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Showing 1 to 18 of 18 for “"crustal assimilation"”.
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Quantifying Crustal Assimilation in Historical to Recent (1329-2005) Lavas at Mt. Etna, Italy: Insights from Thermodynamic Modeling
… enrichment, two major arguments are invoked: (1) crustal contributions (e.g., assimilation of the sedimentary basement), and (2) changes in the mantle source, possibly due to increased interaction between the mantle source and subduction related fluids, and/or a mantle source that was melted to …
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Mineral-Scale Sr Isotopic Study of Plagioclase in the Mafic Dikes of the North American Wall and the Diorite of the Rockslides, Yosemite Valley, California.
… for the mantle, indicating the presence of a crustal component in the system. Plagioclase phenocrysts within each unit display bimodal compositional populations. Subhedral to euhedral partially resorbed calcic cores (mode = An84-88) are reminiscent of a mafic magma, while sodic rims (mode = …
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A multi-isotopic geochemical investigation of the Lower Zone, Bushveld Complex, South Africa: implications for a crustal component for parental magmas
… and isotopic systems to determine the origin of crustal signatures, i.e. crustal assimilation or recycled crust in the mantle source, present throughout the Rustenburg Layered Suite (RLS) such as elevated 18O values. These geochemical and isotopic systems include major elements, trace elements, …
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The petrogenesis of the Pliocene Araral stratovolcano in the Andean Central Volcanic Zone, Northern Chile
… and magma differentiation processes, such as crustal assimilation as the magma ascends through the thick crust. The APMB is a large regional melt anomaly proposed to be the source of APVC ignimbrites and the lavas of the APVC have a decreased degree of interaction with the APMB towards its …
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The Role of Cumulate Plagioclase Entrainment in the Steens Basalt, SE Oregon: Insights from the Magma Chamber Simulator
… insight into magmatic processes like recharge, crustal assimilation, cumulate entrainment, and fractional crystallization. Because large and abundant plagioclase are found in other flood basalt provinces worldwide, these results could also enhance understanding of magma evolution and storage …
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Timing and Source of Alkali Enrichment at Mt. Etna, Sicily: Constraints from Clinopyroxene Geobarometry and In Situ SR Isotope Data
… with end-member hypotheses involving mantle vs. crustal contributions. To further characterize the evolution of the subvolcanic magma storage and transport system, as well as the timing and source of alkali-enrichment, clinopyroxene from ten samples erupted between 1329 and 2004 was targeted for …
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Decarbonization related to continental arc magmatism as a possible mechanism for Cretaceous warming
… specifically as a volatile produced during crustal assimilation and contact metamorphism of carbonates around plutons. Bedrock maps of the North American Cordillera (a region of active continental arc magmatism during the Cretaceous), the relative locations of the carbonates, the Cretaceous …
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Origin and evolution of parental magmas associated with Pliocene-Quaternary low-silica volcanism within the Altiplano-Puna Volcanic Complex of northern Chile
… eruption products reflect varying degrees of crustal assimilation. Physical interactions between mafic and felsic magmas for this arc are therefore difficult to recognize due to the differentiation of mantle-derived magma during ascent through the thickened crust and a corresponding lack of …
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The petrogenesis and geochemistry of the Namaqualand olivine melilitite pipe cluster, western South Africa
… experienced significant (e.g., more than 5-10%) assimilation of local continental crust. The Namaqualand melilitites are characterized by extraordinarily high and variable Nb/Rb and U/Th ratios, and correlations with other elements indicate that these ratios have been affected by variable …
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Evolution of a Flood Basalt Crustal Magmatic System: In Situ Mineral Data and Computational Modeling of the Steens Basalt
… excellent opportunity to quantify how mantle and crustal influences change during a long-lived, large volume mafic magmatic event. Computational modeling of whole-rock and mineral compositional changes up-section in Steens Basalt using MELTS and the Magma Chamber Simulator indicates that recharge, …
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Oxygen and radiogenic isotope constraints on the generation of coexisting silica-undersaturated and oversaturated felsic magmas of the Ditrau Alkaline Massif (Romania)
… with the oversaturated rocks being produced by crustal assimilation (Foland et al., 1993); (2) both are derived from the same mantle source, but do not evolve from the same parental melt (Giret and Lameyre, 1985); (3) the sources are heterogeneous on a scale that allows undersaturated and …
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Documenting Mantle and Crustal Contributions to Flood Basalt Magmatism via Computational Modeling of the Steens Basalt, Southeast Oregon
… Results from the Energy-Constrained Recharge Assimilation Fractional Crystallization (EC-RAFC) computational modeling tool make predictions about the relative roles that magmatic processes (recharge, assimilation, and fraction crystallization) have in time (upsection), thus yielding estimates …
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Spatially controlled Fe isotope variations at Torres Del Paine
… been suggested to reflect four mechanisms: (1) crustal assimilation, (2) fractional crystallization, (3) late stage fluid exsolution and (4) thermal migration. Assimilation of isotopically light country rock would not produce the isotopically heavy Torres del Paine granites. Likewise, …
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Martian meteorites as windows into planetary volcanism: insights from olivine-phyric shergottite meteorites
… parent melts and evaluate the possibility of crustal assimilation or open system processes during evolution. To do this, in chapter 3 I present the first full REE dataset for Mg-rich olivine in shergottites in a comprehensive suite of depleted, intermediate, and enriched olivine-phyric …
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Origin of the Kleva Ni-Cu sulphide mineralisation in Småland, southeast Sweden
… Evidence for contamination of the magma through crustal assimilation during its ascent are inconclusive. Low IPGE/Ni together with high S/Se, indicate sulphide melt saturation prior to final emplacement, possibly induced by crustal contamination. Nb/La vs La/Sm indicate contamination with …
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The thermal evolution of subduction zone lithosphere: Evidence from the chemical development of Mt. Ruapehu and surrounding vents, New Zealand.
… the TVZ. A detailed study of volcanic rocks and crustal xenoliths collected from Mt. Ruapehu and nearby satellite vents was conducted to establish how differentiation processes in arc magmas change with time in response to tectonic movements in the arc lithosphere. The thickness and composition …
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Stratigraphy and petrogenesis of the Parana continental flood basalts, southern Brazil
… The Gramado magma type is dominated by AFC (assimilation / fractional crystallisation), and the geochemical variations are consistent with taking an average Palmas rhyolite composition (the best estimate of a local crustal melt) to be the contaminant. Within the southern Paraná region, the …
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B isotope variations at variable scales in arc volcanoes: a case study of lavas from Paniri and Toconce, Northern Chile
… lavas assimilated most of the 11B-depleted crustal material locally available, with lava δ11B compositions trending towards basement granitoids and metasediments δ11B values (-11 ‰ to -5 ‰). With continued eruption, lavas progressively contain more 11B-enriched values reflecting parental …