Moho comparison
... Comparison of Mohos with zero distance corresponding to 12oN, and a vertical exaggeration of 7. Generally, the Moho contains steeper segments in the east (TRIN and 64W) and is smoother to the west. ...
... Comparison of Mohos with zero distance corresponding to 12oN, and a vertical exaggeration of 7. Generally, the Moho contains steeper segments in the east (TRIN and 64W) and is smoother to the west. ...
Geology 101 Name(s): magma
... derived from existing rocks which have been exposed to increased pressure and/or temperature to the point where they begin to alter, both texturally and mineralogically. Sedimentary rocks (from the Latin word, sedimentum = settling) form by the accumulation and consolidation of unconsolidated materi ...
... derived from existing rocks which have been exposed to increased pressure and/or temperature to the point where they begin to alter, both texturally and mineralogically. Sedimentary rocks (from the Latin word, sedimentum = settling) form by the accumulation and consolidation of unconsolidated materi ...
Subduction of the Rivera plate beneath the Jalisco block as imaged
... batholith intrusion, early Cretaceous to Holocene volcanism, and active sedimentation (Taran et al., 2002). It is located between 19 and 21 degrees of latitude north, and 104 and 106 degrees of longitude west. The inland limits of the JB (Figure 1) are two rift systems, namely the Colima and the Tep ...
... batholith intrusion, early Cretaceous to Holocene volcanism, and active sedimentation (Taran et al., 2002). It is located between 19 and 21 degrees of latitude north, and 104 and 106 degrees of longitude west. The inland limits of the JB (Figure 1) are two rift systems, namely the Colima and the Tep ...
The California Arc: Thick Granitic Batholiths, Eclogitic Residues
... show that a significant fraction of the crust (~33 km) in the central Sierra Nevada batholith is granitic, requiring that the batholith be underlain by a significant residual mass prior to Cenozoic extension. Although batholith residua are commonly thought to be granulites, xenolith data indicate th ...
... show that a significant fraction of the crust (~33 km) in the central Sierra Nevada batholith is granitic, requiring that the batholith be underlain by a significant residual mass prior to Cenozoic extension. Although batholith residua are commonly thought to be granulites, xenolith data indicate th ...
PDF 3.2 MB - users.monash.edu.au
... lithological contacts, which are conduits for hydrothermal fluid flow during the formation of orogenicgold deposits. In this study, fractal dimensions, calculated on a 10 km grid across a geologic map of the Yilgarn Craton of uniform data quality, highlight relationships between geologic complexity an ...
... lithological contacts, which are conduits for hydrothermal fluid flow during the formation of orogenicgold deposits. In this study, fractal dimensions, calculated on a 10 km grid across a geologic map of the Yilgarn Craton of uniform data quality, highlight relationships between geologic complexity an ...
composition of biotite from granitic rocks
... Biotite, the dominant ferromagnesian mineral in Paleozoic granitic rocks of the Canadian Appalachians, has been analyzed with an electron microprobe (wavelength dispersion) for major elements and by 57Fe Mössbauer spectroscopy. We sampled a wide variety of rock types, ranging from gabbro, diorite, s ...
... Biotite, the dominant ferromagnesian mineral in Paleozoic granitic rocks of the Canadian Appalachians, has been analyzed with an electron microprobe (wavelength dispersion) for major elements and by 57Fe Mössbauer spectroscopy. We sampled a wide variety of rock types, ranging from gabbro, diorite, s ...
ABSTRACT: Rocks of granitic composition occur in the area around
... The Indo-Pakistan and Asian plates are directly in contact along the Indus-Tsangbo Suture Zone (ITS) in India and Nepal (Gansser, 1980), but are separated from one another by the rocks of the Kohistan arc sequence in NW Pakistan (Fig.1). The Kohistan sequence was sutured to the Asian plate along the ...
... The Indo-Pakistan and Asian plates are directly in contact along the Indus-Tsangbo Suture Zone (ITS) in India and Nepal (Gansser, 1980), but are separated from one another by the rocks of the Kohistan arc sequence in NW Pakistan (Fig.1). The Kohistan sequence was sutured to the Asian plate along the ...
the karoo volcanic rocks and related intrusions in
... in South Africa (Cleverly & Bristow 1979), only a narrow sliver of these fine-grained, low-MgO basalts are exposed north of the Singuédzi River on the Mozambican side of the border. At this location, the Sabie River basalts occur in weathered outcrops as massive rocks, lacking amygdules or other feat ...
... in South Africa (Cleverly & Bristow 1979), only a narrow sliver of these fine-grained, low-MgO basalts are exposed north of the Singuédzi River on the Mozambican side of the border. At this location, the Sabie River basalts occur in weathered outcrops as massive rocks, lacking amygdules or other feat ...
Geology 101 Name(s): Lab 2: The rock cycle, minerals and igneous
... derived from existing rocks which have been exposed to increased pressure and/or temperature to the point where they begin to alter, both texturally and mineralogically. Sedimentary rocks (from the Latin word, sedimentum = settling) form by the accumulation and consolidation of unconsolidated materi ...
... derived from existing rocks which have been exposed to increased pressure and/or temperature to the point where they begin to alter, both texturally and mineralogically. Sedimentary rocks (from the Latin word, sedimentum = settling) form by the accumulation and consolidation of unconsolidated materi ...
From oceanic plateaus to allochthonous terranes: Numerical
... Large segments of the continental crust are known to have formed through the amalgamation of oceanic plateaus and continental fragments. However, mechanisms responsible for terrane accretion remain poorly understood. We have therefore analysed the interactions of oceanic plateaus with the leading ed ...
... Large segments of the continental crust are known to have formed through the amalgamation of oceanic plateaus and continental fragments. However, mechanisms responsible for terrane accretion remain poorly understood. We have therefore analysed the interactions of oceanic plateaus with the leading ed ...
Empplacement Of The Bibai And Gogai Nappes, Northeast Of Quetta
... flats, the thrusting stopped and the thrusts and nappe structures were gently folded, followed by the deposition of the Siwalik group rocks. The employment of nappes can be correlated to collision of the Indian plate with Eurasia (Powell, 1979; Schwan, 1985) in Eocene-Oligocene epochs. It is importa ...
... flats, the thrusting stopped and the thrusts and nappe structures were gently folded, followed by the deposition of the Siwalik group rocks. The employment of nappes can be correlated to collision of the Indian plate with Eurasia (Powell, 1979; Schwan, 1985) in Eocene-Oligocene epochs. It is importa ...
Cratons and Fold Belts of India - ReadingSample - Beck-Shop
... The Indian shield is made up of a mosaic of Precambrian metamorphic terrains that exhibit low to high-grade crystalline rocks in the age range of 3.6–2.6 Ga. These terrains, constituting the continental crust, attained tectonic stability for prolonged period (since Precambrian time) and are designat ...
... The Indian shield is made up of a mosaic of Precambrian metamorphic terrains that exhibit low to high-grade crystalline rocks in the age range of 3.6–2.6 Ga. These terrains, constituting the continental crust, attained tectonic stability for prolonged period (since Precambrian time) and are designat ...
View - GFZpublic
... subduction: Insights from 3-D thermomechanical laboratory experiments, Tectonics, 31, TC2015, doi:10.1029/2011TC003060. ...
... subduction: Insights from 3-D thermomechanical laboratory experiments, Tectonics, 31, TC2015, doi:10.1029/2011TC003060. ...
Cratons of the Indian Shield
... The Indian shield is made up of a mosaic of Precambrian metamorphic terrains that exhibit low to high-grade crystalline rocks in the age range of 3.6–2.6 Ga. These terrains, constituting the continental crust, attained tectonic stability for prolonged period (since Precambrian time) and are designat ...
... The Indian shield is made up of a mosaic of Precambrian metamorphic terrains that exhibit low to high-grade crystalline rocks in the age range of 3.6–2.6 Ga. These terrains, constituting the continental crust, attained tectonic stability for prolonged period (since Precambrian time) and are designat ...
East Coast SBT Habitat Report - The Australian Fisheries
... climatology beginning about April is influenced by limited tag data in this period: the model uses the limited SBT data from the first portion of the year (Figure 5), then transitions to using the bulk of data available after April. This discontinuity will exist until more data from tags at liberty ...
... climatology beginning about April is influenced by limited tag data in this period: the model uses the limited SBT data from the first portion of the year (Figure 5), then transitions to using the bulk of data available after April. This discontinuity will exist until more data from tags at liberty ...
Invited Review Gillian R. Foulger Dept. Earth Sciences, Science
... The Paraná basalts erupted ~ 5 Ma before the South Atlantic at the same latitude opened. It seems unlikely that Paraná volcanism was unrelated to breakup. In general, there are two options for extension-related volcanism: 1. Melt accumulated over a longer time-period than eruption, ponded, for examp ...
... The Paraná basalts erupted ~ 5 Ma before the South Atlantic at the same latitude opened. It seems unlikely that Paraná volcanism was unrelated to breakup. In general, there are two options for extension-related volcanism: 1. Melt accumulated over a longer time-period than eruption, ponded, for examp ...
Geochemistry of intermediate to siliceous volcanic rocks of the
... et al. 1995), there is a general increase in abundance of SiO2 moving upward in the Rooiberg Group succession (Fig. 4). Harmer and von Gruenewaldt (1991), Hatton and Schweitzer (1995), Schweitzer et al. (1995), and Buchanan et al. (1999) determined that most of the volcanic rocks of the lower to mid ...
... et al. 1995), there is a general increase in abundance of SiO2 moving upward in the Rooiberg Group succession (Fig. 4). Harmer and von Gruenewaldt (1991), Hatton and Schweitzer (1995), Schweitzer et al. (1995), and Buchanan et al. (1999) determined that most of the volcanic rocks of the lower to mid ...
Mull and Iona - Scottish Natural Heritage
... these landscapes relate to the underlying geology, by explaining how the rocks were formed and by telling something of the long history of the islands that spans millions of years before St Columba first landed on Iona. ...
... these landscapes relate to the underlying geology, by explaining how the rocks were formed and by telling something of the long history of the islands that spans millions of years before St Columba first landed on Iona. ...
CHAPTER 8 STRUCTURE
... each other along fractures, faults, and shear zones. Deformation of this type is common in regions of intense folding, such as in the southern parts of the Arabian Shield, where the rocks are exposed in upright, tight to isoclinal folds, bedding dips are steep to vertical, and shears and faults tren ...
... each other along fractures, faults, and shear zones. Deformation of this type is common in regions of intense folding, such as in the southern parts of the Arabian Shield, where the rocks are exposed in upright, tight to isoclinal folds, bedding dips are steep to vertical, and shears and faults tren ...
structural or climatic control in granite landforms? the
... but the field evidence overwhelmingly points to structural control. Some features are developed after the exposure of the granitic bodies, for joggling of the brittle crust continues and external agencies also achieve change but the origin of some forms can be traced to the emplacement of the granit ...
... but the field evidence overwhelmingly points to structural control. Some features are developed after the exposure of the granitic bodies, for joggling of the brittle crust continues and external agencies also achieve change but the origin of some forms can be traced to the emplacement of the granit ...
Unit II - SP College
... Organically, Sedimentary rocks are further sub-divided into many types on the basis of their chemical compositions: 1. Calcareous Rocks; these rocks contain large amounts of carbonates of Calcium and Magnesium and are derived from the skeletons and remains of those animals and plants which contain ...
... Organically, Sedimentary rocks are further sub-divided into many types on the basis of their chemical compositions: 1. Calcareous Rocks; these rocks contain large amounts of carbonates of Calcium and Magnesium and are derived from the skeletons and remains of those animals and plants which contain ...
Rocks: Materials of the Solid Earth
... • Oxygen dissolved in water causes oxidation • Carbon dioxide dissolved in water is carbonic acid – Abundant at Earth’s surface – Interaction with minerals changes their crystalline structure • Feldspar minerals are broken down into clay minerals • Silica is carried away by ground water ...
... • Oxygen dissolved in water causes oxidation • Carbon dioxide dissolved in water is carbonic acid – Abundant at Earth’s surface – Interaction with minerals changes their crystalline structure • Feldspar minerals are broken down into clay minerals • Silica is carried away by ground water ...
Rankin et al AJS 2007
... ABSTRACT. Pre-Silurian strata of the Bronson Hill arch (BHA) in the Upper Connecticut Valley, NH-VT are host to the latest Ludlow Comerford Intrusive Suite consisting, east to west, of a mafic dike swarm with sheeted dikes, and an intrusive complex. The rocks are mostly mafic but with compositions r ...
... ABSTRACT. Pre-Silurian strata of the Bronson Hill arch (BHA) in the Upper Connecticut Valley, NH-VT are host to the latest Ludlow Comerford Intrusive Suite consisting, east to west, of a mafic dike swarm with sheeted dikes, and an intrusive complex. The rocks are mostly mafic but with compositions r ...
Metamorphism and Metamorphic Rocks
... Subduction Related Metamorphism - At a subduction zone, the oceanic crust is pushed downward resulting in the basaltic crust and ocean floor sediment being subjected to relatively high pressure. But, because the oceanic crust by the time it subducts is relatively cool, the temperatures in the crust ...
... Subduction Related Metamorphism - At a subduction zone, the oceanic crust is pushed downward resulting in the basaltic crust and ocean floor sediment being subjected to relatively high pressure. But, because the oceanic crust by the time it subducts is relatively cool, the temperatures in the crust ...
Site Account
... closely related rocks, forming the St David's Head Intrusion. The intrusion is broadly sheet-like in form and, as a result of Caledonian folding, occurs as two linear, near continuous outcrops, up to 2 km in length, on opposing limbs of a tight NE-trending syncline. Where present, an igneous layerin ...
... closely related rocks, forming the St David's Head Intrusion. The intrusion is broadly sheet-like in form and, as a result of Caledonian folding, occurs as two linear, near continuous outcrops, up to 2 km in length, on opposing limbs of a tight NE-trending syncline. Where present, an igneous layerin ...
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.