نتایج جستجو برای: magmatism
تعداد نتایج: 1960 فیلتر نتایج به سال:
One of the characteristic features of Ordovician tectonism in the east Lachlan Fold Belt is the occurrence of calcalkaline to shoshonitic basalts, which have been recognised as part of an intraoceanic arc environment (Glen et al. 1998), consistent with early tectonic interpretations (Oversby 1971; Scheibner 1973). Aside from typical traceelement abundances of intraoceanic arcs, critical evidenc...
During its 25 years of production from 1972 to 1998, the Gibraltar Cu-Mo mine in east-central British Columbia (Figure 1) milled a total of 324 million tons of ore containing an average 0.351% Cu from four open pits. Fieldwork during 2000 involved just over two weeks of detailed pit mapping at the mine. Results of this work and several earlier intervals of pit mapping conducted in 1998 and 1999...
Stikine Terrane arc rocks in the re,:ion host !;(m:ral copper-gold and copper-molybdenum ocnlwerlces (MINFILE 104 G and H). The volcrrnic strat.i,:raphy hosting these deposits is, however, poorly const:aimd. The Tatogga Lake project will attemp; to characterize individual deposits, desclibe their h a 1 and rcgictnal stratigraphic and structural settings, and deternme the ages of magmatism ...
Plagioclase crystal fragments and a block of anorthosite occur in small basaltic dykes on the Jos Plateau. The anorthosite is unusual, for the feldspar is labradoritic, but the interstitial mineralogy is granitic rather than basic, displaying granophyric intergrowths in places. The anorthosite is probably not an intermediate stage in fractionation from a basic parent magma towards granite, sinc...
The earliest history of the Moon is poorly preserved in the surface geologic record due to the high flux of impactors, but aspects of that history may be preserved in subsurface structures. Application of gravity gradiometry to observations by the Gravity Recovery and Interior Laboratory (GRAIL) mission results in the identification of a population of linear gravity anomalies with lengths of hu...
Silicic calderas form during explosive volcanic eruptions when magma withdrawal triggers collapse along bounding faults. The nature of specific interactions between magmatism and tectonism in caldera-forming systems is, however, unclear. Regional stress patterns may control the location and geometry of magma reservoirs, which in turn may control the spatial and temporal development of faults. H...
In this review, we attempted to summarize and interpret the Phanerozoic geology mineralization following article (vol. 71 in Resource Geology) which reviewed Precambrian of North Korea. The basement Korean peninsula was built during gradually became more evolved complex Phanerozoic. northern part active passive continental margins Korea–China platform tectonic environments Phanerozoic, province...
gabal el-zeit block at the western coast of the gulf of suez region in egypt consists of two varieties of precambrian granites, namely monzogranite and a peripheral zone of alkali granite. both granitic varieties display moderate (60.1-68.5 wt%) and high silica (73.36-76.16 wt%) contents with high na2o+k2o (7.21-8.61 wt%), respectively. the investigated monzogranite is calc-alkaline metaluminou...
Samples returned from the surface of planetary bodies are both complementary to orbital and in situ observations and provide a unique perspective for understanding the nature and evolution of that body. This unique perspective is based on the scale the sample is viewed (mm– ( A), the ability to manipulate the sample, the capability to analyze the sample at high precision and accuracy, and the a...
A program of geologic mapping and lithogeochemical and geochronological sampling has been carried out over a 745-km area of the Atacama Desert surrounding the porphyry Cu deposits at Escondida, Zaldívar, and Chimborazo (Cordillera de Domeyko, northern Chile). The purpose of this study was to examine the regional tectonic and magmatic setting of this preeminent porphyry Cu district for evidence ...
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