Genesis of diamonds-the metamorphic point of view
... The first river-bed (alluvial) diamonds were probably discovered in India, in around 800 B.C. The volcanic source of these diamonds was never discovered, but the alluvial deposits were rich enough to supply most of the world's diamonds until the eighteenth century, when dwindling Indian supplies pro ...
... The first river-bed (alluvial) diamonds were probably discovered in India, in around 800 B.C. The volcanic source of these diamonds was never discovered, but the alluvial deposits were rich enough to supply most of the world's diamonds until the eighteenth century, when dwindling Indian supplies pro ...
Geological Society of Malaysia Bulletin 49
... Continental Deposits Continental deposits in this belt can be found in Bukit Keluang area including Pulau Rhu, the western part of Pulau Redang, the southern parts of Pulau Kapas and Gunung Gagau. The rocks in Bukit Keluang and Pulau Rhu are the older group while those in Gunung Gagau are younger. T ...
... Continental Deposits Continental deposits in this belt can be found in Bukit Keluang area including Pulau Rhu, the western part of Pulau Redang, the southern parts of Pulau Kapas and Gunung Gagau. The rocks in Bukit Keluang and Pulau Rhu are the older group while those in Gunung Gagau are younger. T ...
LATE CENOZOIC OROGENY IN JAPAN Late Cenozoic tectonic
... anomalies, low heat-flow values and high mantle seismicity. The belt has subsided during Late Cenozoic, particularly since Late Pliocene (Iijima and Kagami, 1961). The active tectonic state of the belt is also suggested by thick young sediments and young faulting (Ludwig et al., 1966). The outer bel ...
... anomalies, low heat-flow values and high mantle seismicity. The belt has subsided during Late Cenozoic, particularly since Late Pliocene (Iijima and Kagami, 1961). The active tectonic state of the belt is also suggested by thick young sediments and young faulting (Ludwig et al., 1966). The outer bel ...
The India - Eurasia collision, Himalaya and the Tibetan
... Atlantic ocean since middle early Cretaceous (Aptian) until present ...
... Atlantic ocean since middle early Cretaceous (Aptian) until present ...
The India
... Some important characteristics: • Very long duration of continental collision and shortening • Thickest crust and highest topography on earth ...
... Some important characteristics: • Very long duration of continental collision and shortening • Thickest crust and highest topography on earth ...
Origin of Mesoproterozoic A-type granites in Laurentia
... Granitic rocks are commonly used as a means to study chemical evolution of continental crust. In particular, their isotopic compositions reflect the relative contributions of mantle and crustal sources in their genesis. In Laurentia, a distinctive belt of Mesoproterozoic A-type or “anorogenic” grani ...
... Granitic rocks are commonly used as a means to study chemical evolution of continental crust. In particular, their isotopic compositions reflect the relative contributions of mantle and crustal sources in their genesis. In Laurentia, a distinctive belt of Mesoproterozoic A-type or “anorogenic” grani ...
Sample presentation slides (Green curves design)
... geologic effect of regional plate tectonic faulting along a very deeply buried low-angle decollement (a very large regional fault) in rock units composed of soft shale or even salt. Some of the compressive tectonic energy was relieved by the creation of high-angle splay thrust faults that shoot up f ...
... geologic effect of regional plate tectonic faulting along a very deeply buried low-angle decollement (a very large regional fault) in rock units composed of soft shale or even salt. Some of the compressive tectonic energy was relieved by the creation of high-angle splay thrust faults that shoot up f ...
PART II: METAMORPHIC PETROLOGY
... The scope and range of metamorphism is not easy to define. By definition, metamorphism should exclude all sedimentary and igneous processes. Yet the boundary between diagenesis and metamorphism is poorly defined, and is definitely a function of the composition of the rock undergoing such changes. Th ...
... The scope and range of metamorphism is not easy to define. By definition, metamorphism should exclude all sedimentary and igneous processes. Yet the boundary between diagenesis and metamorphism is poorly defined, and is definitely a function of the composition of the rock undergoing such changes. Th ...
1 Evolution of continental crust through two Wilson
... the Wilson cycle (Wilson, 1966), has undergone two cycles of supercontinent assembly and breakup since the Mesoproterozoic. EarthScope research presents opportunities to improve understanding of tectonic inheritance from the Grenville orogen (assembly of Rodinia), though Neoproterozoic supercontinen ...
... the Wilson cycle (Wilson, 1966), has undergone two cycles of supercontinent assembly and breakup since the Mesoproterozoic. EarthScope research presents opportunities to improve understanding of tectonic inheritance from the Grenville orogen (assembly of Rodinia), though Neoproterozoic supercontinen ...
Introduction - San Francisco State University
... examine geometric relations between faults and folds. This paper presents a geologic map and cross section of the study area, macroscopic fold data from radiolarian chert units in the map area (previously collected), and descriptions of map units and structural geology, as well as interpretations of ...
... examine geometric relations between faults and folds. This paper presents a geologic map and cross section of the study area, macroscopic fold data from radiolarian chert units in the map area (previously collected), and descriptions of map units and structural geology, as well as interpretations of ...
Numerical lithospheric modelling: rheology, stress and deformation
... computer hardware, which were primitive in the sense of application runtimes. As computer capabilities have since developed rapidly, this limitation has more or less vanished. At present it is possible to solve more and more complicated and larger numerical models in a shorter time frame. This has w ...
... computer hardware, which were primitive in the sense of application runtimes. As computer capabilities have since developed rapidly, this limitation has more or less vanished. At present it is possible to solve more and more complicated and larger numerical models in a shorter time frame. This has w ...
THE SIGNIFICANCE OF THE METAMORPHIC ROCKS OF TIMOR
... Of the two main divisions of the Lolotoi the higher-grade metamorphic rocks form the earliest unit, perhaps representing fragments of an ancient Precambrian continental shield. This would imply that the greenschist facies volcano-sedimentary sequence accreted to these older continental rocks during ...
... Of the two main divisions of the Lolotoi the higher-grade metamorphic rocks form the earliest unit, perhaps representing fragments of an ancient Precambrian continental shield. This would imply that the greenschist facies volcano-sedimentary sequence accreted to these older continental rocks during ...
Mr. Lee – Layers of the Earth rap
... And the core is really dense and metallic Memorize this song and you’ll know everything about the Crust and mantle, crust and mantle, crust and mantle, crust and mantle Moving on down there are two more layers called the Outer core, inner core, outer core, inner core When the rock breaks, there’s a ...
... And the core is really dense and metallic Memorize this song and you’ll know everything about the Crust and mantle, crust and mantle, crust and mantle, crust and mantle Moving on down there are two more layers called the Outer core, inner core, outer core, inner core When the rock breaks, there’s a ...
rifted margin
... The continent/ocean boundary was created when Pangea rifted apart, creating a transition from continental to oceanic crust through extensional thinning and magmatic emplacement. This type of continental margin has historically been referred to as a “passive” continental margin. The newer and more ap ...
... The continent/ocean boundary was created when Pangea rifted apart, creating a transition from continental to oceanic crust through extensional thinning and magmatic emplacement. This type of continental margin has historically been referred to as a “passive” continental margin. The newer and more ap ...
The Kaapvaal craton (South Africa): no evidence for a supercontinental
... concomitant loss of ≤1.5 km of stratigraphy must logically have been due to far-field tectonic effects, but no known mobile belt or even greenstone belts can be related to this. At ~2714-2709 Ma, a large mantle plume impinged beneath the thinned crust underlying the Witwatersrand basin, forming thic ...
... concomitant loss of ≤1.5 km of stratigraphy must logically have been due to far-field tectonic effects, but no known mobile belt or even greenstone belts can be related to this. At ~2714-2709 Ma, a large mantle plume impinged beneath the thinned crust underlying the Witwatersrand basin, forming thic ...
Densities of metapelitic rocks at high to ultrahigh
... significantly less dense than the ultrabasic upper mantle at corresponding depths. However, this could be a prejudice based on the situation at shallower depths where many ordinary rocks such as orthogneisses, consisting mainly of quartz and feldspar, have, indeed, densities still below a value of 3 ...
... significantly less dense than the ultrabasic upper mantle at corresponding depths. However, this could be a prejudice based on the situation at shallower depths where many ordinary rocks such as orthogneisses, consisting mainly of quartz and feldspar, have, indeed, densities still below a value of 3 ...
A Proterozoic mylonite zone in the Kongsberg Series north of
... east of Øverbykollen (Fig. l) and was reported by Jøsang (1%6) to trace for another 8 km further north. Strong blastomylonitic recrystallisations may have helped to disguise cataclased zones in the north. These have already been mentioned, but are especially strong near Simoa. They were possibly enh ...
... east of Øverbykollen (Fig. l) and was reported by Jøsang (1%6) to trace for another 8 km further north. Strong blastomylonitic recrystallisations may have helped to disguise cataclased zones in the north. These have already been mentioned, but are especially strong near Simoa. They were possibly enh ...
4.4 billion years of crustal maturation: oxygen isotope ratios of
... readily altered by metamorphic, hydrothermal, or diagenetic processes, zircons are generally not affected. Zircons with heavy radiation damage or postmagmatic alteration can be identified and avoided prior to analysis. No other mineral permits d18O(magma) to be coupled to age of crystallization with s ...
... readily altered by metamorphic, hydrothermal, or diagenetic processes, zircons are generally not affected. Zircons with heavy radiation damage or postmagmatic alteration can be identified and avoided prior to analysis. No other mineral permits d18O(magma) to be coupled to age of crystallization with s ...
Rocks and Landscapes of the Boonah District
... The prominent peaks of the valley with few exceptions are composed of resistant rhyolite and trachyte. Mount Greville and Mount Moon were probably domes of rhyolite magma intruded beneath the surface rather than vent fillings. Mount Edwards was a similar body of trachyte. During its erosion it has b ...
... The prominent peaks of the valley with few exceptions are composed of resistant rhyolite and trachyte. Mount Greville and Mount Moon were probably domes of rhyolite magma intruded beneath the surface rather than vent fillings. Mount Edwards was a similar body of trachyte. During its erosion it has b ...
Without hot rock, much of North America would be underwater
... thickness [24 miles] and composition [2.85 times difference between the peaks of the mid-ocean the density of water],” Chapman says. “Once ridges and older seafloor. we’ve done that, we can see the thermal effect.” Given that, Chapman says he has been puzzled that differences in rock temperature nev ...
... thickness [24 miles] and composition [2.85 times difference between the peaks of the mid-ocean the density of water],” Chapman says. “Once ridges and older seafloor. we’ve done that, we can see the thermal effect.” Given that, Chapman says he has been puzzled that differences in rock temperature nev ...
PDF
... Nd and Hf indicate derivation from depleted mantle. This information supports the idea that crust beneath southern Louisiana formed as a magma-starved rifted margin on the northern flank of the Gulf of Mexico ca. 160 Ma. These results also confirm that some magnetic highs mark accumulations of mafic ...
... Nd and Hf indicate derivation from depleted mantle. This information supports the idea that crust beneath southern Louisiana formed as a magma-starved rifted margin on the northern flank of the Gulf of Mexico ca. 160 Ma. These results also confirm that some magnetic highs mark accumulations of mafic ...
Mantle Plumes and Intraplate Volcanism Volcanism on the Earth
... evolved through just a few pathways. What are these? No one is certain. Some ideas: – 1. Mixing between primitive and depleted mantle – 2. Recycling of oceanic crust and sediment – 3. “Delamination” of the mantle lithosphere beneath the continents, which could be enriched in incompatible elements by ...
... evolved through just a few pathways. What are these? No one is certain. Some ideas: – 1. Mixing between primitive and depleted mantle – 2. Recycling of oceanic crust and sediment – 3. “Delamination” of the mantle lithosphere beneath the continents, which could be enriched in incompatible elements by ...
PDF file - FSU GK
... don’t flow well. Geologists call thickness viscosity. If lava is thick, they say it is viscous. 1. Which lava was thinner, or less viscous? Basaltic lavas have very little silica. They are thin so they flow easily. Most lava flows that you have seen on TV were basaltic lavas. 2. How might this affec ...
... don’t flow well. Geologists call thickness viscosity. If lava is thick, they say it is viscous. 1. Which lava was thinner, or less viscous? Basaltic lavas have very little silica. They are thin so they flow easily. Most lava flows that you have seen on TV were basaltic lavas. 2. How might this affec ...
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.