geology of the storkollen blankenberg area, kragerø, norway
... irregular dip to the south. The texture of the slickensides indicates that at least in one movement, the south (kragerøite) wall moved down and to the west relative to the north wall. The larger eastern rutile mine follows the second fault for about twenty meters at its entrance tunnel, before turni ...
... irregular dip to the south. The texture of the slickensides indicates that at least in one movement, the south (kragerøite) wall moved down and to the west relative to the north wall. The larger eastern rutile mine follows the second fault for about twenty meters at its entrance tunnel, before turni ...
THE CQPPER DEPOSITS N,EAH SALMON, `IDAHO:
... the oldest formation exposed in the area examined. The metamorphism of these rocks is everywhere more striking than that of any of the other formations exposed .. The ]netamorphic rocks consist in general of quartzitic argillite and micaceous quartzite, with some beds of comparatively pure quartzite ...
... the oldest formation exposed in the area examined. The metamorphism of these rocks is everywhere more striking than that of any of the other formations exposed .. The ]netamorphic rocks consist in general of quartzitic argillite and micaceous quartzite, with some beds of comparatively pure quartzite ...
Major Gold Deposits and Belts of the North and South American
... Many of the gold belts and major isolated deposits were generated under extensional or transtensional tectonic conditions in either arc or back-arc settings. Nevertheless, the two main high-sulfidation epithermal gold belts were generated in thickening or already-thickened crust during low-angle sub ...
... Many of the gold belts and major isolated deposits were generated under extensional or transtensional tectonic conditions in either arc or back-arc settings. Nevertheless, the two main high-sulfidation epithermal gold belts were generated in thickening or already-thickened crust during low-angle sub ...
MAJOR-ELEMENT CHEMISTRY OF PLUTONIC ROCK SUITES
... Cenozoic plutonic suites generated at these plate boundaries. Compressional plutonic rock suites are characterized by intermediate unimodal frequency distributions of differentiation index and normative plagioclase, calc/alkali indexes in the range of 60--64, and distinctive patterns on AFM diagrams ...
... Cenozoic plutonic suites generated at these plate boundaries. Compressional plutonic rock suites are characterized by intermediate unimodal frequency distributions of differentiation index and normative plagioclase, calc/alkali indexes in the range of 60--64, and distinctive patterns on AFM diagrams ...
Revised history of Izanagi-Pacific ridge subduction
... As part of a revised global plate tectonic model for 140 Ma to the present, including the reconstruction of now subducted ocean floor [Müller, et al., 2007], we present a revised plate reconstruction for the western Pacific. In our plate model mid-ocean ridge subduction beneath southern Japan occurs ...
... As part of a revised global plate tectonic model for 140 Ma to the present, including the reconstruction of now subducted ocean floor [Müller, et al., 2007], we present a revised plate reconstruction for the western Pacific. In our plate model mid-ocean ridge subduction beneath southern Japan occurs ...
Geological Features and Evolution
... uring recent decades, the Province of Almería has developed as one of the more economically dynamic regions of Andalucía and Spain. Its exceptional environmental conditions due to a favourable geographical situation, and the enterprising character of its people, have made the blossoming prosperity a ...
... uring recent decades, the Province of Almería has developed as one of the more economically dynamic regions of Andalucía and Spain. Its exceptional environmental conditions due to a favourable geographical situation, and the enterprising character of its people, have made the blossoming prosperity a ...
Hydrocarbon basins in SE Asia: understanding why they are there
... ABSTRACT: There are numerous hydrocarbon-rich sedimentary basins in Indonesia, Malaysia and southern Thailand. Almost all these basins began to form in the Early Cenozoic, they are filled with Cenozoic sediments, most are rifted basins that are the product of regional extension, and they formed main ...
... ABSTRACT: There are numerous hydrocarbon-rich sedimentary basins in Indonesia, Malaysia and southern Thailand. Almost all these basins began to form in the Early Cenozoic, they are filled with Cenozoic sediments, most are rifted basins that are the product of regional extension, and they formed main ...
Thermal Structure and Metamorphic Evolution of Subducting Slabs
... Uyeda, 1975]. Subduction zones are regions of intense earthquake activity, explosive volcanism, and complex mass transfer between the crust, mantle, hydrosphere, and atmosphere. In this contribution, I focus on the thermal, petrologic, and seismological processes that occur in subducting slabs. The ...
... Uyeda, 1975]. Subduction zones are regions of intense earthquake activity, explosive volcanism, and complex mass transfer between the crust, mantle, hydrosphere, and atmosphere. In this contribution, I focus on the thermal, petrologic, and seismological processes that occur in subducting slabs. The ...
Introduction: Anatomy of rifting: Tectonics and magmatism in
... volcanism. Studies of a wide variety of extensional processes ranging from plate thinning to magma intrusion have helped scientists understand how continents are broken apart to form ocean basins. However, deformation processes vary significantly during the development of continental rifts and midoc ...
... volcanism. Studies of a wide variety of extensional processes ranging from plate thinning to magma intrusion have helped scientists understand how continents are broken apart to form ocean basins. However, deformation processes vary significantly during the development of continental rifts and midoc ...
Diapirs as the source of the sediment signature in arc lavas
... of subducted sediments, has been interpreted to reflect a ‘sediment melt’ signature in arc lavas2–4 . Subduction zone thermal models that incorporate temperature- and stress-dependent viscosity5–8 produce slab-top temperatures above the fluid-saturated sediment solidus (>600–700 ◦ C at ≤3 GPa; refs ...
... of subducted sediments, has been interpreted to reflect a ‘sediment melt’ signature in arc lavas2–4 . Subduction zone thermal models that incorporate temperature- and stress-dependent viscosity5–8 produce slab-top temperatures above the fluid-saturated sediment solidus (>600–700 ◦ C at ≤3 GPa; refs ...
Igneous Rock Associations 8. Arc Magmatism II: Geo
... enstatite. Equilibrium crystallization or fractionation of these minerals drives the residual liquid composition away initially from olivine (X to T) until it reaches and then descends the olivineenstatite curve (T to P). Along pathway X to P, the magma becomes enriched in other components, includin ...
... enstatite. Equilibrium crystallization or fractionation of these minerals drives the residual liquid composition away initially from olivine (X to T) until it reaches and then descends the olivineenstatite curve (T to P). Along pathway X to P, the magma becomes enriched in other components, includin ...
Document
... 1994; Agard et al. 2005). The Zagros Orogen extends from eastern Turkey through northern Iraq and northwest of Iran to the Hormuz Strait and Oman (Alavi 1994; McQuarrie 2004; Agard et al. 2005; Homke et al. 2010). Because of the key situation of the Zagros Orogen within the Alpine–Himalayan Orogenic ...
... 1994; Agard et al. 2005). The Zagros Orogen extends from eastern Turkey through northern Iraq and northwest of Iran to the Hormuz Strait and Oman (Alavi 1994; McQuarrie 2004; Agard et al. 2005; Homke et al. 2010). Because of the key situation of the Zagros Orogen within the Alpine–Himalayan Orogenic ...
Structural and stratigraphic control of porphyry and related
... intrusive, felsic volcanic and quartz clasts. Stratigraphic and sedimentologic data from Jack Formation sections are consistent with depositional control by penecontemporaneous, basin-bounding faults and by volcanic centres. The McTagg anticlinorium was probably a topographic high during sedimentati ...
... intrusive, felsic volcanic and quartz clasts. Stratigraphic and sedimentologic data from Jack Formation sections are consistent with depositional control by penecontemporaneous, basin-bounding faults and by volcanic centres. The McTagg anticlinorium was probably a topographic high during sedimentati ...
Detrital geochronology and geochemistry of Cretaceous–Early
... The onset of mountain building in the western part of the Himalayan orogenic belt has been documented in the synorogenic stratigraphic record of northern Pakistan and India as Early to Middle Eocene (~52 Ma). Eocene strata in the Tethyan portion of the central part of the Himalayan orogenic belt con ...
... The onset of mountain building in the western part of the Himalayan orogenic belt has been documented in the synorogenic stratigraphic record of northern Pakistan and India as Early to Middle Eocene (~52 Ma). Eocene strata in the Tethyan portion of the central part of the Himalayan orogenic belt con ...
Rock and Mineral 10-Specimen Kit Companion Book
... Igneous—Igneous rocks are made when magma (melted rock below the earth’s surface) or lava (the melted rock that flows from volcanoes above the surface) cools and hardens. Most of the earth’s crust is made of igneous rock. Granite is one example of igneous rock. Sedimentary—Sedimentary rocks are made ...
... Igneous—Igneous rocks are made when magma (melted rock below the earth’s surface) or lava (the melted rock that flows from volcanoes above the surface) cools and hardens. Most of the earth’s crust is made of igneous rock. Granite is one example of igneous rock. Sedimentary—Sedimentary rocks are made ...
14. Some Aspects of Plate Tectonics in the Arabian Sea
... 25 and 26 are not recognizable on three Owen profiles passing to the north of the site. In their place there are east-west-trending anomalies with shorter wavelengths. Nevertheless, the identification is accepted here because it also agrees with the only other long almost north-south magnetic profil ...
... 25 and 26 are not recognizable on three Owen profiles passing to the north of the site. In their place there are east-west-trending anomalies with shorter wavelengths. Nevertheless, the identification is accepted here because it also agrees with the only other long almost north-south magnetic profil ...
GEOTHERMAL SYSTEMS IN GLOBAL PERSPECTIVE
... Yellowstone is the world’s largest rhyolite volcano. A huge, composite caldera has formed in it following major ignimbrite eruptions. Rhyolite volcanoes generally contain little other than rhyolite the low density rock type possibly forming a volcanic shadow zone, impenetrable for heavier less silic ...
... Yellowstone is the world’s largest rhyolite volcano. A huge, composite caldera has formed in it following major ignimbrite eruptions. Rhyolite volcanoes generally contain little other than rhyolite the low density rock type possibly forming a volcanic shadow zone, impenetrable for heavier less silic ...
Faulting and hydration of the Juan de Fuca plate system
... Fig. 1. Juan de Fuca plate regional seismicity and crustal age superimposed over grayscale bathymetry. Crustal scale marine MCS profiles from eight regional surveys are shown using thick brown lines. Line numbers are defined as in original surveys. White sections on transects 17-3-1, 34-32 and 87-89-7 ...
... Fig. 1. Juan de Fuca plate regional seismicity and crustal age superimposed over grayscale bathymetry. Crustal scale marine MCS profiles from eight regional surveys are shown using thick brown lines. Line numbers are defined as in original surveys. White sections on transects 17-3-1, 34-32 and 87-89-7 ...
Deep structures and breakup along volcanic rifted margins: insights
... porosity function (Brigaud, Chapmans, & Le Douaran, 1990), the temperature for a vertical heat flow, at 13 – 15 km, should remain above the Curie temperature isotherms. Furthermore, elevated heat flow induced by thick instantaneous underplating, emplaced during Paleocene, is unlikely to have a therm ...
... porosity function (Brigaud, Chapmans, & Le Douaran, 1990), the temperature for a vertical heat flow, at 13 – 15 km, should remain above the Curie temperature isotherms. Furthermore, elevated heat flow induced by thick instantaneous underplating, emplaced during Paleocene, is unlikely to have a therm ...
Impact of lower plate structure on upper plate
... highlights those portions of the seafloor shaped by active tectonic, depositional and/or erosional processes. The greatest slope gradients are located in the frontal 30 km of the forearc, at the toe of the accretionary wedge. This suggests that long-term deformation rates are highest here and that p ...
... highlights those portions of the seafloor shaped by active tectonic, depositional and/or erosional processes. The greatest slope gradients are located in the frontal 30 km of the forearc, at the toe of the accretionary wedge. This suggests that long-term deformation rates are highest here and that p ...
Marathon, Ontario - University of Minnesota Duluth
... intrusions occur in an area that extends extends from Alkalic rock intrusions the north shore of Lake Superior in a north to east of north km. The The diatreme structures direction for approximately 140 km. Slate Islands(Sage, Islands(Sage, 1991) 1991) and and the the carbonatite carbonatite found o ...
... intrusions occur in an area that extends extends from Alkalic rock intrusions the north shore of Lake Superior in a north to east of north km. The The diatreme structures direction for approximately 140 km. Slate Islands(Sage, Islands(Sage, 1991) 1991) and and the the carbonatite carbonatite found o ...
Chapter 11 SEDIMENTARY BASINS
... 7.1 The concept of geosynclines was developed in the last century to deal with the existence of thick successions of sedimentary rocks in what we would today call orogenic belts. A geosyncline is large troughlike or basinlike downwarping of the crust in which thick sedimentary and volcanic rocks acc ...
... 7.1 The concept of geosynclines was developed in the last century to deal with the existence of thick successions of sedimentary rocks in what we would today call orogenic belts. A geosyncline is large troughlike or basinlike downwarping of the crust in which thick sedimentary and volcanic rocks acc ...
ABSTRACT The gneiss complex around and north of Pouso Alegre
... and petrography of these gneisses. A typical aspect is the occurrence of mafic shlieren and clots of hornblende and garnet in many of these rocks which might lead one to suppose that they are restites or residual source material as in the examples discussed by Chappell et al. (1987). However, there ...
... and petrography of these gneisses. A typical aspect is the occurrence of mafic shlieren and clots of hornblende and garnet in many of these rocks which might lead one to suppose that they are restites or residual source material as in the examples discussed by Chappell et al. (1987). However, there ...
Carlin-Type and Low-Sulphidation Epithermal Gold Deposits
... clastic sediments (800 to 340 Million years ago) and the development of a “passive continental margin”; 2) deformation - the sedimentary rocks were folded and faulted during tectonic squeezing or “accretion” along that margin (340 to 65 Million years ago); at this time, important thrust faults forme ...
... clastic sediments (800 to 340 Million years ago) and the development of a “passive continental margin”; 2) deformation - the sedimentary rocks were folded and faulted during tectonic squeezing or “accretion” along that margin (340 to 65 Million years ago); at this time, important thrust faults forme ...
A narrowly spaced double-seismic zone in the subducting Nazca plate
... subducted Nazca plate [ANCORP Working Group, 1999; Yoon et al., 2003]. Thus, seismicity in the upper band occurs near the top of the down going oceanic crust, just beneath its interface with the South American continental mantle. Since the crustal thickness of the subducting Nazca plate, determined ...
... subducted Nazca plate [ANCORP Working Group, 1999; Yoon et al., 2003]. Thus, seismicity in the upper band occurs near the top of the down going oceanic crust, just beneath its interface with the South American continental mantle. Since the crustal thickness of the subducting Nazca plate, determined ...
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.