Kimberlites and Lamproites: Primary Sources of Diamond
... A variety of mantle-derived igneous rocks comprise the primary sources of diamond, with the principal hosts being kimberlite and lamproite. Primary diamonds or graphite pseudomorphs after diamond are also known to occur in some lamprophyres (Jaques, Kerr et al., 1989), alkali basalts and alpine type ...
... A variety of mantle-derived igneous rocks comprise the primary sources of diamond, with the principal hosts being kimberlite and lamproite. Primary diamonds or graphite pseudomorphs after diamond are also known to occur in some lamprophyres (Jaques, Kerr et al., 1989), alkali basalts and alpine type ...
secondary planar structural elements
... Disjunctive fracture cleavage with shear movement is not a “true” foliation in terms of finite strain: it is a false cleavage. Solution cleavage Solution cleavage consists of regularly spaced dissolution surfaces (e.g. stylolitic joints) that divide the rock into a series of microlithons without int ...
... Disjunctive fracture cleavage with shear movement is not a “true” foliation in terms of finite strain: it is a false cleavage. Solution cleavage Solution cleavage consists of regularly spaced dissolution surfaces (e.g. stylolitic joints) that divide the rock into a series of microlithons without int ...
Tourmaline Isotopes: No Element Left Behind
... (Hawthorne and Dirlam 2011 this issue). Once formed, tourmaline is highly stable in a variety of rock types over SEAWATER, AND THE CONTINENTAL CRUST an exceptionally large P–T range, extending from surface Subduction zones are areas of intense interest to geoscienconditions to the diamond stability ...
... (Hawthorne and Dirlam 2011 this issue). Once formed, tourmaline is highly stable in a variety of rock types over SEAWATER, AND THE CONTINENTAL CRUST an exceptionally large P–T range, extending from surface Subduction zones are areas of intense interest to geoscienconditions to the diamond stability ...
full text - NWT Protected Area Strategy
... locality have yielded ages of greater than 4 billion years old. The Acasta gneisses are a finite resource with significant scientific and cultural value. For this reason, the area is being considered for protection under the NWT Protected Areas Strategy. As part of the process for protection, a cand ...
... locality have yielded ages of greater than 4 billion years old. The Acasta gneisses are a finite resource with significant scientific and cultural value. For this reason, the area is being considered for protection under the NWT Protected Areas Strategy. As part of the process for protection, a cand ...
Petrology and structure of syenite intrusions of the Okenyenya
... chemical and mineralogical differences from the other rocks of the study and may appropriately be termed microgranites. Other quartz-rich rocks have been produced locally at the contact of the intrusive complex by the recrystallisation or partial melting of sandstones and metasedimentary rocks. The ...
... chemical and mineralogical differences from the other rocks of the study and may appropriately be termed microgranites. Other quartz-rich rocks have been produced locally at the contact of the intrusive complex by the recrystallisation or partial melting of sandstones and metasedimentary rocks. The ...
Abstract
... Salt walls are located north of the Sedom diapir. Here, the salt has constructed a wall against the fault. This took on its shape during normal faulting. There are also many elongated salt ridges that can be found in the northern basin. These ridges have an oblique trend, which makes them en echelon ...
... Salt walls are located north of the Sedom diapir. Here, the salt has constructed a wall against the fault. This took on its shape during normal faulting. There are also many elongated salt ridges that can be found in the northern basin. These ridges have an oblique trend, which makes them en echelon ...
CHAPTER 5 Mafic-ultramafic complexes
... The Penrose definition came out of the widely accepted view that ideal oceanic crust had a uniform, layered composition. But with ongoing research, it came to be realized that the oceanic crust is not homogeneous, but variable in its development and stratigraphy, which means that ophiolites are more ...
... The Penrose definition came out of the widely accepted view that ideal oceanic crust had a uniform, layered composition. But with ongoing research, it came to be realized that the oceanic crust is not homogeneous, but variable in its development and stratigraphy, which means that ophiolites are more ...
MAJOR-ELEMENT CHEMISTRY OF PLUTONIC ROCK SUITES
... shows that the compressional suites have unimodal distributions with intermediate modes, whereas the extensional suites have bimodal distributions with acidic--basic modes. Other types of relative frequency distributions were examined (e.g., SiO2, Larsen index), b u t differentiation index and norma ...
... shows that the compressional suites have unimodal distributions with intermediate modes, whereas the extensional suites have bimodal distributions with acidic--basic modes. Other types of relative frequency distributions were examined (e.g., SiO2, Larsen index), b u t differentiation index and norma ...
The Mings Bight Ophiolite Complex, Newfoundland: Appalachian
... eastward vergence at the northern end of the Baie Verte Lineament. This narrow ophiolitic belt, and (to the south) an adjacent zone of early Devonian volcanic rocks and sediments, were affected by a strong Acadian (Middle Devonian?) deformation between more resistant blocks consisting mainly of rock ...
... eastward vergence at the northern end of the Baie Verte Lineament. This narrow ophiolitic belt, and (to the south) an adjacent zone of early Devonian volcanic rocks and sediments, were affected by a strong Acadian (Middle Devonian?) deformation between more resistant blocks consisting mainly of rock ...
Bulletin of the Geological Society of Denmark, Vol. 39/3-4 pp. 179-197
... Sadel@,Bj~rneoenand part of the peninsula between Qussuk and inner Godthåbsfjord - was never metamorphosed above amphibolite facies. Most of the rest of the terrane was metamorphosed to granulite facies, with peak metamorphic conditions on Nordlandet estimated to have been 800 50°C and 7.9 1.0 kbar ...
... Sadel@,Bj~rneoenand part of the peninsula between Qussuk and inner Godthåbsfjord - was never metamorphosed above amphibolite facies. Most of the rest of the terrane was metamorphosed to granulite facies, with peak metamorphic conditions on Nordlandet estimated to have been 800 50°C and 7.9 1.0 kbar ...
Elevated 87Sr/86Sr Ratios From Mafic Intrusions in the Atlanta Lobe
... the granitic rocks, was the realization that rather than being simple crustal melts, most of the granitic rocks formed from - or evolved in close association with - these mafic magmas through complex processes of assimilation, mixing, hybridization, and fractional crystallization. These observations ...
... the granitic rocks, was the realization that rather than being simple crustal melts, most of the granitic rocks formed from - or evolved in close association with - these mafic magmas through complex processes of assimilation, mixing, hybridization, and fractional crystallization. These observations ...
Geology of the Central Peloncillo Mountains, Hidalgo County, New
... epidote, and a younger sequence of mostly rhyolitic rock, the extrusion of which was probably accompanied by explosions, for pyroclastic debris is common. Nuees ardentes eruptions resulted in the thick sequence of ignimbrite which covers much of the southern part of the area. A few small copper, lea ...
... epidote, and a younger sequence of mostly rhyolitic rock, the extrusion of which was probably accompanied by explosions, for pyroclastic debris is common. Nuees ardentes eruptions resulted in the thick sequence of ignimbrite which covers much of the southern part of the area. A few small copper, lea ...
CK-12 Earth Science For High School - Workbook
... the paper is accepted for publication, several scientists who are experts in the same field will review it. This is called peer review. These other scientists may suggest changes to the paper, and they will recommend whether or not the paper should be published. Once a paper is published, other scie ...
... the paper is accepted for publication, several scientists who are experts in the same field will review it. This is called peer review. These other scientists may suggest changes to the paper, and they will recommend whether or not the paper should be published. Once a paper is published, other scie ...
Mafic eclogites in the Czech part of the Erzgebirge
... (Košler et al. 2004). They show medium-pressure amphibolite facies conditions with no signs of eclogite facies metamorphism (Konopásek, 1998). The lower nappe is formed by gneisses with HP-UHP rocks (Schmädicke et al., 1992; Mingram, 1998; Rötzler et al., 1998; Willner et al., 1997; Gross 2008). In ...
... (Košler et al. 2004). They show medium-pressure amphibolite facies conditions with no signs of eclogite facies metamorphism (Konopásek, 1998). The lower nappe is formed by gneisses with HP-UHP rocks (Schmädicke et al., 1992; Mingram, 1998; Rötzler et al., 1998; Willner et al., 1997; Gross 2008). In ...
GEOLOGY OF MINNESOTA: A Centennial Volume
... Hornblende Peridotite in Ely Greenstone ....................................................... . Differentiated Mafic-Ultramafic Bodies in Newton Lake Formation ................................. . Similarities to Ultramafic Rocks in Northwestern Ontario ........................................... . ...
... Hornblende Peridotite in Ely Greenstone ....................................................... . Differentiated Mafic-Ultramafic Bodies in Newton Lake Formation ................................. . Similarities to Ultramafic Rocks in Northwestern Ontario ........................................... . ...
On the relationship between the Bushveld Complex and its felsic
... the contact with the Upper Zone. Small photos taken of the rocks observed immediately above the contact including the small metased- ...
... the contact with the Upper Zone. Small photos taken of the rocks observed immediately above the contact including the small metased- ...
Answer
... – The general game for the accumulation of rock and soil materials deposited at the end or sides of glaciers ...
... – The general game for the accumulation of rock and soil materials deposited at the end or sides of glaciers ...
Learning Outcome mapping of old spec to new
... changes in stress in rocks, changes in water levels in wells, changes in ground levels, magnetism and animal behaviour describe and explain the social consequences of attempted earthquake ...
... changes in stress in rocks, changes in water levels in wells, changes in ground levels, magnetism and animal behaviour describe and explain the social consequences of attempted earthquake ...
Age, Origin and Emplacement of Diamonds
... answered is: From what type of magma or preexisting material do diamonds actually crystallize? The two most rewarding areas of investigation in which answers to this question have been found are: (1) the study of diamond-bearing xenoliths, and (2) the study of mineral inclusions within diamonds. ...
... answered is: From what type of magma or preexisting material do diamonds actually crystallize? The two most rewarding areas of investigation in which answers to this question have been found are: (1) the study of diamond-bearing xenoliths, and (2) the study of mineral inclusions within diamonds. ...
Anomalous Occurrence of Cretaceous Placer Deposits: A
... Global temperature covaried with atmospheric CO2 during the Phanerozoic [27; 28, 29; Fig. 2]. The extreme global warmth experienced during the Cretaceous was a direct consequence of the high level of atmospheric CO2 that prevailed globally at that time [30, 31]. Variations in the sea level are an im ...
... Global temperature covaried with atmospheric CO2 during the Phanerozoic [27; 28, 29; Fig. 2]. The extreme global warmth experienced during the Cretaceous was a direct consequence of the high level of atmospheric CO2 that prevailed globally at that time [30, 31]. Variations in the sea level are an im ...
A Geochemical Study of Crustal Plutonic Rocks from the Southern
... Rosemary Hickey-Vargas, who guided, motivated, and inspired me all these years; my committee members for their revisions, suggestions and tolerance of my penchant for waiting until the eleventh hour; the NSF grant that funded most of the data analyses and three semesters of an assistantship and tuit ...
... Rosemary Hickey-Vargas, who guided, motivated, and inspired me all these years; my committee members for their revisions, suggestions and tolerance of my penchant for waiting until the eleventh hour; the NSF grant that funded most of the data analyses and three semesters of an assistantship and tuit ...
Granitoids in Poland, AM Monograph No
... The middle part of the intrusion is formed of the fine-grained biotite granite which intruded after the medium-grained variety. The fine-grained biotite granite forms an E-W trending dyke dipping to the north (Morawski, Kościówko 1975). Near the contact of the two granites, streaks and lenses of th ...
... The middle part of the intrusion is formed of the fine-grained biotite granite which intruded after the medium-grained variety. The fine-grained biotite granite forms an E-W trending dyke dipping to the north (Morawski, Kościówko 1975). Near the contact of the two granites, streaks and lenses of th ...
Ultramafic-mafic intrusions, volcanic rocks and PGE-Cu
... Stillwater, etc.) and PGE-copper-nickel sulfide deposits (Sudbury, Voisey’s Bay, Jinchuan, Duluth, etc.). The Norilsk deposits have both ore types combined within a single intrusive body (i.e., coppernickel sulfide, also enriched with platinum group elements (PGE) and low-sulfide platinum). They are ...
... Stillwater, etc.) and PGE-copper-nickel sulfide deposits (Sudbury, Voisey’s Bay, Jinchuan, Duluth, etc.). The Norilsk deposits have both ore types combined within a single intrusive body (i.e., coppernickel sulfide, also enriched with platinum group elements (PGE) and low-sulfide platinum). They are ...
Economic geology research, volume 1 1999-2000
... Granberg, Viterliden, Gråberget, Sarvasåive, Sadenåive, Vaikijaur, Iekelvare, and Sjisjka. Most deposits share common characteristics, such as being hosted by intermediate to felsic intrusive rocks. They are all also Cu±Au±Fe oxide dominated deposits with a similar ore mineralogy and they generally ...
... Granberg, Viterliden, Gråberget, Sarvasåive, Sadenåive, Vaikijaur, Iekelvare, and Sjisjka. Most deposits share common characteristics, such as being hosted by intermediate to felsic intrusive rocks. They are all also Cu±Au±Fe oxide dominated deposits with a similar ore mineralogy and they generally ...
Weathering
Weathering is the breaking down of rocks, soil and minerals as well as artificial materials through contact with the Earth's atmosphere, biota and waters. Weathering occurs in situ, roughly translated to: ""with no movement"" , and thus should not be confused with erosion, which involves the movement of rocks and minerals by agents such as water, ice, snow, wind, waves and gravity and then being transported and deposited in other locations.Two important classifications of weathering processes exist – physical and chemical weathering; each sometimes involves a biological component. Mechanical or physical weathering involves the breakdown of rocks and soils through direct contact with atmospheric conditions, such as heat, water, ice and pressure. The second classification, chemical weathering, involves the direct effect of atmospheric chemicals or biologically produced chemicals also known as biological weathering in the breakdown of rocks, soils and minerals. While physical weathering is accentuated in very cold or very dry environments, chemical reactions are most intense where the climate is wet and hot. However, both types of weathering occur together, and each tends to accelerate the other. For example, physical abrasion (rubbing together) decreases the size of particles and therefore increases their surface area, making them more susceptible to rapid chemical reactions. The various agents act in concert to convert primary minerals (feldspars and micas) to secondary minerals (clays and carbonates) and release plant nutrient elements in soluble forms.The materials left over after the rock breaks down combined with organic material creates soil. The mineral content of the soil is determined by the parent material, thus a soil derived from a single rock type can often be deficient in one or more minerals for good fertility, while a soil weathered from a mix of rock types (as in glacial, aeolian or alluvial sediments) often makes more fertile soil. In addition, many of Earth's landforms and landscapes are the result of weathering processes combined with erosion and re-deposition.