Rheological Response to Tectonic and Volcanic
... depth beneath central Iceland (Fig. 2) (Darbyshire et al. 2000). However, different authors have derived somewhat different conclusions on crustal thickness (see Sigmundsson 2006). Previous models have used seismic and gravity data to determine the thermal structure beneath Iceland (e.g., Flóvenz & ...
... depth beneath central Iceland (Fig. 2) (Darbyshire et al. 2000). However, different authors have derived somewhat different conclusions on crustal thickness (see Sigmundsson 2006). Previous models have used seismic and gravity data to determine the thermal structure beneath Iceland (e.g., Flóvenz & ...
Differentiation of the continental crust by relamination
... from continental crust (DeBari and Sleep, 1991; Greene et al., 2006). This is so because garnet-free mafic rocks that are either density-stable or too viscous to founder remain in the cold, upper and middle crust. Whereas foundering of dense material could potentially produce a differentiated contine ...
... from continental crust (DeBari and Sleep, 1991; Greene et al., 2006). This is so because garnet-free mafic rocks that are either density-stable or too viscous to founder remain in the cold, upper and middle crust. Whereas foundering of dense material could potentially produce a differentiated contine ...
Land Zones of Queensland - Department of Environment and
... Complex coastal geomorphology on the Townsville coastal plain............................................ 14 Playa (ephemeral salt lakes) of Land Zone 3 are common landforms in arid Queensland ...... 15 Quaternary alluvial fans of Mt Elliott, south of Townsville with streams and gullies from Mt Elli ...
... Complex coastal geomorphology on the Townsville coastal plain............................................ 14 Playa (ephemeral salt lakes) of Land Zone 3 are common landforms in arid Queensland ...... 15 Quaternary alluvial fans of Mt Elliott, south of Townsville with streams and gullies from Mt Elli ...
Rocks-Minerals - WordPress.com
... Electrons can be thought of as being transferred from one atom to another in an ionic bond. Common table salt (NaCl) is a mineral composed of chlorine and sodium linked together by ionic bonds. The mineral name for NaCl is halite. An element like chlorine can also form bonds without forming ions. Fo ...
... Electrons can be thought of as being transferred from one atom to another in an ionic bond. Common table salt (NaCl) is a mineral composed of chlorine and sodium linked together by ionic bonds. The mineral name for NaCl is halite. An element like chlorine can also form bonds without forming ions. Fo ...
Introduction to Faults
... fault.wall, a gouge may be dug on the wall. forces.. In a Thrust Fault, the footwall ...
... fault.wall, a gouge may be dug on the wall. forces.. In a Thrust Fault, the footwall ...
Did westward subduction cause Cretaceous
... or utilized plate models for the main development of the Cordilleran orogenic belt postulate Neoproterozoic to Cambrian rifting of Laurentia to form a westerly facing passive margin, active until the late Devonian; then 110 m.y., from the Late Devonian to the early Triassic, punctuated by the succes ...
... or utilized plate models for the main development of the Cordilleran orogenic belt postulate Neoproterozoic to Cambrian rifting of Laurentia to form a westerly facing passive margin, active until the late Devonian; then 110 m.y., from the Late Devonian to the early Triassic, punctuated by the succes ...
Next Generation Sunshine State Standards Chapter 3
... In our discussion of the rock cycle, we pointed out that igneous rocks form as magma cools and crystallizes. But what is magma, and what is its source? Magma is molten rock generated by partial melting of rocks in Earth’s mantle and, in much smaller amounts, in the lower crust. This molten material ...
... In our discussion of the rock cycle, we pointed out that igneous rocks form as magma cools and crystallizes. But what is magma, and what is its source? Magma is molten rock generated by partial melting of rocks in Earth’s mantle and, in much smaller amounts, in the lower crust. This molten material ...
the caribbean plate and the question of its formation
... strike-slip faults into a pre-existent Jurassic Proto Caribbean basin between North and South America. The Alternative model inferred an intra-plate history of the Caribbean between both Americas as a result of the eastward trending spreading axis of the Jurassic Atlantic Ocean. Both models become s ...
... strike-slip faults into a pre-existent Jurassic Proto Caribbean basin between North and South America. The Alternative model inferred an intra-plate history of the Caribbean between both Americas as a result of the eastward trending spreading axis of the Jurassic Atlantic Ocean. Both models become s ...
Earthquakes and Seismic Hazard in the Yukon
... and 1957. A detailed study (Cassidy et al., 2002) showed that they were quite different from those in the Richardson Mountains just to the north. They had well-defined aftershock sequences, occurred in the upper crust at a depth of 7-15 km, and were associated with thrust faulting along shallow-dipp ...
... and 1957. A detailed study (Cassidy et al., 2002) showed that they were quite different from those in the Richardson Mountains just to the north. They had well-defined aftershock sequences, occurred in the upper crust at a depth of 7-15 km, and were associated with thrust faulting along shallow-dipp ...
Immobile Element Fingerprinting of Ophiolites
... rocks raised to temperatures approaching the melting points of either the metamorphosed lavas themselves or their surrounding sediments. A number of key elements (e.g. Th, Nb, Zr) may be mobile under these conditions. Using the Cann (1970) correlation-based method (FIG. 2) to confi rm which elements ...
... rocks raised to temperatures approaching the melting points of either the metamorphosed lavas themselves or their surrounding sediments. A number of key elements (e.g. Th, Nb, Zr) may be mobile under these conditions. Using the Cann (1970) correlation-based method (FIG. 2) to confi rm which elements ...
The continent marginal crust characteristic of nothern South China
... There are many models to explain the evolution of continental margin. The differences between these models are different extension mechanical and igneous activity. The previous studies suggest the north and south margins of the SCS was an asymmetric conjugated pair and the north part can be classif ...
... There are many models to explain the evolution of continental margin. The differences between these models are different extension mechanical and igneous activity. The previous studies suggest the north and south margins of the SCS was an asymmetric conjugated pair and the north part can be classif ...
Slab detachment in laterally varying subduction zones: 3D
... eventually leading to detachment at 125 km depth. Slab thinning initiates at the slab’s center and migrates toward its edge. The total detachment duration lasts up to 3 Myr (Figure 2b; ∼21 Myr). In the first stage, the topography induced by the collision is laterally limited by the transform fault an ...
... eventually leading to detachment at 125 km depth. Slab thinning initiates at the slab’s center and migrates toward its edge. The total detachment duration lasts up to 3 Myr (Figure 2b; ∼21 Myr). In the first stage, the topography induced by the collision is laterally limited by the transform fault an ...
Chapter 8 Let`s take it from the top: the crust and upper mantle
... include the heat-producing elements and members of a number of radiogenic-isotope systems (Rb-Sr, U-Pb, Sm-Nd, Lu-Hf) that are commonly used in mantle geochemistry. Thus the continental crust factors prominently in any massbalance calculation for the Earth as a whole and in estimates of the thermal ...
... include the heat-producing elements and members of a number of radiogenic-isotope systems (Rb-Sr, U-Pb, Sm-Nd, Lu-Hf) that are commonly used in mantle geochemistry. Thus the continental crust factors prominently in any massbalance calculation for the Earth as a whole and in estimates of the thermal ...
THE PETROLOGY OF THE PYROXENE
... No strong evidence has been found of systematic differences between the olivines of different ultramafic bodies. It may be noted that the three most magnesian examples (Fa14, Fa15, Fa16) all come from specimens taken across a body at the south-west end of Uranosvatn, approximately 7.5 km on a bearin ...
... No strong evidence has been found of systematic differences between the olivines of different ultramafic bodies. It may be noted that the three most magnesian examples (Fa14, Fa15, Fa16) all come from specimens taken across a body at the south-west end of Uranosvatn, approximately 7.5 km on a bearin ...
A review of geological origins and relationships in the Ballantrae
... derived from each have been preserved and juxtaposed. The environment of volcanism can be established by the trace element content of the basaltic lavas produced (e.g. Pearce & Cann 1973; Pearce & Norry 1979); either an island arc formed above a subduction zone, or an ocean island (producing lavas a ...
... derived from each have been preserved and juxtaposed. The environment of volcanism can be established by the trace element content of the basaltic lavas produced (e.g. Pearce & Cann 1973; Pearce & Norry 1979); either an island arc formed above a subduction zone, or an ocean island (producing lavas a ...
New data on the deposition age of the volcano
... Carvalho et al., 2000). In fact, on both banks of Cunene River, northwestern Namibia and south Angola, Kröner et al. (2010) defined the Epupa Metamorphic Complex which, according to these authors, extends to southern Angola. It consists of orthogneisses, migmatites and anatetic granites. The zircon ...
... Carvalho et al., 2000). In fact, on both banks of Cunene River, northwestern Namibia and south Angola, Kröner et al. (2010) defined the Epupa Metamorphic Complex which, according to these authors, extends to southern Angola. It consists of orthogneisses, migmatites and anatetic granites. The zircon ...
Sedimentology of Middle Precambrian Animikean Quartzites
... apparently anomalous local quartz-rich bodies within a thick sequence of typically "eugeosynclinal" chloritic slates, graywackes and, basic volcanic rocks. The Pine River member consists of a lower morn-conglomerate, middle cross-stratified quartzite and pebbly quartzite, and upper recta-conglomerat ...
... apparently anomalous local quartz-rich bodies within a thick sequence of typically "eugeosynclinal" chloritic slates, graywackes and, basic volcanic rocks. The Pine River member consists of a lower morn-conglomerate, middle cross-stratified quartzite and pebbly quartzite, and upper recta-conglomerat ...
1. Introduction, Objectives, and Principal Results, Leg 112, Peru
... and Trujillo basins (Fig. 2). Across the ridge, this section is thick in the Delfin drill hole, but is absent on the basement ridge penetrated at the Ballena hole. Eocene sediments do not extend shoreward beneath the Salaverry Basin. Distribution of these Eocene sediments was controlled by (1) the s ...
... and Trujillo basins (Fig. 2). Across the ridge, this section is thick in the Delfin drill hole, but is absent on the basement ridge penetrated at the Ballena hole. Eocene sediments do not extend shoreward beneath the Salaverry Basin. Distribution of these Eocene sediments was controlled by (1) the s ...
Mineral deposits and structurral pattern of the Big Burro Mountains
... and north of the Big Burro Mountains. Gila Conglomerate and Recent gravels fill some of the valleys. Small isolated masses of Precambrian metamorphic rocks of the Bullard Peak series, which antedate the intrusion of the batholithic rocks, occur along the Mangas fault in the Little Burro Mountains, i ...
... and north of the Big Burro Mountains. Gila Conglomerate and Recent gravels fill some of the valleys. Small isolated masses of Precambrian metamorphic rocks of the Bullard Peak series, which antedate the intrusion of the batholithic rocks, occur along the Mangas fault in the Little Burro Mountains, i ...
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 ...
NWGS N. Central WA
... OF QUESNELLIA AND BOUNDING UNITS Modified from Cheney and others (1994, fig. 2). The explanation to this figure also applies to Figures 8, 23, and 24. ...
... OF QUESNELLIA AND BOUNDING UNITS Modified from Cheney and others (1994, fig. 2). The explanation to this figure also applies to Figures 8, 23, and 24. ...
petrology and isotope systematics of magma mushes
... More than 80 coarsely porphyritic granitoid plutons with K-feldspar megacrysts (Itaporanga-type granites) intrude metarnorphic rocks of Northeastern Brazil. Textural evidence for fIlter pressing and flow foliation indicates that these bodies were emplaced as viscous, crystal-laden mushes. A represen ...
... More than 80 coarsely porphyritic granitoid plutons with K-feldspar megacrysts (Itaporanga-type granites) intrude metarnorphic rocks of Northeastern Brazil. Textural evidence for fIlter pressing and flow foliation indicates that these bodies were emplaced as viscous, crystal-laden mushes. A represen ...
A crustal model of the ultrahigh-pressure Dabie Shan orogenic belt
... layers (upper, middle, and lower crust) with average seismic velocities of 6.0 ⫾ 0.2 km/s, 6.5 ⫾ 0.1 km/s, and 6.8 ⫾ 0.1 km/s. The crust reaches a maximum thickness of 41.5 km beneath the northern margin of the orogen, and thus the present-day root beneath the orogen is only 6.5 km thick. The upper ...
... layers (upper, middle, and lower crust) with average seismic velocities of 6.0 ⫾ 0.2 km/s, 6.5 ⫾ 0.1 km/s, and 6.8 ⫾ 0.1 km/s. The crust reaches a maximum thickness of 41.5 km beneath the northern margin of the orogen, and thus the present-day root beneath the orogen is only 6.5 km thick. The upper ...
Hydrothermal vent Activities At the Gjallar Ridge In the
... synthetized were identified by Apps and van de Kamp (1993) as follows: (1) Degassing and / or cooling of mafic magma at spreading centres. The most abundant gases are carbon dioxide and hydrogen sulphide, the presence of methane is also notable. These gases are amongst the fluids emitted by hydrothe ...
... synthetized were identified by Apps and van de Kamp (1993) as follows: (1) Degassing and / or cooling of mafic magma at spreading centres. The most abundant gases are carbon dioxide and hydrogen sulphide, the presence of methane is also notable. These gases are amongst the fluids emitted by hydrothe ...
Constraints on the Lithospheric Structure of Venus from Mechanical
... Study Project, 1981,pp. 682-685]. A diabasecrustis assumed Stylesof UnstableDeformation on the basis of Venera lander results that show surface rocks ...
... Study Project, 1981,pp. 682-685]. A diabasecrustis assumed Stylesof UnstableDeformation on the basis of Venera lander results that show surface rocks ...
Great Lakes tectonic zone
The Great Lakes tectonic zone is bounded by South Dakota at its tip and heads northeast to south of Duluth, Minnesota, then heads east through northern Wisconsin, Marquette, Michigan, and then trends more northeasterly to skim the northern-most shores of lakes Michigan and Huron before ending in the Sudbury, Ontario, Canada, area.During the Late Archean Era the Algoman orogeny added landmass to the Superior province by volcanic activity and continental collision along a boundary that stretches from present-day South Dakota, U.S., into the Lake Huron region near Sudbury, Ontario, Canada.This crustal boundary is the Great Lakes tectonic zone. It is 1,400 km (870 mi) long, and separates the older Archean gneissic terrane to the south from younger Late Archean greenstone-granite terrane to the north.The zone is characterized by active compression during the Algoman orogeny (about 2,700 million years ago), a pulling-apart (extensional) tectonics (2,450 to 2,100 million years ago), a second compression during the Penokean orogeny (1,900 to 1,850 million years ago), a second extension during Middle Proterozoic time (1,600 million years ago) and minor reactivation during Phanerozoic time (the past 500 million years).Collision began along the Great Lakes tectonic zone (GLTZ) with the Algoman mountain-building event and continued for tens of millions of years. During the formation of the GLTZ, the gneissic Minnesota River Valley subprovince was thrust up onto the Superior province's edge as it consumed the Superior province's oceanic crust. Fragmentation of the Kenorland supercontinent began 2,450 million years ago and was completed by 2,100 million years ago. The Wyoming province is the continental landmass that is hypothesized to have rifted away from the southern Superior province portion of Kenorland, before moving rapidly west and docking with the Laurentia supercontinent 1,850 to 1,715 million years ago. Sedimentation from the GLTZ-rifting environment continued into the Penokean orogeny, which is the next major tectonic event in the Great Lakes region. Several earthquakes have been documented in Minnesota, Michigan's Upper Peninsula and Sudbury in the last 120 years along the GLTZ.