Lithostratigraphic and tectonic framework of Jurassic
... The oldest rocks in the south-central Intermontane belt belong to terranes that amalgamated and accreted to North America from late Paleozoic through the middle Mesozoic (Monger 1997). The study area straddles five terranes; Quesnellia, Cache Creek, Stikinia, Cadwallader, and Bridge River (Fig. 1). ...
... The oldest rocks in the south-central Intermontane belt belong to terranes that amalgamated and accreted to North America from late Paleozoic through the middle Mesozoic (Monger 1997). The study area straddles five terranes; Quesnellia, Cache Creek, Stikinia, Cadwallader, and Bridge River (Fig. 1). ...
Interrelationship of sedimentary and volcanic deposits associated
... provide stratigraphic and time markers of basin evolution and, by inference, of marginal fault development. This record has been examined in an east-west belt across south-central Sonora. The volcanic rocks occur in three distinct associations. At the base and interbedded within the lower portions o ...
... provide stratigraphic and time markers of basin evolution and, by inference, of marginal fault development. This record has been examined in an east-west belt across south-central Sonora. The volcanic rocks occur in three distinct associations. At the base and interbedded within the lower portions o ...
Geology of Northern California Geolo
... between the North American and oceanic plates to the west: a transform boundary from Monterey Bay to Cape Mendocino and a remnant convergent boundary to the north. We will explore the consequences of these interactions in more detail in the sections that follow. California and Accreted Terranes: One ...
... between the North American and oceanic plates to the west: a transform boundary from Monterey Bay to Cape Mendocino and a remnant convergent boundary to the north. We will explore the consequences of these interactions in more detail in the sections that follow. California and Accreted Terranes: One ...
Fluid Processes in Subduction Zones Hydrous Minerals and
... brittle behavior and may trigger earthquakes • Hydration structure, rheological structure, and thermal structure of subduction zones are strongly coupled ...
... brittle behavior and may trigger earthquakes • Hydration structure, rheological structure, and thermal structure of subduction zones are strongly coupled ...
Lithospheric Removal as aTrigger for Flood
... clear migration pattern (Fig. 2b; Nieto-Obrego¤n et al., 1981; Moore et al., 1994; Ferrari et al., 2000; Rosas-Elguera et al., 2003), indicating that the ‘flood basalts’ began erupting almost simultaneously over this vast territory, and that this event occurred within a relatively short time span, a ...
... clear migration pattern (Fig. 2b; Nieto-Obrego¤n et al., 1981; Moore et al., 1994; Ferrari et al., 2000; Rosas-Elguera et al., 2003), indicating that the ‘flood basalts’ began erupting almost simultaneously over this vast territory, and that this event occurred within a relatively short time span, a ...
Volcanism of the Palaeoproterozoic Bushveld Large Igneous Province: the Rooiberg
... geochronologic data, the temporal span of the Rooiberg Group is poorly understood. The Rooiberg Group consists of basaltic to rhyolitic lava erupted from fissural volcanism with estimated eruption temperatures of the rhyolitic lavas exceeding 1000°C. Minor explosive eruptions are represented by pyro ...
... geochronologic data, the temporal span of the Rooiberg Group is poorly understood. The Rooiberg Group consists of basaltic to rhyolitic lava erupted from fissural volcanism with estimated eruption temperatures of the rhyolitic lavas exceeding 1000°C. Minor explosive eruptions are represented by pyro ...
29. Sr-, Nd-, AND Pb-ISOTOPIC COMPOSITION OF VOLCANIC
... Nd/144Nd and low 87Sr/86Sr. Second, the lower units of the Lower Series (below Unit 73A; Fig. 2) plot along a trend to low 143Nd/ 144Nd at nearly constant 87Sr/86Sr, toward the isotopic composition of average granulite-facies Lewisian gneiss (Fig. 1). And third, some of the Lower Series lavas (LSb o ...
... Nd/144Nd and low 87Sr/86Sr. Second, the lower units of the Lower Series (below Unit 73A; Fig. 2) plot along a trend to low 143Nd/ 144Nd at nearly constant 87Sr/86Sr, toward the isotopic composition of average granulite-facies Lewisian gneiss (Fig. 1). And third, some of the Lower Series lavas (LSb o ...
Thick-Structured Proterozoic Lithosphere of the Rocky Mountain
... suggest this slab was bodies. This puzzle is trapped against the edge compounded by the of the thick, Archean-age observation that each is Wyoming lithosphere after aligned with both young the subduction polarity volcanic fields and flipped from south- to Proterozoic crustal grain north-directed aft ...
... suggest this slab was bodies. This puzzle is trapped against the edge compounded by the of the thick, Archean-age observation that each is Wyoming lithosphere after aligned with both young the subduction polarity volcanic fields and flipped from south- to Proterozoic crustal grain north-directed aft ...
Did mantle plume magmatism help trigger the Great Oxidation Event?
... Using the 5.49 × 10 moles of SO2 estimated to have been released by the Matachewan LIP, we can calculate that the number of moles of O2 produced by these reactions would have 7.72 × 1016. This equates to a mass of O2 of 2.47 × 1015 kg. The mass of the modern atmosphere is approximately 5.15 × 1018 k ...
... Using the 5.49 × 10 moles of SO2 estimated to have been released by the Matachewan LIP, we can calculate that the number of moles of O2 produced by these reactions would have 7.72 × 1016. This equates to a mass of O2 of 2.47 × 1015 kg. The mass of the modern atmosphere is approximately 5.15 × 1018 k ...
Contractional theory, continental drift and plate tectonics - Perso-sdt
... – energy, forces, and motion of a changing Planet Earth; mountains are the most obvious results of this system. Although nearly all geologically recent and many ancient mountain ranges are at obvious plate boundaries, all continental crust was at some time generated at plate margins, an observation ...
... – energy, forces, and motion of a changing Planet Earth; mountains are the most obvious results of this system. Although nearly all geologically recent and many ancient mountain ranges are at obvious plate boundaries, all continental crust was at some time generated at plate margins, an observation ...
B. A. Part-I Geography Title english.pmd
... several earth sciences, but micro level study of landforms is done in only Geomorphology. In this study land and oceans are studied broadly descriptive manor, because these are first order landforms of the earth. The relief features like mountain, plaetue, plains, ocean floor, continental shelf, con ...
... several earth sciences, but micro level study of landforms is done in only Geomorphology. In this study land and oceans are studied broadly descriptive manor, because these are first order landforms of the earth. The relief features like mountain, plaetue, plains, ocean floor, continental shelf, con ...
Uranium-lead geochronology of two intrusions in the southern
... most famous of these is Canada’s youngest volcanic lava flow, the Aiyansh flow (Sutherland Brown, 1969), just southwest of the Kiteen River map area. In addition, a number of small outliers of (?) Pleistocene flow deposits are recognized in the region (Haggart et al., 1998); collectively, these youn ...
... most famous of these is Canada’s youngest volcanic lava flow, the Aiyansh flow (Sutherland Brown, 1969), just southwest of the Kiteen River map area. In addition, a number of small outliers of (?) Pleistocene flow deposits are recognized in the region (Haggart et al., 1998); collectively, these youn ...
The Geological Concept
... InADictionaryoftheNatural Environment, Monkhouse and Small (1978) define the term "mountain" as follows: "A markedly elevated landform, bounded by steep slopes and rising to prominent ridges or individual summit-peaks. There is no specific altitude, but usually taken to be over 600 m (2000 ft.) in B ...
... InADictionaryoftheNatural Environment, Monkhouse and Small (1978) define the term "mountain" as follows: "A markedly elevated landform, bounded by steep slopes and rising to prominent ridges or individual summit-peaks. There is no specific altitude, but usually taken to be over 600 m (2000 ft.) in B ...
Basaltic macadam-breccias in the Girvan
... Pinbain and other pillow basalts. Variolitic textures have been considered as the equivalents of spherulitic textures in more acid glassy rocks (Carstens 1963). Vuagnat (1946) concluded that variolitic texture is indicative of eruption in deep water, a view also favoured by Walker (in Furnes 1973), ...
... Pinbain and other pillow basalts. Variolitic textures have been considered as the equivalents of spherulitic textures in more acid glassy rocks (Carstens 1963). Vuagnat (1946) concluded that variolitic texture is indicative of eruption in deep water, a view also favoured by Walker (in Furnes 1973), ...
42. The New England Seamounts
... mount, which sits on crust about 87 m.y. old and is the southeasternmost seamount along the New England Sea¬ mount trend, may have had a separate origin; but the 2 m.y. discrepancy is too small to be significant, con¬ sidering the uncertainties in seamount and crustal ages. Two other igneous provinc ...
... mount, which sits on crust about 87 m.y. old and is the southeasternmost seamount along the New England Sea¬ mount trend, may have had a separate origin; but the 2 m.y. discrepancy is too small to be significant, con¬ sidering the uncertainties in seamount and crustal ages. Two other igneous provinc ...
Geochemistry of intermediate to siliceous volcanic rocks of the
... Hatton (1995), and Hatton and Schweitzer (1995) attributed the Rooiberg Group and the Bushveld Complex to partial melting of subcontinental lithosphere and lower crust by a mantle plume. Recently, Buchanan et al. (1999) studied the high Ti and low Ti andesites and basaltic andesites of the Dullstroo ...
... Hatton (1995), and Hatton and Schweitzer (1995) attributed the Rooiberg Group and the Bushveld Complex to partial melting of subcontinental lithosphere and lower crust by a mantle plume. Recently, Buchanan et al. (1999) studied the high Ti and low Ti andesites and basaltic andesites of the Dullstroo ...
The Almeria-Nijar Basin
... minerals may crystallise in an ideal manner, creating rocks with large-sized crystals such as granites. ...
... minerals may crystallise in an ideal manner, creating rocks with large-sized crystals such as granites. ...
Unit 1 Searching for Evidence
... They have learned that spreading ridges form where rising magma — molten rock from Earth’s mantle — breaks the ocean floor along long cracks, or fissures. When a fissure opens, magma squeezes up through it and solidifies, adding to the rock on both sides of the ridge and filling in the crack. Genera ...
... They have learned that spreading ridges form where rising magma — molten rock from Earth’s mantle — breaks the ocean floor along long cracks, or fissures. When a fissure opens, magma squeezes up through it and solidifies, adding to the rock on both sides of the ridge and filling in the crack. Genera ...
Unit 1 - Delmar
... Since discovering spreading ridges in the early s, scientists have studied them extensively using sonar and underwater research vessels. They have learned that spreading ridges form where rising magma — molten rock from Earth’s mantle — breaks the ocean floor along long cracks, or fissures. When ...
... Since discovering spreading ridges in the early s, scientists have studied them extensively using sonar and underwater research vessels. They have learned that spreading ridges form where rising magma — molten rock from Earth’s mantle — breaks the ocean floor along long cracks, or fissures. When ...
GEOLOGICAL MAPPING AND BOREHOLE
... For detailed mapping of selected prospects, the procedure used is the same as for regional mapping except that the scale is larger. As the secondary permeability constitutes by far the most important path for the upflow of geothermal fluids, a special emphasis is is put on the mapping in detail of e ...
... For detailed mapping of selected prospects, the procedure used is the same as for regional mapping except that the scale is larger. As the secondary permeability constitutes by far the most important path for the upflow of geothermal fluids, a special emphasis is is put on the mapping in detail of e ...
Metamorphic processes in the subducting slab and overlying mantle
... subduction zones. Much progress has been made towards addressing the three fundamental science themes proposed by the science plan: (1) How do forcing functions such as convergence rate and upper plate thickness regulate production of magma and fluid from the Subduction Factory? (2) How does the vol ...
... subduction zones. Much progress has been made towards addressing the three fundamental science themes proposed by the science plan: (1) How do forcing functions such as convergence rate and upper plate thickness regulate production of magma and fluid from the Subduction Factory? (2) How does the vol ...
Regional Geologic Setting and Volcanic Stratigraphy
... Volcanism began about 51 Ma with the effusion of voluminous intermediate to mafic lava flows. The early intermediate to mafic lavas are largely covered by ashflow tuffs on the northern and western parts of the field, and the early in&mediate rocks are therefore best exposed in the southeastern part ...
... Volcanism began about 51 Ma with the effusion of voluminous intermediate to mafic lava flows. The early intermediate to mafic lavas are largely covered by ashflow tuffs on the northern and western parts of the field, and the early in&mediate rocks are therefore best exposed in the southeastern part ...
1 BGS Open Report: OR/10/044 GUIDE TO THE GEOLOGY OF
... the Charnian anticline (Figure 2), and also a highly penetrative west-northwesterly cleavage. The recrystallisation of minerals to form the micas that define the cleavage planes occurred at a depth of about 10 km and temperatures of 350o C – conditions that would have prevailed within the ‘roots’ of ...
... the Charnian anticline (Figure 2), and also a highly penetrative west-northwesterly cleavage. The recrystallisation of minerals to form the micas that define the cleavage planes occurred at a depth of about 10 km and temperatures of 350o C – conditions that would have prevailed within the ‘roots’ of ...
M44-2003-A4-eng - Publications du gouvernement du Canada
... rocks that correlate regionally with the youngest part of the Hazelton Group. These rocks expand the known distribution of the Early to Middle Jurassic magmatic arc sequence exposed extensively to the north in central Stikine terrane, south-southeast from Whitesail Lake map area (93 E) into north e ...
... rocks that correlate regionally with the youngest part of the Hazelton Group. These rocks expand the known distribution of the Early to Middle Jurassic magmatic arc sequence exposed extensively to the north in central Stikine terrane, south-southeast from Whitesail Lake map area (93 E) into north e ...
The Kimberley Volcano
... in the area. Diamonds occur in explosive volcanic intrusions (pipes or dykes) of kimberlite or its close relative lamproite. In the Kimberley, Argyle is the oldest such deposit at 1150 million years, and it is the largest diamond mine in the world (by volume of diamonds produced). Kimberlites in the ...
... in the area. Diamonds occur in explosive volcanic intrusions (pipes or dykes) of kimberlite or its close relative lamproite. In the Kimberley, Argyle is the oldest such deposit at 1150 million years, and it is the largest diamond mine in the world (by volume of diamonds produced). Kimberlites in the ...
Geology of the Pacific Northwest
The geology of the Pacific Northwest refers to the study of the composition (including rock, minerals, and soils), structure, physical properties and the processes that shape the Pacific Northwest region of the United States and Canada. The geology of the region produces much of the area's scenic beauty and also causes periodic catastrophes, such as volcanoes and earthquakes.There are at least five geologic provinces in the area: the Cascade Volcanoes, the Columbia Plateau, the North Cascades, the Coast Mountains, and the Insular Mountains. The Cascade Volcanoes are an active volcanic region along the western side of the Pacific Northwest. The Columbia Plateau is a region of subdued geography that is inland of the Cascade Volcanoes, and the North Cascades are a mountainous region in the northwest corner of the United States, extending into British Columbia. The Coast Mountains and Insular Mountains are a strip of mountains along the coast of British Columbia, each with its own geological history.The geology of the Pacific Northwest is vast, complex and confusing. Most of the region was formed about 200 million years ago as the North American Plate started to drift westward during the rupture of Pangaea. Since that date, the western edge of North America has grown westward as a succession of island arcs and assorted ocean-floor rocks have been added along the continental margin.