Regional phases in continental and oceanic environments
... the frames at 30 and 44 s) and transmission into the mantle occurs in each of the pre-critical reflections, helping to enhance the Sn field. The S waves in the oceanic crust are linked to reverberations of P waves in the ocean. These P multiples build a strong wave train following Sn that extends ne ...
... the frames at 30 and 44 s) and transmission into the mantle occurs in each of the pre-critical reflections, helping to enhance the Sn field. The S waves in the oceanic crust are linked to reverberations of P waves in the ocean. These P multiples build a strong wave train following Sn that extends ne ...
The regional tectonic setting and possible causes of Cenozoic
... tonism in the North American Cordillera has was superimposed on widespread compressional been recognized for years as the Basin and features of Mesozoic and early-Tertiary age. Although the earlier mid-Tertiary extension Range Province (Stewart 1978). The Basin and Range Province formed in the centr ...
... tonism in the North American Cordillera has was superimposed on widespread compressional been recognized for years as the Basin and features of Mesozoic and early-Tertiary age. Although the earlier mid-Tertiary extension Range Province (Stewart 1978). The Basin and Range Province formed in the centr ...
chapter 3
... The Coast Range Episode, the second episode in the assembly of the Pacific Northwest, was initiated with the accretion of the Insular Belt megaterrane in mid-Cretaceous time. The accretion of that terrane belt moved the western edge of the continent another several hundred kilometers to the west, est ...
... The Coast Range Episode, the second episode in the assembly of the Pacific Northwest, was initiated with the accretion of the Insular Belt megaterrane in mid-Cretaceous time. The accretion of that terrane belt moved the western edge of the continent another several hundred kilometers to the west, est ...
Metamorphic Rock - mrnicholsscience
... • Sandstone shows dunes (or beaches) • Limestone shows warm shallow ocean. • Coal forms with warm climates --and is found in Antarctica! ...
... • Sandstone shows dunes (or beaches) • Limestone shows warm shallow ocean. • Coal forms with warm climates --and is found in Antarctica! ...
The Outer Hebrides - Scottish Natural Heritage
... the late 19th century, and are named after the Isle of Lewis. They also occur in the northwestern part of the Scottish mainland, between Skye and Cape Wrath. Gneisses are metamorphic rocks – rocks that have been altered under increased temperature or pressure. In northern Scotland, the name ‘Lewisia ...
... the late 19th century, and are named after the Isle of Lewis. They also occur in the northwestern part of the Scottish mainland, between Skye and Cape Wrath. Gneisses are metamorphic rocks – rocks that have been altered under increased temperature or pressure. In northern Scotland, the name ‘Lewisia ...
Escape tectonics and the extrusion of Alaska: Past, present, and future
... From a stable Canadian Cordillera (landward of the Tintina fault system) reference frame, northward translation of crustal slivers of North America along the British Columbia margin drives terrane fragments into the apex of the Alaskan restraining bend. Crust then escapes westward toward the Aleutia ...
... From a stable Canadian Cordillera (landward of the Tintina fault system) reference frame, northward translation of crustal slivers of North America along the British Columbia margin drives terrane fragments into the apex of the Alaskan restraining bend. Crust then escapes westward toward the Aleutia ...
Radiogenic heat production of Archaean to Permian geological
... units as defined by Sigmond (1996). Archaean gneissic rocks (1) Rocks of Archaean crystallisation or depositional age are found in several areas in northern Norway. The most intensely studied area is a chain of islands running from southern Lofoten to the island Vanna in west Troms (Fig. 1a). This a ...
... units as defined by Sigmond (1996). Archaean gneissic rocks (1) Rocks of Archaean crystallisation or depositional age are found in several areas in northern Norway. The most intensely studied area is a chain of islands running from southern Lofoten to the island Vanna in west Troms (Fig. 1a). This a ...
The geologic evolution of Point Lobos
... Up to this point of time, our rocks of Point Lobos are still in Southern California, but that was about to change. Variations in the oceanic plate configuration in the middle Cenozoic were about to rearrange the western margin of North America. Around 40 ma, the process of subduction was consuming ...
... Up to this point of time, our rocks of Point Lobos are still in Southern California, but that was about to change. Variations in the oceanic plate configuration in the middle Cenozoic were about to rearrange the western margin of North America. Around 40 ma, the process of subduction was consuming ...
Metamorphism
... Slaty cleavage – foliation that develops at low temperature and pressure (metamorphosed shale) ...
... Slaty cleavage – foliation that develops at low temperature and pressure (metamorphosed shale) ...
Rock Cycle, Igneous, and Sedimentary Rocks PowerPoint
... • Metamorphic rocks are formed when existing rocks are subjected to high temperature and pressure, which cause changes in the rocks’ textures, mineralogy, and composition. • The three main types of metamorphism are regional, contact, and hydrothermal. • Metamorphic rocks are divided into two textura ...
... • Metamorphic rocks are formed when existing rocks are subjected to high temperature and pressure, which cause changes in the rocks’ textures, mineralogy, and composition. • The three main types of metamorphism are regional, contact, and hydrothermal. • Metamorphic rocks are divided into two textura ...
No Slide Title
... Can occur as multiple events e.g. Sierra Nevada. Form at depths up to 30 km. Generally form elongate mountain ranges. Also found in central parts of continents but are eroded flat. ...
... Can occur as multiple events e.g. Sierra Nevada. Form at depths up to 30 km. Generally form elongate mountain ranges. Also found in central parts of continents but are eroded flat. ...
Precambrian Stratigraphy in the Masi Area, Southwestern Finnmark
... been renamed the Svecokarelian orogeny (Gaal 1982). The most important metamorphic episode in this orogeny occurred about 1800-1900 m.y. ago (Simonen 1980), but the depositional age of rocks involved seems to have been from 2600 to 1800 m.y. (Simonen 1980, Silvennoinen et al. 1980). Even if a direct ...
... been renamed the Svecokarelian orogeny (Gaal 1982). The most important metamorphic episode in this orogeny occurred about 1800-1900 m.y. ago (Simonen 1980), but the depositional age of rocks involved seems to have been from 2600 to 1800 m.y. (Simonen 1980, Silvennoinen et al. 1980). Even if a direct ...
Early cretaceous subduction-related adakite
... east (Fig. 1c). The general lithological features of the Mamuxia Formation are shown in Fig. 2 and summarized in Table 1. As a whole, a Late Jurassic–Early Cretaceous age for deposition of the Mamuxia Formation is indicated by fossil corals, bivalves, and gastropods observed in bioclastic limestone ...
... east (Fig. 1c). The general lithological features of the Mamuxia Formation are shown in Fig. 2 and summarized in Table 1. As a whole, a Late Jurassic–Early Cretaceous age for deposition of the Mamuxia Formation is indicated by fossil corals, bivalves, and gastropods observed in bioclastic limestone ...
Igneous Rock Formation, Compositions, and Textures
... Granitic composition magma is produced at _________________ margins. As the continental crust thickens it begins to partially melt at depth. Igneous intrusions (plutons) form below the mountain belts. ______________ is rare in continental collision boundaries. As collisional tectonic mountain ranges ...
... Granitic composition magma is produced at _________________ margins. As the continental crust thickens it begins to partially melt at depth. Igneous intrusions (plutons) form below the mountain belts. ______________ is rare in continental collision boundaries. As collisional tectonic mountain ranges ...
The Agulhas – Karoo Geoscience Transect: from a sheared margin
... stages of continental lithosphere formation: 2.06 - 1.80 Ga (Eburnian) Kheis Belt, 1.2 - 1.0 (Grenvillian) Namaqua Natal Belt, 0.58 - 0.48 (Pan-African) Saldania Belt, and the 0.25 (Gondwanide) Cape Fold Belt. Large areas of the Namaqua-Natal Belt are covered by Mesozoic Karoo sediments, and most of ...
... stages of continental lithosphere formation: 2.06 - 1.80 Ga (Eburnian) Kheis Belt, 1.2 - 1.0 (Grenvillian) Namaqua Natal Belt, 0.58 - 0.48 (Pan-African) Saldania Belt, and the 0.25 (Gondwanide) Cape Fold Belt. Large areas of the Namaqua-Natal Belt are covered by Mesozoic Karoo sediments, and most of ...
thermal structure of the crust and upper mantle of romania
... As regards the heat flow, one can see in Fig. 5 that on a background of values decreasing from north to south from 33 to 29 mW rne2, a maximum of 45 mW rnp2 appears. Towards the borders of the basin the heat flow is increasing up to 55 mW mA2. The minimum values, of 29-30 mW rnw2, correspond to a zo ...
... As regards the heat flow, one can see in Fig. 5 that on a background of values decreasing from north to south from 33 to 29 mW rne2, a maximum of 45 mW rnp2 appears. Towards the borders of the basin the heat flow is increasing up to 55 mW mA2. The minimum values, of 29-30 mW rnw2, correspond to a zo ...
Subduction zone backarcs, mobile belts, and orogenic heat
... An important attribute of most continental mobile belts that indicates they are hot is high elevation. They are mountain belts. This elevation is usually in spite of relatively thin crust. For example, very little of the North America Cordillera has a crustal thickness greater than ~35 km (Mooney et ...
... An important attribute of most continental mobile belts that indicates they are hot is high elevation. They are mountain belts. This elevation is usually in spite of relatively thin crust. For example, very little of the North America Cordillera has a crustal thickness greater than ~35 km (Mooney et ...
Sample Lesson Plan - Desert Outdoor Center
... temperatures. The temperatures are not hot enough to melt the rock, otherwise it would be igneous. 3. Sedimentary Rocks – When rocks are weathered and eroded they break down into smaller pieces of rocks and minerals called sediment. The sediments are compacted (pressed down). In time the particles a ...
... temperatures. The temperatures are not hot enough to melt the rock, otherwise it would be igneous. 3. Sedimentary Rocks – When rocks are weathered and eroded they break down into smaller pieces of rocks and minerals called sediment. The sediments are compacted (pressed down). In time the particles a ...
Proterozoic Rocks, Glacier NP
... – indicates that North America may have had – an Early Proterozoic ice sheet centered southwest of Hudson Bay ...
... – indicates that North America may have had – an Early Proterozoic ice sheet centered southwest of Hudson Bay ...
Earth`s Crust Name
... oceanic crust is in the Ionian Sea, part of the eastern Mediterranean basin. Continental crust is mostly composed of different types of granites. The continental crust is thicker but slightly less dense (about 2.7 grams per cubic centimeter (1.6 ounces per cubic inch). As with oceanic crust, contine ...
... oceanic crust is in the Ionian Sea, part of the eastern Mediterranean basin. Continental crust is mostly composed of different types of granites. The continental crust is thicker but slightly less dense (about 2.7 grams per cubic centimeter (1.6 ounces per cubic inch). As with oceanic crust, contine ...
Geologic Provinces of the Caribbean Region
... Chorotega and Choco Blocks Geographically, this province comprises Costa Rica, Panama and northwestern Colombia. The Choco Block, west of and overridden by the Cordillera Occidental of the Colombian Andes, comprises a sequence of uplifted Upper Cretaceous to Paleogene oceanic crust and magmatic arc ...
... Chorotega and Choco Blocks Geographically, this province comprises Costa Rica, Panama and northwestern Colombia. The Choco Block, west of and overridden by the Cordillera Occidental of the Colombian Andes, comprises a sequence of uplifted Upper Cretaceous to Paleogene oceanic crust and magmatic arc ...
Subduction-zone metamorphism, calc-alkaline - U
... Alpine-type collisional complexes consist of preexisting sialic massifs, as well as deformed, superjacent autochthonous and allochthonous units. Metamorphic belts are not paired (Frey et al., 1974). Subsolidus HP recrystallization is common, with mineral parageneses comparable to those of Pacific-typ ...
... Alpine-type collisional complexes consist of preexisting sialic massifs, as well as deformed, superjacent autochthonous and allochthonous units. Metamorphic belts are not paired (Frey et al., 1974). Subsolidus HP recrystallization is common, with mineral parageneses comparable to those of Pacific-typ ...
Testing Your Knowledge
... a. when forces are applied to an object, the object is under stress b. strain is the change in shape or size (volume), or both, while an object is undergoing stress c. stresses can be compressive, tensional, or shear d. all of the preceding 10. The compass direction of a line formed by the intersect ...
... a. when forces are applied to an object, the object is under stress b. strain is the change in shape or size (volume), or both, while an object is undergoing stress c. stresses can be compressive, tensional, or shear d. all of the preceding 10. The compass direction of a line formed by the intersect ...
Structural Geology Introduction/Review of Basic Principles
... compact the sediment, compressing clays together, clays act as binding agents. 2) cementation - solutions carry ions into pours between sediments, with time ions may be precipitated as cements under appropriate chemical condition. Common cements include calcite, silica, and iron oxide. 3. Sed. rocks ...
... compact the sediment, compressing clays together, clays act as binding agents. 2) cementation - solutions carry ions into pours between sediments, with time ions may be precipitated as cements under appropriate chemical condition. Common cements include calcite, silica, and iron oxide. 3. Sed. rocks ...
Geologic Trips, Sierra Nevada
... All of the granitic, volcanic, sedimentary and metamorphic rocks that you will see in the Sierra are formed from minerals. The minerals are the building blocks of the rocks, and usually appear as grains in the rock, giving the rock a granular texture. Some rocks consist of grains of a single mineral ...
... All of the granitic, volcanic, sedimentary and metamorphic rocks that you will see in the Sierra are formed from minerals. The minerals are the building blocks of the rocks, and usually appear as grains in the rock, giving the rock a granular texture. Some rocks consist of grains of a single mineral ...
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.