Peridotites in ophiolites exposed along Himalayan suture zone open window to study deep Earth processes. We report c.2 km thick well exposed mantle section of Shergol ophiolite in the Indus Suture Zone (ISZ). The mantle section comprises lherzolite, serpentinised peridotite with cumulate chromitites. The in situ evidences from micron-sized mineral exsolutions are studied using optical microscopy, scanning electron microscopy and micro-Raman spectroscopy. From the ISZ lherzolite, ilmenite mineral exsolution is noted in the olivine grain. The exsolved ilmenites are oriented topotactically following former {111} planes of magnetite, providing evidence of spinel precursor. In another observation, the disoriented 1–3 µm wide and 10–80 µm long ilmenite needles are hosted in the olivine, is characterised by Raman peaks at 685, 370 cm⁻¹ with low peaks at 308 cm⁻¹,523 cm⁻¹, 683 cm⁻¹, 693 cm⁻¹ and 731 cm⁻¹ point to mixed mineral phases of magnetite with Cr–Fe–Al. Based on morphologies, crystal-chemical structure and modal calculation of exsolutions, we infer, exsolved Fe–Ti phases in Shergol peridotite is sourced from deeper part of the upper mantle. With the Fe–Ti phases, tiny silicate inclusions in chrome spinel and accompanying opaque base metal sulphides are also observed in the same peridotite, attributes successive stages of partial melting and subsequent cooling of metal enriched mantle. These observations, challenge shallow intra-oceanic arc setting for Shergol ophiolite and proposes, part of exsolved mineral phases in ophiolite has deep Earth origin. These mineral phases would ascent at the shallow mantle level beneath Neotethyan spreading ridge aided by dunite channel.

沿着喜马拉雅缝合带暴露的蛇绿岩中的橄榄岩打开了研究地球深部过程的窗口。我们报告了印度河缝合带 (ISZ) 中约 2 公里厚的 Shergol 蛇绿岩暴露的地幔部分。地幔部分包括二镁橄榄岩、蛇纹石化橄榄岩和堆积的铬铁矿。micron -s 的原位证据使用光学显微镜、扫描电子显微镜和显微拉曼光谱研究了矿物外溶物。从 ISZ 锂辉石中，橄榄石颗粒中发现钛铁矿矿物出溶。溶出的钛铁矿沿磁铁矿的前 {111} 面进行拓扑取向，提供了尖晶石前体的证据。在另一项观察中，错位的 1-3 µm 宽和 10-80 µm 长的钛铁矿针位于橄榄石中，其特征是在 685、370 cm ^{-1 处}有拉曼峰，在 308 cm ^-1 ,523 cm ^-1处有低峰, 683 cm ^-1 , 693 cm ^-1和 731 cm ^-1指出磁铁矿与 Cr-Fe-Al 的混合矿物相。根据出溶的形态、晶体化学结构和模态计算，我们推断，Shergol橄榄岩中出溶的Fe-Ti相来自上地幔的更深处。对于 Fe-Ti 相，铬尖晶石中的微小硅酸盐夹杂物和伴随的不透明贱金属硫化物也在同一橄榄岩中观察到，这归因于富金属地幔的部分熔化和随后冷却的连续阶段。这些观察结果挑战了 Shergol 蛇绿岩的浅海弧环境，并提出，蛇绿岩中的部分出溶矿物相起源于地球深处。这些矿物相将在新特提斯扩张脊下方的浅​​地幔水平上升，并在纯晶通道的帮助下进行。