The Huaqiao clinopyroxenite and Maodu gabbro are Neoproterozoic mafic-ultramafic rocks located in the western Jiangnan Orogen. Both rocks contain fresh clinopyroxenes. The in situ analysis of fresh clinopyroxenes from these rocks provides essential information about their parental magmas and mantle sources. Here, we present in situ major and trace element compositions of clinopyroxenes from these rocks to determine their petrogenesis and tectonic setting. Clinopyroxene grains from the Huaqiao clinopyroxenite exhibit relatively high values of Mg^# (80.6–84.1), Cr₂O₃ (0.38–1.00 wt%), TiO₂ (0.44–1.84 wt%), Ni (324–460 ppm), V (314–611 ppm), and Co (37–46 ppm); the calculated Mg^# values of the parental liquid(s) are 52–58 (average 55). Clinopyroxene grains from the Maodu gabbro display lower Mg^# (71.5–79.1), Cr₂O₃ (0–0.88 wt%), Al₂O₃ (1.72–4.75 wt%), and Na₂O (0.24–0.88 wt%) contents but higher TiO₂ (0.88–1.89 wt%) contents than those from the Huaqiao clinopyroxenite; they show relatively high Cr (15–4145 ppm, with an average of 1774 ppm), V (34–663 ppm, with an average of 535 ppm), and Co (32–60 ppm) contents; the Mg^# values of the parental liquid(s) are estimated to be 39–49 (average 45). Therefore, we infer that clinopyroxene grains from the Huaqiao clinopyroxenite and Maodu gabbro crystallized from evolved basaltic melts. Mineral-melt partition coefficients reveal that the estimated parental magma composition in equilibrium with clinopyroxene for the Huaqiao clinopyroxenite exhibits slight enrichments in light rare earth elements (LREEs, La_N/Yb_N = 1.12–2.71; subscript N: chondrite normalized) with flat heavy REEs (HREEs, Gd_N/Yb_N = 1.15–1.85). It displays negative high field strength element (HFSE, such as Nb, Zr, and Hf) anomalies, resembling those of typical arc basalt. The calculated parental melt for the Maodu gabbro is characterized by pronounced enrichments in LREEs with La_N/Yb_N ratios of 11.36–19.02, and in large ion lithophile elements (LILEs) relative to HFSEs and lacks significant Nb, Zr, and Hf troughs, comparable to those of ocean island basalts (OIBs). Hence, we infer that the magma source of the Huaqiao clinopyroxenite was an arc mantle metasomatized by subduction melts and/or fluids from the subducted slab formed in a subduction setting; the nature of the source for the Maodu gabbro was the asthenospheric mantle that experienced upwelling and partial melting in an extensional setting.

花桥斜辉绿岩和毛都辉长岩是位于江南造山带西部的新元古代镁铁质-超镁铁质岩石。两种岩石均含有新鲜的斜柏。对这些岩石中新鲜的斜柏石进行原位分析可提供有关其母岩浆和地幔来源的重要信息。在这里，我们介绍了这些岩石中的斜辉石的主要和微量元素组成，以确定它们的成岩作用和构造环境。花桥斜辉石中的斜辉石晶粒显示出相对较高的Mg ^＃（80.6–84.1），Cr ₂ O ₃（0.38–1.00 wt％），TiO ₂（0.44–1.84 wt％），Ni（324–460 ppm），V （314–611 ppm）和Co（37–46 ppm）；计算的镁^＃母液的值是52-58（平均值55）。毛都长白垩纪的斜辉石颗粒显示出较低的Mg ^＃（71.5–79.1），Cr ₂ O ₃（0–0.88 wt％），Al ₂ O ₃（1.72–4.75 wt％）和Na ₂ O（0.24–0.88 wt％） ）含量，但比华侨斜辉石中的TiO ₂（0.88–1.89 wt％）含量高；它们显示出相对较高的Cr（15–4145 ppm，平均1774 ppm），V（34–663 ppm，平均535 ppm）和Co（32–60 ppm）含量；镁^＃母液的值估计为39-49（平均值45）。因此，我们推断花桥斜辉石和茂都辉长岩中的斜辉石晶粒是从演化的玄武质熔体中结晶出来的。矿物熔体分配系数表明，在华桥斜辉石中，与斜辉石平衡的估计父母母岩浆成分在轻稀土元素（LREEs，La _N / Yb _N = 1.12–2.71；下标N：球粒陨石归一化）中略有富集。稀土元素（稀土元素，Gd _N / Yb _N= 1.15–1.85）。它显示出负的高场强元素（HFSE，例如Nb，Zr和Hf）异常，类似于典型的弧形玄武岩。计算出的毛都辉长岩的母体熔体的特征在于，La _N / Yb _N比为11.36–19.02的LREE中有明显的富集，相对于HFSE而言是大型的离子亲石元素（LILE），并且没有明显的Nb，Zr和Hf谷，可与大洋玄武岩（OIBs）相提并论。因此，我们推断花桥斜辉石的岩浆源是由俯冲环境中形成的俯冲板块的俯冲熔体和/或流体交代而成的弧幔。毛都辉长岩的源头性质是软流圈地幔，在扩张的环境中经历了上升流和部分融化。