Article
... geometry [1], which the Devonian and Triassic sample sets show in Fig 4. The recycled Devonian sample set is dominated by Precambrian ages with good correlation to the “Cordilleran supersource I”, with lesser fractions derived from Paleozoic arcs. Detrital zircons from the exotic Devonian sample set ...
... geometry [1], which the Devonian and Triassic sample sets show in Fig 4. The recycled Devonian sample set is dominated by Precambrian ages with good correlation to the “Cordilleran supersource I”, with lesser fractions derived from Paleozoic arcs. Detrital zircons from the exotic Devonian sample set ...
The Penokean orogeny in the Lake Superior region
... margin of the Archean Superior craton marking the end of a period of south-directed subduction. The docking of the buoyant craton to the arc resulted in a subduction jump to the south and development of back-arc extension both in the initial arc and adjacent craton margin to the north. A belt of vol ...
... margin of the Archean Superior craton marking the end of a period of south-directed subduction. The docking of the buoyant craton to the arc resulted in a subduction jump to the south and development of back-arc extension both in the initial arc and adjacent craton margin to the north. A belt of vol ...
Western Greece and Ionian Sea petroleum systems
... zones (Figure 1B). From the Triassic to the Late Cretaceous, western Greece was part of the Apulian continental block on the southern passive margin of the Tethys Ocean (Figure 1A). In this area, siliceous facies are widely associated with organic carbon-rich deposits. Pre-Apulian zone rocks consist ...
... zones (Figure 1B). From the Triassic to the Late Cretaceous, western Greece was part of the Apulian continental block on the southern passive margin of the Tethys Ocean (Figure 1A). In this area, siliceous facies are widely associated with organic carbon-rich deposits. Pre-Apulian zone rocks consist ...
Heavy Mineral Characteristics and Their Implication for Provenance
... monazite-apatite-tourmaline-antase, and 17.52% of the interpreted information of F2 represents the rutile-ilmenite-leucoxene-pyroxene combination. The first two main factors contain the unstable mineral pyroxene and the unstable minerals apatite, monazite, ilmenite and leucoxene; the rest of the min ...
... monazite-apatite-tourmaline-antase, and 17.52% of the interpreted information of F2 represents the rutile-ilmenite-leucoxene-pyroxene combination. The first two main factors contain the unstable mineral pyroxene and the unstable minerals apatite, monazite, ilmenite and leucoxene; the rest of the min ...
Stratigraphic and structural evolution of the Blue Nile Basin
... Field and remote sensing studies have been focused on four accessible key areas along the Gorge of the Nile (Figure 2) that expose representative Mesozoic and Cenozoic stratigraphic successions and allow for examination of various structural styles and orientations (areas 1, 2, 3 and 4 on Figure 2). ...
... Field and remote sensing studies have been focused on four accessible key areas along the Gorge of the Nile (Figure 2) that expose representative Mesozoic and Cenozoic stratigraphic successions and allow for examination of various structural styles and orientations (areas 1, 2, 3 and 4 on Figure 2). ...
Nappes of the southern Tien Shan
... The southern Tien Shan is a folded area with widespread Paleozoic nappes. The ensembles of nappes distributed in Uzbekistan, Tajikistan, Kyrgyzstan, and China are described, and their structural similarity and distinctions in different parts of the area are shown. Nappes of the southern Tien Shan oc ...
... The southern Tien Shan is a folded area with widespread Paleozoic nappes. The ensembles of nappes distributed in Uzbekistan, Tajikistan, Kyrgyzstan, and China are described, and their structural similarity and distinctions in different parts of the area are shown. Nappes of the southern Tien Shan oc ...
Chapter 11 SEDIMENTARY BASINS
... with the existence of thick successions of sedimentary rocks in what we would today call orogenic belts. A geosyncline is large troughlike or basinlike downwarping of the crust in which thick sedimentary and volcanic rocks accumulated. Usually, but not always, such accumulations are deformed during ...
... with the existence of thick successions of sedimentary rocks in what we would today call orogenic belts. A geosyncline is large troughlike or basinlike downwarping of the crust in which thick sedimentary and volcanic rocks accumulated. Usually, but not always, such accumulations are deformed during ...
Field Trip Guide to the Upper Cretaceous Hornbrook Formation and
... Jurassic Mt. Ashland pluton and Early Cretaceous Grants Pass pluton (Hotz 1971; Gribble et al., 1990). During the Late Jurassic to Early Cretaceous, a subduction zone complex and forearc basin developed along the western margin of North America while folding and thrusting of Paleozoic and lower Meso ...
... Jurassic Mt. Ashland pluton and Early Cretaceous Grants Pass pluton (Hotz 1971; Gribble et al., 1990). During the Late Jurassic to Early Cretaceous, a subduction zone complex and forearc basin developed along the western margin of North America while folding and thrusting of Paleozoic and lower Meso ...
44. Mesozoic-Cenozoic Geology of the Eastern Margin of the Grand
... from a continental depositional environment accompanying initial rifting to deposition in marine water from the Tethys as rifting progressed. Deposition occurred in an arid climatic belt in restricted evaporite basins, followed by coastal sabkhas, tidal flats, and restricted lagoons, and finally, by ...
... from a continental depositional environment accompanying initial rifting to deposition in marine water from the Tethys as rifting progressed. Deposition occurred in an arid climatic belt in restricted evaporite basins, followed by coastal sabkhas, tidal flats, and restricted lagoons, and finally, by ...
Plate Tectonics - The Open University
... geology of our planet. It has also affected the hydrosphere through the changes in the shape and size of the oceans, the ocean-atmosphere circulation, the configuration and extremities of the Earth's climate zones and, perhaps, even the nature of the biosphere and the course of the evolution of life ...
... geology of our planet. It has also affected the hydrosphere through the changes in the shape and size of the oceans, the ocean-atmosphere circulation, the configuration and extremities of the Earth's climate zones and, perhaps, even the nature of the biosphere and the course of the evolution of life ...
Geology and U-Pb geochronology of the Annidale Group, southern
... zones of extensive alteration characterized by the presence of carbonate, silica and chromium-rich micas in which numer ous significant gold and base metal occurrences have been identified. The central sequence, here termed the Lawson Brook Formation, is composed of felsic volcanic rocks, felsic mi ...
... zones of extensive alteration characterized by the presence of carbonate, silica and chromium-rich micas in which numer ous significant gold and base metal occurrences have been identified. The central sequence, here termed the Lawson Brook Formation, is composed of felsic volcanic rocks, felsic mi ...
Geology of Ethiopia
... development of the Ethiopian basement ranging in age from 880 to 550 Ma. This folded and tilted Proterozoic basement underwent intense erosion, which lasted one hundred million years, and destroyed any relief of the Precambrian orogen. Ordovician to Silurian fluviatile sediments and Late Carbonifero ...
... development of the Ethiopian basement ranging in age from 880 to 550 Ma. This folded and tilted Proterozoic basement underwent intense erosion, which lasted one hundred million years, and destroyed any relief of the Precambrian orogen. Ordovician to Silurian fluviatile sediments and Late Carbonifero ...
2. - Teacher Friendly Guides
... the crust due to compression, subduction, or mountain building. ...
... the crust due to compression, subduction, or mountain building. ...
Ocean Drilling Program Scientific Results Volume 124
... environment protected from significant volumes of terrigenous sediment. The preserved organic fraction in the red clays, however, appears to be entirely of terrigenous origin, and the clay mineral composition is indistinguishable from that of the green clay stones above. Paleomagnetic inclinations s ...
... environment protected from significant volumes of terrigenous sediment. The preserved organic fraction in the red clays, however, appears to be entirely of terrigenous origin, and the clay mineral composition is indistinguishable from that of the green clay stones above. Paleomagnetic inclinations s ...
Empplacement Of The Bibai And Gogai Nappes, Northeast Of Quetta
... nappe suggesl that these rocks were deposited on the continental slope while the same foxmation is well bedded at the base of Bibai nappe indicating deposition on continental shelf. All these observations indicate that a considerable tectonic transport was involved in the emplacement of Gogai nappe ...
... nappe suggesl that these rocks were deposited on the continental slope while the same foxmation is well bedded at the base of Bibai nappe indicating deposition on continental shelf. All these observations indicate that a considerable tectonic transport was involved in the emplacement of Gogai nappe ...
Abstract Volume
... Jason R. Ali, J. Godfrey Fitton and Claude Herzberg ............................................................................................ 8 Triassic Tectonics in the South-Western Margin of the South China Block and the Welding of the South China -Indochina Blocks Michel Faure, Claude Lepvrie ...
... Jason R. Ali, J. Godfrey Fitton and Claude Herzberg ............................................................................................ 8 Triassic Tectonics in the South-Western Margin of the South China Block and the Welding of the South China -Indochina Blocks Michel Faure, Claude Lepvrie ...
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... events are discussed although ∼ 20% of the present continental crust formed or was remobilized during this time. Processes responsible for forming and deforming the continental crust during Neoproterozoic time were similar to those of the modern Earth and took place mostly but not entirely at conver ...
... events are discussed although ∼ 20% of the present continental crust formed or was remobilized during this time. Processes responsible for forming and deforming the continental crust during Neoproterozoic time were similar to those of the modern Earth and took place mostly but not entirely at conver ...
chapter4 - Geological Sciences
... Unconformities are surfaces of discontinuity in the rock deposition sequence which encompass significant periods of time. Unconformities may result from nondeposition and/or erosion. These surfaces encompass long periods of geologic time for which there is no geologic record at that location. ...
... Unconformities are surfaces of discontinuity in the rock deposition sequence which encompass significant periods of time. Unconformities may result from nondeposition and/or erosion. These surfaces encompass long periods of geologic time for which there is no geologic record at that location. ...
Field Geology: Northern Arizona
... The Lewis and Clark Expedition in the early years of the 19th century opened up large and unknown areas of the American frontier. By May of 1869, the transcontinental railroad joined east and west at Promontory Point in Utah. Miners, trappers and adventurers delved deep into the hidden recesses of ...
... The Lewis and Clark Expedition in the early years of the 19th century opened up large and unknown areas of the American frontier. By May of 1869, the transcontinental railroad joined east and west at Promontory Point in Utah. Miners, trappers and adventurers delved deep into the hidden recesses of ...
tectonic models for the geological evolution of crust, cratons and
... [email protected] Abstract The earliest sialic crust was probably destroyed by meteorite impacts, leaving only detrital 4.2-3.9 Ga zircons in later sediments. The oldest rocks are 3.9-3.8 Ga high-grade gneisses commonly associated with lavas and sediments which were transported into the deep crust. They ...
... [email protected] Abstract The earliest sialic crust was probably destroyed by meteorite impacts, leaving only detrital 4.2-3.9 Ga zircons in later sediments. The oldest rocks are 3.9-3.8 Ga high-grade gneisses commonly associated with lavas and sediments which were transported into the deep crust. They ...
KAROO SEDIMENTS OF THE ERONGO MOUNTAINS, THEIR
... detritus in depressions in a hilly country. Elevated areas of the pre-Karoo surface rise above the Karoo sediments and are directly covered by basalt of the Erongo Igneous Complex. This can be observed on Krantzberg (2115 DB), where the formation measures 75 m at the north-eastern corner, increases ...
... detritus in depressions in a hilly country. Elevated areas of the pre-Karoo surface rise above the Karoo sediments and are directly covered by basalt of the Erongo Igneous Complex. This can be observed on Krantzberg (2115 DB), where the formation measures 75 m at the north-eastern corner, increases ...
cycles in nature biological cycle - National Open University of Nigeria
... their energy from the plant by taking in oxygen from the atmosphere released by plant cellular respiration which releases energy the animal while carbon dioxide is given off into the atmosphere. In anaerobic environments such as water logged soil or bottom of still water with poor illustrator decomp ...
... their energy from the plant by taking in oxygen from the atmosphere released by plant cellular respiration which releases energy the animal while carbon dioxide is given off into the atmosphere. In anaerobic environments such as water logged soil or bottom of still water with poor illustrator decomp ...
Lithostratigraphic and tectonic framework of Jurassic
... (Highway 97) to the east, and between latitudes 51°N and 54°N. The Intermontane belt is the central of the five geomorphogeologic belts of the Canadian Cordillera (Fig. 1 inset). It is characterized by relatively low metamorphic grade and subdued topography, in contrast to the Coast crystalline belt ...
... (Highway 97) to the east, and between latitudes 51°N and 54°N. The Intermontane belt is the central of the five geomorphogeologic belts of the Canadian Cordillera (Fig. 1 inset). It is characterized by relatively low metamorphic grade and subdued topography, in contrast to the Coast crystalline belt ...
Inosilicates (Pyroxenes and Amphiboles)
... All of the amphiboles except Anthophyllite are monoclinic, and all show the excellent prismatic cleavage on {110}. The angles between the cleavages, however are 56o and 124o making all amphiboles easy to distinguish from the pyroxenes. Looking at faces that show only a single cleavage trace would sh ...
... All of the amphiboles except Anthophyllite are monoclinic, and all show the excellent prismatic cleavage on {110}. The angles between the cleavages, however are 56o and 124o making all amphiboles easy to distinguish from the pyroxenes. Looking at faces that show only a single cleavage trace would sh ...
Geological history of Earth
The geological history of Earth follows the major events in Earth's past based on the geologic time scale, a system of chronological measurement based on the study of the planet's rock layers (stratigraphy). Earth formed about 4.54 billion years ago by accretion from the solar nebula, a disk-shaped mass of dust and gas left over from the formation of the Sun, which also created the rest of the Solar System.Earth was initially molten due to extreme volcanism and frequent collisions with other bodies. Eventually, the outer layer of the planet cooled to form a solid crust when water began accumulating in the atmosphere. The Moon formed soon afterwards, possibly as the result of a Mars-sized object with about 10% of the Earth's mass impacting the planet in a glancing blow. Some of this object's mass merged with the Earth, significantly altering its internal composition, and a portion was ejected into space. Some of the material survived to form an orbiting moon. Outgassing and volcanic activity produced the primordial atmosphere. Condensing water vapor, augmented by ice delivered from comets, produced the oceans.As the surface continually reshaped itself over hundreds of millions of years, continents formed and broke apart. They migrated across the surface, occasionally combining to form a supercontinent. Roughly 750 million years ago, the earliest-known supercontinent Rodinia, began to break apart. The continents later recombined to form Pannotia, 600 to 540 million years ago, then finally Pangaea, which broke apart 180 million years ago.The present pattern of ice ages began about 40 million years ago, then intensified at the end of the Pliocene. The polar regions have since undergone repeated cycles of glaciation and thaw, repeating every 40,000–100,000 years. The last glacial period of the current ice age ended about 10,000 years ago.