Geochronology and thermochronology of Cretaceous
... Table 3). Squares with numbers are localities where outcrop-scale structures were measured and compiled in Fig .3. ...
... Table 3). Squares with numbers are localities where outcrop-scale structures were measured and compiled in Fig .3. ...
geology of the kajiado area - Library
... System. He described a type section in a tributary of the river Turoka, about two miles above Turoka station and to the south of the old safari track, but it was not positively located during the present survey. His sequence could well be applied to many localities in the vicinity, and the term Turo ...
... System. He described a type section in a tributary of the river Turoka, about two miles above Turoka station and to the south of the old safari track, but it was not positively located during the present survey. His sequence could well be applied to many localities in the vicinity, and the term Turo ...
Principal Gold Producing Districts of the United States
... 3. Annual gold production of Alabama, Gorgia, North Carolina, South Carolina, and Virginia, 1823-1960 .................................... 4. Annual gold production of Alaska, 1880-1965 ......................... Map showing gold-mining districts of Alaska .................................. Graph sho ...
... 3. Annual gold production of Alabama, Gorgia, North Carolina, South Carolina, and Virginia, 1823-1960 .................................... 4. Annual gold production of Alaska, 1880-1965 ......................... Map showing gold-mining districts of Alaska .................................. Graph sho ...
ch 4
... In contrast to the events of the more distant past, the events of this episode have preserved a true abundance of information on the course of geologic evolution here. We can map the appearance of magma species, the orientation and magnitude of folds, the character and displacement of faults, and w ...
... In contrast to the events of the more distant past, the events of this episode have preserved a true abundance of information on the course of geologic evolution here. We can map the appearance of magma species, the orientation and magnitude of folds, the character and displacement of faults, and w ...
The Mississippi Valley-type Zn-Pb deposit of
... to bedding with dips ~70° to the east, or parallel to bedding, dipping ~25-30° westerly. Zebra structures display identical concordant and discordant relationships relative to bedding. The preferential orientation of the gangue structures is interpreted within a dextral shear zone model, where they ...
... to bedding with dips ~70° to the east, or parallel to bedding, dipping ~25-30° westerly. Zebra structures display identical concordant and discordant relationships relative to bedding. The preferential orientation of the gangue structures is interpreted within a dextral shear zone model, where they ...
The Use of Magnetic Susceptibility of Rocks in Geological
... field-independent and called the initial susceptibility. In most ferromagnetic minerals the initial susceptibility is measured in the fields less than 10 A/m, only in the case of pyrrhotite the field should be much lower. As the measuring field in the Kappameters of the KT series is less than 1 A/m, ...
... field-independent and called the initial susceptibility. In most ferromagnetic minerals the initial susceptibility is measured in the fields less than 10 A/m, only in the case of pyrrhotite the field should be much lower. As the measuring field in the Kappameters of the KT series is less than 1 A/m, ...
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 ...
Natural zeolites filling amygdales and veins in
... although it also encompasses quartzites, marbles, graphitic schists and amphibolites, which are thought have been formed from a wide variety of even older igneous and sedimentary rocks whose original composition and structure became modified by the effects of heat and intense pressure deep in the ea ...
... although it also encompasses quartzites, marbles, graphitic schists and amphibolites, which are thought have been formed from a wide variety of even older igneous and sedimentary rocks whose original composition and structure became modified by the effects of heat and intense pressure deep in the ea ...
Age and tectonic setting of the Tysfjord gneiss granite, Efjord, North
... The basement rocks of the Efjord area can be grouped into three, (l) mafic gneisses, (2) coarse-grained biotite-gneiss granite ('JYsfjord gneiss granite) and (3) biotite-poor fine-grained aplitic granite. The basic rocks occur as small lenses and layers in the 'JYsfjord gneiss granite and the bounda ...
... The basement rocks of the Efjord area can be grouped into three, (l) mafic gneisses, (2) coarse-grained biotite-gneiss granite ('JYsfjord gneiss granite) and (3) biotite-poor fine-grained aplitic granite. The basic rocks occur as small lenses and layers in the 'JYsfjord gneiss granite and the bounda ...
FAILURE OF TRANSVERSELY ISOTROPIC ROCK
... The fracture length within the various rock samples is estimated and used as a tool to distinguish between the different failure modes. First, the length of all fractures in the sample is measured. Second, the length corresponding to the various fracture types is considered. When a fracture is class ...
... The fracture length within the various rock samples is estimated and used as a tool to distinguish between the different failure modes. First, the length of all fractures in the sample is measured. Second, the length corresponding to the various fracture types is considered. When a fracture is class ...
Anorthosite and the lower crust
... anorthosite and mid- and lower crustal rocks (Barnichon et al., 1999). The model confirms that diapirism of an anorthosite mush through the lower crust can take place in a relatively short time (2-3 Myr), and gives rise to strain regimes and pluton shapes in agreement with field observations. The ti ...
... anorthosite and mid- and lower crustal rocks (Barnichon et al., 1999). The model confirms that diapirism of an anorthosite mush through the lower crust can take place in a relatively short time (2-3 Myr), and gives rise to strain regimes and pluton shapes in agreement with field observations. The ti ...
Merlinleigh and Byro Sub-Basins
... The eastern part of the Merlinleigh Sub-basin and the Byro Sub-basin are less known. Their hydrocarbon potential may be comparable to that of the drilled portion of the Merlinleigh Sub-basin, but additional data are required in order to make conclusive assessments. Geochemical studies confirm the go ...
... The eastern part of the Merlinleigh Sub-basin and the Byro Sub-basin are less known. Their hydrocarbon potential may be comparable to that of the drilled portion of the Merlinleigh Sub-basin, but additional data are required in order to make conclusive assessments. Geochemical studies confirm the go ...
Ultramafic-mafic intrusions, volcanic rocks and PGE-Cu
... Stillwater, etc.) and PGE-copper-nickel sulfide deposits (Sudbury, Voisey’s Bay, Jinchuan, Duluth, etc.). The Norilsk deposits have both ore types combined within a single intrusive body (i.e., coppernickel sulfide, also enriched with platinum group elements (PGE) and low-sulfide platinum). They are ...
... Stillwater, etc.) and PGE-copper-nickel sulfide deposits (Sudbury, Voisey’s Bay, Jinchuan, Duluth, etc.). The Norilsk deposits have both ore types combined within a single intrusive body (i.e., coppernickel sulfide, also enriched with platinum group elements (PGE) and low-sulfide platinum). They are ...
Ojo - New Mexico Geological Society
... well-cemented, massive to thin-bedded, volcaniclastic conglomerate, sandstone, and siltstone; includes a white ash-fall or ash-flow tuff north of Black Mountain andesite flows interbedded with volcaniclastic sedimentary rocks (Tc) gray, welded to nonwelded tuff containing 5-30% phenocrysts (quartz, ...
... well-cemented, massive to thin-bedded, volcaniclastic conglomerate, sandstone, and siltstone; includes a white ash-fall or ash-flow tuff north of Black Mountain andesite flows interbedded with volcaniclastic sedimentary rocks (Tc) gray, welded to nonwelded tuff containing 5-30% phenocrysts (quartz, ...
Geochemistry of volcanic rocks from the Geysers geothermal area
... and Suemnicht (1980) first described that a hypabyssal plutonic body underlies the Geysers steam reservoir. While early literature frequently refers to this body as the dFelsiteT, we prefer the term Geysers Plutonic Complex (GPC) in recognition of its composite nature. The northwest trending antifor ...
... and Suemnicht (1980) first described that a hypabyssal plutonic body underlies the Geysers steam reservoir. While early literature frequently refers to this body as the dFelsiteT, we prefer the term Geysers Plutonic Complex (GPC) in recognition of its composite nature. The northwest trending antifor ...
Carbonaceous schists of the Main Central Thrust zone as a source
... Carbonaceous materials in metasedimentary rocks recrystallize to form graphite structure with increasing diagenesis and metamorphism and reaches to the fully ordered graphite. This recrystallization is called graphitization and can be examined by the X-ray powder Diffractometer. X-ray diffraction an ...
... Carbonaceous materials in metasedimentary rocks recrystallize to form graphite structure with increasing diagenesis and metamorphism and reaches to the fully ordered graphite. This recrystallization is called graphitization and can be examined by the X-ray powder Diffractometer. X-ray diffraction an ...
The Regolith Glossary
... Most scientific disciplines have classifications which make use of words in very specific ways. This glossary has included the more common of these, particularly words for landforms and soils. An example is the word ‘hill’, which is completely well understood by all English speakers, but which is de ...
... Most scientific disciplines have classifications which make use of words in very specific ways. This glossary has included the more common of these, particularly words for landforms and soils. An example is the word ‘hill’, which is completely well understood by all English speakers, but which is de ...
Bulletin 51: Geology of the Quessta molybdenum (Moly) mine area
... of the range and in small scattered areas elsewhere in the range. At the mine, conglomerates, arkosic graywackes, siltstones, and limestones overlie the Precambrian and are correlated tentatively with the Pennsylvanian-Permian Sangre de Cristo formation. A thick sequence of Miocene (?) volcanics (th ...
... of the range and in small scattered areas elsewhere in the range. At the mine, conglomerates, arkosic graywackes, siltstones, and limestones overlie the Precambrian and are correlated tentatively with the Pennsylvanian-Permian Sangre de Cristo formation. A thick sequence of Miocene (?) volcanics (th ...
Metallogeny of the Gold Quadrilateral: style and characteristics of
... It is widely believed and generally accepted by economic geologists that high-sulfidation epithermal deposits form in part by interaction of magmatic volatiles with cooler ground water (Hayba et al., 1985; Hedenquist, 1987; Berger & Henley, 1989; Gammons & Williams-Jones, 1997). As a consequence and ...
... It is widely believed and generally accepted by economic geologists that high-sulfidation epithermal deposits form in part by interaction of magmatic volatiles with cooler ground water (Hayba et al., 1985; Hedenquist, 1987; Berger & Henley, 1989; Gammons & Williams-Jones, 1997). As a consequence and ...
Presentation - Copernicus.org
... dykes are presented dolerite trachydolerites, syenite, Minetti, bostonitami, different in composition lamprophyres (camptonite, spessartite, Vosges), avgitite, melanephelinite, alnёite, limburgite alkaline picrites, meimechites. The content of major oxides in rocks of the dykes vary widely: SiO2 35, ...
... dykes are presented dolerite trachydolerites, syenite, Minetti, bostonitami, different in composition lamprophyres (camptonite, spessartite, Vosges), avgitite, melanephelinite, alnёite, limburgite alkaline picrites, meimechites. The content of major oxides in rocks of the dykes vary widely: SiO2 35, ...
Geological Society, London, Special Publications
... variety of manganese deposits in the past. Only major deposits and those providing distinctive evidence of their environment of deposition will be considered here. ...
... variety of manganese deposits in the past. Only major deposits and those providing distinctive evidence of their environment of deposition will be considered here. ...
Mesa Central of México: Stratigraphy, structure, and Cenozoic
... Raisz (1959), as “a basin surrounded by more elevated mountains. More high and flat than the Basin and Range province (located to the north). Instead of elongated ranges, this one has low elevated areas, mainly dissecting old volcanic rocks.” If we observe the orographic configuration of the Mexican ...
... Raisz (1959), as “a basin surrounded by more elevated mountains. More high and flat than the Basin and Range province (located to the north). Instead of elongated ranges, this one has low elevated areas, mainly dissecting old volcanic rocks.” If we observe the orographic configuration of the Mexican ...
GEOLOGY OF MINNESOTA: A Centennial Volume
... BURNTSIDE GRANITE GNEISS, VERMILION DISTRICT - P. K. Sims and M. G. Mudrey, Jr . .. . 98 SAGANAGA BATHOLITH - Gilbert N. Hanson . .............................................. . 102 Geologic Setting ............................................................................ . 102 Saganaga Tonalite ...
... BURNTSIDE GRANITE GNEISS, VERMILION DISTRICT - P. K. Sims and M. G. Mudrey, Jr . .. . 98 SAGANAGA BATHOLITH - Gilbert N. Hanson . .............................................. . 102 Geologic Setting ............................................................................ . 102 Saganaga Tonalite ...
Permian and Triassic rocks of the Appleby district (part of Sheet 30
... present resurvey. These breccias would occupy a stratigraphical position many tens of metres above the base of the Penrith Sandstone Formation. Brockram is largely unknown from the remainder of the district, though exposure of the Permian sequence is admittedly poor. In the Burrells-Hoff area, the B ...
... present resurvey. These breccias would occupy a stratigraphical position many tens of metres above the base of the Penrith Sandstone Formation. Brockram is largely unknown from the remainder of the district, though exposure of the Permian sequence is admittedly poor. In the Burrells-Hoff area, the B ...
Adakite-like Lavas from Antisana Volcano (Ecuador): Evidence for
... two phases. The southeastern part represents the old edifice, which encompasses two-thirds of the volcano. It is composed of numerous volcanic breccia deposits, lava and pyroclastic flows whose eruptive history is totally unknown. Glacial erosion has strongly remodelled this old edifice. It seems th ...
... two phases. The southeastern part represents the old edifice, which encompasses two-thirds of the volcano. It is composed of numerous volcanic breccia deposits, lava and pyroclastic flows whose eruptive history is totally unknown. Glacial erosion has strongly remodelled this old edifice. It seems th ...
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.