title: High water content in primitive continental flood basalts.
abstract: As the main constituent of large igneous provinces, the generation of continental flood basalts (CFB) that are characterized by huge eruption volume (>10(5) km(3)) within short time span (<1-3 Ma) is in principle caused by an abnormally high temperature, extended decompression, a certain amount of mafic source rocks (e.g., pyroxenite), or an elevated H2O content in the mantle source. These four factors are not mutually exclusive. There are growing evidences for high temperature, decompression and mafic source rocks, albeit with hot debate. However, there is currently no convincing evidence of high water content in the source of CFB. We retrieved the initial H2O content of the primitive CFB in the early Permian Tarim large igneous province (NW China), using the H2O content of ten early-formed clinopyroxene (cpx) crystals that recorded the composition of the primitive Tarim basaltic melts and the partition coefficient of H2O between cpx and basaltic melt. The arc-like H2O content (4.82 ± 1.00 wt.%) provides the first clear evidence that H2O plays an important role in the generation of CFB.
authors.affiliation: School of Earth Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Qun-Ke
authors.initials: QK
authors.lastname: Xia
authors.affiliation: School of Earth and Space Sciences, University of Science and Technology of China, Hefei, China.
authors.forename: Yao
authors.initials: Y
authors.lastname: Bi
authors.affiliation: School of Earth Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Pei
authors.initials: P
authors.lastname: Li
authors.affiliation: School of Earth and Space Sciences, Peking University, Beijing, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Tian
authors.affiliation: Key Laboratory of Marine Geology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.
authors.forename: Xun
authors.initials: X
authors.lastname: Wei
authors.affiliation: School of Earth Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Han-Lin
authors.initials: HL
authors.lastname: Chen