One rift, two models
... Volcanism in both regions moved with time along intricate pathways, generally westward, i.e., actually in the counter direction relative to the Eurasian plate motion. This may be evidence of tectonic control of magma ascent at the junction of compressional and extensional structures. On the other ha ...
... Volcanism in both regions moved with time along intricate pathways, generally westward, i.e., actually in the counter direction relative to the Eurasian plate motion. This may be evidence of tectonic control of magma ascent at the junction of compressional and extensional structures. On the other ha ...
Chapter 10—Early Paleozoic Events
... Cambrian, Ordovician, and Silurian. These three periods together lasted about 126 million years. The geologic history of the Paleozoic is characterized by long periods of sedimentation, and punctuated by intervals of mountain building. In North America, the mountain-building events are called Taconi ...
... Cambrian, Ordovician, and Silurian. These three periods together lasted about 126 million years. The geologic history of the Paleozoic is characterized by long periods of sedimentation, and punctuated by intervals of mountain building. In North America, the mountain-building events are called Taconi ...
Collision and Postcollision Structural Evolution of the Andrianovka
... conditions of the kyanite-sillimanite facies (T = 560800°ë and P up to 7-8 kbar) and then experienced a retrograde metamorphism, resulting in the reverse or compound zoning of garnet, the partial or complete biotitization, and the replacement of kyanite with andalusite [32]. The rocks of the Kolpako ...
... conditions of the kyanite-sillimanite facies (T = 560800°ë and P up to 7-8 kbar) and then experienced a retrograde metamorphism, resulting in the reverse or compound zoning of garnet, the partial or complete biotitization, and the replacement of kyanite with andalusite [32]. The rocks of the Kolpako ...
(Neoproterozoic-Paleozoic) and plate reconstructions
... microcontinent we demonstrate its evolution in the Early Paleozoic and its collision with Siberia in the Late Paleozoic. These data along with an extensive published paleomagnetic database for the cratons of Laurentia, Baltica, Siberia, and Gondwana are the basis for the presented paleotectonic reco ...
... microcontinent we demonstrate its evolution in the Early Paleozoic and its collision with Siberia in the Late Paleozoic. These data along with an extensive published paleomagnetic database for the cratons of Laurentia, Baltica, Siberia, and Gondwana are the basis for the presented paleotectonic reco ...
Presentation - Copernicus.org
... The Low Triassic dyke swarm belt is strengthening at about 500 km along the northern margin of Siberian platform D ike area spread is limited to the north rift structure of the Yenisei-Khatanga trough, and from the south - Kystyktah-Ayan-Ambardah uprise. From west to east dyke belt is routed through ...
... The Low Triassic dyke swarm belt is strengthening at about 500 km along the northern margin of Siberian platform D ike area spread is limited to the north rift structure of the Yenisei-Khatanga trough, and from the south - Kystyktah-Ayan-Ambardah uprise. From west to east dyke belt is routed through ...
The Scandinavian Caledonides and their relationship to the
... sedimentary wedge of far-travelled nappes in which the Caledonian strain intensity and metamorphic grade increase upward and westward. Granulite-facies rocks, probably of Precambrian age, are reported in the Upper Allochthon which also contains retrogressed Caledonian eclogites and garnet peridotit ...
... sedimentary wedge of far-travelled nappes in which the Caledonian strain intensity and metamorphic grade increase upward and westward. Granulite-facies rocks, probably of Precambrian age, are reported in the Upper Allochthon which also contains retrogressed Caledonian eclogites and garnet peridotit ...
NAPPES, GNEISS DOMES AND PLUTONIC SHEETS OF WEST
... Bethlehem Gneiss (or KQM) have also been mapped, for example the Bellows Falls pluton. Geophysical investigations, combined with geologic structural constraints, indicate that these plutons are floored by metasedimentary rocks and were probably emplaced as large sill-like bodies, not much thicker th ...
... Bethlehem Gneiss (or KQM) have also been mapped, for example the Bellows Falls pluton. Geophysical investigations, combined with geologic structural constraints, indicate that these plutons are floored by metasedimentary rocks and were probably emplaced as large sill-like bodies, not much thicker th ...
Volcanic Arizona Bureau of Geology and Mineral Technology Summer 1986 by Stephen
... Cretaceous, whereas southern Arizona was largely free of volcanoes and was locally inundated by shallow seas from the east. Arizona's fourth volcanic episode occurred during Late Cretaceous to early Tertiary time (85 to 45 m.y. ago), when volcanism and associated igneous activity migrated eastward b ...
... Cretaceous, whereas southern Arizona was largely free of volcanoes and was locally inundated by shallow seas from the east. Arizona's fourth volcanic episode occurred during Late Cretaceous to early Tertiary time (85 to 45 m.y. ago), when volcanism and associated igneous activity migrated eastward b ...
Tethyan and Indian subduction viewed from the Himalayan high
... (3) Ultrahigh-pressure rocks on both sides of the western syntaxis (Kaghan and Tso Morari massifs) formed during the early stage of subduction/exhumation of the Indian northern margin at the time of the Paleocene–Eocene boundary. (4) Granulitized eclogites in the Lesser Himalaya Sequence in southern ...
... (3) Ultrahigh-pressure rocks on both sides of the western syntaxis (Kaghan and Tso Morari massifs) formed during the early stage of subduction/exhumation of the Indian northern margin at the time of the Paleocene–Eocene boundary. (4) Granulitized eclogites in the Lesser Himalaya Sequence in southern ...
bureau of geology - Department of Geosciences
... non-genetic sense to describe LS-tectonites that exhibit contrasting brittle and plastic behavior of mineral components, and which show a pronounced reduction in grain size rather than significant grain growth. Foliation is largely defined by a strong preferential orientation of micas, flattened qua ...
... non-genetic sense to describe LS-tectonites that exhibit contrasting brittle and plastic behavior of mineral components, and which show a pronounced reduction in grain size rather than significant grain growth. Foliation is largely defined by a strong preferential orientation of micas, flattened qua ...
Document
... early diagenesis. In modern analogues radiolarian cherts are deposited in an oceanic environment in areas of upwelling cool water associated with high planktonic productivity. Alternatively, the cherts may be related to contemporaneous volcanism. No volcanic material has been found within the cherts ...
... early diagenesis. In modern analogues radiolarian cherts are deposited in an oceanic environment in areas of upwelling cool water associated with high planktonic productivity. Alternatively, the cherts may be related to contemporaneous volcanism. No volcanic material has been found within the cherts ...
isotopic and chemical constraints on the development of
... plutons, Caledonide zones, major faults and locations referred to in the text. ...
... plutons, Caledonide zones, major faults and locations referred to in the text. ...
Geology
... Geological Survey of Canada, Centre Géoscientifique de Québec, 490 de la Couronne, Quebec City, Quebec G1K 9A9, Canada ...
... Geological Survey of Canada, Centre Géoscientifique de Québec, 490 de la Couronne, Quebec City, Quebec G1K 9A9, Canada ...
BEHAVIOR OF STORED MAGMA IN ARC CRUST
... flow, suppressing surface expression of dike structures. The rise of basalt is further impeded by interaction with stored magmas, yielding a complex output that is a combination of mantle, crustal, and fractionated components. Repeated episodes of dike intrusion along the same structure- and stress- ...
... flow, suppressing surface expression of dike structures. The rise of basalt is further impeded by interaction with stored magmas, yielding a complex output that is a combination of mantle, crustal, and fractionated components. Repeated episodes of dike intrusion along the same structure- and stress- ...
The Making of the Japan Sea and the Japanese Mountains
... formed as a repercussion of the distant collision of India into Eurasia; the other attributes it to the far earlier but closer loss of the crustal “root” from the eastern Eurasian coast. The first hypothesis focusses on India,9 postulating that the collision and intrusion of the Indian sub-continent ...
... formed as a repercussion of the distant collision of India into Eurasia; the other attributes it to the far earlier but closer loss of the crustal “root” from the eastern Eurasian coast. The first hypothesis focusses on India,9 postulating that the collision and intrusion of the Indian sub-continent ...
Alteration processes in the Maliman (hipo) bentonite
... and on the role they played during the transformation of fresh vitreous rocks to bentonite. 2. Location and geological setting The Maliman deposit is located 200 km NW of San Juan, at 69°10' W and 29°50' S. The main outcrops are found on the eastern margin of the Blanco river (Fig. 1A), northeastern ...
... and on the role they played during the transformation of fresh vitreous rocks to bentonite. 2. Location and geological setting The Maliman deposit is located 200 km NW of San Juan, at 69°10' W and 29°50' S. The main outcrops are found on the eastern margin of the Blanco river (Fig. 1A), northeastern ...
Powerpoint Presentation Physical Geology, 10/e
... Coal – sedimentary rock forming from compaction of partially decayed plant material • organic material deposited in water with low oxygen content (i.e., stagnant) ...
... Coal – sedimentary rock forming from compaction of partially decayed plant material • organic material deposited in water with low oxygen content (i.e., stagnant) ...
Sedimentary Rocks - Mr. Volpe`s Earth Science Emporium
... ANOTHER CLASTIC SEDIMENTARY ROCK • This clastic rock is shale. It is made of sediments that are less than .0004 cm. See the ESRT sedimentary rock classification scheme for the size of the clasts in each rock type. ...
... ANOTHER CLASTIC SEDIMENTARY ROCK • This clastic rock is shale. It is made of sediments that are less than .0004 cm. See the ESRT sedimentary rock classification scheme for the size of the clasts in each rock type. ...
1. Serpentine Hill
... chrysotile is a rare associate of stichtite, but occurs in some nearby serpentinites. Discrete macroscopic stichtite crystals are unknown, but in thin section it consists of finegrained platy or micaceous to radiating fibrous aggregates of crystallites to 2 mm or more in size. It forms radiating agg ...
... chrysotile is a rare associate of stichtite, but occurs in some nearby serpentinites. Discrete macroscopic stichtite crystals are unknown, but in thin section it consists of finegrained platy or micaceous to radiating fibrous aggregates of crystallites to 2 mm or more in size. It forms radiating agg ...
Missing history (16–71 Ma) of the Gala´pagos hotspot: Implications
... found on the Beata Ridge (central Caribbean) and along the western margin of the igneous province, consistent with eastward movement of the province and lower magma production during the latter stage of the igneous event. The transition from Caribbean to (accreted) hotspot-track igneous activity coi ...
... found on the Beata Ridge (central Caribbean) and along the western margin of the igneous province, consistent with eastward movement of the province and lower magma production during the latter stage of the igneous event. The transition from Caribbean to (accreted) hotspot-track igneous activity coi ...
Chapter 7 Lecture PowerPoint Handout
... • Gradation in the degree of metamorphism between slate and schist • Platy minerals not large enough to be identified with the unaided eye • Glossy sheen and wavy surfaces • Exhibits rock cleavage • Composed mainly of fine crystals of muscovite and/or chlorite Figure 7.12 (Phyllite) ...
... • Gradation in the degree of metamorphism between slate and schist • Platy minerals not large enough to be identified with the unaided eye • Glossy sheen and wavy surfaces • Exhibits rock cleavage • Composed mainly of fine crystals of muscovite and/or chlorite Figure 7.12 (Phyllite) ...
pdf - Geological Society of Malaysia
... Eastern Belt. This was followed by deposition of a younger series of continental deposits which are only gently dipping and probably they were uplifted in the late Cretaceous. Significant plutonic acid magmatism occurred during the early Permian, late Permian/early Triassic and the late Triassic in ...
... Eastern Belt. This was followed by deposition of a younger series of continental deposits which are only gently dipping and probably they were uplifted in the late Cretaceous. Significant plutonic acid magmatism occurred during the early Permian, late Permian/early Triassic and the late Triassic in ...
Mildly peraluminous high-silica granites in the central part of the
... Gravimetric data indicate that the batholith is a relatively thin (about 3 km thick) tabular body with one or more root-like extensions in the eastern-central area (Ramberg 1976). Alternatively the data could be interpreted as a pseudo-cylindrical body grading downwards into a mixture of stoped bloc ...
... Gravimetric data indicate that the batholith is a relatively thin (about 3 km thick) tabular body with one or more root-like extensions in the eastern-central area (Ramberg 1976). Alternatively the data could be interpreted as a pseudo-cylindrical body grading downwards into a mixture of stoped bloc ...
Current ripple marks
... may be helpful in environmental analyses but it must be used with caution because the same geometry may be found in more than one environment. Geometry can be modified by sediment compaction during lithification and by erosion and deformation ...
... may be helpful in environmental analyses but it must be used with caution because the same geometry may be found in more than one environment. Geometry can be modified by sediment compaction during lithification and by erosion and deformation ...
The Skaergaard Layered Series. Part II
... is not to say that minerals are unaffected; in a dense suspension, some may be deformed, but evidence of this strain is usually weak and may later be erased by recrystallization or annealing. Crystals that grow or recrystallize while magma is being deformed may take on new shapes, sizes, or orientat ...
... is not to say that minerals are unaffected; in a dense suspension, some may be deformed, but evidence of this strain is usually weak and may later be erased by recrystallization or annealing. Crystals that grow or recrystallize while magma is being deformed may take on new shapes, sizes, or orientat ...
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.