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 ...
Sublayer and Offset Dikes of the Sudbury Igneous
... Supplementing existing data with new measurements made along most of the Lithoprobe transect lines, McGrath and Broome (1994) have re-interpreted the gravity map of the Sudbury structure. They conclude that the sub-surface disposition of rock-types that are exposed at surface, as revealed in the sei ...
... Supplementing existing data with new measurements made along most of the Lithoprobe transect lines, McGrath and Broome (1994) have re-interpreted the gravity map of the Sudbury structure. They conclude that the sub-surface disposition of rock-types that are exposed at surface, as revealed in the sei ...
Petrogenetic evolution of Uralian-Alaskan-type mafic
... related to extensional tectonics along the edge of the east European Craton have been postulated as geological setting. The aim of the PhD thesis at hand is to constrain the petrogenetic evolution of three Uralian-Alaskan-type complexes. Based on the detailed analysis of variations in major and trac ...
... related to extensional tectonics along the edge of the east European Craton have been postulated as geological setting. The aim of the PhD thesis at hand is to constrain the petrogenetic evolution of three Uralian-Alaskan-type complexes. Based on the detailed analysis of variations in major and trac ...
bedrock geology of the piedmont of delaware and adjacent
... This report accompanies a new map that revises the original bedrock geologic maps of the Delaware Piedmont compiled by Woodruff and Thompson and published by the Delaware Geological Survey (DGS) in 1972 and 1975. Combined detailed mapping, petrography, geochemistry, and U-Pb geochronology have allow ...
... This report accompanies a new map that revises the original bedrock geologic maps of the Delaware Piedmont compiled by Woodruff and Thompson and published by the Delaware Geological Survey (DGS) in 1972 and 1975. Combined detailed mapping, petrography, geochemistry, and U-Pb geochronology have allow ...
Exhumation of (ultra-)high-pressure terranes: concepts
... Peak pressures are estimated using petrological reactions involving changes in molar volume. The determined pressures are commonly converted to depth by assuming that the pressure experienced is due only to the weight of the overburden (lithostatic pressure). However, recent field data and numerical ...
... Peak pressures are estimated using petrological reactions involving changes in molar volume. The determined pressures are commonly converted to depth by assuming that the pressure experienced is due only to the weight of the overburden (lithostatic pressure). However, recent field data and numerical ...
Batholith tectonics: Formation and deformation of ghost stratigraphy
... Anderson et al. partially molten or, instead, assembled by incremental emplacement of numerous magma batches that cycled across their solidi depending on the rate of replenishment (e.g., Daly, 1903a, 1903b; Marsh, 1982; Hutton, 1996; Petford, 1996; Glazner et al., 2004; Cruden, 2006; Glazner and Bar ...
... Anderson et al. partially molten or, instead, assembled by incremental emplacement of numerous magma batches that cycled across their solidi depending on the rate of replenishment (e.g., Daly, 1903a, 1903b; Marsh, 1982; Hutton, 1996; Petford, 1996; Glazner et al., 2004; Cruden, 2006; Glazner and Bar ...
Cordierite in felsic igneous rocks: a synthesis
... is not surprising that such cordierites may also occur in the complementary granitic magma. Magmatic --formation as the result of solid-melt reactions Type 2 Magmatic: (a) Peritectic (TT). This category includes cordierite that appears only as the result of a melt-producing reaction in response to r ...
... is not surprising that such cordierites may also occur in the complementary granitic magma. Magmatic --formation as the result of solid-melt reactions Type 2 Magmatic: (a) Peritectic (TT). This category includes cordierite that appears only as the result of a melt-producing reaction in response to r ...
Early Paleozoic Tectonic and Thermomechanical
... Coesite- and diamond-bearing ultrahigh-pressure (UHP) metamorphic rocks represent continental materials that were once subducted to depths of >90 km. Identifying how these rocks were subsequently returned to Earth’s surface has been a major challenge. Opinions on this matter vary widely, ranging fro ...
... Coesite- and diamond-bearing ultrahigh-pressure (UHP) metamorphic rocks represent continental materials that were once subducted to depths of >90 km. Identifying how these rocks were subsequently returned to Earth’s surface has been a major challenge. Opinions on this matter vary widely, ranging fro ...
an example to sepiolite formation in volcanic belts by
... crystalline+vitric tuff, vitric tuff and resedimented tuff/tuffite transported by small braided streams, in ascending order. Crystalline tuff is dominant at the Uşakgöl plain, while vitric tuff and ash predominate at the northwestern flanks of the Öküzçayırı stream. Vitric tuff, ash and pumiceous tu ...
... crystalline+vitric tuff, vitric tuff and resedimented tuff/tuffite transported by small braided streams, in ascending order. Crystalline tuff is dominant at the Uşakgöl plain, while vitric tuff and ash predominate at the northwestern flanks of the Öküzçayırı stream. Vitric tuff, ash and pumiceous tu ...
Earth`s first two billion years—The era of internally
... volcanic rocks commonly are assumed to be mostly ensimatic, but no ophiolites or other physical evidence for eruption on oceanic mantle have been found: only felsic gneisses have ever been seen as basement beneath supracrustal rocks in either outcrop or geophysics. If oceanic lithosphere existed dur ...
... volcanic rocks commonly are assumed to be mostly ensimatic, but no ophiolites or other physical evidence for eruption on oceanic mantle have been found: only felsic gneisses have ever been seen as basement beneath supracrustal rocks in either outcrop or geophysics. If oceanic lithosphere existed dur ...
Sabzevar Ophiolite, NE Iran - The University of Texas at Dallas
... and Aliak villages (Appendix 1). Pelagic sediments stratigraphically cover the pillow lava sequence and/or are interbedded with them. Andesitic dikes (1–1.5 m in thickness) occasionally crosscut the pillow ...
... and Aliak villages (Appendix 1). Pelagic sediments stratigraphically cover the pillow lava sequence and/or are interbedded with them. Andesitic dikes (1–1.5 m in thickness) occasionally crosscut the pillow ...
40. Evolution of a layered diorite-gabbro to become a layered quartz
... The eastern border of the Wanup pluton along Route 69 contains thick feldspathic bands that alternate with thinner amphibolite bands (Fig 5 c), similar to those at the north end, except that the feldspathic bands are mostly coarser grained with microcline crystals, 1-2 cm long (Fig. 4). These larger ...
... The eastern border of the Wanup pluton along Route 69 contains thick feldspathic bands that alternate with thinner amphibolite bands (Fig 5 c), similar to those at the north end, except that the feldspathic bands are mostly coarser grained with microcline crystals, 1-2 cm long (Fig. 4). These larger ...
Near-Ultrahigh Pressure Processing of Continental Crust: Miocene
... compositions were measured at Boston University using the remains of thin-section billets. This is not ideal because the samples are contaminated with epoxy from thin-section impregnation, and some include bits of host lava. Billets were first abraded with silicon carbide to remove as much as possib ...
... compositions were measured at Boston University using the remains of thin-section billets. This is not ideal because the samples are contaminated with epoxy from thin-section impregnation, and some include bits of host lava. Billets were first abraded with silicon carbide to remove as much as possib ...
Setting Based Classification
... • Result of thermal (and possibly metasomatic) effects of hot magma intruding cooler shallow rocks • Occur over a wide range of pressures, including very low • Contact aureole ...
... • Result of thermal (and possibly metasomatic) effects of hot magma intruding cooler shallow rocks • Occur over a wide range of pressures, including very low • Contact aureole ...
Tectonic Setting and Regional Geology of the KSZ
... This study integrates petrological, structural, geochemical, geochronological and isotopic investigations of the geodynamic evolution of the Neoproterozoic Keraf Shear Zone (KSZ) in NE Sudan. It is a ~500 km long, thrust-bounded and wedge-shaped belt, that is narrower (∼30 km) in the S and wider (∼1 ...
... This study integrates petrological, structural, geochemical, geochronological and isotopic investigations of the geodynamic evolution of the Neoproterozoic Keraf Shear Zone (KSZ) in NE Sudan. It is a ~500 km long, thrust-bounded and wedge-shaped belt, that is narrower (∼30 km) in the S and wider (∼1 ...
Differentiation of the continental crust by relamination
... The origin and composition of continental crust—particularly the lower crust—remain enigmatic. The principal conundrum to be resolved is how an andesitic to dacitic continental crust has formed when most mantle-derived magmas are basaltic. This differentiation has been explained as the result of low ...
... The origin and composition of continental crust—particularly the lower crust—remain enigmatic. The principal conundrum to be resolved is how an andesitic to dacitic continental crust has formed when most mantle-derived magmas are basaltic. This differentiation has been explained as the result of low ...
Open-File Report 2005-1235
... Mountains of Montana, Idaho, and eastern Washington, brings together forty-three 1:100,000- to 1:250,000-scale digital geologic maps into a common database format. The regional geologic database is an ArcInfo® coverage (NR_GEO) that contains spatial data for both lines (contacts, faults, fold axes, ...
... Mountains of Montana, Idaho, and eastern Washington, brings together forty-three 1:100,000- to 1:250,000-scale digital geologic maps into a common database format. The regional geologic database is an ArcInfo® coverage (NR_GEO) that contains spatial data for both lines (contacts, faults, fold axes, ...
DOWNLOAD YOUR COURSE (handout 1).
... bubbles in the liquid - produces vesicles in volcanic rocks, responsible for explosive nature of volcanic eruptions. The composition of the gas phase varies widely in magmas reflecting the composition, T and P of formation, source material etc. SOLID PHASE: May be crystals which form early as the re ...
... bubbles in the liquid - produces vesicles in volcanic rocks, responsible for explosive nature of volcanic eruptions. The composition of the gas phase varies widely in magmas reflecting the composition, T and P of formation, source material etc. SOLID PHASE: May be crystals which form early as the re ...
GLG101online_08A_Metamorphism_MCC_Leighty
... These notes and web links are your primary “lecture” content in this class. Additionally, various articles are assigned each week to supplement this “lecture” information. I believe you’ll have enough information to reference without having to purchase a costly textbook. These lecture notes are ver ...
... These notes and web links are your primary “lecture” content in this class. Additionally, various articles are assigned each week to supplement this “lecture” information. I believe you’ll have enough information to reference without having to purchase a costly textbook. These lecture notes are ver ...
Intrusive igneous rocks include granite.
... Most Virginia Fossils are of marine organisms. This indicates that large areas of the state have been periodically covered by seawater. ...
... Most Virginia Fossils are of marine organisms. This indicates that large areas of the state have been periodically covered by seawater. ...
Volcanogenic Massive Sulfide Deposits
... to the discharge site, whereas distal deposits may have accumulated at some distance from the vents. Host strata are predominantly volcanic rocks, although the ores themselves may have been deposited in sediments that occur within the volcanic succession. The metals and reduced sulfur are considered ...
... to the discharge site, whereas distal deposits may have accumulated at some distance from the vents. Host strata are predominantly volcanic rocks, although the ores themselves may have been deposited in sediments that occur within the volcanic succession. The metals and reduced sulfur are considered ...
Figs 3.4 - Geoscience Australia
... broadly divided into: (1) primary deposits associated with igneous and hydrothermal processes; and (2) secondary deposits concentrated by sedimentary processes and weathering. Further sub-division of these general categories can be applied using such criteria as lithological association, mineralogy, ...
... broadly divided into: (1) primary deposits associated with igneous and hydrothermal processes; and (2) secondary deposits concentrated by sedimentary processes and weathering. Further sub-division of these general categories can be applied using such criteria as lithological association, mineralogy, ...
ZINCIAN SPINEL ASSOCIATED WITH METAMORPHOSED
... INTRODUCTION Zincian spinel [(Zn,Fe,Mg)Al2O4] occurs in various geological settings and rock types, but is most common in and surrounding metamorphosed massive sulfide deposits; it is also known to occur in aluminous metasedimentary rocks and granitic pegmatites (Spry & Scott 1986a). Textural, exper ...
... INTRODUCTION Zincian spinel [(Zn,Fe,Mg)Al2O4] occurs in various geological settings and rock types, but is most common in and surrounding metamorphosed massive sulfide deposits; it is also known to occur in aluminous metasedimentary rocks and granitic pegmatites (Spry & Scott 1986a). Textural, exper ...
Weathering
Weathering is the breaking down of rocks, soil and minerals as well as artificial materials through contact with the Earth's atmosphere, biota and waters. Weathering occurs in situ, roughly translated to: ""with no movement"" , and thus should not be confused with erosion, which involves the movement of rocks and minerals by agents such as water, ice, snow, wind, waves and gravity and then being transported and deposited in other locations.Two important classifications of weathering processes exist – physical and chemical weathering; each sometimes involves a biological component. Mechanical or physical weathering involves the breakdown of rocks and soils through direct contact with atmospheric conditions, such as heat, water, ice and pressure. The second classification, chemical weathering, involves the direct effect of atmospheric chemicals or biologically produced chemicals also known as biological weathering in the breakdown of rocks, soils and minerals. While physical weathering is accentuated in very cold or very dry environments, chemical reactions are most intense where the climate is wet and hot. However, both types of weathering occur together, and each tends to accelerate the other. For example, physical abrasion (rubbing together) decreases the size of particles and therefore increases their surface area, making them more susceptible to rapid chemical reactions. The various agents act in concert to convert primary minerals (feldspars and micas) to secondary minerals (clays and carbonates) and release plant nutrient elements in soluble forms.The materials left over after the rock breaks down combined with organic material creates soil. The mineral content of the soil is determined by the parent material, thus a soil derived from a single rock type can often be deficient in one or more minerals for good fertility, while a soil weathered from a mix of rock types (as in glacial, aeolian or alluvial sediments) often makes more fertile soil. In addition, many of Earth's landforms and landscapes are the result of weathering processes combined with erosion and re-deposition.