Unblocking temperatures of viscous remanent magnetism in
... Most rocks contain an assemblage of ferrimagnetic particles that record the ambient magnetic field present at the time of the rock’s formation. In the best characterized process of magnetic remanence acquisition, thermal remanent magnetism (TRM) is acquired as the rock cools through the blocking temp ...
... Most rocks contain an assemblage of ferrimagnetic particles that record the ambient magnetic field present at the time of the rock’s formation. In the best characterized process of magnetic remanence acquisition, thermal remanent magnetism (TRM) is acquired as the rock cools through the blocking temp ...
Detrital geochronology and geochemistry of Cretaceous–Early
... P.G. DeCelles et al. / Earth and Planetary Science Letters 227 (2004) 313–330 ...
... P.G. DeCelles et al. / Earth and Planetary Science Letters 227 (2004) 313–330 ...
IOCG and Porphyry-Cu deposits in Northern
... Although Ni–PGE, Mo, BIF, and orogenic gold deposits, and some very minor VMS deposits occur in the Archaean, virtually all economic examples of these deposit types are related to Palaeoproterozoic magmatism, deformation and fluid flow. Besides these major deposit types, the Palaeoproterozoic part o ...
... Although Ni–PGE, Mo, BIF, and orogenic gold deposits, and some very minor VMS deposits occur in the Archaean, virtually all economic examples of these deposit types are related to Palaeoproterozoic magmatism, deformation and fluid flow. Besides these major deposit types, the Palaeoproterozoic part o ...
Magnetic Mineralogy of Continental Deposits, San Juan Basin, New
... chron CRM overprints are not difficult to recognize, but more extensive normal overprints may be more difficult to identify. In Tertiary sedimentary rocks it is not possible to distinguish between the present axial dipole field direction and the normal-polarity direction at the time of deposition be ...
... chron CRM overprints are not difficult to recognize, but more extensive normal overprints may be more difficult to identify. In Tertiary sedimentary rocks it is not possible to distinguish between the present axial dipole field direction and the normal-polarity direction at the time of deposition be ...
provenance analysis and detrital zircons: keys to - ETH E
... nearby Pakistan-Afghanistan border. This change in provenance is attributed to the Paleocene (65-55 Ma) collision between the Afghan plate and an intra-oceanic island arc. Furthermore heavy mineral assemblages and Cr-spinel disclose ophiolite as a subsidiary source. The westward continuation of the ...
... nearby Pakistan-Afghanistan border. This change in provenance is attributed to the Paleocene (65-55 Ma) collision between the Afghan plate and an intra-oceanic island arc. Furthermore heavy mineral assemblages and Cr-spinel disclose ophiolite as a subsidiary source. The westward continuation of the ...
NWGS Priest River
... complex. Cheney (1980) referred to this structure as the Spokane dome. The Spokane dome plunges northward beneath the Selkirk Crest, near the town of Sandpoint, and extends to the south across the Spokane Valley. The Spokane dome is interpreted as a footwall flexure that formed in response to tectoni ...
... complex. Cheney (1980) referred to this structure as the Spokane dome. The Spokane dome plunges northward beneath the Selkirk Crest, near the town of Sandpoint, and extends to the south across the Spokane Valley. The Spokane dome is interpreted as a footwall flexure that formed in response to tectoni ...
PDF file - the Kansas Geological Survey
... inclined layers in a large bed of rock (usually sandstone) that is inclined at a distinct angle to the typically horizontal bedding surface. Formed by currents of water or wind, crossbedding is found in dune, stream channel, or delta deposits. The direction in which the beds are inclined usually ind ...
... inclined layers in a large bed of rock (usually sandstone) that is inclined at a distinct angle to the typically horizontal bedding surface. Formed by currents of water or wind, crossbedding is found in dune, stream channel, or delta deposits. The direction in which the beds are inclined usually ind ...
geology
... the chemistry of the country rock is changed. Contact metasomatism is more commonly produced by wet granitic magmas than by dry gabbroic magmas. Limestones react with the acidic magmatic fluids. This causes a reduction in volume which gives space for the deposition of minerals which may be of econom ...
... the chemistry of the country rock is changed. Contact metasomatism is more commonly produced by wet granitic magmas than by dry gabbroic magmas. Limestones react with the acidic magmatic fluids. This causes a reduction in volume which gives space for the deposition of minerals which may be of econom ...
Carbonates and associated sedimentary rocks of the Upper Visgan
... presence o f thin, laterally discontinuous limestone beds in the lower grey facies of the Mabou Group is a useful guide to stratigraphic position. These carbonate beds include wackestones and grainstones containing intraclasts and ooids as well as ostracods and serpulids. Stromatolites are the most ...
... presence o f thin, laterally discontinuous limestone beds in the lower grey facies of the Mabou Group is a useful guide to stratigraphic position. These carbonate beds include wackestones and grainstones containing intraclasts and ooids as well as ostracods and serpulids. Stromatolites are the most ...
the Middle to Upper Cambrian carbonate shale
... mappable packages in the southern part of the map area. In the southeast, poorly exposed sections of quartzite and lesser carbonate are exposed in thrust panels below the Netson Creek fault. In the far southeastern corner of the map area, thick to massively bedded, brown-weathering, brown to beige q ...
... mappable packages in the southern part of the map area. In the southeast, poorly exposed sections of quartzite and lesser carbonate are exposed in thrust panels below the Netson Creek fault. In the far southeastern corner of the map area, thick to massively bedded, brown-weathering, brown to beige q ...
Sedimentology and stratigraphy of the Upper Cretaceous
... sandstones and mudrocks. Within these lithostratigraphic sequences, five facies associations can be identified: 1) an open water facies; 2) a nearshore facies; 3) a beach, bar and shoal facies; 4) a floodplain facies; and 5) a fluvial facies. A regional study of El Molino Formation stratigraphic sta ...
... sandstones and mudrocks. Within these lithostratigraphic sequences, five facies associations can be identified: 1) an open water facies; 2) a nearshore facies; 3) a beach, bar and shoal facies; 4) a floodplain facies; and 5) a fluvial facies. A regional study of El Molino Formation stratigraphic sta ...
GEOLOGY, ORE DEPOSITS, AND MINERAL POTENTIAL OF THE
... The writer first began geologic studies on the Seward Peninsula in 1952; between 1960 and 1971 he was continuously engaged in studies of the geology and mineral resources of the region for the U.S. Geological Survey, first in the detailed geologic mapping of the region around the Lost River tin-tung ...
... The writer first began geologic studies on the Seward Peninsula in 1952; between 1960 and 1971 he was continuously engaged in studies of the geology and mineral resources of the region for the U.S. Geological Survey, first in the detailed geologic mapping of the region around the Lost River tin-tung ...
GeoEssex Fact Sheet No. 2
... special is that it is homogeneous - the pebbles and the enclosing matrix are the same hardness therefore when a piece of puddingstone is broken the plane of fracture passes through, rather than around, the pebbles. This is very significant and means that it is an unbelievably tough rock. Puddingston ...
... special is that it is homogeneous - the pebbles and the enclosing matrix are the same hardness therefore when a piece of puddingstone is broken the plane of fracture passes through, rather than around, the pebbles. This is very significant and means that it is an unbelievably tough rock. Puddingston ...
Rare Earth Elements (2011) - Department of Natural Resources
... deposits in peralkaline suites define two canic origin, although the former are more common. end-member-types that are respectively dominated by In metasomatic–hydrothermal examples, mineralizamagmatic and metasomatic–hydrothermal processes, tion is superimposed on pre-existing rock units but many d ...
... deposits in peralkaline suites define two canic origin, although the former are more common. end-member-types that are respectively dominated by In metasomatic–hydrothermal examples, mineralizamagmatic and metasomatic–hydrothermal processes, tion is superimposed on pre-existing rock units but many d ...
THE PALEOPROTEROZOIC METAVOLCANIC
... facies. This dominantly metasedimentary package commonly displays primary sedimentary features such as ripple marks and crossbedding. In contrast, in the Rangers Bight area, the area comprises dominantly a metavolcanic package of dominated by felsic tuff, basalt, rhyolite and lesser interbedded cong ...
... facies. This dominantly metasedimentary package commonly displays primary sedimentary features such as ripple marks and crossbedding. In contrast, in the Rangers Bight area, the area comprises dominantly a metavolcanic package of dominated by felsic tuff, basalt, rhyolite and lesser interbedded cong ...
Gold-enriched Skarn Deposits of British Columbia
... thelowerButtleLakelimestoneandupperMyravolcaniclastic rocks. Jurassic quartz diorite contains epidoteamphibole endoskarn at surface and is associated with massive garnet-wollastonite skarn replacing limestone at depth. The latter consists of coarse-grained euhedral garnet varying from amassiveyellow ...
... thelowerButtleLakelimestoneandupperMyravolcaniclastic rocks. Jurassic quartz diorite contains epidoteamphibole endoskarn at surface and is associated with massive garnet-wollastonite skarn replacing limestone at depth. The latter consists of coarse-grained euhedral garnet varying from amassiveyellow ...
THE AGUABLANCA Ni–Cu–PGE DEPOSIT, SOUTHWESTERN
... The Aguablanca Ni–Cu–PGE ore deposit, in southwestern Iberia, has a magmatic origin, and has been reworked by later skarn-related hydrothermal activity. Base-metal sulfides are associated with igneous cumulates displaying subvertical layering consisting of gabbro, norite and dolerite, with fragments ...
... The Aguablanca Ni–Cu–PGE ore deposit, in southwestern Iberia, has a magmatic origin, and has been reworked by later skarn-related hydrothermal activity. Base-metal sulfides are associated with igneous cumulates displaying subvertical layering consisting of gabbro, norite and dolerite, with fragments ...
Sa˜o Luıs Craton and Gurupi Belt
... Abstract: The São Luı́s Craton and the Palaeoproterozoic basement rocks of the Neoproterozoic Gurupi Belt in northern Brazil are part of an orogen having an early accretionary phase at 2240– 2150 Ma and a late collisional phase at 2080 + 20 Ma. Geological, geochronological and isotopic evidence, al ...
... Abstract: The São Luı́s Craton and the Palaeoproterozoic basement rocks of the Neoproterozoic Gurupi Belt in northern Brazil are part of an orogen having an early accretionary phase at 2240– 2150 Ma and a late collisional phase at 2080 + 20 Ma. Geological, geochronological and isotopic evidence, al ...
Carlin-Type and Low-Sulphidation Epithermal Gold Deposits
... SLIDE 47: Another visible indicator of ore grades is the presence of the arsenicbearing minerals realgar and orpiment. In many deposits, these are typically associated with zones of enriched gold grades. ...
... SLIDE 47: Another visible indicator of ore grades is the presence of the arsenicbearing minerals realgar and orpiment. In many deposits, these are typically associated with zones of enriched gold grades. ...
Late Palaeozoic lam pro phyres and as so ci ated mafic subvolcanic
... the crystalline basement and, locally, the overlying molasse deposits. The dyke swarms are adjacent to major regional dislocations, represent distinctive magmatic centres that are related to separate magmatic systems and each are characterized by specific parental melts that have undergone individua ...
... the crystalline basement and, locally, the overlying molasse deposits. The dyke swarms are adjacent to major regional dislocations, represent distinctive magmatic centres that are related to separate magmatic systems and each are characterized by specific parental melts that have undergone individua ...
Precambrian Rocks of Alaska
... but suggested that the two subdivisions, each as much as 2,000 m thick, merit separate group names. Young subdivided the Tindir Group into 11 units. The lower Tindir Group consists mainly of carbonates and sandstones that were deposited in a shallow marine environment; a black shale unit is a deeper ...
... but suggested that the two subdivisions, each as much as 2,000 m thick, merit separate group names. Young subdivided the Tindir Group into 11 units. The lower Tindir Group consists mainly of carbonates and sandstones that were deposited in a shallow marine environment; a black shale unit is a deeper ...
Cenozoic Sediments, Volcanics, and Related Uranium in the Basin
... The fine-grained facies generally consists of lightcolored to greenish mudstone, calcareous shale, and limestone with some gypsiferous beds. The presence of red fanglomerate and monolMhologic megabreccia overlying or underlying fine-grained members indicates that nearby areas had high relief. The 2, ...
... The fine-grained facies generally consists of lightcolored to greenish mudstone, calcareous shale, and limestone with some gypsiferous beds. The presence of red fanglomerate and monolMhologic megabreccia overlying or underlying fine-grained members indicates that nearby areas had high relief. The 2, ...
The Origin of Oceanic Trenches
... downward forming trenches. Gravity is still smoothing out these imbalances—shifting (not drifting) material, including continents, toward trenches. ...
... downward forming trenches. Gravity is still smoothing out these imbalances—shifting (not drifting) material, including continents, toward trenches. ...
Physical volcanology of the Rooiberg Group near Loskop Dam, By
... Within the scope of the study area (Loskop Dam), eight lithofacies types could be identified, ranging from coherent lava flows and massive tuffs to cross-bedded sandstones and conglomerates. The lithofacies types can be grouped into syn-, and inter-eruptive lithofacies associations, thus, illustrati ...
... Within the scope of the study area (Loskop Dam), eight lithofacies types could be identified, ranging from coherent lava flows and massive tuffs to cross-bedded sandstones and conglomerates. The lithofacies types can be grouped into syn-, and inter-eruptive lithofacies associations, thus, illustrati ...
TRANSACTIONS THE GEOLOGICAL SOCI ETY
... result of vertical or radial (epeirogenic) rnovements. A Graben is u foundered strip of the earth's crust lying between more or less pandlel faults or monodinal flexures, along which it has been let down as a result of epeirogenic mo·vements. In the \Vittpuetz trough we have to do vvith an extensive ...
... result of vertical or radial (epeirogenic) rnovements. A Graben is u foundered strip of the earth's crust lying between more or less pandlel faults or monodinal flexures, along which it has been let down as a result of epeirogenic mo·vements. In the \Vittpuetz trough we have to do vvith an extensive ...
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.