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

点击翻译按钮获取中文摘要

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.