Cordierite in felsic igneous rocks: a synthesis
... peraluminous felsic igneous rocks. This statement does not diminish the importance of other mechani s m s for p r o d u c i n g p e r a l u m i n o u s g r a n i t e s (fractionation of hornblende from metaluminous melts, contamination, vapour-phase transfer; Clarke 1981a; Halliday et al., 1981), no ...
... peraluminous felsic igneous rocks. This statement does not diminish the importance of other mechani s m s for p r o d u c i n g p e r a l u m i n o u s g r a n i t e s (fractionation of hornblende from metaluminous melts, contamination, vapour-phase transfer; Clarke 1981a; Halliday et al., 1981), no ...
Batholith tectonics: Formation and deformation of ghost stratigraphy
... 1982) that inferred that batholiths may crystallize over millions of years, thermal models have demonstrated that a single mapped intrusion may record a protracted duration of crystallization and that portions of the growing pluton may be fully crystallized while other portions may be partially molt ...
... 1982) that inferred that batholiths may crystallize over millions of years, thermal models have demonstrated that a single mapped intrusion may record a protracted duration of crystallization and that portions of the growing pluton may be fully crystallized while other portions may be partially molt ...
Elevated 87Sr/86Sr Ratios From Mafic Intrusions in the Atlanta Lobe
... American continents are some of the most obvious examples of recent genesis and reworking of continental crust, and their origins are of fundamental geologic importance. The volumetric dominance of monzogranites, granodiorites, and tonalites in these batholiths was recognized very early. However, it ...
... American continents are some of the most obvious examples of recent genesis and reworking of continental crust, and their origins are of fundamental geologic importance. The volumetric dominance of monzogranites, granodiorites, and tonalites in these batholiths was recognized very early. However, it ...
An Investigation of the carbonatites of the Kaapvaal Craton and their
... association of carbonatites with rifting environments, this dissertation proposes that: carbonatites occur in extensional tectonic settings and therefore carbonatite occurrence can be used to constrain an extensional setting for related occurrences. In order to give context in which to consider this ...
... association of carbonatites with rifting environments, this dissertation proposes that: carbonatites occur in extensional tectonic settings and therefore carbonatite occurrence can be used to constrain an extensional setting for related occurrences. In order to give context in which to consider this ...
1 MELT VISCOSITY, TEMPERATURE AND TRANSPORT
... 4. Viscosity of the CY-1/1A lavas Melt viscosities were calculated for reported rock compositions from the CY1/1A drill holes, using the method of Shaw [23] (Fig. 5). We did not use more complex formulations which include the effects of crystallinity (e.g., [24]) because the crystal content during v ...
... 4. Viscosity of the CY-1/1A lavas Melt viscosities were calculated for reported rock compositions from the CY1/1A drill holes, using the method of Shaw [23] (Fig. 5). We did not use more complex formulations which include the effects of crystallinity (e.g., [24]) because the crystal content during v ...
univERsity oF copEnhAGEn
... to form magma that, after solidification, will have the characteristic low average density of the crystalline basement (Arndt, this volume; Hawkesworth et al., this volume). The continental crust is subsequently affected by a variety of tectonic, erosional, depositional and metamorphic processes, whi ...
... to form magma that, after solidification, will have the characteristic low average density of the crystalline basement (Arndt, this volume; Hawkesworth et al., this volume). The continental crust is subsequently affected by a variety of tectonic, erosional, depositional and metamorphic processes, whi ...
Moho and magmatic underplating
... to form magma that, after solidification, will have the characteristic low average density of the crystalline basement (Arndt, this volume; Hawkesworth et al., this volume). The continental crust is subsequently affected by a variety of tectonic, erosional, depositional and metamorphic processes, whi ...
... to form magma that, after solidification, will have the characteristic low average density of the crystalline basement (Arndt, this volume; Hawkesworth et al., this volume). The continental crust is subsequently affected by a variety of tectonic, erosional, depositional and metamorphic processes, whi ...
Mantle-derived magmas and magmatic Ni-Cu-(PGE) deposits
... Melting can occur via a variety of different physical processes, including: 1) equilibrium (batch) melting in which the melt remains in equilibrium with the source, resulting in only moderate fractionation of highly from moderately incompatible elements; 2) fractional melting, in which the melt is c ...
... Melting can occur via a variety of different physical processes, including: 1) equilibrium (batch) melting in which the melt remains in equilibrium with the source, resulting in only moderate fractionation of highly from moderately incompatible elements; 2) fractional melting, in which the melt is c ...
Petrology and Geochemistry of the Nipissing Gabbro
... Effects of the Textural Variations in the Gabbro on the Analytical Data . . . . . . . . . . . . . . . . . . . . . . . . Geochemical Evidence for the Emplacement and In-situ Differentiation of Nipissing Intrusions . . . . Duration of Nipissing Magmatic Activity and Associated Compositional Variation ...
... Effects of the Textural Variations in the Gabbro on the Analytical Data . . . . . . . . . . . . . . . . . . . . . . . . Geochemical Evidence for the Emplacement and In-situ Differentiation of Nipissing Intrusions . . . . Duration of Nipissing Magmatic Activity and Associated Compositional Variation ...
Dyke swarm emplacement in the Ethiopian Large Igneous Province
... owing to the large number of linear valleys observed to cut the plateau edge. These valleys can result from preferential water £ow and erosion along dykes or along other types of fractures. Determining whether these valleys highlight dykes or other fracture types is necessary to place constraints on ...
... owing to the large number of linear valleys observed to cut the plateau edge. These valleys can result from preferential water £ow and erosion along dykes or along other types of fractures. Determining whether these valleys highlight dykes or other fracture types is necessary to place constraints on ...
Geological Survey of Canada, 601 Booth Street, Ottawa, Ontario
... ed in depressions (embayments) along the base of the melt sheet. The Murray mine is in such an embayment (Fig. 5; Souch et al., 1969). Sulphide liquid also accompanied melt into the offsets. On cooling, the sulphide liquid crystallized to form Ni-Cu-PGE ores. In some of the embayments, sulphide melt ...
... ed in depressions (embayments) along the base of the melt sheet. The Murray mine is in such an embayment (Fig. 5; Souch et al., 1969). Sulphide liquid also accompanied melt into the offsets. On cooling, the sulphide liquid crystallized to form Ni-Cu-PGE ores. In some of the embayments, sulphide melt ...
High-Mg# andesitic lavas of the Shisheisky Complex, Northern
... interpretations imply that high-Mg# andesites are a primary arc magma type that is generated below the crust–mantle boundary under hydrous conditions in the subduction zone environment. This conclusion has been questioned by studies which argue that high-Mg# andesites are produced within the crust b ...
... interpretations imply that high-Mg# andesites are a primary arc magma type that is generated below the crust–mantle boundary under hydrous conditions in the subduction zone environment. This conclusion has been questioned by studies which argue that high-Mg# andesites are produced within the crust b ...
PDF (Chapter 9. The Source Region)
... dispersed, as in peridotite, or how much olivine and orthopyroxene are in the source region. The basalt fraction of pyrolite, a hypothetical source peridotite, is arbitrary. Experimental petrology cannot constrain the bulk composition of the source region. The existence of meteorites rich in olivine ...
... dispersed, as in peridotite, or how much olivine and orthopyroxene are in the source region. The basalt fraction of pyrolite, a hypothetical source peridotite, is arbitrary. Experimental petrology cannot constrain the bulk composition of the source region. The existence of meteorites rich in olivine ...
Magma Genesis and Mantle Dynamics at the Harrat Ash
... distance of 2500 km to southeastern Turkey (Fig. 1a). These volcanic fields, the so-called Harrats, cover an area of ~200 000 km2, with an average thickness of about 100 m (Coleman et al., 1983; Nasir, 1994; Tarawneh et al., 2000). The Harrat Ash Shamah (or Harrat Ash-Shaam: HAS) is the largest volc ...
... distance of 2500 km to southeastern Turkey (Fig. 1a). These volcanic fields, the so-called Harrats, cover an area of ~200 000 km2, with an average thickness of about 100 m (Coleman et al., 1983; Nasir, 1994; Tarawneh et al., 2000). The Harrat Ash Shamah (or Harrat Ash-Shaam: HAS) is the largest volc ...
Petrology and structure of syenite intrusions of the Okenyenya
... along fractures and rims, are a distinctive component of the syenite, frequently occurring in aggregates with ilmenite, clinopyroxene, rare orthopyroxene, amphibole and apatite. Iron-rich augite (En14-28 Fs27-43 Wo41-46: Table 3) is present as anhedral to subhedral crystals <2 mm in size. Pyroxene c ...
... along fractures and rims, are a distinctive component of the syenite, frequently occurring in aggregates with ilmenite, clinopyroxene, rare orthopyroxene, amphibole and apatite. Iron-rich augite (En14-28 Fs27-43 Wo41-46: Table 3) is present as anhedral to subhedral crystals <2 mm in size. Pyroxene c ...
Unusual nickel and copper to noble
... 220 S. -1. Barnes The Rånbogen samples have similar Ni/Cu ratios to high-MgO basalts but lower Pd/Ir ratios; there fore, on the Pd/Ir versus Ni/Cu plot, the Rån bogen samples plot below the high-MgO basalts, but still within the field of layered intrusions. The differences in the composition of t ...
... 220 S. -1. Barnes The Rånbogen samples have similar Ni/Cu ratios to high-MgO basalts but lower Pd/Ir ratios; there fore, on the Pd/Ir versus Ni/Cu plot, the Rån bogen samples plot below the high-MgO basalts, but still within the field of layered intrusions. The differences in the composition of t ...
Fig. 1
... Despite the importance of continental breakup in plate tectonics, precisely how extensional processes such as brittle faulting, ductile plate stretching, and magma intrusion evolve in space and time during the development of new ocean basins remains poorly understood. The rifting of Arabia from Afri ...
... Despite the importance of continental breakup in plate tectonics, precisely how extensional processes such as brittle faulting, ductile plate stretching, and magma intrusion evolve in space and time during the development of new ocean basins remains poorly understood. The rifting of Arabia from Afri ...
PDF
... The Arabian-Nubian Shield (fig. 1) is mostly juvenile continental crust created in Neoproterozoic time, as demonstrated by oceanic lithologies such as ophiolites (Stern and others, 2004) and by mantle-like isotopic compositions of especially Sr and Nd (Stern, 2002a; Stoeser and Frost, 2006). The ANS ...
... The Arabian-Nubian Shield (fig. 1) is mostly juvenile continental crust created in Neoproterozoic time, as demonstrated by oceanic lithologies such as ophiolites (Stern and others, 2004) and by mantle-like isotopic compositions of especially Sr and Nd (Stern, 2002a; Stoeser and Frost, 2006). The ANS ...
1 Origin and geodynamic relationships of the Late Miocene to
... (1300-1400oC) along with number of further observations we exclude the existence of mantle ...
... (1300-1400oC) along with number of further observations we exclude the existence of mantle ...
Sabzevar Ophiolite, NE Iran - The University of Texas at Dallas
... respectively. The crustal sequence of the Sabzevar ophiolite is dominated by supra-subduction zone (SSZ)-type volcanic as well as plutonic rocks with minor Oceanic Island Basalt (OIB)-like pillowed and massive lavas. The ophiolite is covered by Late Campanian to Early Maastrichtian (~ 75–68 Ma) pela ...
... respectively. The crustal sequence of the Sabzevar ophiolite is dominated by supra-subduction zone (SSZ)-type volcanic as well as plutonic rocks with minor Oceanic Island Basalt (OIB)-like pillowed and massive lavas. The ophiolite is covered by Late Campanian to Early Maastrichtian (~ 75–68 Ma) pela ...
Kurzlaukis and Lorenz_Gibeon Volcanic Field
... updoming of country rock beds along their margins, similar to the observations of Wagner (1914, 1971) for kimberlites in southern Africa. This is typically absent in the vicinity of carbonatite dikes and diatremes surrounding Gross Brukkaros. Updoming is most obvious along dikes and diatremes intrud ...
... updoming of country rock beds along their margins, similar to the observations of Wagner (1914, 1971) for kimberlites in southern Africa. This is typically absent in the vicinity of carbonatite dikes and diatremes surrounding Gross Brukkaros. Updoming is most obvious along dikes and diatremes intrud ...
the Scanned PDF
... of the plagioclase phenocryst have essentially the same composition as the plagioclasein wehrlite and gabbro inclusions. The Iki plagioclasehas up to 0.9 percent of total iron, but MgO, TiO2 and MnO are negligible. It seemslikely, therefore,that thesecomponentsmay be presentboth as impurities andf o ...
... of the plagioclase phenocryst have essentially the same composition as the plagioclasein wehrlite and gabbro inclusions. The Iki plagioclasehas up to 0.9 percent of total iron, but MgO, TiO2 and MnO are negligible. It seemslikely, therefore,that thesecomponentsmay be presentboth as impurities andf o ...
Melting of the Uppermost Metasomatized Asthenosphere Triggered
... The Quaternary Chugaryeong volcano, located in the centre of the Korean Peninsula, is one of a number of alkaline volcanoes at the eastern margin of the Eurasian Plate. Because some basaltic lavas from the Chugaryeong volcano have less differentiated chemical compositions, we can use them to investi ...
... The Quaternary Chugaryeong volcano, located in the centre of the Korean Peninsula, is one of a number of alkaline volcanoes at the eastern margin of the Eurasian Plate. Because some basaltic lavas from the Chugaryeong volcano have less differentiated chemical compositions, we can use them to investi ...
Mackenzie Large Igneous Province
The Mackenzie Large Igneous Province (MLIP) is a major Mesoproterozoic large igneous province of the southwestern, western and northwestern Canadian Shield in Canada. It consists of a group of related igneous rocks that were formed during a massive igneous event starting about 1,270 million years ago. The large igneous province extends from the Arctic in Nunavut to near the Great Lakes in Northwestern Ontario where it meets with the smaller Matachewan dike swarm. Included in the Mackenzie Large Igneous Province are the large Muskox layered intrusion, the Coppermine River flood basalt sequence and the massive northwesterly trending Mackenzie dike swarm.As a large igneous province, it is an extremely large area of related igneous rocks that were emplaced over an extremely short geological time span. The igneous rocks comprising the Mackenzie Large Igneous Province originated from processes not associated with normal plate tectonics and seafloor spreading. It is one of the several large igneous provinces scattered throughout the Canadian landscape, which can be thousands of kilometres in volume and area. The Mackenzie Large Igneous Province is also one of the largest Proterozoic magmatic provinces on Earth, as well as the world's largest and best-preserved continental flood basalt terrain. Igneous rocks of the Mackenzie Large Igneous Province are generally mafic in composition, including basalt and gabbro.Even though the Mackenzie Large Igneous Province is classified as a large igneous province like other extremely large accumulations of igneous rocks on Earth, it is much larger than large igneous province standards. The standard size classification for large igneous provinces is a minimum areal extent of 100,000 km2 (39,000 sq mi). However, the Mackenzie dike swarm itself occupies an area of at least 2,700,000 km2 (1,000,000 sq mi), making the Mackenzie Large Igneous Province larger than the Ontong Java Plateau in the southwestern Pacific Ocean and the U.S. state of Alaska.