- Stanford University
... The true sharp discontinuity, identified by the two-dimensional studies, between the felsic upper crust and mafic lower crust is smoothed vertically in the model. A strong lateral velocity contrast is observed in the lower crust centered under the San Andreas fault and Mendocino fracture zone (Fig. ...
... The true sharp discontinuity, identified by the two-dimensional studies, between the felsic upper crust and mafic lower crust is smoothed vertically in the model. A strong lateral velocity contrast is observed in the lower crust centered under the San Andreas fault and Mendocino fracture zone (Fig. ...
Geology of the Solomon and New Hebrides Islands
... and Bell consider that petrogenetically, "the suite appears to have affinities with both midocean and island-arc associations, the latter to much lesser degree ." Eastern New Georgi a Island has a noteworthy occurrence of a coarse-grained pyroxene diori te, a stock intrusive into the lavas and possi ...
... and Bell consider that petrogenetically, "the suite appears to have affinities with both midocean and island-arc associations, the latter to much lesser degree ." Eastern New Georgi a Island has a noteworthy occurrence of a coarse-grained pyroxene diori te, a stock intrusive into the lavas and possi ...
CHAPTER 4 GEOCHRONOLOGY AND ISOTOPIC CHARACTER OF
... Geochronology and isotopic character of the Arabian Shield DRAFT March 22 2010 the carbon cycle at different stages of biological evolution and seawater composition and signal rapid changes in global environmental conditions. Abrupt variations, referred to as “excursions” have been identified and pr ...
... Geochronology and isotopic character of the Arabian Shield DRAFT March 22 2010 the carbon cycle at different stages of biological evolution and seawater composition and signal rapid changes in global environmental conditions. Abrupt variations, referred to as “excursions” have been identified and pr ...
Plate-Tectonics Teaching Slides
... • Found along plate boundaries or hotspots • Can be found on land or under water • Volcanoes on land : often form flat cones and the expulsions build up over the years. ...
... • Found along plate boundaries or hotspots • Can be found on land or under water • Volcanoes on land : often form flat cones and the expulsions build up over the years. ...
Heterogeneous crustal deformation along the central-northern
... magnetotelluric survey lines by Ogawa et al. (2002) and Ogawa and Honkura (2004). Thins red lines denote active faults. ...
... magnetotelluric survey lines by Ogawa et al. (2002) and Ogawa and Honkura (2004). Thins red lines denote active faults. ...
View PDF - Cengage
... orogeny—forms a repeating geotectonic cycle of the breakup and re-formation of supercontinents (this makes sense: on a finite Earth, continents can only diverge so much before they begin to converge on the opposite side of the globe). In New York and New Jersey, rocks preserve evidence for four majo ...
... orogeny—forms a repeating geotectonic cycle of the breakup and re-formation of supercontinents (this makes sense: on a finite Earth, continents can only diverge so much before they begin to converge on the opposite side of the globe). In New York and New Jersey, rocks preserve evidence for four majo ...
BEHAVIOR OF STORED MAGMA IN ARC CRUST
... Although the magmatic product of subduction is basalt, truly primitive magma rarely survives transit through arc crust, and even fractionated basalts are often underrepresented. Basalt is generally introduced into the crust as long dikes, as exemplified spectacularly in the 1975 eruption of Tolbachi ...
... Although the magmatic product of subduction is basalt, truly primitive magma rarely survives transit through arc crust, and even fractionated basalts are often underrepresented. Basalt is generally introduced into the crust as long dikes, as exemplified spectacularly in the 1975 eruption of Tolbachi ...
Origin of gypsum formations in copper deposit of Murgul, NE Turkey
... orebodies forming the Cu deposit of Murgul must have been completed before supergene alteration and erosion occurring in short periods of time under atmospheric conditions in the area. Furthermore, pyroclastics and sediments (up to 10 m in the Cu deposit of Murgul) represent the short time interval ...
... orebodies forming the Cu deposit of Murgul must have been completed before supergene alteration and erosion occurring in short periods of time under atmospheric conditions in the area. Furthermore, pyroclastics and sediments (up to 10 m in the Cu deposit of Murgul) represent the short time interval ...
geol_15_patton_sprin..
... ANSWER: Rocks across a fault are stressed and bent elastically. Ultimately, they fracture during an earthquake, and the two sides straighten out, leaving them offset across the fault. 1. The age of the Earth is about ________________. A. 10 million years B. 100 million years C. 1000 million years D. ...
... ANSWER: Rocks across a fault are stressed and bent elastically. Ultimately, they fracture during an earthquake, and the two sides straighten out, leaving them offset across the fault. 1. The age of the Earth is about ________________. A. 10 million years B. 100 million years C. 1000 million years D. ...
MANTLE- AND CRUST-DERIVED MAGMATISM IN THE
... as island-arc, passive continental margin, oceanic terranes, etc.). According to Korja et al. (2006), in general all continental orogens have formed in accretionary modes at convergent margins, where lateral growth of the continental plates mainly takes place, and only some of the orogenies then evo ...
... as island-arc, passive continental margin, oceanic terranes, etc.). According to Korja et al. (2006), in general all continental orogens have formed in accretionary modes at convergent margins, where lateral growth of the continental plates mainly takes place, and only some of the orogenies then evo ...
WS5: Continental Drift
... New evidence for magnetic drift was discovered in the 1950s from studies of Earth’s magnetic history. Earth has a magnetic field like that of a bar magnet, with magnetic north and south poles. The magnetic poles are located near the geographic poles. In the 1950s, scientists studied the magnetic pro ...
... New evidence for magnetic drift was discovered in the 1950s from studies of Earth’s magnetic history. Earth has a magnetic field like that of a bar magnet, with magnetic north and south poles. The magnetic poles are located near the geographic poles. In the 1950s, scientists studied the magnetic pro ...
13. Time to Accumulate Chloride Ions in the World`s Oceans, More
... than 9000 km (Birkeland and Larson 1989).The times involved when many Cl– ions were being recycled during all subduction periods (including those in the Precambrian) are not included in the 3.6-billion–year age, and, therefore, an additional unknown period of time should be added to the 3.6 billion ...
... than 9000 km (Birkeland and Larson 1989).The times involved when many Cl– ions were being recycled during all subduction periods (including those in the Precambrian) are not included in the 3.6-billion–year age, and, therefore, an additional unknown period of time should be added to the 3.6 billion ...
Earthquakes - California State University, Northridge
... JAPAN • This thrust earthquake occurred near the north-east shore of the island of Honshu, Japan. In this region, the convergence of the Pacific plate and the Eurasian plate generates numerous earthquakes. The Pacific plate is moving west at a rate of about 9 cm per year relative to the Eurasian pla ...
... JAPAN • This thrust earthquake occurred near the north-east shore of the island of Honshu, Japan. In this region, the convergence of the Pacific plate and the Eurasian plate generates numerous earthquakes. The Pacific plate is moving west at a rate of about 9 cm per year relative to the Eurasian pla ...
Lesson 2: “Seafloor Spreading”
... 1. During World War I, scientists used underwater ________________ to detect the varying depths of the ocean. This is known as “sonar” today. 2. While using this method of echo location, they discovered an underwater system of ____________________ (mountains) and ____________________. 3. In the Atla ...
... 1. During World War I, scientists used underwater ________________ to detect the varying depths of the ocean. This is known as “sonar” today. 2. While using this method of echo location, they discovered an underwater system of ____________________ (mountains) and ____________________. 3. In the Atla ...
Geological Society of America Bulletin - User Web Pages
... in Table 1. Rolland and Pêcher (2001) estimated upper-amphibolite conditions for rocks from this part of the complex, with peak temperatures around 700–750 °C and pressures of 4–5 kbar. During metamorphism, the biotiterich end member of its metaclastic sequence is interpreted to have melted in situ ...
... in Table 1. Rolland and Pêcher (2001) estimated upper-amphibolite conditions for rocks from this part of the complex, with peak temperatures around 700–750 °C and pressures of 4–5 kbar. During metamorphism, the biotiterich end member of its metaclastic sequence is interpreted to have melted in situ ...
C2.3 Plate boundary earthquakes C2.3.1 Strike
... less dense continental crust e.g. Cascadia, west coast South America, Sumatra ...
... less dense continental crust e.g. Cascadia, west coast South America, Sumatra ...
tectonic evolution of the betic cordillera: an overview
... subduction similar to the western Pacific back-arc basins (e.g. Malinverno and Ryan, 1986; Morales et al., 1999). Others envisage subduction with detachment and sinking of a lithospheric slab (e.g. Zeck et al., 1992; Royden, 1993; Lonergan and White, 1997). Convective removal of a cool and dense lit ...
... subduction similar to the western Pacific back-arc basins (e.g. Malinverno and Ryan, 1986; Morales et al., 1999). Others envisage subduction with detachment and sinking of a lithospheric slab (e.g. Zeck et al., 1992; Royden, 1993; Lonergan and White, 1997). Convective removal of a cool and dense lit ...
Granitoids
... A few broad generalizations: 1) Most granitoids of significant volume occur in areas where the continental crust has been thickened by orogeny, either continental arc subduction or collision of sialic masses. Many granites, however, may postdate the thickening event by tens of millions of years. Ima ...
... A few broad generalizations: 1) Most granitoids of significant volume occur in areas where the continental crust has been thickened by orogeny, either continental arc subduction or collision of sialic masses. Many granites, however, may postdate the thickening event by tens of millions of years. Ima ...
KOPER, KEITH Indian Ocean Quake 9/27/12 1
... roughly 90-mile length, breaking “bilaterally” both west-northwestward and east-southeastward, and also at least 30 miles deep, “almost ripping through the whole plate,” Koper says. The seafloor on one side of the fault slipped about 100 feet past the seafloor on the fault’s other side. ...
... roughly 90-mile length, breaking “bilaterally” both west-northwestward and east-southeastward, and also at least 30 miles deep, “almost ripping through the whole plate,” Koper says. The seafloor on one side of the fault slipped about 100 feet past the seafloor on the fault’s other side. ...
Chapter 4 Rocks
... ____ 17. A student finds a rock with seashells in it. What kind of rock is it? a. an igneous rock c. a metamorphic rock b. a sedimentary rock d. an extrusive rock ____ 18. Which type of scientist analyzes the composition of rocks? a. an environmentalist c. a geologist b. a naturalist d. a biologist ...
... ____ 17. A student finds a rock with seashells in it. What kind of rock is it? a. an igneous rock c. a metamorphic rock b. a sedimentary rock d. an extrusive rock ____ 18. Which type of scientist analyzes the composition of rocks? a. an environmentalist c. a geologist b. a naturalist d. a biologist ...
A Digital Atlas of Terranes for the Northern Cordillera
... The framework of the Cordilleran orogen of northwestern North America is commonly depicted as a ‘collage’ of terranes – crustal blocks containing records of a variety of geodynamic environments including continental fragments, pieces of island arc crust and oceanic crust. The series of maps avail ...
... The framework of the Cordilleran orogen of northwestern North America is commonly depicted as a ‘collage’ of terranes – crustal blocks containing records of a variety of geodynamic environments including continental fragments, pieces of island arc crust and oceanic crust. The series of maps avail ...
water-rock interaction in a low-enthalpy back-rift
... containing organic material and high in Sr. Of the rock formations underlying the HRZ, only the graben fill has peat (Brathwaite and Christie, 1996) where I (Fehn and Snyder, 2003) may originate. The Li, Na, Rb and Cl contents of waters, rising along all three fault systems, increase with increasing ...
... containing organic material and high in Sr. Of the rock formations underlying the HRZ, only the graben fill has peat (Brathwaite and Christie, 1996) where I (Fehn and Snyder, 2003) may originate. The Li, Na, Rb and Cl contents of waters, rising along all three fault systems, increase with increasing ...
Ch 17-19 Study Guide with embedded grid
... What and where are the following features found in a volcano? Draw and label one here a. vent ___________________________________________________________ b. crater __________________________________________________________ c. caldera _________________________________________________________ Study ...
... What and where are the following features found in a volcano? Draw and label one here a. vent ___________________________________________________________ b. crater __________________________________________________________ c. caldera _________________________________________________________ Study ...
Geochemistry and petrogenesis of extrusive rocks, dykes and high
... The island of Oldra, part of the Late Ordovician Solund-Stavfjord Ophiolite Complex of the western Norwegian Caledonides, comprises extrusive rocks, a sheeted dyke complex and high-leve! gabbros. The metabasalts are of N-MORB affinity, and their Nd isotopic composition (eNd=+7.8 to +8.4) indicates g ...
... The island of Oldra, part of the Late Ordovician Solund-Stavfjord Ophiolite Complex of the western Norwegian Caledonides, comprises extrusive rocks, a sheeted dyke complex and high-leve! gabbros. The metabasalts are of N-MORB affinity, and their Nd isotopic composition (eNd=+7.8 to +8.4) indicates g ...
A Digital Atlas of Terranes for the Northern Cordillera
... The framework of the Cordilleran orogen of northwestern North America is commonly depicted as a ‘collage’ of terranes – crustal blocks containing records of a variety of geodynamic environments including continental fragments, pieces of island arc crust and oceanic crust. The series of maps avail ...
... The framework of the Cordilleran orogen of northwestern North America is commonly depicted as a ‘collage’ of terranes – crustal blocks containing records of a variety of geodynamic environments including continental fragments, pieces of island arc crust and oceanic crust. The series of maps avail ...
Algoman orogeny
The Algoman orogeny, known as the Kenoran orogeny in Canada, was an episode of mountain-building (orogeny) during the Late Archean Eon that involved repeated episodes of continental collisions, compressions and subductions. The Superior province and the Minnesota River Valley terrane collided about 2,700 to 2,500 million years ago. The collision folded the Earth's crust and produced enough heat and pressure to metamorphose the rock. Blocks were added to the Superior province along a 1,200 km (750 mi) boundary that stretches from present-day eastern South Dakota into the Lake Huron area. The Algoman orogeny brought the Archaen Eon to a close, about 2,500 million years ago; it lasted less than 100 million years and marks a major change in the development of the earth’s crust.The Canadian shield contains belts of metavolcanic and metasedimentary rocks formed by the action of metamorphism on volcanic and sedimentary rock. The areas between individual belts consist of granites or granitic gneisses that form fault zones. These two types of belts can be seen in the Wabigoon, Quetico and Wawa subprovinces; the Wabigoon and Wawa are of volcanic origin and the Quetico is of sedimentary origin. These three subprovinces lie linearly in southwestern- to northeastern-oriented belts about 140 km (90 mi) wide on the southern portion of the Superior Province.The Slave province and portions of the Nain province were also affected. Between about 2,000 and 1,700 million years ago these combined with the Sask and Wyoming cratons to form the first supercontinent, the Kenorland supercontinent.