Zircon U–Pb geochronology, major-trace elements and Sr–Nd isotope geochemistry of Mashhad granodiorites (NE Iran) and their mafic microgranular enclaves: evidence for magma mixing and mingling Maryam Deyhimi a School of Geology, College of Science, University of Tehran, Tehran, Iran View further author …
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Petrogenesis of high Mg# adakitic rocks in intracontinental settings is still a matter of debate. This paper reports major and trace element, whole-rock Sr-Nd isotope, zircon U-Pb and Hf isotope data for a suite of adakitic monzogranite and its mafic microgranular enclaves (MMEs) at Yangba in the northwestern margin of the South China Block. …
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Detailed images of the mixing features present at Grizzly Lake (Yellowstone) (a, b) and Soufrière Hills volcano (Montserrat) (c, d).Figure 1a shows the rhyolitic magma (white) has apparently intruded into the basaltic magma and the hybrid portions are present at the contact between the two end-members. Two large basaltic enclaves are visible at …
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Geochemical modeling of magma mixing allows for evaluation of volumes of magma storage reservoirs and magma plumbing configurations. A new analytical expression is derived for a simple two-component box-mixing model describing the proportions of mixing components in erupted lavas as a function of time. Four versions of this model are …
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Magma mixing is probably the dominant means of contamina- tion; but assimilation of solid rock is also a proven process (Eichelberger, 1975}. Commonly sufficient record remains in the texture of glassy rocks to permit a sound choice between alternatives. In cases where magma mixing can be inferred, portions of crystals which …
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These results suggest that magma mixing between basaltic andesite and the rhyolite magma at a depth of two to three kilometers is the principal process for the calc alkaline series of Koru Volcanics. In Biga Peninsula, Turkey, Tertiary volcanism (34.3±1.2 and 0.4±0.7 Ma) has produced tuffs and agglomerates of trachytic, latitic, dacitic and ...
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Since the first hypothesis, evidences of magma mixing processes have been accumulated in the literature allowing this natural phaenomenon to be defined as fundamental petrological processes playing a role in activating volcanic eruptions and generating compositional variability in igneous systems. Here, we review the key concepts to …
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Field relations and whole-rock geochemistry indicate that magma mixing has been important in the genesis of the late Mesozoic I-type igneous complexes at Pingtan and Tonglu in SE China. Morphological and trace-element studies of zircon populations in rocks from each of these complexes have defined several distinct growth stages [Mineral. …
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Research Institute of Earthquake and Volcano Geology, Geological Survey of Japan, AIST, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8567, Japan. 2. ... Magma mixing …
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Magma mixing is the key to revealing deep geodynamic processes. High Ba-Sr granitoids (Ba > 500 ppm; Sr > 300 ppm) are initially defined as products that reflect the entrainment of mantle sources into the melting zone, which could provide constraints for magma mixing. Here, we collected a suite of spatiotemporally correlated high Ba-Sr granitoids …
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Sample 9 is from a lava dome or flow in the wall of the summit crater and dated by K–Ar yielding a whole-rock age of 0·27 ± 0·006 Ma (Duffield et al., 1984).Sample 5a is a bread-crust bomb on top of a pyroclastic flow southwest of the summit (McGee et al., 1987).Major and minor elements of both samples were performed by J. Taggert at US …
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An apparent association of extensive basalt-rhyolite magma mixing with a proclivity for effusive eruptive behavior suggests a potential control on the extent of reservoir degassing. We show that the very …
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The origin of mafic enclaves in granitoid plutons has long been a matter of debate. In this paper, we present detailed petrographic, mineralogical, geochemical, and Srsbnd Ndsbnd Hf isotopic data, Usbnd Pb zircon dates, and field and petrological observations, for mafic microgranular enclaves (MMEs) and their host quartz monzonites from the Muchen …
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The 1875 plinian eruption of Askja, Iceland is an example of an explosive eruption triggered by magma mixing. Nature - Magma mixing: a mechanism for …
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Intrusive complexes with compositional diversity commonly document magma mixing processes and provide insights into regional magmatism and tectonics. Here, we present an integrated study involving detailed field investigations, petrography, mineral chemistry, whole-rock geochemistry, Srsbnd Nd isotopic compositions, and zircon U-Pb-Hf …
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adshelp[at]cfa.harvard.edu The ADS is operated by the Smithsonian Astrophysical Observatory under NASA Cooperative Agreement NNX16AC86A
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2.1 Deciphering Magma Chamber Evolution and Estimation of Eruptive Activity Using Magma Mixing. In Chap. 7 we have discussed the occurrence of magmatic enclaves in the Pietre Cotte lava flow, erupted on the Island of Vulcano (Aeolian Islands, Italy) in A.D. 1739. Here latitic enclaves are dispersed in an obsidian rhyolitic mass (Fig. …
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Magma in Earth's crust is in a crystal-rich mushy state, yet must be fluidized before eruptions. Numerical simulations show that rapid injection of new magma into a reservoir creates a mixing ...
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This type of magma mixing may result in crystal resorption, thus invalidating an assumption that resorption textures in crystals are typically the result of a magma heating event; (3) illustration of the differing effects of stoped block temperature and composition on hybrid magma temperature and phase state; and (4) illustration of a …
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We present coupled textural, elemental, and boron isotopic data of tourmaline from the large Zhunuo-Beimulang collision-related porphyry copper deposits (PCDs) located within the western Gangdese, Tibet. Based on morphology and high-resolution mapping, the tourmaline is classified into three paragenetic generations. The first generation of …
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The above discussed textural and structural evidence of magma mixing is the consequence of variations in the geochemical composition of the magmatic system. There is general consensus that linear trends in binary plots (for any couple of major or trace elements) point to magma mixing …
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A small amount of rhyolitic magma is entrained into the lower basaltic magma layer, and two magmas can mix essentially in a liquid state. The mixed dacitic magma is formed in the lower layer. The second stage is mixing caused by forced convection during the ascent through a conduit just before eruption.
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Irvine, T. N. (1986) Magma mixing and the origin of the stratiform oxide zones in the Bushveld and Stillwater complexes, in B. Carter (ed), Metallogeny of basic and ultrabasic rocks, Institute of Mining and Metallurgy, ... Western Australia, Institution of Mining and Metallurgy, London, ...
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Sulfide immiscibility probably was caused by mixing of fractionated residual melt with more primitive liquid, which periodically intruded the magma chamber. Evidence of mixing is seen in gradational chemical variations across the interface of cyclic units and in the occurrence of inclusions of olivine crystals and crystal aggregates in ...
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Try logging in through your library or institution to get access to these tools. Find your institution now. ... Role of magma mixing in the petrogenesis of tephra erupted during the 1990-98 explosive activity of Nevado Sabancaya, southern Peru. Gerbe, Marie-christine; Thouret, Jean-claude. Bulletin of Volcanology; Heidelberg Vol. 66, Iss. 6 ...
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Timing of granitic magma mixing in the southeastern Gyeongsang Basin, Korea: SHRIMP-RG zircon data Byoung-Hoon Hwang Nuclear Physics and Radiation Technology Institute, Pusan National University, Busan, South Korea; Department of Geological and Environmental Sciences, Stanford University, Stanford, CA, USA …
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Detailed images of the mixing features present at Grizzly Lake (Yellowstone) (a, b) and Soufrière Hills volcano (Montserrat) (c, d).Figure 1a shows the rhyolitic …
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Postcollisional mafic igneous rocks commonly exhibit petrological and geochemical heterogeneities, but their origin still remains enigmatic. While source mixing is substantial due to the crust-mantle interaction during continental collision, magma mixing is also significant during postcollisional magmatism. The two processes are illustrated by Early …
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Typically, magma mixing/mingling occurs during replenishment by a mafic magma of a felsic and mushy reservoir 8,9,10,11,12,13,14, either deep or shallow, …
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The mixing time (t mix) is defined as the time required for the intensity of segregation to decay to a certain value. Magma mixing occurs by complex time-dependent flows with …
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