Volcanic plumbing filters on ocean-island basalt geochemistry
| العنوان: | Volcanic plumbing filters on ocean-island basalt geochemistry |
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| المؤلفون: | Teresa Ubide, Patricia Larrea, Carlos Galé, Laura Becerril |
| المصدر: | Geology. 50:26-31 |
| بيانات النشر: | Geological Society of America, 2022. |
| سنة النشر: | 2022 |
| مصطلحات موضوعية: | geography, geography.geographical_feature_category, Volcano, Geochemistry, Geology, Ocean island basalt |
| الوصف: | Ocean-island basalts (OIBs) are considered to be messengers from the deep mantle, yet the filtering effect of the plumbing systems that bring OIB melts to the surface remains poorly assessed. We investigated volcanic products from El Hierro island (Canary Islands) from textural and chemical perspectives. The majority of geochemical data cluster at relatively fractionated basaltic compositions of 5 wt% MgO. Compositions ≥10 wt% MgO are porphyritic whole rocks that accumulate mafic minerals. Near-primary melts do not erupt. Instead, we show that carrier melts (crystal-free whole rocks, glasses, and melt inclusions) are consistently buffered to low-MgO compositions during passage through the plumbing system. We tested our model of melt fractionation and crystal accumulation on a global compilation of OIBs. Similar to El Hierro, the majority of data cluster at evolved compositions of 5 wt% MgO (alkaline) to 7 wt% MgO (tholeiitic). Modeling the fractionation of OIB parental melts, we show that with 50% crystallization, OIB melts reach 5 wt% MgO with reduced density, increased volatile content, and overall low viscosity, becoming positively buoyant relative to wall rocks and highly eruptible when reaching volatile saturation at depths around the crust-mantle boundary. Under these conditions, 5 wt% MgO OIB “sweet spot” melts are propelled to the surface and erupt carrying an assortment of recycled crystals. This mechanism is consistent with the petrography and chemistry of erupted products and suggests OIB volcanoes are dominated by low-MgO basaltic melts. |
| تدمد: | 1943-2682 0091-7613 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_________::487bc375bed474b78bc8c4db6d108f2f https://doi.org/10.1130/g49224.1 |
| حقوق: | OPEN |
| رقم الأكسشن: | edsair.doi...........487bc375bed474b78bc8c4db6d108f2f |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 19432682 00917613 |
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