The Spontang Ophiolite complex represents the most complete ophiolite sequence amongst the South Ladakh ophiolites and comprises mantle rocks (depleted harzburgites, dunites and minor lherzolites) as well as crustal rocks (basalt, isotropic gabbros, layered gabbros etc.). In the present study, detailed geochemistry (whole rock as well as mineral chemistry) and Sr-Nd isotopic analyses of thirty-six ultramafic- mafic samples have been attempted to constraint the evolution and petrogenetic history of the Tethyan oceanic crust. Major, trace-element and REE patterns of the peridotites and their minerals indicate that the lherzolites experienced lower degrees of partial melting resembling abyssal peridotites (at higher temperatures, T_REE = ∼1216 °C) than the harzburgites (6%–8% versus 15%–17%). Elevated ε_Nd(t) and variable ⁸⁷Sr/⁸⁶Sr(t) ratios along with REE patterns suggest that the Spontang mafic rocks display N-MORB affinity with negligible participation of oceanic sediments in their genesis are originated from a depleted upper mantle with little contribution from subduction-related fluids. MORB-type Neotethyan oceanic crust is associated with the earliest phase of subduction (of older Jurassic age) through which a younger intra-oceanic island arc (Spong arc) subsequently developed. Harzburgites REE display typical U-shaped patterns, suggesting that these rocks have been metasomatized by LREE-enriched fluids. On the other side, mafic rocks are characterized by heterogeneous (Nb/La)_PM and (Hf/Sm)_PM and relatively homogeneous ε_Nd(t), indicating interaction of subduction-related melts with the upper mantle during the initiation of subduction, in Early Cretaceous times.

Spontang蛇绿岩杂岩代表了南拉达克蛇绿岩中最完整的蛇绿岩序列，包括地幔岩（贫化菱镁矿、纯英岩和次长辉长岩）以及地壳岩石（玄武岩、各向同性辉长岩、层状辉长岩等）。在本研究中，已尝试对 36 个超基性岩样品进行详细的地球化学（全岩和矿物化学）和 Sr-Nd 同位素分析，以限制特提斯洋壳的演化和成岩历史。橄榄岩及其矿物的主要、微量元素和 REE 模式表明，橄榄岩经历了类似于深海橄榄岩的部分熔融程度（在更高的温度下，T _REE  = ∼1216 °C）比方辉橄榄岩（6%–8% 对15%–17%）。高架ε _Nd ( t ) 和可变的⁸⁷ Sr/ ⁸⁶ Sr( t ) 比率以及 REE 模式表明，Spontang 基性岩显示出 N-MORB 亲和性，海洋沉积物在其成因中的参与可忽略不计，起源于枯竭的上地幔，贡献很小来自与俯冲相关的流体。MORB 型新特提斯洋壳与最早的俯冲阶段（较旧的侏罗纪时代）有关，随后形成了较年轻的洋内岛弧（海绵弧）。Harzburgites REE 显示出典型的 U 形图案，表明这些岩石已被富含 LREE 的流体交代。另一方面，基性岩的特征是非均质 (Nb/La) _PM和 (Hf/Sm) _PM和相对均匀的ε _Nd ( t )，表明在早白垩世俯冲开始期间与俯冲相关的熔体与上地幔的相互作用。