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- W4207039621 startingPage "71" @default.
- W4207039621 abstract "Corundum megacrysts from Cenozoic alkaline basaltic fields, notably in eastern Asia and Australia, are economically important but poorly understood in their genesis. Here we present new crushing noble gas (He, Ne and Ar) data of alkali basalt-related corundum and some other mineral megacrysts from several localities worldwide to better constrain their ultimate fluid (material) source and forming process. Markedly, the corundum megacrysts have widespread mid ocean ridge basalts (MORB)-like 3 He/ 4 He ratios (8 ± 1 R A , where R A is atmospheric 3 He/ 4 He ratio of 1.39 × 10 −6 ) in each locality, although lower than MORB 3 He/ 4 He ratios also occur in some cases. The latter could be interpreted as the addition of ingrowth 4 He but not reflect the initially trapped compositions. The initially MORB-like 3 He/ 4 He and high 40 Ar/ 36 Ar isotopic ratios, combined with major element and fluid inclusion data, support that the asthenosphere-derived melts/fluids are the primary source for their formation, which is genetically related to the generation of the Cenozoic continental alkaline basalts and mafic megacrysts like clinopyroxene and garnet. Elemental fractionation between helium and argon, enriched in helium compared to the current mantle production value, was observed in most blue-green-yellow (BGY) sapphires, notably for the samples from Changle, eastern China and Ban Huai Sai, Laos. However, the blue sapphires from Wenchang, China do not show such an enrichment. The elevated 4 He/ 40 Ar* ( 40 Ar* is radiogenic Ar corrected for atmospheric Ar) ratios are interpreted as a solubility-controlled fractionation during magma degassing. Based on the degree of fractionation, the degassing scheme is most likely to be a single-stage process in closed systems (e.g., in a magma chamber), and the original volatile (assuming pure CO 2 ) content of the parental melts before vesiculation is estimated to be ∼3.5 wt.% in minimum. The degassing process may have caused a sudden Al-saturation of the parental magma and facilitated the crystallization of sapphires by losing alkalis from the magma and decreasing the system's temperature. However, the “degassing” model, so far, has limitations to interpret the Wenchang data. After crystallization of the BGY sapphires at depths of deep to middle crust levels, a new pulse of alkaline basaltic melt carries them to the surface." @default.
- W4207039621 created "2022-01-26" @default.
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- W4207039621 date "2022-04-01" @default.
- W4207039621 modified "2023-10-13" @default.
- W4207039621 title "Helium, neon and argon in alkaline basalt-related corundum megacrysts: Implications for their origin and forming process" @default.
- W4207039621 cites W1669472802 @default.
- W4207039621 cites W1971453987 @default.
- W4207039621 cites W1981838028 @default.
- W4207039621 cites W1981971984 @default.
- W4207039621 cites W1982928408 @default.
- W4207039621 cites W1982978456 @default.
- W4207039621 cites W1983199689 @default.
- W4207039621 cites W1983248190 @default.
- W4207039621 cites W1985501963 @default.
- W4207039621 cites W1988184583 @default.
- W4207039621 cites W1994393193 @default.
- W4207039621 cites W1997310688 @default.
- W4207039621 cites W1998350691 @default.
- W4207039621 cites W1998453907 @default.
- W4207039621 cites W1999373964 @default.
- W4207039621 cites W2001426515 @default.
- W4207039621 cites W2001869050 @default.
- W4207039621 cites W2004319141 @default.
- W4207039621 cites W2004845239 @default.
- W4207039621 cites W2004965920 @default.
- W4207039621 cites W2005195754 @default.
- W4207039621 cites W2006580726 @default.
- W4207039621 cites W2009087340 @default.
- W4207039621 cites W2009227467 @default.
- W4207039621 cites W2012017496 @default.
- W4207039621 cites W2013207924 @default.
- W4207039621 cites W2014508478 @default.
- W4207039621 cites W2016756950 @default.
- W4207039621 cites W2017299709 @default.
- W4207039621 cites W2019212611 @default.
- W4207039621 cites W2020007896 @default.
- W4207039621 cites W2020467041 @default.
- W4207039621 cites W2020537018 @default.
- W4207039621 cites W2022939468 @default.
- W4207039621 cites W2024281324 @default.
- W4207039621 cites W2025242466 @default.
- W4207039621 cites W2025592450 @default.
- W4207039621 cites W2028386031 @default.
- W4207039621 cites W2029011462 @default.
- W4207039621 cites W2029570599 @default.
- W4207039621 cites W2030661127 @default.
- W4207039621 cites W2031400338 @default.
- W4207039621 cites W2034207475 @default.
- W4207039621 cites W2035305023 @default.
- W4207039621 cites W2036172342 @default.
- W4207039621 cites W2036198033 @default.
- W4207039621 cites W2036704484 @default.
- W4207039621 cites W2037117034 @default.
- W4207039621 cites W2037293419 @default.
- W4207039621 cites W2040295368 @default.
- W4207039621 cites W2040666238 @default.
- W4207039621 cites W2041514173 @default.
- W4207039621 cites W2046253637 @default.
- W4207039621 cites W2050146663 @default.
- W4207039621 cites W2050201301 @default.
- W4207039621 cites W2050623401 @default.
- W4207039621 cites W2056607446 @default.
- W4207039621 cites W2058660077 @default.
- W4207039621 cites W2059271008 @default.
- W4207039621 cites W2059506020 @default.
- W4207039621 cites W2059522146 @default.
- W4207039621 cites W2062710632 @default.
- W4207039621 cites W2066357442 @default.
- W4207039621 cites W2066997802 @default.
- W4207039621 cites W2067274448 @default.
- W4207039621 cites W2077673084 @default.
- W4207039621 cites W2078236626 @default.
- W4207039621 cites W2081928884 @default.
- W4207039621 cites W2086096504 @default.
- W4207039621 cites W2086679038 @default.
- W4207039621 cites W2088541838 @default.
- W4207039621 cites W2090258675 @default.
- W4207039621 cites W2092411281 @default.
- W4207039621 cites W2098490586 @default.
- W4207039621 cites W2098849316 @default.
- W4207039621 cites W2109527252 @default.
- W4207039621 cites W2109772946 @default.
- W4207039621 cites W2110965563 @default.
- W4207039621 cites W2112730105 @default.
- W4207039621 cites W2119732083 @default.
- W4207039621 cites W2120561922 @default.
- W4207039621 cites W2124726938 @default.
- W4207039621 cites W2125674181 @default.
- W4207039621 cites W2130583897 @default.
- W4207039621 cites W2134865438 @default.