Serpentinization processes occur at geological settings notably during oceanic subduction and obduction, where mantle rocks interact with water. Different types of serpentine minerals form according to temperature and pressure conditions, and potentially chemical exchanges. Therefore, the characterization of serpentine minerals, and the possible occurrence of multiple serpentine generations in mantle rocks provide essential constraints on the conditions of fluid–rock interactions in the mantle. The serpentinite sole of the Peridotite Nappe of New Caledonia (Southwest Pacific) is the result of several superimposed serpentinisation events. The latter were discriminated using mineralogical and geochemical approaches and modeling. Lizardite represents more than 80% of the entire serpentine content of the ophiolite. It is crosscut by several veins of other serpentine species in the serpentinite sole. The relative chronology appears as follows: lizardite 1 → lizardite 2 → antigorite → chrysotile → polygonal serpentine. The transition from primary/magmatic minerals to lizardite 1 is almost isochemical. Then, the development of lizardite 2 yields an enrichment in fluid-mobile elements such as Cs, Rb, Ba, U and light rare-earth elements and an apparent increase of the Fe3+/FeT ratio. The modeling of δ18O values (1.9–13.9‰) and δD values (88–106‰) of all serpentine species through Monte-Carlo simulations show that New Caledonia serpentines were mainly formed in equilibrium with fluids released by the dehydration of altered oceanic crust (AOC) during subduction between 250 and 350 °C. AOC-derived fluids are not the unique source of fluids since a low temperature (100–150 °C) meteoric component is also predicted by the models. Thus, serpentine acts as a tape-recorder of fluid–rock interactions into the mantle from depth to (sub-)surface.

中文翻译：

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新喀里多尼亚橄榄岩的蛇纹石化：从深度到（亚）地表

蛇纹石化过程发生在地质环境中，特别是在海洋俯冲和俯冲期间，地幔岩石与水相互作用。根据温度和压力条件以及潜在的化学交换形成不同类型的蛇纹石矿物。因此，蛇纹石矿物的特征以及地幔岩石中可能出现多代蛇纹石对地幔中流体-岩石相互作用的条件提供了必要的约束。新喀里多尼亚（西南太平洋）橄榄岩推覆的蛇纹岩底部是多次叠加蛇纹石化事件的结果。后者是通过矿物学和地球化学方法和建模来区分的。Lizardite 占蛇绿岩全部蛇纹石含量的 80% 以上。它被蛇纹岩底部的其他蛇纹石种类的几条脉横切。相对年表如下：蜥蜴石 1 → 蜥蜴石 2 → 叶蛇纹石 → 温石棉 → 多角蛇纹石。从原生/岩浆矿物到蜥蜴石 1 的转变几乎是等化学的。然后，蜥蜴石 2 的发展产生了流体流动元素如 Cs、Rb、Ba、U 和轻稀土元素的富集，以及 Fe3+/FeT 比的明显增加。通过蒙特卡罗模拟对所有蛇纹石物种的 δ18O 值（1.9-13.9‰）和 δD 值（88-106‰）进行建模表明，新喀里多尼亚蛇纹石主要是与蚀变洋壳脱水释放的流体平衡形成的（ AOC) 在 250 到 350 °C 之间的俯冲期间。AOC 衍生的流体不是流体的唯一来源，因为模型还预测了低温 (100–150 °C) 大气成分。因此，蛇纹石作为流体-岩石相互作用从深处到（亚）表面进入地幔的录音机。