Petrological and geochronological constraints on lower crust
... terrane, as opposed to a structurally controlled differential exhumation (Percival et al., 1992; Percival and Skulski, 2000; Cagnard et al., 2007; Gapais et al., 2008; 2009). However, spatial variations in geothermal gradients and contrasting metamorphic grades between domains of similar ages have b ...
... terrane, as opposed to a structurally controlled differential exhumation (Percival et al., 1992; Percival and Skulski, 2000; Cagnard et al., 2007; Gapais et al., 2008; 2009). However, spatial variations in geothermal gradients and contrasting metamorphic grades between domains of similar ages have b ...
causes of variation in granite suites
... fractionated I- and S-type granites. In all of these rocks the contents of the major elements are very similar and do not change with fractionation, being governed by equilibrium between melt and crystals in the Tuttle & Bowen (1958) haplogranite system. However, trace element abundances change mark ...
... fractionated I- and S-type granites. In all of these rocks the contents of the major elements are very similar and do not change with fractionation, being governed by equilibrium between melt and crystals in the Tuttle & Bowen (1958) haplogranite system. However, trace element abundances change mark ...
REE-Y, Ti, and P Remobilization in Magmatic Rocks by
... al., 2009). Indeed, these experiments show that for chloriderich fluids such as those responsible for the formation of porphyry copper deposits (Seedorff et al., 2005), chloride complexes may control the transport of REE, as is also indicated by thermodynamic modelling (e.g., Douville et al., 1999). ...
... al., 2009). Indeed, these experiments show that for chloriderich fluids such as those responsible for the formation of porphyry copper deposits (Seedorff et al., 2005), chloride complexes may control the transport of REE, as is also indicated by thermodynamic modelling (e.g., Douville et al., 1999). ...
secondary planar structural elements
... which refers to rock regions with different compositions and fabrics. The cleavage consists in spaced bands of strongly aligned, recrystallised platy minerals anastomosing around domains of not or weakly deformed quartz grains and phyllosilicate grains subparallel to bedding and showing kinks and un ...
... which refers to rock regions with different compositions and fabrics. The cleavage consists in spaced bands of strongly aligned, recrystallised platy minerals anastomosing around domains of not or weakly deformed quartz grains and phyllosilicate grains subparallel to bedding and showing kinks and un ...
as a PDF
... SiO2 content (65–74 wt %) and exhibit characteristics of a highAl tonalite–trondhjemite–granitoid (TTG) suite, including light rare earth element (LREE) enrichment, low Y, Nb and Rb/Sr, and high Al2O3 and Sr. These compositions are consistent with an origin by 10–40% partial melting of a low-K thole ...
... SiO2 content (65–74 wt %) and exhibit characteristics of a highAl tonalite–trondhjemite–granitoid (TTG) suite, including light rare earth element (LREE) enrichment, low Y, Nb and Rb/Sr, and high Al2O3 and Sr. These compositions are consistent with an origin by 10–40% partial melting of a low-K thole ...
AREA IN
... ably, there is no other area in the Trondheim region, at any rate not in the southern and central part, which display so low-grade meta morphism. The occurrence of several fossil horizons through a greater part of the series of strata in the area is evidently conditioned by this Iow-grade metamorph ...
... ably, there is no other area in the Trondheim region, at any rate not in the southern and central part, which display so low-grade meta morphism. The occurrence of several fossil horizons through a greater part of the series of strata in the area is evidently conditioned by this Iow-grade metamorph ...
SEDIMENTATION OF DINOSAUR
... Nemegt Basin is given by EFREMOV (1950, 1954a, 1955). According to this writer, an erosional "channel" is present at the Nemegt locality. EFREMOV regarded this " channel" as cutting into older Upper Cretaceous rocks, represented by red unfossiliferous sandstones (the so-called "unfossiliferous serie ...
... Nemegt Basin is given by EFREMOV (1950, 1954a, 1955). According to this writer, an erosional "channel" is present at the Nemegt locality. EFREMOV regarded this " channel" as cutting into older Upper Cretaceous rocks, represented by red unfossiliferous sandstones (the so-called "unfossiliferous serie ...
Clay mineral evolution - Brown University Planetary Geosciences
... monly found interstratified with other clay minerals, most often with smectite. Note that the official IMA status of illite and glauconite is pending, and phengite [K(Mg,Al)2(Si,Al)4O10(OH)2], which was once included in this group, has been discredited as a distinct mineral species. Note, however, t ...
... monly found interstratified with other clay minerals, most often with smectite. Note that the official IMA status of illite and glauconite is pending, and phengite [K(Mg,Al)2(Si,Al)4O10(OH)2], which was once included in this group, has been discredited as a distinct mineral species. Note, however, t ...
Geodiversity Audit and Action Plan
... The study and recommendations presented here represent the first attempt to address the varied facets of geodiversity within the Northumberland National Park and adjoining area, which for the purpose of this publication is called the district, shown on the inside front cover. Moreover, as the first co ...
... The study and recommendations presented here represent the first attempt to address the varied facets of geodiversity within the Northumberland National Park and adjoining area, which for the purpose of this publication is called the district, shown on the inside front cover. Moreover, as the first co ...
Bulletin 84: Geology of the Walnut Wells Quadrangle, Hidalgo
... Big Hatchet Mountains fifteen miles to the east. The Early Cretaceous Hell-to-Finish, U-Bar, and Mojado Formations described from the Big Hatchet Mountains area are recognized in this quadrangle. A new Cretaceous conglomerate formation, which overlies the Mojado, is named Cowboy Spring Formation. La ...
... Big Hatchet Mountains fifteen miles to the east. The Early Cretaceous Hell-to-Finish, U-Bar, and Mojado Formations described from the Big Hatchet Mountains area are recognized in this quadrangle. A new Cretaceous conglomerate formation, which overlies the Mojado, is named Cowboy Spring Formation. La ...
Geology and Geochemistry of Hadean Zircon Bearing
... outcrop-scale geological and geochemical context of these rocks is not well documented. New mapping reveals a varied suite of isoclinally folded, sheared and variably deformed chromiterich banded and massive quartzites, garnet-bearing siliceous paragneisses, amphibolite, quartzbiotite schists and a ...
... outcrop-scale geological and geochemical context of these rocks is not well documented. New mapping reveals a varied suite of isoclinally folded, sheared and variably deformed chromiterich banded and massive quartzites, garnet-bearing siliceous paragneisses, amphibolite, quartzbiotite schists and a ...
Explanatory memoir to accompany sheets 3,4,5 (in part), 9,10,11 (in
... There can be as little doubt ...
... There can be as little doubt ...
Advances in Ni-Cu-PGE Sulphide Deposit Models and Implications
... It is commonly possible to identify groups of orebodies within one cluster or camp of temporally and spatially constrained deposits that have common empirical traits, and to then develop successful exploration technologies based on these similarities. Models developed for exploration for contact, fo ...
... It is commonly possible to identify groups of orebodies within one cluster or camp of temporally and spatially constrained deposits that have common empirical traits, and to then develop successful exploration technologies based on these similarities. Models developed for exploration for contact, fo ...
effects of weathering in the rock and rock
... Earth Observation of the University of Twente. All views and opinions expressed therein remain the sole responsibility of the author, and do not necessarily represent those of the Faculty. ...
... Earth Observation of the University of Twente. All views and opinions expressed therein remain the sole responsibility of the author, and do not necessarily represent those of the Faculty. ...
XIII Meeting of the Petrology Group of the Mineralogical Society of
... Olivine grains are up to 1 cm, have straight mutual grain boundaries. Olivine is Fo82.2-90.1 and contain minor MnO (0.14-0.23 wt %) and NiO (0.13-0.40 wt %). The range of MgO, as well as NiO and MnO, is similar to those of olivine from mantlederived peridotite xenoliths worldwide. Within 10-30 µm fr ...
... Olivine grains are up to 1 cm, have straight mutual grain boundaries. Olivine is Fo82.2-90.1 and contain minor MnO (0.14-0.23 wt %) and NiO (0.13-0.40 wt %). The range of MgO, as well as NiO and MnO, is similar to those of olivine from mantlederived peridotite xenoliths worldwide. Within 10-30 µm fr ...
Untitled
... the crystal structure. The weathering of weak minerals such as biotite often leads to decomposition of the entire rock due to the accompanying volume increase. When Fe2+- ions in the biotite becomes exposed to oxygen and water they oxidize to Fe3+ which have a low solubility and therefore precipitat ...
... the crystal structure. The weathering of weak minerals such as biotite often leads to decomposition of the entire rock due to the accompanying volume increase. When Fe2+- ions in the biotite becomes exposed to oxygen and water they oxidize to Fe3+ which have a low solubility and therefore precipitat ...
Crystallization sequences in the Muskox intrusion and other layered
... common in the Bushveld Complex and Great Dyke in southern Africa and in the Stillwater Complex in Montana, bodies in which dozens of examples ranging from a few inches to about 15 ft in thickness have been traced for distances of tens of miles.* The layers are of interest both as major ore deposits ...
... common in the Bushveld Complex and Great Dyke in southern Africa and in the Stillwater Complex in Montana, bodies in which dozens of examples ranging from a few inches to about 15 ft in thickness have been traced for distances of tens of miles.* The layers are of interest both as major ore deposits ...
Geology, age and field relations of Hadean zircon-bearing
... ion beam continues to sputter into the sample while at the same time collecting data that is transformed into a continuous age and composition profile of several micrometers (Mojzsis and Harrison, 2002). Further details of a depth-profiled ca. 4000 Ma grain (Bear2_5-6) from the Quad Creek locality des ...
... ion beam continues to sputter into the sample while at the same time collecting data that is transformed into a continuous age and composition profile of several micrometers (Mojzsis and Harrison, 2002). Further details of a depth-profiled ca. 4000 Ma grain (Bear2_5-6) from the Quad Creek locality des ...
book of abstracts
... The hydrothermal alteration of ultramafic rocks is a widespread process described in many geological settings, wherever warm aqueous fluids react with mantle-forming minerals (olivine, pyroxenes) to precipitate Mg-phyllosilicates (serpentine, brucite, talc). It presents several fundamental and socie ...
... The hydrothermal alteration of ultramafic rocks is a widespread process described in many geological settings, wherever warm aqueous fluids react with mantle-forming minerals (olivine, pyroxenes) to precipitate Mg-phyllosilicates (serpentine, brucite, talc). It presents several fundamental and socie ...
The Sudbury impact layer in the Paleoproterozoic iron ranges of
... The Sudbury impact layer in Michigan is a bed of breccia and related rocks. Because sites vary from a single drill hole or outcrop to clusters of drill holes and outcrops, the amount of information is quite variable between sites. Table 1 provides some general information about each site, and Figure ...
... The Sudbury impact layer in Michigan is a bed of breccia and related rocks. Because sites vary from a single drill hole or outcrop to clusters of drill holes and outcrops, the amount of information is quite variable between sites. Table 1 provides some general information about each site, and Figure ...
surficial geologic map of the dent quadrangle, clearwater county
... the hydrogeologic regime, and the occurrence of basalt overlying clay-rich weathered basement rocks. The largest landslides occur where canyoncutting has exposed landslide-prone sediments to steep topography. Slope failures have occurred where the fine-grained sedimentary interbeds and weathered bas ...
... the hydrogeologic regime, and the occurrence of basalt overlying clay-rich weathered basement rocks. The largest landslides occur where canyoncutting has exposed landslide-prone sediments to steep topography. Slope failures have occurred where the fine-grained sedimentary interbeds and weathered bas ...
SECTION 1: - Limestone Landscapes
... either of fragments of older rocks or of organic materials such as plant or shell debris, usually underwater or more occasionally on land. As layers of sediment build up, the lower ones become progressively more compacted and eventually cement together to form rock. Sandstone is a rock formed of san ...
... either of fragments of older rocks or of organic materials such as plant or shell debris, usually underwater or more occasionally on land. As layers of sediment build up, the lower ones become progressively more compacted and eventually cement together to form rock. Sandstone is a rock formed of san ...
New Chemical Weathering Indices for Estimating
... Aydın (2003) explained that geochemical signatures of weathering should be used to establish a framework for the interpretation of the heterogeneity level and the prediction of the variability in engineering properties of rocks. Before proceeding with the chemical weathering indices, it is useful to ...
... Aydın (2003) explained that geochemical signatures of weathering should be used to establish a framework for the interpretation of the heterogeneity level and the prediction of the variability in engineering properties of rocks. Before proceeding with the chemical weathering indices, it is useful to ...
Industrial Minerals Studies - Ministry of Energy and Mines and
... analyses (Graf, 1985; Pell, 1987) indicate CaF, contents for this type of mineralization of between 24.6 and 70.65 per cent. The rare-earth element and pyrite contents of these rocks are relatively low. Massive fluorite lnineralization has not been found in place, but abundant float occurs at the so ...
... analyses (Graf, 1985; Pell, 1987) indicate CaF, contents for this type of mineralization of between 24.6 and 70.65 per cent. The rare-earth element and pyrite contents of these rocks are relatively low. Massive fluorite lnineralization has not been found in place, but abundant float occurs at the so ...
ore deposit types and their primary expressions
... Additional and essential requirements include energy (generally thermal, gravitational or deformational) to power the transport mechanism and a suitable crustal structure to focus ore-forming components and accommodate their deposition. Metals are largely derived from the mantle or crust by partial ...
... Additional and essential requirements include energy (generally thermal, gravitational or deformational) to power the transport mechanism and a suitable crustal structure to focus ore-forming components and accommodate their deposition. Metals are largely derived from the mantle or crust by partial ...
Sedimentary rock
Sedimentary rocks are types of rock that are formed by the deposition of material at the Earth's surface and within bodies of water. Sedimentation is the collective name for processes that cause mineral and/or organic particles (detritus) to settle and accumulate or minerals to precipitate from a solution. Particles that form a sedimentary rock by accumulating are called sediment. Before being deposited, sediment was formed by weathering and erosion in a source area, and then transported to the place of deposition by water, wind, ice, mass movement or glaciers which are called agents of denudation.The sedimentary rock cover of the continents of the Earth's crust is extensive, but the total contribution of sedimentary rocks is estimated to be only 8% of the total volume of the crust. Sedimentary rocks are only a thin veneer over a crust consisting mainly of igneous and metamorphic rocks. Sedimentary rocks are deposited in layers as strata, forming a structure called bedding. The study of sedimentary rocks and rock strata provides information about the subsurface that is useful for civil engineering, for example in the construction of roads, houses, tunnels, canals or other structures. Sedimentary rocks are also important sources of natural resources like coal, fossil fuels, drinking water or ores.The study of the sequence of sedimentary rock strata is the main source for scientific knowledge about the Earth's history, including palaeogeography, paleoclimatology and the history of life. The scientific discipline that studies the properties and origin of sedimentary rocks is called sedimentology. Sedimentology is part of both geology and physical geography and overlaps partly with other disciplines in the Earth sciences, such as pedology, geomorphology, geochemistry and structural geology.