Kimberlites and Lamproites: Primary Sources of Diamond
... On the basis of this evidence, it is now believed that some diamonds are derived by the disaggregation of such source rocks. Thus, the recognition of purple subcalcic chrome pyrope xenocrysts, known colloquially as GI0 garnets, in kimberlites Is commonly regarded as a key indicator for the presence ...
... On the basis of this evidence, it is now believed that some diamonds are derived by the disaggregation of such source rocks. Thus, the recognition of purple subcalcic chrome pyrope xenocrysts, known colloquially as GI0 garnets, in kimberlites Is commonly regarded as a key indicator for the presence ...
Chapter 8 Earthquakes
... When tectonic plates move, pressure builds up on the rock near the edges of the plates. When rock is put under pressure, it changes shape, or deforms. This is called deformation. Some rock can bend and fold like clay. When the pressure is taken away, the rock stays folded. When rock stays folded aft ...
... When tectonic plates move, pressure builds up on the rock near the edges of the plates. When rock is put under pressure, it changes shape, or deforms. This is called deformation. Some rock can bend and fold like clay. When the pressure is taken away, the rock stays folded. When rock stays folded aft ...
Environmental Chemistry
... – Divergent boundaries where plates move away from each other allowing hot magma to flow upward and create new lithosphere and ocean ridges – Convergent boundaries in which plates move toward each other creating a subduction zone where new magma is formed or mountain ranges created – Transform fault ...
... – Divergent boundaries where plates move away from each other allowing hot magma to flow upward and create new lithosphere and ocean ridges – Convergent boundaries in which plates move toward each other creating a subduction zone where new magma is formed or mountain ranges created – Transform fault ...
the geology of the volcanic island jan mayen arctic ocean
... eruptions have mostly occurred through the central crater of the volcanic cone Beerenberg and short radial fissures or single craters on its flanks. On Sor-Jan the eruptions have occurred on short NE trending fissures, single craters and domes. In many cases the eruptions were submarine resulting in ...
... eruptions have mostly occurred through the central crater of the volcanic cone Beerenberg and short radial fissures or single craters on its flanks. On Sor-Jan the eruptions have occurred on short NE trending fissures, single craters and domes. In many cases the eruptions were submarine resulting in ...
SIGNIFICANT VOLCANIC CONTRIBUTION TO SOME QUARTZ
... ABSTRACT: Quartz-rich sedimentary rocks are commonly assumed to be the eroded products of cratons or recycled orogens. However, active or eroded acidic volcanic regions can also be an important, but commonly overlooked, source of quartz. Cenozoic sandstones from East Java, Indonesia, illustrate this ...
... ABSTRACT: Quartz-rich sedimentary rocks are commonly assumed to be the eroded products of cratons or recycled orogens. However, active or eroded acidic volcanic regions can also be an important, but commonly overlooked, source of quartz. Cenozoic sandstones from East Java, Indonesia, illustrate this ...
New Mexico Geological Society
... clast conglomerate and grades up into granitic-clast facies. The granitic-clast lithofacies is restricted to the most northeastern section of the main outcrop area and scattered exposures of Glance Conglomerate further north. This facies rests either on the mixed-clast facies or unconformably on Pre ...
... clast conglomerate and grades up into granitic-clast facies. The granitic-clast lithofacies is restricted to the most northeastern section of the main outcrop area and scattered exposures of Glance Conglomerate further north. This facies rests either on the mixed-clast facies or unconformably on Pre ...
IJNlliEl\$.lTY OF ICl:`LAND - Nordic Volcanological Center
... fissure swarm (Bjornsson et al. 1977). This activity has been characterized by alternating inflations and deflations of the volcano, and episodic widenings of the fissure swarm (Fig. 1). The inflation of the volcano progresses at a rate of 0.5 to 1.0 cm per day for one to seven months between deflat ...
... fissure swarm (Bjornsson et al. 1977). This activity has been characterized by alternating inflations and deflations of the volcano, and episodic widenings of the fissure swarm (Fig. 1). The inflation of the volcano progresses at a rate of 0.5 to 1.0 cm per day for one to seven months between deflat ...
Rhenium^Osmium Isotope and Platinum
... rock differentiation series from dunite cumulates, peridotites, pyroxenites, and gabbros, to granophyres. Second, it is one of the most ultramafic large layered intrusions so far recognized on Earth and has been considered to be related in space and time to the extensive 127 Ga giant Mackenzie dyke ...
... rock differentiation series from dunite cumulates, peridotites, pyroxenites, and gabbros, to granophyres. Second, it is one of the most ultramafic large layered intrusions so far recognized on Earth and has been considered to be related in space and time to the extensive 127 Ga giant Mackenzie dyke ...
Variations in amount and direction of seafloor spreading along
... of low amplitude (Figure 1) [e.g., Price et al., 1997]. Mosar et al. [2002] calculated spreading rates along each of the Reykjanes, Aegir and Mohns Ridges, showing that there was significant variation in spreading rates across the JMFZ. They suggested that this differential spreading was responsible ...
... of low amplitude (Figure 1) [e.g., Price et al., 1997]. Mosar et al. [2002] calculated spreading rates along each of the Reykjanes, Aegir and Mohns Ridges, showing that there was significant variation in spreading rates across the JMFZ. They suggested that this differential spreading was responsible ...
Origin of the West Taiwan basin by orogenic loading and flexure of a
... subtracting a 5 5 min grid of the present-day topography and bathymetry of the margin (e.g., Figure 1b) from the paleobathymetry. The surface loads comprise of both a subaerial and submarine component. (c) Flexure due to surface loads on a 3-D elastic plate with Te = 10 km. Other parameters are as ...
... subtracting a 5 5 min grid of the present-day topography and bathymetry of the margin (e.g., Figure 1b) from the paleobathymetry. The surface loads comprise of both a subaerial and submarine component. (c) Flexure due to surface loads on a 3-D elastic plate with Te = 10 km. Other parameters are as ...
loch loyal syenite complex
... minerals and have a larger radiometric anomaly because of high concentrations of thorite (Gallagher et al., 1971). Mapping by McErlean (1993) reported by Holdsworth and Strachan (in press) has revealed that the Cnoc nan Cùilean intrusion was emplaced as a series of NWtrending sheets, and that the sy ...
... minerals and have a larger radiometric anomaly because of high concentrations of thorite (Gallagher et al., 1971). Mapping by McErlean (1993) reported by Holdsworth and Strachan (in press) has revealed that the Cnoc nan Cùilean intrusion was emplaced as a series of NWtrending sheets, and that the sy ...
Weathering
... Changes to Earth’s Surface You know that Earth’s crust and upper mantle are broken into huge slabs called plates. Forces deep within Earth cause these plates to move and change the surface. For example, most mountains form when plates come together. ...
... Changes to Earth’s Surface You know that Earth’s crust and upper mantle are broken into huge slabs called plates. Forces deep within Earth cause these plates to move and change the surface. For example, most mountains form when plates come together. ...
ax2009ag.aw
... The more common geomorphic processes of interest to landscape-scale analysis are sedimentation and hydrologic processes. Specific processes are mass wasting, surface erosion, runoff, channel processes, and subsurface water movement and storage. Processes can be described and analyzed but are difficu ...
... The more common geomorphic processes of interest to landscape-scale analysis are sedimentation and hydrologic processes. Specific processes are mass wasting, surface erosion, runoff, channel processes, and subsurface water movement and storage. Processes can be described and analyzed but are difficu ...
the form of the fongen-hyllingen gabbro complex, trondheim region
... with a decrease in the anorthite content of the plagioclase, to give oligo clase-andesine compositions. Amphibole is the major primary mafic mineral, together with minor amounts of biotite. Along the rather poorly exposed easterJ;� margin further north, the possible occurrence of dioritic types is ...
... with a decrease in the anorthite content of the plagioclase, to give oligo clase-andesine compositions. Amphibole is the major primary mafic mineral, together with minor amounts of biotite. Along the rather poorly exposed easterJ;� margin further north, the possible occurrence of dioritic types is ...
A detailed study of the Gagua Ridge: A fracture zone uplifted during
... to belong rather to the Luzon Volcanic Arc, except for the gabbro samples which may come from the Gagua Ridge. Another dredge, which was made on the west flank of the ridge (at 21◦290 N, far from the Luzon Arc), reveals gabbros, and no other rocks like an- ...
... to belong rather to the Luzon Volcanic Arc, except for the gabbro samples which may come from the Gagua Ridge. Another dredge, which was made on the west flank of the ridge (at 21◦290 N, far from the Luzon Arc), reveals gabbros, and no other rocks like an- ...
Geological Society of America Bulletin - User Web Pages
... The sequence of rocks comprising the Pangong metamorphic complex is described 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 ...
... The sequence of rocks comprising the Pangong metamorphic complex is described 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 ...
final study guide
... the upper crust, creating a larger area for earthquakes to rupture. Strong coupling also allows for more earthquakes as blocks of rock are strongly bounded. ...
... the upper crust, creating a larger area for earthquakes to rupture. Strong coupling also allows for more earthquakes as blocks of rock are strongly bounded. ...
Bulletin 41 Geology of Puertecito Quadrangle, Socorro County, New
... folded with older beds during this deformation. The second orogeny took place in late-Miocene(?) time before the cessation of volcanism. Normal faulting, with a large horizontal component of movement, resulted from this deformation, which apparently was a product of a force couple directed in an eas ...
... folded with older beds during this deformation. The second orogeny took place in late-Miocene(?) time before the cessation of volcanism. Normal faulting, with a large horizontal component of movement, resulted from this deformation, which apparently was a product of a force couple directed in an eas ...
FELDSPAR EQUILIBRIA AND THEIR IMPLICATION I A. Feldspar in
... In this diagram feldspars from the same rock and thus presum abiy in equilibrium with each other at the time of crystallization are connected with lines. The diagram clearly demonstrates that calcic plagioclase is in equilibrium with potassic sanidine, and sodic plagio clase with sodic sanidine. I ...
... In this diagram feldspars from the same rock and thus presum abiy in equilibrium with each other at the time of crystallization are connected with lines. The diagram clearly demonstrates that calcic plagioclase is in equilibrium with potassic sanidine, and sodic plagio clase with sodic sanidine. I ...
Hewitt/Lyons/Suchocki/Yeh, Conceptual Integrated Science
... Classifying Sedimentary Rock • Rock types are based on the source of the material: — Detrital or Clastic rocks—transported sediment particles—bits and pieces of weathered rock — Chemical rocks—sediments that were once in solution ...
... Classifying Sedimentary Rock • Rock types are based on the source of the material: — Detrital or Clastic rocks—transported sediment particles—bits and pieces of weathered rock — Chemical rocks—sediments that were once in solution ...
Chapter F4
... • Tectonic Letdown Subsidence can also occur when the lithosphere becomes stretched in rift zones. • A rift zone is a set of deep cracks that forms between two tectonic plates that are pulling away from each other. • As tectonic plates pull apart, stress between the plates causes a series of faults ...
... • Tectonic Letdown Subsidence can also occur when the lithosphere becomes stretched in rift zones. • A rift zone is a set of deep cracks that forms between two tectonic plates that are pulling away from each other. • As tectonic plates pull apart, stress between the plates causes a series of faults ...
Geological Society of America Bulletin
... and stopped at ca. 15 Ma, while remaining prolific toward the west (Fig. 1, inset). Late Cretaceous and younger magmatism resulted from north-dipping subduction that is interpreted to have started at 66 Ma along the western edge of the Caribbean plate, defining the time when the Caribbean and Farall ...
... and stopped at ca. 15 Ma, while remaining prolific toward the west (Fig. 1, inset). Late Cretaceous and younger magmatism resulted from north-dipping subduction that is interpreted to have started at 66 Ma along the western edge of the Caribbean plate, defining the time when the Caribbean and Farall ...
Large igneous province
A large igneous province (LIP) is an extremely large accumulation of igneous rocks, including liquid rock (intrusive) or volcanic rock formations (extrusive), when hot magma extrudes from inside the Earth and flows out. The source of many or all LIPs is variously attributed to mantle plumes or to processes associated with plate tectonics. Types of LIPs can include large volcanic provinces (LVP), created through flood basalt and large plutonic provinces (LPP). Eleven distinct flood basalt episodes occurred in the past 250 million years, creating volcanic provinces, which coincided with mass extinctions in prehistoric times. Formation depends on a range of factors, such as continental configuration, latitude, volume, rate, duration of eruption, style and setting (continental vs. oceanic), the preexisting climate state, and the biota resilience to change.