1 The role of the mantle wedge in subduction zone dynamics and
... Techniques using electromagnetic methods have been used to map high conductivity areas in convergent margins [59-62] that can be interpreted as regions with high water and/or melt content. In general these studies are limited to depths of about 40 km [63]. In some cases deeper images can be obtained ...
... Techniques using electromagnetic methods have been used to map high conductivity areas in convergent margins [59-62] that can be interpreted as regions with high water and/or melt content. In general these studies are limited to depths of about 40 km [63]. In some cases deeper images can be obtained ...
05_chapter 1
... charnockites and pyroxene granulites. Progressive transformation of khondalite to charnockites and retrogressive of charnockites to garnet biotite are observed. The charnockite suite consists of hypersthene and/ or diopside bearing granulite, their retrograded equivalents, hornblende granulites and ...
... charnockites and pyroxene granulites. Progressive transformation of khondalite to charnockites and retrogressive of charnockites to garnet biotite are observed. The charnockite suite consists of hypersthene and/ or diopside bearing granulite, their retrograded equivalents, hornblende granulites and ...
Range front faulting and volcanism in the Mono Basin, eastern
... taken up by faulting. Sincethe basin is extending obliquely to the trend of the frontal faults, there is a componentof dextral sheaxto their motion, so that the Mono Craters may be forming on an extensional boundary of a pull-apaxt basin. If the craters represent incipient caldera formation, then ca ...
... taken up by faulting. Sincethe basin is extending obliquely to the trend of the frontal faults, there is a componentof dextral sheaxto their motion, so that the Mono Craters may be forming on an extensional boundary of a pull-apaxt basin. If the craters represent incipient caldera formation, then ca ...
Brigham Young University Geology Studies
... A detailed map of the basaltic lava flows and their subsequent deformation was prepared after several months of field s h d y and from evaluation of high- and lowaltitude aerial photographs. These data were compiled on 1:62,500-scale Fairchild aerial photomosaics, and a final map was produced using ...
... A detailed map of the basaltic lava flows and their subsequent deformation was prepared after several months of field s h d y and from evaluation of high- and lowaltitude aerial photographs. These data were compiled on 1:62,500-scale Fairchild aerial photomosaics, and a final map was produced using ...
Cordierite in felsic igneous rocks: a synthesis
... Lipari, Aeolian Islands. Note anhedral shape, relict sector twinning, and vermicular inclusions of iron-rich glass (arrow, medium gray in ppl and black in xn) produced as the cordierite melted. (c,d) Type lb restitic cordierite (in ppl and xn, respectively) with inclusions of sillimanite in microgra ...
... Lipari, Aeolian Islands. Note anhedral shape, relict sector twinning, and vermicular inclusions of iron-rich glass (arrow, medium gray in ppl and black in xn) produced as the cordierite melted. (c,d) Type lb restitic cordierite (in ppl and xn, respectively) with inclusions of sillimanite in microgra ...
geology and mineral resources in the ojo caliente no. 2 mining
... GEOLOGIC AND TECTONIC SETTING The Ojo Caliente No. 2 mining district lies in a tectonically active and structurally complex area of the southwestern U.S. that is known for numerous types of mineral deposits associated with Eocene-Oligocene volcanic rocks. The Mogollon-Datil volcanic field is part of ...
... GEOLOGIC AND TECTONIC SETTING The Ojo Caliente No. 2 mining district lies in a tectonically active and structurally complex area of the southwestern U.S. that is known for numerous types of mineral deposits associated with Eocene-Oligocene volcanic rocks. The Mogollon-Datil volcanic field is part of ...
Students report
... rocks. The sequence is best visible at the Fortification Hill (east to southeast of Lake Mead); it consists of coarse, red Miocene sandstones on the foot, overlain by a large basaltic lava flow (Fortification Hill basalt). Located further east are the Black Mountains, where Miocene plutonic and volc ...
... rocks. The sequence is best visible at the Fortification Hill (east to southeast of Lake Mead); it consists of coarse, red Miocene sandstones on the foot, overlain by a large basaltic lava flow (Fortification Hill basalt). Located further east are the Black Mountains, where Miocene plutonic and volc ...
Magnetic Mineralogy of Continental Deposits, San Juan Basin, New
... difficult. Because of the chemical changes that occur while these clay-rich rocks are heated, it is also difficult to perform useful progressive thermal demagnetizations. In addition, Tertiary continental sedimentary sequences are commonly devoid of sedimentary or tectonic structures, so that field ...
... difficult. Because of the chemical changes that occur while these clay-rich rocks are heated, it is also difficult to perform useful progressive thermal demagnetizations. In addition, Tertiary continental sedimentary sequences are commonly devoid of sedimentary or tectonic structures, so that field ...
A new model of lunar crust: asymmetry in crustal composition... Tomoko Arai , Hiroshi Takeda , Akira Yamaguchi
... (roughly half of the crustal rocks) has a higher modal abundance of plagioclase feldspar (> modal 90 vol%) and lower Mg/(Mg+Fe) ratios than the other group. Rocks belonging to the former group are designated as ferroan anorthosites (FAN), while those of the latter include Mg-suite rocks plus some ro ...
... (roughly half of the crustal rocks) has a higher modal abundance of plagioclase feldspar (> modal 90 vol%) and lower Mg/(Mg+Fe) ratios than the other group. Rocks belonging to the former group are designated as ferroan anorthosites (FAN), while those of the latter include Mg-suite rocks plus some ro ...
Gravity modeling of the lithosphere in the Calatrava
... The origin of the intraplate volcanism in the Calatrava Volcanic Province (CVP) is controversial. On the basis of its geochemical signature, it has been ascribed to an “aborted” rift, implying lithospheric thinning. However, the volcanism occurred during the generalized Cenozoic NW−SE-oriented compr ...
... The origin of the intraplate volcanism in the Calatrava Volcanic Province (CVP) is controversial. On the basis of its geochemical signature, it has been ascribed to an “aborted” rift, implying lithospheric thinning. However, the volcanism occurred during the generalized Cenozoic NW−SE-oriented compr ...
The Asia–Kohistan–India Collision: Review and Discussion
... and Karakoram (Eurasian) plates, the Kohistan Complex is bound by two suture zones: the Karakoram– Kohistan Suture (KKS), to the north, and the Indus Suture (IS), to the south. In this paper, the term Shyok Suture is avoided to describe the KKS because the Shyok is a river several hundred kilometres ...
... and Karakoram (Eurasian) plates, the Kohistan Complex is bound by two suture zones: the Karakoram– Kohistan Suture (KKS), to the north, and the Indus Suture (IS), to the south. In this paper, the term Shyok Suture is avoided to describe the KKS because the Shyok is a river several hundred kilometres ...
Tectonic Framework of Basin Evolution in Peru
... structural inversion. It is, thus, essential that any exploration strategy be built upon a thorough understanding of basin dynamics. There are two important elements that control basin formation. Subsidence of a sedimentary basin depends in some way upon the interaction of regional stress fields wit ...
... structural inversion. It is, thus, essential that any exploration strategy be built upon a thorough understanding of basin dynamics. There are two important elements that control basin formation. Subsidence of a sedimentary basin depends in some way upon the interaction of regional stress fields wit ...
2. Geophysics and the Structure of the Lesser Antilles Forearc
... The accretionary complex can be divided into zones running parallel to the arc, starting with a zone of initial accretion at the front of the complex where sediment is stripped from the ocean floor and the rate of deformation is greatest. This zone passes into one of stabilization where the deformat ...
... The accretionary complex can be divided into zones running parallel to the arc, starting with a zone of initial accretion at the front of the complex where sediment is stripped from the ocean floor and the rate of deformation is greatest. This zone passes into one of stabilization where the deformat ...
Thermal evolution of the Earth as recorded by komatiites
... generation, and therefore provide important constraints on mantle conditions throughout Earth history. It is here that komatiites have played an important role, because their compositional characteristics have been used to trace mantle melting depths, temperatures and processes back into the Archean ...
... generation, and therefore provide important constraints on mantle conditions throughout Earth history. It is here that komatiites have played an important role, because their compositional characteristics have been used to trace mantle melting depths, temperatures and processes back into the Archean ...
A Geology Training Manual for Grand Canyon National
... research and education, it has been a window into the past, revealing vast ...
... research and education, it has been a window into the past, revealing vast ...
From rifting to oceanic spreading in the Gulf of Aden: a synthesis
... parallel to the inherited grabens. Only the transfer faults crosscut the inherited grabens, and some of these faults later developed into transform faults. The most important of these transform faults follow a Precambrian trend. Volcanic margins were formed in the west of the Gulf, up to the Guban g ...
... parallel to the inherited grabens. Only the transfer faults crosscut the inherited grabens, and some of these faults later developed into transform faults. The most important of these transform faults follow a Precambrian trend. Volcanic margins were formed in the west of the Gulf, up to the Guban g ...
Gold and platinum group minerals in drainage between the river
... Leveridge, pers. comm. 1989). The strata dip generally southwards at moderate angles with some areas were dip increases to vertical. Units are separated by south-dipping thrusts trending between 070 and 090 degrees which are displaced by later faulting. Two directions of major faulting are prominent ...
... Leveridge, pers. comm. 1989). The strata dip generally southwards at moderate angles with some areas were dip increases to vertical. Units are separated by south-dipping thrusts trending between 070 and 090 degrees which are displaced by later faulting. Two directions of major faulting are prominent ...
OKINAWA TROUGH: ORIGIN OF A BACK
... upper sediment section beneath the trough floor, unconformably overlying a highly faulted lower section which has a velocity of 4.9 km/sec. Exceptions to this structural relationship are fault grabens cutting the upper section along the axial and southeastern regions of the trough and normal faults ...
... upper sediment section beneath the trough floor, unconformably overlying a highly faulted lower section which has a velocity of 4.9 km/sec. Exceptions to this structural relationship are fault grabens cutting the upper section along the axial and southeastern regions of the trough and normal faults ...
The origin of Mount St. Helens andesites
... features of representative lavas erupted during the past 2200 years can distinguish three basaltic and three andesitic variants. The mafic lavas include: (a) transitional, olivine + plagioclase basalts with low K2O and incompatible trace-element abundances: (b) calc-alkaline, olivine + plagioclase ± ...
... features of representative lavas erupted during the past 2200 years can distinguish three basaltic and three andesitic variants. The mafic lavas include: (a) transitional, olivine + plagioclase basalts with low K2O and incompatible trace-element abundances: (b) calc-alkaline, olivine + plagioclase ± ...
Kurzlaukis and Lorenz_Gibeon Volcanic Field
... are also observed. These diapirs point inwards from the dike margins and suggest relatively slow cooling after emplacement of the dike. Most diatremes are located on and cut downwards into dikes and, therefore, the dikes in all probability represent the feeders for the diatremes. The diatremes are o ...
... are also observed. These diapirs point inwards from the dike margins and suggest relatively slow cooling after emplacement of the dike. Most diatremes are located on and cut downwards into dikes and, therefore, the dikes in all probability represent the feeders for the diatremes. The diatremes are o ...
Use of Hydrothermal Mineralogy and Geological Structures in
... Generally, permeability is low in the West field and its distribution is strongly controlled by the lithostratigraphic contacts, fractured lava and fault zones. The fault zones show higher permeability with wells drilled within the structures having larger total mass outputs with some wells producin ...
... Generally, permeability is low in the West field and its distribution is strongly controlled by the lithostratigraphic contacts, fractured lava and fault zones. The fault zones show higher permeability with wells drilled within the structures having larger total mass outputs with some wells producin ...
Applications of PGE Radioisotope Systems in Geo
... In addition, the now-extinct isotope 107Pd decays to 107Ag tell geologic time. For this purpose, the remarkable success (half-life = 6.5 × 106 y) (TABLE 1). A key feature of these systems of PGE-based systems is based on their application to mateis that they track the unique chemical behavior of the ...
... In addition, the now-extinct isotope 107Pd decays to 107Ag tell geologic time. For this purpose, the remarkable success (half-life = 6.5 × 106 y) (TABLE 1). A key feature of these systems of PGE-based systems is based on their application to mateis that they track the unique chemical behavior of the ...
Origin and consequences of western Mediterranean subduction
... et al. [2011] and van Hinsbergen and Schmid [2012]. Most importantly, our reconstruction allows for burial of sediments that are now metamorphosed (i.e., units disappear from the surface) and their subsequent exhumation (i.e., units reappear to the surface). This approach differs from recent reconst ...
... et al. [2011] and van Hinsbergen and Schmid [2012]. Most importantly, our reconstruction allows for burial of sediments that are now metamorphosed (i.e., units disappear from the surface) and their subsequent exhumation (i.e., units reappear to the surface). This approach differs from recent reconst ...
Peridotite and Metabasic Rocks of the Marianské Lázně
... plagioclase + sodic augite ± amphibole symplectite, garnet by plagioclase + amphibole ± sodic augite kelyphite, kyanite by spinel and plagioclase, which contains lamellar sapphirine and corundum, and rutile by titanite; locally, coronas of sodic augite + orthopyroxene + plagioclase + amphibole occur ...
... plagioclase + sodic augite ± amphibole symplectite, garnet by plagioclase + amphibole ± sodic augite kelyphite, kyanite by spinel and plagioclase, which contains lamellar sapphirine and corundum, and rutile by titanite; locally, coronas of sodic augite + orthopyroxene + plagioclase + amphibole occur ...
47. the ocean/continent transition beneath the iberia abyssal plain
... the ocean/continent transition is defined by an 80- to 130-km-wide region beneath the Iberia Abyssal Plain between the most oceanward-tilted basement fault blocks (continental crust?) and a 300-km-long narrow peridotite ridge parallel to the margin. Leg 149 drilled a west-to-east transect of holes a ...
... the ocean/continent transition is defined by an 80- to 130-km-wide region beneath the Iberia Abyssal Plain between the most oceanward-tilted basement fault blocks (continental crust?) and a 300-km-long narrow peridotite ridge parallel to the margin. Leg 149 drilled a west-to-east transect of holes a ...
Algoman orogeny
The Algoman orogeny, known as the Kenoran orogeny in Canada, was an episode of mountain-building (orogeny) during the Late Archean Eon that involved repeated episodes of continental collisions, compressions and subductions. The Superior province and the Minnesota River Valley terrane collided about 2,700 to 2,500 million years ago. The collision folded the Earth's crust and produced enough heat and pressure to metamorphose the rock. Blocks were added to the Superior province along a 1,200 km (750 mi) boundary that stretches from present-day eastern South Dakota into the Lake Huron area. The Algoman orogeny brought the Archaen Eon to a close, about 2,500 million years ago; it lasted less than 100 million years and marks a major change in the development of the earth’s crust.The Canadian shield contains belts of metavolcanic and metasedimentary rocks formed by the action of metamorphism on volcanic and sedimentary rock. The areas between individual belts consist of granites or granitic gneisses that form fault zones. These two types of belts can be seen in the Wabigoon, Quetico and Wawa subprovinces; the Wabigoon and Wawa are of volcanic origin and the Quetico is of sedimentary origin. These three subprovinces lie linearly in southwestern- to northeastern-oriented belts about 140 km (90 mi) wide on the southern portion of the Superior Province.The Slave province and portions of the Nain province were also affected. Between about 2,000 and 1,700 million years ago these combined with the Sask and Wyoming cratons to form the first supercontinent, the Kenorland supercontinent.