The Qingshuiquan-Tatuo ophiolites (QTOs), which are located in the central fault of the Kunlun Orogen, can provide critical information regarding the subduction processes of the Proto-Tethys Ocean. This study presents petrological, whole-rock geochemical, SrNd isotopic, and zircon UPb data on these ophiolites. The QTOs consist of mantle peridotites, pyroxenites, and fine-grained low- and high-Ti (alkaline) gabbros (LTGs and HTGs, respectively) and lack mafic lava units. The QTO mafic units can be geochemically subdivided into LTGs and HTGs. The LTGs have high MgO contents (mostly >8.0%), V/Ti ratios (37.41–158.77) and low TiO₂ (mostly <0.5%), REE contents and variable ɛ_Nd(t) values (−3.48 to +3.89), and they exhibit geochemical similarities to forearc mafic rocks. Zircon UPb data yield a crystallization age of 516 Ma for the LTGs. In contrast, the HTGs show relatively high total alkali (1.72–5.66%), TiO₂ (1.45–3.68%) and REE contents, high (La/Yb)_N (3.37–14.06), Ti/Y (290.78–1058.94), and low ɛ_Nd(t) values (−3.02 to −3.55), which suggest a geochemical signature of oceanic island basalt (OIB) and continental rift-like basalt. The zircon UPb data yield crystallization ages of 486–485 Ma for the HTGs. Petrogenetic analyses suggest that the LTGs were derived from remelting of forearc mantle peridotites and that the serpentinites (harzburgites) represent the forearc mantle after the extraction of low-Ti mafic melts. In contrast, the HTGs were derived from a fertile asthenospheric mantle upwelling through a slab window followed by minor subcontinental lithospheric mantle (SCLM)/crust contamination. The findings suggest that the QTOs were generated in an epicontinental environment above the subduction zone, which was geodynamically related to slab rollback at 516 Ma and subsequent oceanic-ridge oblique subduction at 485 Ma.

位于昆仑造山带中部断层的清水泉-塔托蛇绿岩（QTOs）可以提供有关特提特斯洋俯冲过程的关键信息。这项研究提供了这些蛇绿岩的岩石学，全岩地球化学，Sr Nd同位素和锆石U Pb数据。QTO由地幔橄榄岩，辉绿岩和细粒低钛和高Ti（碱性）辉长岩（分别为LTG和HTG）组成，缺乏镁铁质熔岩单元。QTO基部可以按地球化学细分为LTG和HTG。所述LTGS具有高的MgO含量（主要是> 8.0％），V / Ti的比（37.41-158.77）和低的TiO ₂（主要是<0.5％），稀土元素含量和可变ɛ_钕（吨）值（-3.48至+3.89），并且它们与前基性镁铁质岩具有相似的地球化学特征。锆石U Pb数据得出LTG的结晶年龄为516 Ma。相比之下，HTG的总碱含量较高（1.72-5.66％），TiO ₂（1.45-3.68％）和REE含量，高（La / Yb）_N（3.37-14.06），Ti / Y（290.78-1058.94）_Nd（t）值低（-3.02至-3.55），表明海洋岛屿玄武岩（OIB）和大陆裂谷状玄武岩的地球化学特征。锆石U铅数据显示HTG的结晶年龄为486–485 Ma。岩石成因分析表明，LTG来源于前陆幔幔橄榄岩的重熔，而蛇纹岩（哈茨伯格岩）代表了低钛铁镁铁质熔体提取后的前幔幔。相比之下，HTGs来自一块肥沃的软流圈地幔，并通过板状窗口上升，随后是次大陆性岩石圈以下地幔（SCLM）/地壳污染。研究结果表明，QTOs是在俯冲带上方的陆上环境中产生的，这与板坯在516 Ma的回滚以及随后在485 Ma的大洋脊倾斜俯冲在地球动力学上有关。