Metasomatic diopsidite, nephrite, epidosite, and rodingite veins: witnesses of fluid flow in the history of formation and emplacement of the Oman Ophiolite

阿曼蛇绿岩中的交代岩对阿曼蛇绿岩从中生代扩张到白垩纪俯冲到古近纪抬升到新近纪挤压和再活化到今天的蛇纹岩和碳酸盐化的动态演化具有重要的意义。一些交代岩被认为是在洋壳和海水流体(透辉岩、霞石、硬壳岩)发生高温反应时形成的。这些岩性在开发洋壳冷却模型时被赋予了相当大的相关性。此外，地幔剖面中的交代辉长岩(辉长岩)很有意义，因为它们是在蛇纹岩作用期间形成的，具有提供关于PT条件、流体成分和蛇纹岩作用时间的巨大潜力。在这项小额赠款的建议中，我们要求提供资金，对交代岩进行初步的岩相学和矿物化学分析。这些研究将导致对这些交代岩石类型进行综合的地球化学/流体包裹体/热力学模拟研究，以(1)检验它们的形成假说(例如，与大洋中脊和俯冲有关)，(2)破译引起交代反应的流体的性质和来源，以及(3)了解交代事件的时间以及与阿曼蛇绿岩构造演化的关系。这里要求的小额拨款的结果将用于撰写一份完整的提案，将于今年秋天提交。

Metasomatic rocks from the Oman Ophiolite allow crucial insights into the dynamic evolution of the Oman Ophiolite from Mesozoic spreading to Cretaceous obduction to Paleogene uplift to Neogene compression and reactivitation to present-day serpentinization and carbonation. Some metasomatic rocks are believed to have formed during high-temperature reactions between ocean crust and seawater-derived fluids (diopsidites, nephrites, epidosites). These lithologies have been assigned considerable relevance in developing models for cooling of the ocean crust. Moreover, metasomatized gabbro dikes in the mantle section (rodingites) are of interest, because they form during serpentinization and have great potential for providing information on pT conditions, fluid composition, and timing of serpentinization. In this proposal for a small grant, we request funds to conduct preliminary petrographic and mineral chemical analyses of metasomatic rocks. These investigations will lead into a combined geochemical/fluid inclusion/thermodynamic modeling study of these metasomatic rock types to (1) test hypotheses for their formation (e.g., mid-ocean ridge versus obduction related), (2) decipher the nature and sources of fluids causing the metasomatic reactions, and (3) learn about the timing of metasomatic events and the relation to the tectonic evolution of the Oman Ophiolite. The results that will come out of the small grant requested here will be used in composing a full proposal to be submitted this fall.