In situ characterization of forearc serpentinized peridotite from the Sulu ultrahigh-pressure terrane: Behavior of fluid-mobile elements in continental subduction zone
In situ characterization of forearc serpentinized peridotite from the Sulu ultrahigh-pressure terrane: Behavior of fluid-mobile elements in continental subduction zone
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苏鲁超高压地体弧前蛇纹石化橄榄岩的原位表征：大陆俯冲带流体流动元素的行为
DOI：
10.1016/j.gsf.2021.101139
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发表时间：
2021-07
影响因子：
8.9
通讯作者：
Wang Jian
中科院分区：
文献类型：
--
作者：
Xie Zhipeng;Hattori Keiko;Dong Youpu;Wang Jian
苏鲁超高压地体阳口(YK)、索洛树(SLS)和呼家林(HJL)地区的蛇纹状橄榄岩代表了北中国克拉通下方古老的次大陆岩石圈地幔的遗迹。它们的原岩方辉橄榄岩和纯橄榄岩被扬子大陆俯冲释放的水流体不同程度地水化。岩石富含流动元素(FME)，包括Sb(亏损地幔的42-333倍)和Pb(30-476倍)。弧前蛇纹岩的富集度与喜马拉雅弧前蛇纹岩相当，高于马里亚纳弧前地幔蛇纹岩，表明大陆俯冲带弧前蛇纹岩的富集度大于大洋俯冲带。YK地区SLS蛇纹岩中橄榄石和斜方辉石之后的蛇纹岩对Sb和As的富集度高于橄榄石和斜方辉石之后的反钙辉石。反辉石对铅、铀、铯、轻稀土元素具有高度的富集性，而对蜥蜴岩的富集度较低。两种蛇纹石中FME的丰度反映了不同的水化温度。当温度低于300℃时，地幔楔形浅层形成的菱锌矿含有在低温下可流动的元素，如Sb和As；当温度高于300℃时，在相对较深的地幔楔形形成的反辉石结合了更多来自俯冲大陆板片(或碎屑)的FME，包括Pb、U、Cs、LREE以及Sb和As。反辉石(600-700℃)在进退变质作用中的最终破裂将向俯冲通道和(或)上地幔排放水和FME。
Serpentinized peridotites in the Yangkou(YK), Suoluoshu(SLS)and Hujialin(HJL)areas in the Sulu ultrahighpressure terrane represent the relic of ancient subcontinental lithospheric mantle belowthe North China Craton. Their protoliths, harzburgite and dunite, were variably hydrated by aqueous fluids released from subducting Yangtze continent. The rocks are enriched in fluid-mobile elements(FME)including Sb(42-333 times the depleted mantle value)and Pb(30-476 times). The degrees of the FME enrichment are comparable to that of the Himalayan forearc serpentinites, and greater than forearc mantle serpentinites from Marianas, suggesting that the degrees of FME enrichment in the forearc serpentinites are greater in continental subduction zones than those in the oceanic subduction zones. Lizardite after olivine in the SLS serpentinite shows higher degrees of enrichment in Sb and As than those for antigorite after both olivine and orthopyroxene in the YK area. The antigorite has highly enriched in Pb, U, Cs, and LREE, but not for the lizardite. The abundance of FME in two different species of serpentine reflects the different temperature of hydration. At temperature lower than 300 °C, formed lizardite at shallow depths of the mantle wedge incorporates elements that are fluid mobile at low temperatures, such as Sb and As.When the temperature greater than 300 °C, formed antigorite at a relatively deep mantlewedge incorporate more FME fromthe subducting continental slab(or fragments), including Pb, U, Cs, LREE as well as Sb and As. The eventual breakdown of antigorite(600-700 °C)in prograde metamorphism would discharge water as well as FME into the subducting channel and/or the overlying mantle.
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影响因子：
3.5
作者：
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通讯作者：
E. Cannaò
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影响因子：
3.5
作者：
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通讯作者：
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影响因子：
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作者：
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通讯作者：
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影响因子：
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作者：
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通讯作者：
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影响因子：
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作者：
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通讯作者：
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