Zircon Behaviour during Low-temperature
... thought to be the result of water diffusion promoting solidstate recrystallization (Geisler et al., 2003a), with the first structural changes at c. 758C (Geisler et al., 2003c). Putnis (2002) disputed a solid-state, diffusion-driven cationexchange mechanism and favoured simultaneous dissolution^repr ...
... thought to be the result of water diffusion promoting solidstate recrystallization (Geisler et al., 2003a), with the first structural changes at c. 758C (Geisler et al., 2003c). Putnis (2002) disputed a solid-state, diffusion-driven cationexchange mechanism and favoured simultaneous dissolution^repr ...
USGS Professional Paper 1697 - Alaska Resources Library and
... http://pubs.usgs.gov//pp/p1692/ Additional USGS publications can be found at: http://geology.usgs.gov/products.html For more information about the USGS and its products: Telephone: 1–888–ASK–USGS (1–888–275–8747) World Wide Web: http://www.usgs.gov/ ...
... http://pubs.usgs.gov//pp/p1692/ Additional USGS publications can be found at: http://geology.usgs.gov/products.html For more information about the USGS and its products: Telephone: 1–888–ASK–USGS (1–888–275–8747) World Wide Web: http://www.usgs.gov/ ...
GEOLOGY OF THE PURCELL SUPERGROUP SOUTHEASTERN
... The Purcell Supergroup comprises athick accumulation of clastic and carbonaterocks that are interpreted to have been deposited in a large intracratonic basin. The northeastern margin of the hasin is exposed in the northern part of the Fernie west-half sheet. It developed by growth faulting and is ch ...
... The Purcell Supergroup comprises athick accumulation of clastic and carbonaterocks that are interpreted to have been deposited in a large intracratonic basin. The northeastern margin of the hasin is exposed in the northern part of the Fernie west-half sheet. It developed by growth faulting and is ch ...
Mineral and Energy Resources of the Mimbres Resource Area
... The Mogollon-Datil volcanic field, mainly in Grant and Hidalgo Counties, is a high plateau consisting of thick volcanic ash-flow sheets, remnants of volcanoes, and plutonic rocks; it is covered by 2-3 km of Eocene and Oligocene volcanic ash flows The Mogollon-Datil volcanic field separates the Color ...
... The Mogollon-Datil volcanic field, mainly in Grant and Hidalgo Counties, is a high plateau consisting of thick volcanic ash-flow sheets, remnants of volcanoes, and plutonic rocks; it is covered by 2-3 km of Eocene and Oligocene volcanic ash flows The Mogollon-Datil volcanic field separates the Color ...
mineral and energy resources of the mimbres resource area in
... The Mogollon-Datil volcanic field, mainly in Grant and Hidalgo Counties, is a high plateau consisting of thick volcanic ash-flow sheets, remnants of volcanoes, and plutonic rocks; it is covered by 2-3 km of Eocene and Oligocene volcanic ash flows The Mogollon-Datil volcanic field separates the Color ...
... The Mogollon-Datil volcanic field, mainly in Grant and Hidalgo Counties, is a high plateau consisting of thick volcanic ash-flow sheets, remnants of volcanoes, and plutonic rocks; it is covered by 2-3 km of Eocene and Oligocene volcanic ash flows The Mogollon-Datil volcanic field separates the Color ...
Tectonostratigraphic Terranes and Tectonic Evolution of Mexico
... Part 2 of this work (Sedlock, Speed, and Ortega-Gutierrez) is a speculative model of the Late Precambrian to Cenozoic tectonic evolution of the terranes that comprise México and northern Central America. First, we discuss numerous formal premises on which the model is predicated, including Late Jura ...
... Part 2 of this work (Sedlock, Speed, and Ortega-Gutierrez) is a speculative model of the Late Precambrian to Cenozoic tectonic evolution of the terranes that comprise México and northern Central America. First, we discuss numerous formal premises on which the model is predicated, including Late Jura ...
GEOLOGICAL SURVEY OF FINLAND Special Paper 51 2011
... 1200–1500 m depth, as revealed by the high resolution seismic reflection data. Elbra et al. (this volume) also measured the seismic velocities of core samples at elevated pressures and temperatures. The velocities were observed to vary significantly throughout the core due to variations in mineralog ...
... 1200–1500 m depth, as revealed by the high resolution seismic reflection data. Elbra et al. (this volume) also measured the seismic velocities of core samples at elevated pressures and temperatures. The velocities were observed to vary significantly throughout the core due to variations in mineralog ...
Magmatic Apatite: A Powerful, Yet Deceptive
... elongate). Equant apatite is generally defi ned by wellformed crystal faces (FIG. 1), and is often easily recognized by its hexagonal shape. This habit is interpreted to have grown under near-equilibrium conditions. Less commonly, equant apatite occurs with no well-formed crystal faces as an interst ...
... elongate). Equant apatite is generally defi ned by wellformed crystal faces (FIG. 1), and is often easily recognized by its hexagonal shape. This habit is interpreted to have grown under near-equilibrium conditions. Less commonly, equant apatite occurs with no well-formed crystal faces as an interst ...
Mineral profile - British Geological Survey
... about 20 metres thick and mid-Tertiary25 to recent in age. They are principally worked for nickel with cobalt as a by-product. The cobalt is contained within limonite and goethite as well as erythrite and asbolite. At deeper levels, weathering of ultramafic rocks is less intense and the nickeliferou ...
... about 20 metres thick and mid-Tertiary25 to recent in age. They are principally worked for nickel with cobalt as a by-product. The cobalt is contained within limonite and goethite as well as erythrite and asbolite. At deeper levels, weathering of ultramafic rocks is less intense and the nickeliferou ...
SOIL MAP OF AFRICA SCALE 1 TO 5000000 Explanatory
... At the beginning the co-ordinating Service found itself faced with a number of major obstacles: the available maps were few and the important lacunae were many, the mapping units were characterized by criteria and levels of abstraction which often varied from one map to the next, definitions lacked ...
... At the beginning the co-ordinating Service found itself faced with a number of major obstacles: the available maps were few and the important lacunae were many, the mapping units were characterized by criteria and levels of abstraction which often varied from one map to the next, definitions lacked ...
nature and composition of the continental crust
... improved correlation of phases on record sections. The variety of waves recorded in typical refraction surveys provide the basis for seismic velocity models of the crust. In addition to the direct wave that travels through the uppermost crust (Pg), various waves are reflected and refracted (head wav ...
... improved correlation of phases on record sections. The variety of waves recorded in typical refraction surveys provide the basis for seismic velocity models of the crust. In addition to the direct wave that travels through the uppermost crust (Pg), various waves are reflected and refracted (head wav ...
The rift-related mafic dyke complex of the Rohkunborri Nappe, Indre
... tråsk area. However, the contact is poorly exposed and for the purpose of this paper it is regarded as an internat unit at the base of the Målselv Nappe. ...
... tråsk area. However, the contact is poorly exposed and for the purpose of this paper it is regarded as an internat unit at the base of the Målselv Nappe. ...
.USGS
... of the the alluvial alluvial deposits deposits are are reworked reworked glacial glacial sediments. sediments. HYDROGEOLOGIC SETTING HYDROGEOLOGIC SETTING Glacial deposits Glacial deposits consist consist mostly mostly of of clay, clay, silt, silt, sand, sand, and and gravel gravel in in various var ...
... of the the alluvial alluvial deposits deposits are are reworked reworked glacial glacial sediments. sediments. HYDROGEOLOGIC SETTING HYDROGEOLOGIC SETTING Glacial deposits Glacial deposits consist consist mostly mostly of of clay, clay, silt, silt, sand, sand, and and gravel gravel in in various var ...
Ophiolite concept and its evolution
... Hess, 1938, 1955) and experimental petrologists (Bowen, 1927, 1928) regarding their close spatial association with volcanic and sedimentary rocks (Young, this volume, Chapter 4; Bernoulli et al., this volume, Chapter 7). While explaining the ophiolitic assemblages as a product of magmatic differenti ...
... Hess, 1938, 1955) and experimental petrologists (Bowen, 1927, 1928) regarding their close spatial association with volcanic and sedimentary rocks (Young, this volume, Chapter 4; Bernoulli et al., this volume, Chapter 7). While explaining the ophiolitic assemblages as a product of magmatic differenti ...
Analcime phenocrysts in igneous rocks: Primary or secondary
... analcime. Although the Crowsnest locality is noteworthy for its large fresh analcime crystals, such pristine analcime is actually rare within the formation. Most of the analcime is altered in some fashion. It might be stressedhere that the alteration of the analcime is not the well-known pseudoleuci ...
... analcime. Although the Crowsnest locality is noteworthy for its large fresh analcime crystals, such pristine analcime is actually rare within the formation. Most of the analcime is altered in some fashion. It might be stressedhere that the alteration of the analcime is not the well-known pseudoleuci ...
the orivesi granite batholith, southern central finland
... (see Selonen 1991; 1994). Our goal is to identify geological factors crucial for the formation of rock portions suitable for the extraction of dimension stone. In this paper we will analyse the geological setting and the structures in the Orivesi granite batholith and discuss the emplacement of the ...
... (see Selonen 1991; 1994). Our goal is to identify geological factors crucial for the formation of rock portions suitable for the extraction of dimension stone. In this paper we will analyse the geological setting and the structures in the Orivesi granite batholith and discuss the emplacement of the ...
*αí *ß>* * æn*ôn* m* m m m m m m m m m m m m m m m
... stockwork veining and the exsolution of volatiles and fluids. Pressure draw-down caused by cooling of the intrusion and parent melt facilitates the downward percolation of meteoric w aters to porphyry depths, and results in overprinting retrograde alteration. Porphyry copper mineralization is interp ...
... stockwork veining and the exsolution of volatiles and fluids. Pressure draw-down caused by cooling of the intrusion and parent melt facilitates the downward percolation of meteoric w aters to porphyry depths, and results in overprinting retrograde alteration. Porphyry copper mineralization is interp ...
GEOLOGICAL SURVEY OF FINLAND Special Paper 48 2008 GTK
... and for predicting natural disasters. The GTK Consortium (GTK as the leading partner together with ITC the Netherlands, SGU Sweden, GEUS Denmark and Gondwana Lda Mozambique) was responsible for projects that produced geological and mineral resources maps covering an area of 480 000 sq km, which is a ...
... and for predicting natural disasters. The GTK Consortium (GTK as the leading partner together with ITC the Netherlands, SGU Sweden, GEUS Denmark and Gondwana Lda Mozambique) was responsible for projects that produced geological and mineral resources maps covering an area of 480 000 sq km, which is a ...
ATLAS of plutonic rocks and orthogneisses in the Bohemian Massif
... vol %) in the Earth´s upper continental crust; Wedepohl 1991). Even now, the proportion of granitoids and associated volcanic rocks present on Earth is low, about 0.1 % of the bulk Earth (Clarke 1996). Like other igneous rocks, they represent probes into the deep planetary interiors and they are clo ...
... vol %) in the Earth´s upper continental crust; Wedepohl 1991). Even now, the proportion of granitoids and associated volcanic rocks present on Earth is low, about 0.1 % of the bulk Earth (Clarke 1996). Like other igneous rocks, they represent probes into the deep planetary interiors and they are clo ...
King_2005.pdf
... rheological properties which govern how they will respond to stresses and how they will interact with the layers above and below. Because no location or method exists to observe or record information about active deformation in the deep crust, the properties of middle and lower crustal layers carry ...
... rheological properties which govern how they will respond to stresses and how they will interact with the layers above and below. Because no location or method exists to observe or record information about active deformation in the deep crust, the properties of middle and lower crustal layers carry ...
Acrobat PDF file - 1 Mb (text and Table 1)
... Leg 209 was devoted to drilling mantle peridotites and associated gabbroic rocks along the Mid-Atlantic Ridge from 14° to 16°N. This area was identified at the 1996 Workshop on Oceanic Lithosphere and Scientific Drilling into the 21st Century (OL Workshop) as the ideal region for drilling of a strik ...
... Leg 209 was devoted to drilling mantle peridotites and associated gabbroic rocks along the Mid-Atlantic Ridge from 14° to 16°N. This area was identified at the 1996 Workshop on Oceanic Lithosphere and Scientific Drilling into the 21st Century (OL Workshop) as the ideal region for drilling of a strik ...
field trip guidebook - Geologian tutkimuskeskus
... with the Svecofennian Orogeny (1900-1800 Ma). In the first stage after consolidation, when the layering was mostly quite flat, many of the intrusions became affected by brittle vertical faults, which commonly broke up the intrusions into several blocks and moved them on different levels. Land uplift a ...
... with the Svecofennian Orogeny (1900-1800 Ma). In the first stage after consolidation, when the layering was mostly quite flat, many of the intrusions became affected by brittle vertical faults, which commonly broke up the intrusions into several blocks and moved them on different levels. Land uplift a ...
Mitchell Range introduction: The Mitchell Range, 240 km northwest
... Also in northeast ridge are areas with very coarse-grained poiki1oclastic textures which grade from massive to foliated .(Fig. 3-4b). Poiki1oclastic texture is defined by poiki1oclasts of anhedral orthopyroxene enclosing 2 to 10 mm subhedra1 olivine grains. Poiki1oc1astic textures are ascribed to cu ...
... Also in northeast ridge are areas with very coarse-grained poiki1oclastic textures which grade from massive to foliated .(Fig. 3-4b). Poiki1oclastic texture is defined by poiki1oclasts of anhedral orthopyroxene enclosing 2 to 10 mm subhedra1 olivine grains. Poiki1oc1astic textures are ascribed to cu ...
Chapter 7
... and local melt contents were somewhat higher in the olivine-orthopyroxene sample 5249 when compared to the olivine material, sample 5072. Furthermore, the microstructures in the annealed specimens (fig 3.17) indicate that melting in the olivine-orthopyroxene material occurs primarily along olivine-o ...
... and local melt contents were somewhat higher in the olivine-orthopyroxene sample 5249 when compared to the olivine material, sample 5072. Furthermore, the microstructures in the annealed specimens (fig 3.17) indicate that melting in the olivine-orthopyroxene material occurs primarily along olivine-o ...
Petroleum Geology and Reservoirs of the Wessex Basin
... shale beds (these are usually thinly-laminated paper shales) is usually about 6 weight per cent. In argillaceous limestone beds, such as those of the Blue Lias, it is lower, round about 0.5 weight per cent . The organic matter is in the state of kerogen, a microscopic brown waxy substance dispersed ...
... shale beds (these are usually thinly-laminated paper shales) is usually about 6 weight per cent. In argillaceous limestone beds, such as those of the Blue Lias, it is lower, round about 0.5 weight per cent . The organic matter is in the state of kerogen, a microscopic brown waxy substance dispersed ...
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.