منابع مشابه
Petrology and geochemistry of lavas
“This continuity disappears, however, if one considers individual parts of the [Central American] chain and examines separate groups of volcanoes within a restricted volcanic field. It then becomes apparent that the continuity of the province as a whole is the result of grouping excessively large segments of the chain.” A.R. McBirney: Compositional variations in Cenozoic calcalkaline suites of ...
متن کاملOxygen Isotope Geochemistry of Oceanic-Arc Lavas
Variations of oxygen isotope ratios in arc-related lavas can constrain trace-element enrichment in a mantle source being fluxed by addition the contributions of subducted crustal igneous rocks, sediments, and of aqueous fluid. Comparison of this model with observed variations fluids to the sub-arc mantle. We have measured oxygen isotope in the geochemistry of lavas from the Vanuatu–Fiji–New Cal...
متن کاملThe hottest lavas of the Phanerozoic
The mantle plume hypothesis is widely accepted for the formation of large igneous provinces and many modern day hotspot volcanoes. Petrologic models suggest that plume-derived melts originate at high mantle temperatures (>1500 °C) relative to those generated at ambient midocean ridge conditions (~1350 °C). Earth’s mantle has also appreciably cooled during its history due to heat loss and decrea...
متن کاملEarly life recorded in archean pillow lavas.
Pillow lava rims from the Mesoarchean Barberton Greenstone Belt in South Africa contain micrometer-scale mineralized tubes that provide evidence of submarine microbial activity during the early history of Earth. The tubes formed during microbial etching of glass along fractures, as seen in pillow lavas from recent oceanic crust. The margins of the tubes contain organic carbon, and many of the p...
متن کاملMetasomatized lithosphere and the origin of alkaline lavas.
Recycled oceanic crust, with or without sediment, is often invoked as a source component of continental and oceanic alkaline magmas to account for their trace-element and isotopic characteristics. Alternatively, these features have been attributed to sources containing veined, metasomatized lithosphere. In melting experiments on natural amphibole-rich veins at 1.5 gigapascals, we found that par...
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ژورنال
عنوان ژورنال: Places Journal
سال: 2019
ISSN: 2164-7798
DOI: 10.22269/191001