Radiometric Dating Reappraised
... Thus open systems caused by geologic events (“geological interpretation”) is claimed as a cause of spurious dates, but a less self-congratulatory view would be that only a select number of dates are accepted as indicating the true age of the rock; others explained away as having become open systems. ...
... Thus open systems caused by geologic events (“geological interpretation”) is claimed as a cause of spurious dates, but a less self-congratulatory view would be that only a select number of dates are accepted as indicating the true age of the rock; others explained away as having become open systems. ...
Petrology of Olkiluoto
... gneisses make up over 64% of the volume of the Olkiluoto bedrock, with the veined gneisses accounting for 43%, the stromatic gneisses for 0.4% and the diatexitic gneisses for 21%, based on drill core logging. Of the remaining lithologies, TGG gneisses constitute 8% and pegmatitic granites almost 20% ...
... gneisses make up over 64% of the volume of the Olkiluoto bedrock, with the veined gneisses accounting for 43%, the stromatic gneisses for 0.4% and the diatexitic gneisses for 21%, based on drill core logging. Of the remaining lithologies, TGG gneisses constitute 8% and pegmatitic granites almost 20% ...
Sphalerite composition in relation to deposition and metamorphism
... generally been preserved in lithologies which are are usually equant and can reach 30/~m in diameter, rich in quartz, barium feldspars, baryte, and may be randomly dispersed, orientated along carbonates, whereas micaceous rocks are usually crystallographic planes, or concentrated towards highly schi ...
... generally been preserved in lithologies which are are usually equant and can reach 30/~m in diameter, rich in quartz, barium feldspars, baryte, and may be randomly dispersed, orientated along carbonates, whereas micaceous rocks are usually crystallographic planes, or concentrated towards highly schi ...
List by Deposit Group - Ministry of Energy and Mines and
... DEPOSITIONAL ENVIRONMENT / GEOLOGICAL SETTING: Peat deposits occur in topographic depressions often caused by melting ice in glacial tills or flat plains, usually overlying relatively impermeable materials, such as glaciolacustrine sediments and clay-rich tills. They are common in areas with poorly ...
... DEPOSITIONAL ENVIRONMENT / GEOLOGICAL SETTING: Peat deposits occur in topographic depressions often caused by melting ice in glacial tills or flat plains, usually overlying relatively impermeable materials, such as glaciolacustrine sediments and clay-rich tills. They are common in areas with poorly ...
Bulletin 80: Precambrian Geology of La Madera Quadrangle, Rio
... 21. Schematic cross section of third deformation fold system . ......... 115 22. Schematic diagram illustrating Precambrian geologic history in La Madera quadrangle ......................................................... 126 PLATES ...
... 21. Schematic cross section of third deformation fold system . ......... 115 22. Schematic diagram illustrating Precambrian geologic history in La Madera quadrangle ......................................................... 126 PLATES ...
SEDIMENTATION OF DINOSAUR
... Within the horst massifsforming the northern flank of the Nemegt Basin, the oldrock complex is covered in places by continental sediments, preserved in a tectonic downfaulted area. These sediments probably belong to the Cretaceous and are older than the Cretaceous sediments exposed within the graben ...
... Within the horst massifsforming the northern flank of the Nemegt Basin, the oldrock complex is covered in places by continental sediments, preserved in a tectonic downfaulted area. These sediments probably belong to the Cretaceous and are older than the Cretaceous sediments exposed within the graben ...
STUDIES OF THE PRECAMBRIAN HEREFOSS GRANITE
... K-feldspar. At several sites on the east, orthoclase occurs together with K-feldspars of near maximum obliquity (center and southeast); however, the east side is characterized by maximum L1-values that are in places, associated with subordinate amounts of variable L1-values. The rocks on the west si ...
... K-feldspar. At several sites on the east, orthoclase occurs together with K-feldspars of near maximum obliquity (center and southeast); however, the east side is characterized by maximum L1-values that are in places, associated with subordinate amounts of variable L1-values. The rocks on the west si ...
Berg Porphyry Copper
... veins, both with and without alteration envelopes, were deposited from saline fluids at temperatures in excess of 400 degreesCelsius. Later veins were deposited from cooler, less saline fluids and commonly have retrograde alteration envelopes or bleached margins. A gypsum-filled subhorizontal fractu ...
... veins, both with and without alteration envelopes, were deposited from saline fluids at temperatures in excess of 400 degreesCelsius. Later veins were deposited from cooler, less saline fluids and commonly have retrograde alteration envelopes or bleached margins. A gypsum-filled subhorizontal fractu ...
Economic Geology - Sociedad Geológica de Chile
... The Oyu Tolgoi porphyry Cu-Au system in the South Gobi desert, Mongolia, comprises five deposits that extend over 6 km in a north-northeast–oriented zone. They occur in a middle to late Paleozoic arc terrane and are related to Late Devonian quartz monzodiorite intrusions. The Hugo Dummett deposits a ...
... The Oyu Tolgoi porphyry Cu-Au system in the South Gobi desert, Mongolia, comprises five deposits that extend over 6 km in a north-northeast–oriented zone. They occur in a middle to late Paleozoic arc terrane and are related to Late Devonian quartz monzodiorite intrusions. The Hugo Dummett deposits a ...
full text, PDF
... Measured stratigraphic section of the upper of the sequence in which sepiolite formations are located, is prepared in order to detailly observe and to describe the superposition manner and the textural features, mineral composition and its variation. Furthermore, 34 trenchs in sepiolite-rich beds ve ...
... Measured stratigraphic section of the upper of the sequence in which sepiolite formations are located, is prepared in order to detailly observe and to describe the superposition manner and the textural features, mineral composition and its variation. Furthermore, 34 trenchs in sepiolite-rich beds ve ...
fenites associated with carbonatites
... carbonatite-associated fenites remain to make this study viable. Fenites around carbonatites come in many varieties. Heinrich (1985) identified three principal types: potassic, sodic–potassic and sodic. All are syenitic in appearance, and some are all-too-easily mistaken for igneous syenites unless ...
... carbonatite-associated fenites remain to make this study viable. Fenites around carbonatites come in many varieties. Heinrich (1985) identified three principal types: potassic, sodic–potassic and sodic. All are syenitic in appearance, and some are all-too-easily mistaken for igneous syenites unless ...
Gold mineralization and associated alteration zones of the Biely vrch
... The deposit is located in the central zone of the Neogene Javorie stratovolcano, and shares many properties typical for Au-porphyry deposits. Parental intrusion of diorite to andesite porphyry and its andesitic volcanic host rocks are affected by extensive alteration, dominated by intermediate argil ...
... The deposit is located in the central zone of the Neogene Javorie stratovolcano, and shares many properties typical for Au-porphyry deposits. Parental intrusion of diorite to andesite porphyry and its andesitic volcanic host rocks are affected by extensive alteration, dominated by intermediate argil ...
chapter 4 mineralogical characteristics of host rocks
... Olympus CX31 make) to determine the properties of minerals and their textural relationships. (a) Phyllite: The mineralogical composition of this rock is chlorite, feldspar, clay and some ferruginous matter. In some samples, rounded reddish brown coloured mineral is found. These minerals are weakly a ...
... Olympus CX31 make) to determine the properties of minerals and their textural relationships. (a) Phyllite: The mineralogical composition of this rock is chlorite, feldspar, clay and some ferruginous matter. In some samples, rounded reddish brown coloured mineral is found. These minerals are weakly a ...
The Precambrian schists and gneisses of Lakselv valley, northern
... locally), sodic plagioclase (Ans to An2o), and epidote. Quartz is fairly abundant in most specimens. The principal accessory minerals are scapolite, sphene, apatite, magnetite and ilmenite, biotite, calcite and the alteration products sericite and chlorite. The hornblende diorite and associated horn ...
... locally), sodic plagioclase (Ans to An2o), and epidote. Quartz is fairly abundant in most specimens. The principal accessory minerals are scapolite, sphene, apatite, magnetite and ilmenite, biotite, calcite and the alteration products sericite and chlorite. The hornblende diorite and associated horn ...
19. contrasting characteristics of magmatic and
... if a higher limit is set, say 100 meters, what is to prevent metasomatism from occurring at distances of 101 meters? If K-metasomatism can occur in a pluton even at one centimeter, given enough time and appropriate conditions, almost any distance across the pluton should be possible. The extent depe ...
... if a higher limit is set, say 100 meters, what is to prevent metasomatism from occurring at distances of 101 meters? If K-metasomatism can occur in a pluton even at one centimeter, given enough time and appropriate conditions, almost any distance across the pluton should be possible. The extent depe ...
Foliation (Passchier and Trouw, 1996)
... – Convergent fan - foliation converges from the convex toward the concave side of the folded layer, e.g., in competent rocks such as sandstone. – Divergent fan - foliation diverges from the convex toward the concave side of the folded layer, e.g., in the less competent rocks such as shale or schist. ...
... – Convergent fan - foliation converges from the convex toward the concave side of the folded layer, e.g., in competent rocks such as sandstone. – Divergent fan - foliation diverges from the convex toward the concave side of the folded layer, e.g., in the less competent rocks such as shale or schist. ...
Types, grade and facies of metamorphism
... Relative terms such as high-temperature or low-pressure are often used to refer to the physical conditions of metamorphism but without precise designation of the temperatures and pressures involved. In order to maintain similarity of meaning it is proposed that the whole spectrum of temperature cond ...
... Relative terms such as high-temperature or low-pressure are often used to refer to the physical conditions of metamorphism but without precise designation of the temperatures and pressures involved. In order to maintain similarity of meaning it is proposed that the whole spectrum of temperature cond ...
effects of weathering in the rock and rock
... of excavation and this will influence the rate at which the rock mass properties deteriorate in the engineering lifetime of the slope. It is shown in this study that the response of different volcanic rock and the associated volcanoclastic rocks respond to weathering differently, but still reflectiv ...
... of excavation and this will influence the rate at which the rock mass properties deteriorate in the engineering lifetime of the slope. It is shown in this study that the response of different volcanic rock and the associated volcanoclastic rocks respond to weathering differently, but still reflectiv ...
the Minerals and Rocks
... brings out clearly the typical appearance and the characteristics by which the mineral and rock can be recognized. These well-labeled drawings, based upon sketches that were made especially for this book by the author's wife and were prepared in close collaboration with his writing of the text, will ...
... brings out clearly the typical appearance and the characteristics by which the mineral and rock can be recognized. These well-labeled drawings, based upon sketches that were made especially for this book by the author's wife and were prepared in close collaboration with his writing of the text, will ...
PreCambrian geology of the Picuris Range, northcentral New Mexico
... metamorphic rocks plainly were of sedimentary origin, but metamorphosed igneous rocks also were recognized. Later igneous rocks, only slightly metamorphosed, were intruded into the metamorphic terrane; the notable pegmatites of the area are associated with these rocks. All of these crystalline rocks ...
... metamorphic rocks plainly were of sedimentary origin, but metamorphosed igneous rocks also were recognized. Later igneous rocks, only slightly metamorphosed, were intruded into the metamorphic terrane; the notable pegmatites of the area are associated with these rocks. All of these crystalline rocks ...
composition and provenance of clastic material in the vendian
... and red-brownish in colour. No fossils have been found in the ¯arnowiec Fm. At the top it gradually passes into marine sandstones and sand-mud heteroliths which are early Cambrian in age. The ¯arnowiec Fm. is believed to represent the Vendian and earliest Cambrian. Mineral composition of the ¯arnowi ...
... and red-brownish in colour. No fossils have been found in the ¯arnowiec Fm. At the top it gradually passes into marine sandstones and sand-mud heteroliths which are early Cambrian in age. The ¯arnowiec Fm. is believed to represent the Vendian and earliest Cambrian. Mineral composition of the ¯arnowi ...
Petrology, Petrophysics and Fracture Mineralogy of the Drill Core Sample OL-KR8
... exceeds 20% in these rocks. Cordierite or pinite porphyroblasts, typically 5 – 10 mm in diameter, are common constituents for one subgroup of mica rich rocks. Mafic gneisses and schists have been seen as different variants that have been called amphibolites, hornblende gneisses and chlorite schists. ...
... exceeds 20% in these rocks. Cordierite or pinite porphyroblasts, typically 5 – 10 mm in diameter, are common constituents for one subgroup of mica rich rocks. Mafic gneisses and schists have been seen as different variants that have been called amphibolites, hornblende gneisses and chlorite schists. ...
Industrial Minerals Studies - Ministry of Energy and Mines and
... INTRODUCTION Fluorspar is the commercial name for the mineral fluorite, CaF,. Fluorite is a very attractive mineral which often occurs in well-formed crystals ranging in colour from white to amber, green, blue, purple and black. It forms in a wide range of temperature and pressure conditions and the ...
... INTRODUCTION Fluorspar is the commercial name for the mineral fluorite, CaF,. Fluorite is a very attractive mineral which often occurs in well-formed crystals ranging in colour from white to amber, green, blue, purple and black. It forms in a wide range of temperature and pressure conditions and the ...
surficial geologic map of the dent quadrangle, clearwater county
... flows form laterally traceable ledges. More gently sloping areas are mantled with thin loess (typically 1-5 feet thick), especially near boundaries with loess mantling basalt residuum (QTlbr). Distribution and thickness of colluvium is dependent on slope aspect, upper and lower slope position, basal ...
... flows form laterally traceable ledges. More gently sloping areas are mantled with thin loess (typically 1-5 feet thick), especially near boundaries with loess mantling basalt residuum (QTlbr). Distribution and thickness of colluvium is dependent on slope aspect, upper and lower slope position, basal ...
Physical Properties of Reservoir Rocks
... are sedimentary in origin. Sedimentary rocks that contain oil and gas are generally divided into two categories: clastic sedimentary rocks and carbonate sedimentary rocks. The former chiefly includes conglomerate, sandstone, and mudstone, while the latter usually refers to limestone and dolomite. Sa ...
... are sedimentary in origin. Sedimentary rocks that contain oil and gas are generally divided into two categories: clastic sedimentary rocks and carbonate sedimentary rocks. The former chiefly includes conglomerate, sandstone, and mudstone, while the latter usually refers to limestone and dolomite. Sa ...
Mudrock
Mudrocks are a class of fine grained siliciclastic sedimentary rocks. The varying types of mudrocks include: siltstone, claystone, mudstone, slate, and shale. Most of the particles are less than 0.0625 mm (1/16th mm or 0.0025 inches) and are too small to study readily in the field. At first sight the rock types look quite similar; however, there are important differences in composition and nomenclature. There has been a great deal of disagreement involving the classification of mudrocks. There are a few important hurdles to classification, including:Mudrocks are the least understood, and one of the most understudied sedimentary rocks to dateIt is difficult to study mudrock constituents, due to their diminutive size and susceptibility to weathering on outcropsAnd most importantly, there is more than one classification scheme accepted by scientistsMudrocks make up fifty percent of the sedimentary rocks in the geologic record, and are easily the most widespread deposits on Earth. Fine sediment is the most abundant product of erosion, and these sediments contribute to the overall omnipresence of mudrocks. With increased pressure over time the platey clay minerals may become aligned, with the appearance of fissility or parallel layering. This finely bedded material that splits readily into thin layers is called shale, as distinct from mudstone. The lack of fissility or layering in mudstone may be due either to original texture or to the disruption of layering by burrowing organisms in the sediment prior to lithification. From the beginning of civilization, when pottery and mudbricks were made by hand, to now, mudrocks have been important. The first book on mudrocks, Geologie des Argils by Millot, was not published until 1964; however, scientists, engineers, and oil producers have understood the significance of mudrocks since the discovery of the Burgess Shale and the relatedness of mudrocks and oil. Literature on the elusive yet omnipresent rock-type has been increasing in recent years, and technology continues to allow for better analysis.