Continental crust generated in oceanic arcs
... Figure 3 | Seismic signature of Costa Rica from active source experiments. P-wave velocity (VP ) model from active source experiments across Costa Rica. a, Location of the seismic experiment and modelled cross-section. Stars denote explosion sources and triangles are active volcanoes. b, Compression ...
... Figure 3 | Seismic signature of Costa Rica from active source experiments. P-wave velocity (VP ) model from active source experiments across Costa Rica. a, Location of the seismic experiment and modelled cross-section. Stars denote explosion sources and triangles are active volcanoes. b, Compression ...
Labreport HHohmeister
... the Black Forest. Rocks from these times have been subject to convolution and bedding, and are mainly sediments or metamorphites. Many of these rocks were exposed to several formations of rock masses, and were thus intensively deformed. Lava rose repeatedly from the earth’s crust, and granitic [Plut ...
... the Black Forest. Rocks from these times have been subject to convolution and bedding, and are mainly sediments or metamorphites. Many of these rocks were exposed to several formations of rock masses, and were thus intensively deformed. Lava rose repeatedly from the earth’s crust, and granitic [Plut ...
Continental crust generated in oceanic arcs
... Figure 3 | Seismic signature of Costa Rica from active source experiments. P-wave velocity (VP ) model from active source experiments across Costa Rica. a, Location of the seismic experiment and modelled cross-section. Stars denote explosion sources and triangles are active volcanoes. b, Compression ...
... Figure 3 | Seismic signature of Costa Rica from active source experiments. P-wave velocity (VP ) model from active source experiments across Costa Rica. a, Location of the seismic experiment and modelled cross-section. Stars denote explosion sources and triangles are active volcanoes. b, Compression ...
High pore pressures and porosity at 35 km depth in the Cascadia
... The observed Vp/Vs values of 2.35 ± 0.10 for the low-velocity layer beneath southern Vancouver Island are best matched by the properties of crystalline rocks with fluid-filled porosity of 2.7%–4.0%, with the fluid under near lithostatic pressure (Pdiff = 0–5MPa) (Fig. 3C). The estimated porosity bas ...
... The observed Vp/Vs values of 2.35 ± 0.10 for the low-velocity layer beneath southern Vancouver Island are best matched by the properties of crystalline rocks with fluid-filled porosity of 2.7%–4.0%, with the fluid under near lithostatic pressure (Pdiff = 0–5MPa) (Fig. 3C). The estimated porosity bas ...
Update and economic significance of geological mapping in the
... potential, have also been significantly clarified. In addition, this work provides an improved geological context for a series of locally auriferous stockworkbreccia quartz-vein systems north of Gem Lake. One of these systems can be traced for 1.2 km along strike and appears to be developed along a br ...
... potential, have also been significantly clarified. In addition, this work provides an improved geological context for a series of locally auriferous stockworkbreccia quartz-vein systems north of Gem Lake. One of these systems can be traced for 1.2 km along strike and appears to be developed along a br ...
Intrusive felsic-mafic net-veined complexes in north
... pillows (Fig. 5), to scattered, mainly angular, mafic inclusions probably representing pieces of fragmented pillows (Fig. 3). Dark margins to pillows may be due partly to primary chilling against felsic magma, and partly to metasomatic alteration of the marginal pillow rock during crystallisation of ...
... pillows (Fig. 5), to scattered, mainly angular, mafic inclusions probably representing pieces of fragmented pillows (Fig. 3). Dark margins to pillows may be due partly to primary chilling against felsic magma, and partly to metasomatic alteration of the marginal pillow rock during crystallisation of ...
ch09
... Cryogenian Period, between 745 and 725 million years ago, and the other was in the Ediacaran Period, between 590 and 550 million years ago. Cryogenian and Ediacaran periods are associated with banded iron formations and capped by carbonate rocks. Snowball Earth hypothesis - The concept that during t ...
... Cryogenian Period, between 745 and 725 million years ago, and the other was in the Ediacaran Period, between 590 and 550 million years ago. Cryogenian and Ediacaran periods are associated with banded iron formations and capped by carbonate rocks. Snowball Earth hypothesis - The concept that during t ...
Appalachian Planation Surfaces
... in the north to Alabama in the south. It is 125 miles (200 km) at its widest point near the Virginia-North Carolina border. The Piedmont is bordered on the east by the Atlantic Coastal Plain Province, the boundary being the Fall Line, and its elevation gradually rises westward toward the Blue Ridge ...
... in the north to Alabama in the south. It is 125 miles (200 km) at its widest point near the Virginia-North Carolina border. The Piedmont is bordered on the east by the Atlantic Coastal Plain Province, the boundary being the Fall Line, and its elevation gradually rises westward toward the Blue Ridge ...
Melting Relations of MORB^Sediment Me
... crustal rocks as the cause of the silicic magmatism. It also conflicts with their derivation from a volumetrically limited source within the continental crust. In the case of assimilation, a parallel evolution to compositions richer in silica and alkalis on the one hand, and with more radiogenic Sr ...
... crustal rocks as the cause of the silicic magmatism. It also conflicts with their derivation from a volumetrically limited source within the continental crust. In the case of assimilation, a parallel evolution to compositions richer in silica and alkalis on the one hand, and with more radiogenic Sr ...
Caribbean Geological Conference 18th
... of a transition zone of the mantle section of the harzburgite-type of alpine peridotite complexes. The main parent rock is harzburgite, which in a form of about 20-30 percent serpentinized rock, makes up about 50% of the outcrop. The remainder is almost entirely serpentinite-talc. Orthopyroxene gene ...
... of a transition zone of the mantle section of the harzburgite-type of alpine peridotite complexes. The main parent rock is harzburgite, which in a form of about 20-30 percent serpentinized rock, makes up about 50% of the outcrop. The remainder is almost entirely serpentinite-talc. Orthopyroxene gene ...
View
... ject. These maps are the culmination of efforts by the project partners (Manitoba Geological Services Branch (MGSB), Saskatchewan Geological Survey (SGS), Geological Survey of Canada (GSC» and build on the rich history of geoscience mapping in the Flin Flon Belt. A companion set of surficial geology ...
... ject. These maps are the culmination of efforts by the project partners (Manitoba Geological Services Branch (MGSB), Saskatchewan Geological Survey (SGS), Geological Survey of Canada (GSC» and build on the rich history of geoscience mapping in the Flin Flon Belt. A companion set of surficial geology ...
pdf file - Pacific Northwest Geodetic Array
... Please send your comments and/or additions to this draft! RATIONALE Subduction zones are the most dynamic tectonic environments on earth. The fastest relative plate motions and the highest mass fluxes of sediment, magma, and related fluids into the continental crust and mantle occur at subduction zo ...
... Please send your comments and/or additions to this draft! RATIONALE Subduction zones are the most dynamic tectonic environments on earth. The fastest relative plate motions and the highest mass fluxes of sediment, magma, and related fluids into the continental crust and mantle occur at subduction zo ...
Earth Power Point
... This is a picture from The Hunchback of Notre Dame. This guy breaks out of these stocks and he says “I’m Free” several times and keeps getting trapped again. The waves change speed several times throughout the Earth. They may feel like they are free when traveling through solids. ...
... This is a picture from The Hunchback of Notre Dame. This guy breaks out of these stocks and he says “I’m Free” several times and keeps getting trapped again. The waves change speed several times throughout the Earth. They may feel like they are free when traveling through solids. ...
SESSIONE TS1.3 Processi magmatici e metamorfici nella crosta
... limited enrichment in HfO2 (up to 1.5 %), suggesting crystallization in a slightly more evolved magma. The bright areas also have HfO2 between 1.1 and 1.5, but Y2O3 does not exceed 0.2 %; UO2 is always < 0.05 % and ThO2 almost absent; they could represent “recrystallization fronts” formed during hig ...
... limited enrichment in HfO2 (up to 1.5 %), suggesting crystallization in a slightly more evolved magma. The bright areas also have HfO2 between 1.1 and 1.5, but Y2O3 does not exceed 0.2 %; UO2 is always < 0.05 % and ThO2 almost absent; they could represent “recrystallization fronts” formed during hig ...
From Ores to Metals
... are thought to contain more than 85 % of all the copper in the earth’s crust that can be considered ore under present and projected technological, economic, and social constraints. The change from underground to open-pit mining in the early twentieth century reflected the exhaustion of richer copper ...
... are thought to contain more than 85 % of all the copper in the earth’s crust that can be considered ore under present and projected technological, economic, and social constraints. The change from underground to open-pit mining in the early twentieth century reflected the exhaustion of richer copper ...
The Río de la Plata Craton: a review of units, boundaries, ages and
... located between Arroyo Grande and San José Belts. Decameter- to kilometer-sized xenoliths of micaschists, paragneisses and amphibolites are common within the granites and gneisses. Several post-tectonic granites also intrude the central granitic gneiss belt. U–Pb age determinations are not availabl ...
... located between Arroyo Grande and San José Belts. Decameter- to kilometer-sized xenoliths of micaschists, paragneisses and amphibolites are common within the granites and gneisses. Several post-tectonic granites also intrude the central granitic gneiss belt. U–Pb age determinations are not availabl ...
Continental breakup and the onset of ultraslow seafloor spreading
... basis of results of the wide-angle data (Funck et al., 2003). A clear difference between seismic phases observed west of OBS 19 and those observed to the east (Fig. 2) is best explained by assuming an oceanic layer 2–layer 3 velocity structure to the east. Combined with results of the reflection dat ...
... basis of results of the wide-angle data (Funck et al., 2003). A clear difference between seismic phases observed west of OBS 19 and those observed to the east (Fig. 2) is best explained by assuming an oceanic layer 2–layer 3 velocity structure to the east. Combined with results of the reflection dat ...
Document
... The tectonic setting of the Southern Uplands sedimentary basin during the deposition of the Crawford Group remains uncertain. The oceanic affinity of the radiolarian deposits was taken as an indication that they were deposited well within the Iapetus Ocean (Leggett 1987). However, these rocks are n ...
... The tectonic setting of the Southern Uplands sedimentary basin during the deposition of the Crawford Group remains uncertain. The oceanic affinity of the radiolarian deposits was taken as an indication that they were deposited well within the Iapetus Ocean (Leggett 1987). However, these rocks are n ...
Crustal structure of the southern margin of the African - ePIC
... [8] The offshore section of this western profile starts about 20 km off the coast and stretches over 400 km south, past the Agulhas-Falkland Fracture Zone (AFFZ, Figure 1). Between the AFFZ and the present coast a network of basins, collectively referred to as the Outeniqua Basin (Figure 1), is loca ...
... [8] The offshore section of this western profile starts about 20 km off the coast and stretches over 400 km south, past the Agulhas-Falkland Fracture Zone (AFFZ, Figure 1). Between the AFFZ and the present coast a network of basins, collectively referred to as the Outeniqua Basin (Figure 1), is loca ...
Crustal contributions to arc magmatism in the Andes of Central Chile
... among neighboring suites (which lack zircon and alkali feldspar) largely reflects local variability of intracrustal (not slab or mantle) contributions. Pb-isotope data define a limited range that straddles the Stacey-Kramers line, is bracketed by values of local basement rocks, in part plots above t ...
... among neighboring suites (which lack zircon and alkali feldspar) largely reflects local variability of intracrustal (not slab or mantle) contributions. Pb-isotope data define a limited range that straddles the Stacey-Kramers line, is bracketed by values of local basement rocks, in part plots above t ...
Kimberlites and the start of plate tectonics
... powers plate motions. Although subduction the mantle was low, mostly delivered by delamizones are not part of the formal definition of PT, nation and lithospheric drips, so fluid pressure we now know that convergent plate margins are at the top of asthenosphere was mostly low and surficial expressio ...
... powers plate motions. Although subduction the mantle was low, mostly delivered by delamizones are not part of the formal definition of PT, nation and lithospheric drips, so fluid pressure we now know that convergent plate margins are at the top of asthenosphere was mostly low and surficial expressio ...
- BIROn - Birkbeck Institutional Research Online
... zones because of the scarcity of data for these areas at that time. We consider the close link between the magmatism and the extensional evolution of the main lithospheric blocks and their boundaries. The rheological properties of the lithosphere (i.e. whether it is rigid or weak) cause specific mag ...
... zones because of the scarcity of data for these areas at that time. We consider the close link between the magmatism and the extensional evolution of the main lithospheric blocks and their boundaries. The rheological properties of the lithosphere (i.e. whether it is rigid or weak) cause specific mag ...
NAPPES, GNEISS DOMES AND PLUTONIC SHEETS OF WEST
... mineral suggesting zones of restite entrained within the magma. The Bethlehem Gneiss is a more homogeneous micaceous granodiorite distinguished from the KQM by a prominent gneissic foliation and the lack of potassium feldspar megacrysts and restites. Lathrop and others (1994, 1996) made detailed Sr, ...
... mineral suggesting zones of restite entrained within the magma. The Bethlehem Gneiss is a more homogeneous micaceous granodiorite distinguished from the KQM by a prominent gneissic foliation and the lack of potassium feldspar megacrysts and restites. Lathrop and others (1994, 1996) made detailed Sr, ...
Geochemistry and petrogenesis of extrusive rocks, dykes and high
... sequence. Dykes appear in close association with extrusive rocks. A mixed zone of dykes and screens of extrusive rocks represents a transition zone between the sheeted dyke complex and the volcanic sequence. The pillow lavas are aphyric to moderately phyric (
... sequence. Dykes appear in close association with extrusive rocks. A mixed zone of dykes and screens of extrusive rocks represents a transition zone between the sheeted dyke complex and the volcanic sequence. The pillow lavas are aphyric to moderately phyric (
Verkhoyansk Project Final Report - IIS Windows Server
... in order to examine all the principal lithologic units that characterize each structural domain within the thrust belt. We had Russian geological maps of covering most of our transects at 1:200,000 scale (Ferdman et al. 1963; Losev et al. 1970; Starnikov, 1983; Yan-Shin-Tshin, 1971), as well as a co ...
... in order to examine all the principal lithologic units that characterize each structural domain within the thrust belt. We had Russian geological maps of covering most of our transects at 1:200,000 scale (Ferdman et al. 1963; Losev et al. 1970; Starnikov, 1983; Yan-Shin-Tshin, 1971), as well as a co ...
Baltic Shield
The Baltic Shield (sometimes referred to as the Fennoscandian Shield) is located in Fennoscandia (Norway, Sweden and Finland), northwest Russia and under the Baltic Sea. The Baltic Shield is defined as the exposed Precambrian northwest segment of the East European Craton. It is composed mostly of Archean and Proterozoic gneisses and greenstones which have undergone numerous deformations through tectonic activity (see Geology of Fennoscandia map [1]). The Baltic Shield contains the oldest rocks of the European continent. The lithospheric thickness is about 200-300 km. During the Pleistocene epoch, great continental ice sheets scoured and depressed the shield's surface, leaving a thin covering of glacial material and innumerable lakes and streams. The Baltic Shield is still rebounding today following the melting of the thick glaciers during the Quaternary Period.