Memoir 36: Geology of Organ Mountains and southern San Andres
... description of the ore deposits and his petrographic work with the igneous and metamorphic rocks are not likely to be improved upon for many years. Besides being of interest for the local geology, the book is also of general value because Dunham carefully martials evidence from the Organs on such to ...
... description of the ore deposits and his petrographic work with the igneous and metamorphic rocks are not likely to be improved upon for many years. Besides being of interest for the local geology, the book is also of general value because Dunham carefully martials evidence from the Organs on such to ...
chapter – 4 geological studies
... of these changes is often preserved as different proxies on the earth. Many changes we are observing on the earth’s surface, at present, are due to natural processes. To assess the changes in the vegetation, landform, climate due to anthropogenic activity, it is very important to understand the chan ...
... of these changes is often preserved as different proxies on the earth. Many changes we are observing on the earth’s surface, at present, are due to natural processes. To assess the changes in the vegetation, landform, climate due to anthropogenic activity, it is very important to understand the chan ...
Special Report 142, 1980. Geology and Slope Stability in Selected
... Surface and ground water ........................................................................................................................................................28 Vegetation ............................................................................................................. ...
... Surface and ground water ........................................................................................................................................................28 Vegetation ............................................................................................................. ...
Sabzevar Ophiolite, NE Iran - The University of Texas at Dallas
... and Aliak villages (Appendix 1). Pelagic sediments stratigraphically cover the pillow lava sequence and/or are interbedded with them. Andesitic dikes (1–1.5 m in thickness) occasionally crosscut the pillow ...
... and Aliak villages (Appendix 1). Pelagic sediments stratigraphically cover the pillow lava sequence and/or are interbedded with them. Andesitic dikes (1–1.5 m in thickness) occasionally crosscut the pillow ...
Ghikas et al.IGR2010
... Shallo et al. 1990; Jones and Robertson 1991; Dilek and Rowland 1993; Malpas et al. 1993; Saccani et al. 2003), prior to the onset of seafloor spreading and oceanic crust formation in the Tethyan basins (Dilek and Flower 2003). Subophiolitic mélange units form thin (several hundred metres) slivers ...
... Shallo et al. 1990; Jones and Robertson 1991; Dilek and Rowland 1993; Malpas et al. 1993; Saccani et al. 2003), prior to the onset of seafloor spreading and oceanic crust formation in the Tethyan basins (Dilek and Flower 2003). Subophiolitic mélange units form thin (several hundred metres) slivers ...
Guidebook
... and metavolcanic rocks screen these laccoliths and rare granites belong to the plutonic association. Few intrusion ages are available. They span from 99 to 82 Ma, giving evidence for a succession of short-lived plutonic events; 82 Ma-old rocks are kyanite-bearing pegmatites produced by partial remel ...
... and metavolcanic rocks screen these laccoliths and rare granites belong to the plutonic association. Few intrusion ages are available. They span from 99 to 82 Ma, giving evidence for a succession of short-lived plutonic events; 82 Ma-old rocks are kyanite-bearing pegmatites produced by partial remel ...
Stable Isotopes II High Temperature Applications
... parameters for the temperature dependence of silicate and oxide fractionation factors at low temperatures. Because oxygen occupies a generally similar lattice site in virtually all mantle minerals, it is covalently bonded to silicon and ionically bonded to other cations (e.g., Mg, Fe, Ca, etc.), fra ...
... parameters for the temperature dependence of silicate and oxide fractionation factors at low temperatures. Because oxygen occupies a generally similar lattice site in virtually all mantle minerals, it is covalently bonded to silicon and ionically bonded to other cations (e.g., Mg, Fe, Ca, etc.), fra ...
Christiansen, EH, and Keith, JD, 1996, Trace
... magma (crystals plus liquid). After magma segregation, restitic mineral phases may become dissolved at lower pressure or after continued reaction with the melt. However, restite unmixing is probably not important in the generation of the observed elemental trends in rhyolites and granites, except so ...
... magma (crystals plus liquid). After magma segregation, restitic mineral phases may become dissolved at lower pressure or after continued reaction with the melt. However, restite unmixing is probably not important in the generation of the observed elemental trends in rhyolites and granites, except so ...
Textural evidence for liquid immiscibility in tholeiites
... of mesostasis. Cooling rates, which must vary considerably through a flow of this thickness, can therefore have little to do with the textural change from a subophitic intergrowth to the finer multigrained aggregate of a mesostasis. Thus, a finergrained late-crystallizing fraction could still be exp ...
... of mesostasis. Cooling rates, which must vary considerably through a flow of this thickness, can therefore have little to do with the textural change from a subophitic intergrowth to the finer multigrained aggregate of a mesostasis. Thus, a finergrained late-crystallizing fraction could still be exp ...
THE TECTONIC RELATIONSHIPS OF THE HILLABEE CHLORITE
... Mountain Formation (Neathery, 1975). Bearce (1973b) subdivided the northern Talladega Group into three units: the Heflin Phyllite, the Abel Gap Formation, and the Chulafinnee Schist. Tull (1977) interpreted the Hollins Line fault as a major thrust fault and included the Hillabee within the Talladeg ...
... Mountain Formation (Neathery, 1975). Bearce (1973b) subdivided the northern Talladega Group into three units: the Heflin Phyllite, the Abel Gap Formation, and the Chulafinnee Schist. Tull (1977) interpreted the Hollins Line fault as a major thrust fault and included the Hillabee within the Talladeg ...
GW_Rpt_41_Appendix_07_stratigraphic_units
... Basalt of Three-mile Reservoir (Pleistocene or Pliocene) Gray to weathering dark brown aphyric, diktytaxitic basalt Unit has interacted with water Total thickness is unknown Basalt of Boggs Lake (Pleistocene or Pliocene) Gray, cumulophyric basalt Appears to be a single flow, with a general thickness ...
... Basalt of Three-mile Reservoir (Pleistocene or Pliocene) Gray to weathering dark brown aphyric, diktytaxitic basalt Unit has interacted with water Total thickness is unknown Basalt of Boggs Lake (Pleistocene or Pliocene) Gray, cumulophyric basalt Appears to be a single flow, with a general thickness ...
Geology and Geochemistry of Hadean Zircon Bearing
... identified detrital zircons from the Southern Cross Granite-Greenstone terrane in the central part of the Yilgarn craton as old as 4350 Ma. Due to the geographic proximity of the Southern Cross with the Narryer Gneisses, it is likely that they shared the same crustal source for old zircons. Because ...
... identified detrital zircons from the Southern Cross Granite-Greenstone terrane in the central part of the Yilgarn craton as old as 4350 Ma. Due to the geographic proximity of the Southern Cross with the Narryer Gneisses, it is likely that they shared the same crustal source for old zircons. Because ...
PDF
... of ancient xenocrystic zircons. Multigrain fractions that define discordia between Neoproterozoic and older ages indicate that such xenocrysts exist but large uncertainties on upper intercept ages may suggest that xenocrysts of more than one age are present. In contrast, samples dated using single z ...
... of ancient xenocrystic zircons. Multigrain fractions that define discordia between Neoproterozoic and older ages indicate that such xenocrysts exist but large uncertainties on upper intercept ages may suggest that xenocrysts of more than one age are present. In contrast, samples dated using single z ...
garwin_et_al_2005 Au-Cu Cenozoic magmatic arcs SE Asia
... accretion is inferred to have increased the coupling force between the arc and subducting Pacific plate (Okino et al., 1999). Two stages of arc rifting are recognized, including middle Miocene and latest Pliocene to Quaternary. The middle Miocene rifting occurred in the northern part of the backarc ...
... accretion is inferred to have increased the coupling force between the arc and subducting Pacific plate (Okino et al., 1999). Two stages of arc rifting are recognized, including middle Miocene and latest Pliocene to Quaternary. The middle Miocene rifting occurred in the northern part of the backarc ...
Equatorial Segment of the Mid-Atlantic Ridge: initial results of the
... In the light of the data obtained by the expedition, it became clear, that ES in fact has essential features distinct from the adjacent segments of the MAR, usually considered as typical for the ridge. In accordance with the data obtained, the hypothesis was proposed that this segment is a kind of s ...
... In the light of the data obtained by the expedition, it became clear, that ES in fact has essential features distinct from the adjacent segments of the MAR, usually considered as typical for the ridge. In accordance with the data obtained, the hypothesis was proposed that this segment is a kind of s ...
The origin and evolution of the Earth`s continental crust
... La. It is thus a major geochemical reservoir, particularly since the crust is not easily recycled back into the mantle. For these reasons, its composition is a major constraint on all geochemical models of bulk Earth composition and evolution. 41.2 per cent of the surface area of the Earth, or 2.lOx ...
... La. It is thus a major geochemical reservoir, particularly since the crust is not easily recycled back into the mantle. For these reasons, its composition is a major constraint on all geochemical models of bulk Earth composition and evolution. 41.2 per cent of the surface area of the Earth, or 2.lOx ...
Geology and Mineral Resources of Nigeria (Lecture Notes
... of Nigeria. The author has brought together several published and unpublished works into a comprehensive hand-out which I believe will be very useful to policy makers, the international community, investors, researchers and above all our students of geology in tertiary institutions in Nigeria and ab ...
... of Nigeria. The author has brought together several published and unpublished works into a comprehensive hand-out which I believe will be very useful to policy makers, the international community, investors, researchers and above all our students of geology in tertiary institutions in Nigeria and ab ...
Carlin-Type Gold Deposits in Nevada: Critical Geologic
... Carlin-type Au deposits in Nevada have huge Au endowments that have made the state, and the United States, one of the leading Au producers in the world. Forty years of mining and numerous studies have provided a detailed geologic picture of the deposits, yet a comprehensive and widely accepted genet ...
... Carlin-type Au deposits in Nevada have huge Au endowments that have made the state, and the United States, one of the leading Au producers in the world. Forty years of mining and numerous studies have provided a detailed geologic picture of the deposits, yet a comprehensive and widely accepted genet ...
Earth`s first two billion years—The era of internally
... volcanic rocks commonly are assumed to be mostly ensimatic, but no ophiolites or other physical evidence for eruption on oceanic mantle have been found: only felsic gneisses have ever been seen as basement beneath supracrustal rocks in either outcrop or geophysics. If oceanic lithosphere existed dur ...
... volcanic rocks commonly are assumed to be mostly ensimatic, but no ophiolites or other physical evidence for eruption on oceanic mantle have been found: only felsic gneisses have ever been seen as basement beneath supracrustal rocks in either outcrop or geophysics. If oceanic lithosphere existed dur ...
Landslides in Eastern Honshu Induced by the 2011 Off the Pacific
... a narrow river valley. The Ou Range defines the volcanic front of Honshu (Ujiie-Mikoshiba et al., 2006): a 500-km ridge with many Quaternary stratovolcanoes. Since the late Miocene, voluminous magmatic intrusions have been uplifting the Ou Range along its adjoining Uwandaira (east) and Senya (west) ...
... a narrow river valley. The Ou Range defines the volcanic front of Honshu (Ujiie-Mikoshiba et al., 2006): a 500-km ridge with many Quaternary stratovolcanoes. Since the late Miocene, voluminous magmatic intrusions have been uplifting the Ou Range along its adjoining Uwandaira (east) and Senya (west) ...
The Development of Highly Strained Rocks in the Pelican Window
... a sedimentary origin for some of the subunits, not on the basis of their layered nature, but on account of their extensive uniformity and relatively fine grain size, the intimate association with the pe1itic rocks, the presence of discontinuous calc-silicate layers and pods as well as magnetite, and ...
... a sedimentary origin for some of the subunits, not on the basis of their layered nature, but on account of their extensive uniformity and relatively fine grain size, the intimate association with the pe1itic rocks, the presence of discontinuous calc-silicate layers and pods as well as magnetite, and ...
ChemCam results from the Shaler outcrop in Gale crater, Mars
... To aid in the characterization of the Shaler outcrop facies, we conducted a survey of grain sizes using RMI mosaics. The RMI has the highest angular resolution of the mast-mounted cameras on Curiosity (50 lrad; Langevin et al., 2013; Le Mouélic et al., 2015). However, the narrow depth of focus (1 ...
... To aid in the characterization of the Shaler outcrop facies, we conducted a survey of grain sizes using RMI mosaics. The RMI has the highest angular resolution of the mast-mounted cameras on Curiosity (50 lrad; Langevin et al., 2013; Le Mouélic et al., 2015). However, the narrow depth of focus (1 ...
Late Pliocene to Holocene platform evolution in northern Belize, and
... Pliocene to Holocene carbonates in northern Belize are evaluated based on a ca 290 m, continuous section of samples from a well drilled on Ambergris Caye that can be linked directly to outcrops of Pleistocene limestone, and of overlying Holocene sediments. Upper Pliocene outer-ramp deposits are over ...
... Pliocene to Holocene carbonates in northern Belize are evaluated based on a ca 290 m, continuous section of samples from a well drilled on Ambergris Caye that can be linked directly to outcrops of Pleistocene limestone, and of overlying Holocene sediments. Upper Pliocene outer-ramp deposits are over ...
OROGENIC GOLD FORMATION AND TECTONIC EVOLUTION OF
... The present study represents the first detailed modern study on the Grass Valley gold district. The research included a detailed microanalytical and geochronological study of the orehosting granodiorite and the orogenic quartz veins. It is shown the ore-hosting Grass Valley granodiorite was emplaced ...
... The present study represents the first detailed modern study on the Grass Valley gold district. The research included a detailed microanalytical and geochronological study of the orehosting granodiorite and the orogenic quartz veins. It is shown the ore-hosting Grass Valley granodiorite was emplaced ...
Barrovian metamorphism in the central Kootenay Arc, British
... Abstract: A narrow, partly fault-bounded belt of Barrovian amphibolite facies rocks transects the central Kootenay Arc in the internal zone of the southeastern Canadian Cordillera. The following zones of increasing metamorphic grade are recognised in metapelites: chlorite/biotite, garnet, staurolite ...
... Abstract: A narrow, partly fault-bounded belt of Barrovian amphibolite facies rocks transects the central Kootenay Arc in the internal zone of the southeastern Canadian Cordillera. The following zones of increasing metamorphic grade are recognised in metapelites: chlorite/biotite, garnet, staurolite ...
Clastic rock
Clastic rocks are composed of fragments, or clasts, of pre-existing minerals and rock. A clast is a fragment of geological detritus, chunks and smaller grains of rock broken off other rocks by physical weathering. Geologists use the term clastic with reference to sedimentary rocks as well as to particles in sediment transport whether in suspension or as bed load, and in sediment deposits.