Cratons of the Indian Shield
... with their basement gneisses) occurred when their regional foliation (axial plane S2) had a steep disposition with respect to the rising isotherms during regional metamorphism. This is in contrast if the structurally duplicated (or tectonically thickened) crust at depth had gentle inclination of the ...
... with their basement gneisses) occurred when their regional foliation (axial plane S2) had a steep disposition with respect to the rising isotherms during regional metamorphism. This is in contrast if the structurally duplicated (or tectonically thickened) crust at depth had gentle inclination of the ...
Cratons and Fold Belts of India - ReadingSample - Beck-Shop
... with their basement gneisses) occurred when their regional foliation (axial plane S2) had a steep disposition with respect to the rising isotherms during regional metamorphism. This is in contrast if the structurally duplicated (or tectonically thickened) crust at depth had gentle inclination of the ...
... with their basement gneisses) occurred when their regional foliation (axial plane S2) had a steep disposition with respect to the rising isotherms during regional metamorphism. This is in contrast if the structurally duplicated (or tectonically thickened) crust at depth had gentle inclination of the ...
Gold and platinum group minerals in drainage between the river
... and Hg. Rims are generally Pt-rich, often with a significant Au or Cu content which may be recognisable as a distinct thin zone. Other compositions include Pt with a significant Hg content and a combination of roughly equal amounts of Pd, Hg, Au and Pt. Some grains show clear there may be very major ...
... and Hg. Rims are generally Pt-rich, often with a significant Au or Cu content which may be recognisable as a distinct thin zone. Other compositions include Pt with a significant Hg content and a combination of roughly equal amounts of Pd, Hg, Au and Pt. Some grains show clear there may be very major ...
Crooked River caldera - Oregon Department of Geology and Mineral
... with the late Eocene to earliest Miocene (?) John Day Formation, a dissected belt of volcanogenic sedimentary rocks, mafic lavas, rhyolite domes and lavas, and widespread rhyolite ashflow tuff sheets (Swanson, 1969; Robinson, 1975; Robinson and Stensland, 1979; Robinson and Brem, 1981; Robinson and ...
... with the late Eocene to earliest Miocene (?) John Day Formation, a dissected belt of volcanogenic sedimentary rocks, mafic lavas, rhyolite domes and lavas, and widespread rhyolite ashflow tuff sheets (Swanson, 1969; Robinson, 1975; Robinson and Stensland, 1979; Robinson and Brem, 1981; Robinson and ...
Plate-kinematics and crustal dynamics of circum
... oceanic-related and arc-related rocks along northern South America (Fig. 2). It was thought previously that the collision of an arc directly with the northern South American margin had driven Cretaceous metamorphism of these arc complexes more or less in situ (e.g., Maresch, 1974; Beets et al., 1984 ...
... oceanic-related and arc-related rocks along northern South America (Fig. 2). It was thought previously that the collision of an arc directly with the northern South American margin had driven Cretaceous metamorphism of these arc complexes more or less in situ (e.g., Maresch, 1974; Beets et al., 1984 ...
Igneous Rock Associations 8. Arc Magmatism II: Geo
... in arc basalts are more iron-rich than those that are in equilibrium with mantle rocks, suggesting that even the most primitive arc magmas are fractionated to some degree and that true primary magmas (i.e. melts directly derived from the mantle) are rare. Mineral compositions are also susceptible to ...
... in arc basalts are more iron-rich than those that are in equilibrium with mantle rocks, suggesting that even the most primitive arc magmas are fractionated to some degree and that true primary magmas (i.e. melts directly derived from the mantle) are rare. Mineral compositions are also susceptible to ...
Crustal thickness variation in south
... Comparison between observed crustal thicknesses and those predicted by the isostatic model indicates that the Alaska Range is isostatically compensated by the crustal root. Beneath the northern foothills and lowlands the crust is thinner than predicted by our simple isostatic model, suggesting that ...
... Comparison between observed crustal thicknesses and those predicted by the isostatic model indicates that the Alaska Range is isostatically compensated by the crustal root. Beneath the northern foothills and lowlands the crust is thinner than predicted by our simple isostatic model, suggesting that ...
Bedrock geology in New England submarine canyons
... Using the research submersible "Alvin" we explored three deeply submerged canyons along the New England segment of the North American margin. Contemporary submarine erosion in canyon axes provides almost continuous outcrop of Mesozoic and Cenozoic strata. The oldest strata sampled belong to a Neocom ...
... Using the research submersible "Alvin" we explored three deeply submerged canyons along the New England segment of the North American margin. Contemporary submarine erosion in canyon axes provides almost continuous outcrop of Mesozoic and Cenozoic strata. The oldest strata sampled belong to a Neocom ...
program details
... most interesting regions in Earth Sciences. Earliest discoveries related to the Earth’s geology, such as the use of ore deposits or fossil fuels took place in the Eastern Mediterranean. Besides, intense seismic and volcanic activity or extreme climate changes played crucial roles in shaping the civi ...
... most interesting regions in Earth Sciences. Earliest discoveries related to the Earth’s geology, such as the use of ore deposits or fossil fuels took place in the Eastern Mediterranean. Besides, intense seismic and volcanic activity or extreme climate changes played crucial roles in shaping the civi ...
geology of the storkollen blankenberg area, kragerø, norway
... The Pre-Cambrian rocks of the south Norwegian coast from Lange sundsfjord to Kristiansand are known as the Kongsberg-Bamle form ation, which is separated from the main southeastern Norwegian Pre Cambrian area by a major breccia zone (A. BuGGE, 161). Near the northern end of this strip lies the to ...
... The Pre-Cambrian rocks of the south Norwegian coast from Lange sundsfjord to Kristiansand are known as the Kongsberg-Bamle form ation, which is separated from the main southeastern Norwegian Pre Cambrian area by a major breccia zone (A. BuGGE, 161). Near the northern end of this strip lies the to ...
Near-Ultrahigh Pressure Processing of Continental Crust: Miocene
... igneous rocks in the southern Pamir provide important new information regarding the geological processes accompanying tectonism during the Indo-Eurasian collision. Four types have been studied: sanidine eclogites (omphacite, garnet, sanidine, quartz, biotite, kyanite), felsic granulites (garnet, qua ...
... igneous rocks in the southern Pamir provide important new information regarding the geological processes accompanying tectonism during the Indo-Eurasian collision. Four types have been studied: sanidine eclogites (omphacite, garnet, sanidine, quartz, biotite, kyanite), felsic granulites (garnet, qua ...
Granitoids in Poland, AM Monograph No
... Their size and three-dimensional form were deduced by combining mapping, structural data, thermal aureole and by observation of mutual relationships between granitoids and their metamorphic envelope in outcrops and numerous boreholes. The largest intrusions are located in the northern and middle par ...
... Their size and three-dimensional form were deduced by combining mapping, structural data, thermal aureole and by observation of mutual relationships between granitoids and their metamorphic envelope in outcrops and numerous boreholes. The largest intrusions are located in the northern and middle par ...
Kimberlites and Lamproites: Primary Sources of Diamond
... parameters which lie along this geotherm. These are considered to be mantle material which has not been affected by kimbedite-xenolith thermalinteractions. Xenoliths which have higherequilibrationparameters may record kimberlite-xenolith thermal interactions and/or are restites derived from the part ...
... parameters which lie along this geotherm. These are considered to be mantle material which has not been affected by kimbedite-xenolith thermalinteractions. Xenoliths which have higherequilibrationparameters may record kimberlite-xenolith thermal interactions and/or are restites derived from the part ...
On the relationship between the Bushveld Complex and its felsic
... replacing hornblende, and apatite and zircon are common trace phases. The overall texture varies from poorly developed granitoid to locally allotriomorphic granular (Fig. 4). Most of the microgranites are monzonitic, consisting of 20–30 % quartz and 8–10 % hornblende + biotite (bulk SiO2 = 66–72 %) ...
... replacing hornblende, and apatite and zircon are common trace phases. The overall texture varies from poorly developed granitoid to locally allotriomorphic granular (Fig. 4). Most of the microgranites are monzonitic, consisting of 20–30 % quartz and 8–10 % hornblende + biotite (bulk SiO2 = 66–72 %) ...
Miocene Landscape Evolution and Geomorphologic Controls on
... 1969; Tosdal, 1978; Tosdal et al. 1984) extended the history of central Andean cordilleran uplift and regional erosion back at least to the late Oligocene. This is only rendered possible by the remarkable degree of preservation of the early-Neogene landforms resulting from the onset of extremely ari ...
... 1969; Tosdal, 1978; Tosdal et al. 1984) extended the history of central Andean cordilleran uplift and regional erosion back at least to the late Oligocene. This is only rendered possible by the remarkable degree of preservation of the early-Neogene landforms resulting from the onset of extremely ari ...
A structural transect across the coastal mobile belt in the Brazilian
... penetratively developed gneissosity and schistosity. Isolated relics of an older folded fabric occur locally and may represent Transamazonian (2.2–2.0 Ga) deformation. The orogen is kinematically partitioned with the eastern 175 km dominated by moderately- to steeply dipping north-trending dextral s ...
... penetratively developed gneissosity and schistosity. Isolated relics of an older folded fabric occur locally and may represent Transamazonian (2.2–2.0 Ga) deformation. The orogen is kinematically partitioned with the eastern 175 km dominated by moderately- to steeply dipping north-trending dextral s ...
Impact resistance of Illinois limestones and
... falling from a known height. Studies have been made of materials subjected to impact by high velocity projectiles (Whiffin, 1948; Maurer and Rinehart, 1960; and others). Obert et al. (1946) and the Page toughness test (A.S.T.M., 1961) determine impact toughness of rocks by dropping a hammer from con ...
... falling from a known height. Studies have been made of materials subjected to impact by high velocity projectiles (Whiffin, 1948; Maurer and Rinehart, 1960; and others). Obert et al. (1946) and the Page toughness test (A.S.T.M., 1961) determine impact toughness of rocks by dropping a hammer from con ...
Open File NFLD/3172 - Department of Natural Resources
... Western Newfoundland is a classic area for the development of the latest Precambrian to Middle Ordovician succession of the Laurentian passive continental margin. It also provides a world-class record of the foundering of the continental shelf, emplacement of allochthons including oceanic crustal ro ...
... Western Newfoundland is a classic area for the development of the latest Precambrian to Middle Ordovician succession of the Laurentian passive continental margin. It also provides a world-class record of the foundering of the continental shelf, emplacement of allochthons including oceanic crustal ro ...
K-Fsp can be classified as Sanidine on the basis of low
... BAK39). Perovskite (T/s KL05) is found in kimberlites and lamprophyres where it is identified easily due to a dark brown colour and its isotropy. Zeolites (T/s 1229) are a group of minerals (hydrated aluminosilicates) that encompasses more than 40 species. All zeolites have low indices of refraction ...
... BAK39). Perovskite (T/s KL05) is found in kimberlites and lamprophyres where it is identified easily due to a dark brown colour and its isotropy. Zeolites (T/s 1229) are a group of minerals (hydrated aluminosilicates) that encompasses more than 40 species. All zeolites have low indices of refraction ...
CHAPTER 5 Mafic-ultramafic complexes
... over” or “to cover”, and the word is used in Geology to describe to the occurrence of ophiolitic complexes in thrust sheets with the understanding that part of the ocean floor has been structurally drawn over, obducted over, continental supracrustal rocks. Under normal circumstances, sections throug ...
... over” or “to cover”, and the word is used in Geology to describe to the occurrence of ophiolitic complexes in thrust sheets with the understanding that part of the ocean floor has been structurally drawn over, obducted over, continental supracrustal rocks. Under normal circumstances, sections throug ...
Metamorphic Intro
... s1 > s2 = s3 foliation and no lineation s1 = s2 > s3 lineation and no foliation s1 > s2 > s3 both foliation and lineation Flattening of a ductile homogeneous sphere (a) containing randomly oriented flat disks or flakes. In (b), the matrix flows with progressive flattening, and the flakes ...
... s1 > s2 = s3 foliation and no lineation s1 = s2 > s3 lineation and no foliation s1 > s2 > s3 both foliation and lineation Flattening of a ductile homogeneous sphere (a) containing randomly oriented flat disks or flakes. In (b), the matrix flows with progressive flattening, and the flakes ...
borehole geology and alteration mineralogy of well he
... country that lies on the Mid-Atlantic Ridge. Regions of active extension and volcanism in Iceland lie along volcanic rift zones that cross the island from northeast to southwest. This is the boundary between the North American and Eurasian tectonic plates. It is one of the few places on earth where ...
... country that lies on the Mid-Atlantic Ridge. Regions of active extension and volcanism in Iceland lie along volcanic rift zones that cross the island from northeast to southwest. This is the boundary between the North American and Eurasian tectonic plates. It is one of the few places on earth where ...
The Picuris Formation - New Mexico Geological Society
... on this noteworthy Tertiary sedimentary unit in Taos County, New Mexico. Where exposed along the northern and southern flanks of the Picuris Mountains, the formation is composed of: 1) a lower, basement- and volcanic-derived, highly weathered, conglomerate, sandstone, and siltstone member; 2) a middl ...
... on this noteworthy Tertiary sedimentary unit in Taos County, New Mexico. Where exposed along the northern and southern flanks of the Picuris Mountains, the formation is composed of: 1) a lower, basement- and volcanic-derived, highly weathered, conglomerate, sandstone, and siltstone member; 2) a middl ...
Chapter Twelve: Intrusive Rocks
... (1983). These are regions underlain dominantly by (I) 45-54 Ma granodiorite and quartz monzonite and (II) mid Tertiary, Late Cretaceous and older non-migmatitic tonalite orthogneiss and weakly to nonfoliated granite. Isolated plutons and small batholiths occur sporadically and with decreasing abunda ...
... (1983). These are regions underlain dominantly by (I) 45-54 Ma granodiorite and quartz monzonite and (II) mid Tertiary, Late Cretaceous and older non-migmatitic tonalite orthogneiss and weakly to nonfoliated granite. Isolated plutons and small batholiths occur sporadically and with decreasing abunda ...
New data on the deposition age of the volcano
... ferruginous sandstones overlain by red sandstones and red shales, siltstones and also carbonated rocks at the top. The transition between the Chela Group and the overlaying dolomitic limestone of the Leba Formation (Vale & Gonçalves, 1973) could be recognized both by a lithologic discontinuity or an ...
... ferruginous sandstones overlain by red sandstones and red shales, siltstones and also carbonated rocks at the top. The transition between the Chela Group and the overlaying dolomitic limestone of the Leba Formation (Vale & Gonçalves, 1973) could be recognized both by a lithologic discontinuity or an ...
Geology of Great Britain
The geology of Great Britain is renowned for its diversity. As a result of its eventful geological history, Great Britain shows a rich variety of landscapes across the constituent countries of England, Wales and Scotland. Rocks of almost all geological ages are represented at outcrop, from the Archaean onwards.