نتایج جستجو برای: magmatic association
تعداد نتایج: 509311 فیلتر نتایج به سال:
Stratabound deposits within late Carboniferous carbonate units in the Middle–Lower Yangtze River metallogenic belt are important copper producers in China. Hitherto, the genesis of these deposits has been debated, due to poor constraints regarding the timing and source of the mineralization. Proposed models include a late Carboniferous seafloor exhalative formation (SEDEX), or an Early Cretaceo...
The phyllic alteration in a number of circum-Pacific porphyry Cu-Au deposits is related to high-temperature saline magmatic fluids. This contradicts the widely used genetic models wherein phyllic alteration formed as the result of mixing between magmatic and meteoric fluids. At the Endeavour 26 North porphyry deposit in eastern Australia, the transition from early potassic to the main-stage phy...
Continental rifting and seafloor spreading play a fundamental role in the generation of new crust. However, the distribution of magma and its relationship with tectonics and volcanism remain poorly understood, particularly in back-arc settings. We show evidence for a large, long-lived, off-axis magmatic intrusion located on the margin of the Taupo Volcanic Zone, New Zealand. Geodetic data acqui...
This contribution illustrates the procedures of calculating rare earth element (REE) patterns of magmatic fluids in equilibrium with granitic melts. These patterns can then be compared to those of altered and (or) mineralized rocks in order to investigate the source of the ore-fluids. This technique is applied to the Lake George Sb-Au-W-Mo mineral deposit, New Brunswick, Canada. The results sug...
A tephrostratigraphy of the active Antarctic volcano, Mt. Erebus, was determined from englacial tephra on the ice-covered flanks of Erebus and an adjacent volcano. The tephra are, used to reconstruct the eruptive history and magmatic evolution of Erebus. Scanning electron microscope images and Image Particle Analysis suggest the tephra formed in phreatomagmatic and magmatic eruptions and in som...
We explore the potential effects of magmatic assimilation on mineral growth and mineral zoning in an alkali olivine basaltic magma using both equilibrium thermodynamics and kinetics. The equilibrium-model calculations simulate fractional crystallization alone (closed system) and coupled assimilation fractional crystallization (AFC) (open system); the models predict the assemblages ofmagmatig mi...
Since water is only composed of oxygen and hydrogen, δ18O and δ2H values are thus utilized to trace the origin of water(s) and quantify the water-rock interactions. While Triassic high pressure (HP) and ultrahigh pressure (UHP) metamorphic rocks across the Dabie-Sulu orogen in central-eastern China have been well documented, postcollisional magmatism driven hydrothermal systems are little known...
Floor-fractured craters are a class of lunar crater hypothesized to form in response to the emplacement of a shallow magmatic intrusion beneath the crater floor. The emplacement of a shallow magmatic body should result in a positive Bouguer anomaly relative to unaltered complex craters, a signal which is observed for the average Bouguer anomaly interior to the crater walls. We observe the Bougu...
Magmatic density and viscosity exert fundamental controls on the eruptibility of magmas. In this study, we investigate the extent to which magmatic physical properties control the eruptibility of magmas from Iceland’s Northern Volcanic Zone (NVZ). By studying subaerial flows of known age and volume, we are able to directly relate erupted volumes to magmatic physical properties, a task that has ...
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