Deformation phases and tectonic evolution of the Lhasa block
... ing on recording and analyzing the small scale structures along detailed cross sections. Pioneer work has been presented by Hayden (1907) and, since then, numerous informations have been obtained by the Chinese geologists. The Lhasa block could be represented mainly in the eastern part of southern T ...
... ing on recording and analyzing the small scale structures along detailed cross sections. Pioneer work has been presented by Hayden (1907) and, since then, numerous informations have been obtained by the Chinese geologists. The Lhasa block could be represented mainly in the eastern part of southern T ...
nemei lake area - Publications Centre
... The earliest published description of rocks in the area is that of Mclnnes (1913) who in 1910 travelled along the Churchill River and briefly described the gneisses in the northern part of the maparea. The Pelican Narrows quadrangle (63-M), which includes the present area, was reconnoitred in 1929 a ...
... The earliest published description of rocks in the area is that of Mclnnes (1913) who in 1910 travelled along the Churchill River and briefly described the gneisses in the northern part of the maparea. The Pelican Narrows quadrangle (63-M), which includes the present area, was reconnoitred in 1929 a ...
Fast spreading ridges
... upper extrusive volcanic layer Fracturing and hydrothermal alteration contribute to seismic anisotropy ...
... upper extrusive volcanic layer Fracturing and hydrothermal alteration contribute to seismic anisotropy ...
Evolution of magma-poor continental margins from rifting to sea¯oor
... at .3.5 mm yr-1. Exhumation of about 75 km of subcontinental mantle within the ZECM at not less than 7.2 mm yr-1 was mainly accommodated by concave-downward faults10. b, Situation after mantle exhumation along the detachment HHD. The roll-over of HHD can explain three characteristic features: (1) th ...
... at .3.5 mm yr-1. Exhumation of about 75 km of subcontinental mantle within the ZECM at not less than 7.2 mm yr-1 was mainly accommodated by concave-downward faults10. b, Situation after mantle exhumation along the detachment HHD. The roll-over of HHD can explain three characteristic features: (1) th ...
Himalayan Granite
... and deeply buried rocks were metamorphosed or changed as a result of the increase in burial depth, pressure and temperature. Most of the Greater Himalayan ranges are composed of metamorphic rocks that were formed at depths between about 50km and 15km and then thrust southward along giant fault plane ...
... and deeply buried rocks were metamorphosed or changed as a result of the increase in burial depth, pressure and temperature. Most of the Greater Himalayan ranges are composed of metamorphic rocks that were formed at depths between about 50km and 15km and then thrust southward along giant fault plane ...
Cratons, mobile belts, alkaline rocks and
... Africa, a collage of juvenile and old reactivated basement terranes, has suffered regional continental lithospheric mantle delamination during the early stages of this orogeny, as has been postulated for the more recent Himalayan orogeny in Tibet. Delamination of the continental lithospheric mantle ...
... Africa, a collage of juvenile and old reactivated basement terranes, has suffered regional continental lithospheric mantle delamination during the early stages of this orogeny, as has been postulated for the more recent Himalayan orogeny in Tibet. Delamination of the continental lithospheric mantle ...
Short Course in Basic Geology Gregory A. Miles This short course
... Accreted terranes (also called exotic terranes) are pieces of crust that formed in one location, but were later transported by moving plates to another location. Many of these are small scraps of crust that were rafted to a subduction zone, but were too light to subduct so they accreted to ("plaster ...
... Accreted terranes (also called exotic terranes) are pieces of crust that formed in one location, but were later transported by moving plates to another location. Many of these are small scraps of crust that were rafted to a subduction zone, but were too light to subduct so they accreted to ("plaster ...
Carib PISI Stern GSA Denver 2016
... The VGG reveals the extinct spreading ridges and fracture zones as well as a significant change in amplitude across the boundary between continental and oceanic crust (COBs). This is a Mercator projection; grayscale saturates at T20 eotvos units. (Sandwell et al., 2014) ...
... The VGG reveals the extinct spreading ridges and fracture zones as well as a significant change in amplitude across the boundary between continental and oceanic crust (COBs). This is a Mercator projection; grayscale saturates at T20 eotvos units. (Sandwell et al., 2014) ...
Granitization of the Basic Volcanic Rocks in the Contact Aureole of
... decrease in temperature and pressure, the solubility of alkalis and silica in mantle fluids decreases, causing a metasomatic change and nonisochemical partial melting of the crustal protolith. According to [12], these processes require strong heating of the fluid influence zone (the temperature in t ...
... decrease in temperature and pressure, the solubility of alkalis and silica in mantle fluids decreases, causing a metasomatic change and nonisochemical partial melting of the crustal protolith. According to [12], these processes require strong heating of the fluid influence zone (the temperature in t ...
Subduction and collision processes in the Central Andes
... plateaux (about 4 km) has been explained as an isostatic response to crustal thickening2,6. A low average P-wave velocity and low Poisson's ratio in the crust of the northern Altiplano have been reported from seismic observations, indicating tectonic shortening as the dominant mechanism of crustal t ...
... plateaux (about 4 km) has been explained as an isostatic response to crustal thickening2,6. A low average P-wave velocity and low Poisson's ratio in the crust of the northern Altiplano have been reported from seismic observations, indicating tectonic shortening as the dominant mechanism of crustal t ...
Metamorphic rocks
... I can identify different rock types. On page 80 answer questions 1-6. Put these in your notebook. You need to finish during class. Focus and get it done. 1. How are rocks and minerals different? 2. What are the three types of rocks? 3. Which rock types are most common within Earth’s crust? Which typ ...
... I can identify different rock types. On page 80 answer questions 1-6. Put these in your notebook. You need to finish during class. Focus and get it done. 1. How are rocks and minerals different? 2. What are the three types of rocks? 3. Which rock types are most common within Earth’s crust? Which typ ...
Moores and Twiss chapter 5
... The sequence outlines a coherent model of the rifting process based on presently active examples of all stages of rift development. With such a model, we can interpret the data pertaining to two ancient rifted margins that are found in the geologic record and that have been modified by subsequent te ...
... The sequence outlines a coherent model of the rifting process based on presently active examples of all stages of rift development. With such a model, we can interpret the data pertaining to two ancient rifted margins that are found in the geologic record and that have been modified by subsequent te ...
What is this thing?
... I can identify different rock types. On page 80 answer questions 1-6. Put these in your notebook. You need to finish during class. Focus and get it done. 1. How are rocks and minerals different? 2. What are the three types of rocks? 3. Which rock types are most common within Earth’s crust? Which typ ...
... I can identify different rock types. On page 80 answer questions 1-6. Put these in your notebook. You need to finish during class. Focus and get it done. 1. How are rocks and minerals different? 2. What are the three types of rocks? 3. Which rock types are most common within Earth’s crust? Which typ ...
GEOL_2_mid_term_I_ke..
... (32) 1 pt. Linear, magnetic patterns associated with mid-ocean ridges are configured as ________. A) reversed magnetizations along the rift valleys and normal magnetizations along the ridge B) normal and reversed magnetized strips roughly parallel to the ridge C) normal and reversed magnetized strip ...
... (32) 1 pt. Linear, magnetic patterns associated with mid-ocean ridges are configured as ________. A) reversed magnetizations along the rift valleys and normal magnetizations along the ridge B) normal and reversed magnetized strips roughly parallel to the ridge C) normal and reversed magnetized strip ...
flow-layering in alpine peridotite-gabbro
... relations of foliation show that it is younger than the layering in both figures. The crosswise chromite deposits, likewise, are believed to be relatively competent relict masses that were oriented in one direction by early flowage and deformed by later flowage from another direction. It would seem, ...
... relations of foliation show that it is younger than the layering in both figures. The crosswise chromite deposits, likewise, are believed to be relatively competent relict masses that were oriented in one direction by early flowage and deformed by later flowage from another direction. It would seem, ...
Metamorphic_Rocks
... Deep burial and pressure from mountain formation (at least several kilometers). ...
... Deep burial and pressure from mountain formation (at least several kilometers). ...
slide1
... Are KT boundary chromites terrestrial or extra-terrestrial? Terrestrial isotopic signatures for Raton Basin KT boundary chrome spinels would also corroborate evidence for mantle or ultramafic material in KT boundary ejecta as proposed by: DePaolo, Kyte, Marshall, O’Neil & Smit; EPSL Vol. 64, Sept. ...
... Are KT boundary chromites terrestrial or extra-terrestrial? Terrestrial isotopic signatures for Raton Basin KT boundary chrome spinels would also corroborate evidence for mantle or ultramafic material in KT boundary ejecta as proposed by: DePaolo, Kyte, Marshall, O’Neil & Smit; EPSL Vol. 64, Sept. ...
perception of first-year geology students on the tectonic plates theory
... plates was distributed to first-year students of Geology (N = 49). The questionnaire comprised of five (5) questions; each of them had five (5) possible answers. Attempt was made in order to include a list of all essential elements of the theory of tectonic plates in the above mentioned small number ...
... plates was distributed to first-year students of Geology (N = 49). The questionnaire comprised of five (5) questions; each of them had five (5) possible answers. Attempt was made in order to include a list of all essential elements of the theory of tectonic plates in the above mentioned small number ...
PowerPoint プレゼンテーション
... type, the protolith, in a process called metamorphism, which means "change in form". When the pre-existing rocks (sedimentary or igneous rock) are subjected to increased temperature, pressure and action of chemically active fluids, metamorphic rocks are formed. During metamorphism re-crystallization ...
... type, the protolith, in a process called metamorphism, which means "change in form". When the pre-existing rocks (sedimentary or igneous rock) are subjected to increased temperature, pressure and action of chemically active fluids, metamorphic rocks are formed. During metamorphism re-crystallization ...
ben nevis and allt a`mhuilinn
... of internal contacts within each unit suggests that each consists of a number of separate pulses. These contacts are better preserved in the earlier units (e.g. the Fine Quartz-diorite) suggesting more rapid cooling in early units relative to later units. The margin-to-core sequence of intrusion par ...
... of internal contacts within each unit suggests that each consists of a number of separate pulses. These contacts are better preserved in the earlier units (e.g. the Fine Quartz-diorite) suggesting more rapid cooling in early units relative to later units. The margin-to-core sequence of intrusion par ...
Geochemical Characterization of Intermediate to Silicic Rocks in the
... subduction-unrelated, Rift/Continental Margin ophiolites are predominantly basaltic andesite and andesite, whereas MOR type (mid-ocean ridge) ophiolites exhibit nearly equal proportions of basaltic andesite/andesite and rhyodacite and Plume/MOR type ophiolites are characterized by rhyolites. Interme ...
... subduction-unrelated, Rift/Continental Margin ophiolites are predominantly basaltic andesite and andesite, whereas MOR type (mid-ocean ridge) ophiolites exhibit nearly equal proportions of basaltic andesite/andesite and rhyodacite and Plume/MOR type ophiolites are characterized by rhyolites. Interme ...
pdf
... basalts (MORB) magmatism was again replaced by basin-wide alkaline events, caused by a low degree of decompression melting due to tectonic delocalization of deformation. Such “off-axis” magmatism might be a common process in (ultra-) slow oceanic spreading systems, where “magmatic” and “tectonic” sp ...
... basalts (MORB) magmatism was again replaced by basin-wide alkaline events, caused by a low degree of decompression melting due to tectonic delocalization of deformation. Such “off-axis” magmatism might be a common process in (ultra-) slow oceanic spreading systems, where “magmatic” and “tectonic” sp ...
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 ...
Metamorphic Rocks
... • Most regional metamorphism occurs along convergent plate boundaries • Compressional stresses deform plate edge • Occurs in major mountain belts: Alps, Himalayas, and Appalachians • Not necessarily in all mountains, depends on orogenic forces, i.e., uplift versus compression ...
... • Most regional metamorphism occurs along convergent plate boundaries • Compressional stresses deform plate edge • Occurs in major mountain belts: Alps, Himalayas, and Appalachians • Not necessarily in all mountains, depends on orogenic forces, i.e., uplift versus compression ...
Great Lakes tectonic zone
The Great Lakes tectonic zone is bounded by South Dakota at its tip and heads northeast to south of Duluth, Minnesota, then heads east through northern Wisconsin, Marquette, Michigan, and then trends more northeasterly to skim the northern-most shores of lakes Michigan and Huron before ending in the Sudbury, Ontario, Canada, area.During the Late Archean Era the Algoman orogeny added landmass to the Superior province by volcanic activity and continental collision along a boundary that stretches from present-day South Dakota, U.S., into the Lake Huron region near Sudbury, Ontario, Canada.This crustal boundary is the Great Lakes tectonic zone. It is 1,400 km (870 mi) long, and separates the older Archean gneissic terrane to the south from younger Late Archean greenstone-granite terrane to the north.The zone is characterized by active compression during the Algoman orogeny (about 2,700 million years ago), a pulling-apart (extensional) tectonics (2,450 to 2,100 million years ago), a second compression during the Penokean orogeny (1,900 to 1,850 million years ago), a second extension during Middle Proterozoic time (1,600 million years ago) and minor reactivation during Phanerozoic time (the past 500 million years).Collision began along the Great Lakes tectonic zone (GLTZ) with the Algoman mountain-building event and continued for tens of millions of years. During the formation of the GLTZ, the gneissic Minnesota River Valley subprovince was thrust up onto the Superior province's edge as it consumed the Superior province's oceanic crust. Fragmentation of the Kenorland supercontinent began 2,450 million years ago and was completed by 2,100 million years ago. The Wyoming province is the continental landmass that is hypothesized to have rifted away from the southern Superior province portion of Kenorland, before moving rapidly west and docking with the Laurentia supercontinent 1,850 to 1,715 million years ago. Sedimentation from the GLTZ-rifting environment continued into the Penokean orogeny, which is the next major tectonic event in the Great Lakes region. Several earthquakes have been documented in Minnesota, Michigan's Upper Peninsula and Sudbury in the last 120 years along the GLTZ.