or other passive margin elements in eastern Yukon. Figure 2 shows a ...
... Kechika, Askin, Harvey and Seagull groups. TempelmanKluit (2012) concluded that many of these depositional sequences likely correlate with age-equivalent strata of the Cassiar terrane in northern British Columbia (Cassiar Mountains) or other passive margin elements in eastern Yukon. Figure 2 shows a ...
Geology of the Death Valley area
The exposed geology of the Death Valley area presents a diverse and complex set of at least 23 formations of sedimentary units, two major gaps in the geologic record called unconformities, and at least one distinct set of related formations geologists call a group. The oldest rocks in the area that now includes Death Valley National Park are extensively metamorphosed by intense heat and pressure and are at least 1700 million years old. These rocks were intruded by a mass of granite 1400 Ma (million years ago) and later uplifted and exposed to nearly 500 million years of erosion.Marine deposition occurred 1200 to 800 Ma, creating thick sequences of conglomerate, mudstone, and carbonate rock topped by stromatolites, and possibly glacial deposits from the hypothesized Snowball Earth event. Rifting thinned huge roughly linear parts of the supercontinent Rodinia enough to allow sea water to invade and divide its landmass into component continents separated by narrow straits. A passive margin developed on the edges of these new seas in the Death Valley region. Carbonate banks formed on this part of the two margins only to be subsided as the continental crust thinned until it broke, giving birth to a new ocean basin. An accretion wedge of clastic sediment then started to accumulate at the base of the submerged precipice, entombing the region's first known fossils of complex life. These sandy mudflats gave way about 550 Ma to a carbonate platform which lasted for the next 300 million years of Paleozoic time.The passive margin switched to active margin in the early-to-mid Mesozoic when the Farallon Plate under the Pacific Ocean started to dive below the North American Plate, creating a subduction zone; volcanoes and uplifting mountains were created as a result. Erosion over many millions of years created a relatively featureless plain. Stretching of the crust under western North America started around 16 Ma and is thought to be caused by upwelling from the subducted spreading-zone of the Farallon Plate. This process continues into the present and is thought to be responsible for creating the Basin and Range province. By 2 to 3 million years ago this province had spread to the Death Valley area, ripping it apart and creating Death Valley, Panamint Valley and surrounding ranges. These valleys partially filled with sediment and, during colder periods during the current ice age, with lakes. Lake Manly was the largest of these lakes; it filled Death Valley during each glacial period from 240,000 years ago to 10,000 years ago. By 10,500 years ago these lakes were increasingly cut off from glacial melt from the Sierra Nevada, starving them of water and concentrating salts and minerals. The desert environment seen today developed after these lakes dried up.