Geochemical Characterization of the Oman Crust-Mantle Transition Zone, OmanDP Holes CM1A and CM2B
The transition from the gabbroic oceanic crust to the residual mantle harzburgites of the Oman ophiolite has been drilled at Holes CM1A and CM2B (Wadi Tayin massif) during Phase 2 of the International Continental Scientific Drilling Program Oman Drilling Project (November 2017–January 2018). In orde...
| Autores: | , , , , , , , , , , , , |
|---|---|
| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2022 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/356479 |
| Acceso en línea: | http://hdl.handle.net/10261/356479 |
| Access Level: | acceso abierto |
| Palabra clave: | Dunites and harzburgites serpentinization and carbonation Holes CM1A and CM2B ICDP Oman drilling project Oman ophiolite crust-mantle transition Partial melting versus melt-rock reaction |
| Sumario: | The transition from the gabbroic oceanic crust to the residual mantle harzburgites of the Oman ophiolite has been drilled at Holes CM1A and CM2B (Wadi Tayin massif) during Phase 2 of the International Continental Scientific Drilling Program Oman Drilling Project (November 2017–January 2018). In order to unravel the formation processes of ultramafic rocks in the Wadi Tayin massif crust-mantle transition zone and deeper in the mantle sections beneath oceanic spreading centers, our study focuses on the whole rock major and trace element compositions (together with CO and HO concentrations) of these ultramafic rocks (56 dunites and 49 harzburgites). Despite extensive serpentinization and some carbonation, most of the trace element contents (REE, HFSE, Ti, Th, U) record high temperature, magmatic process-related signatures. Two major trends are observed, with good correlations between (a) Th and U, Nb and LREE on one hand, and between (b) heavy REE, Ti and Hf on the other hand. We interpret the first trend as the signature of late melt/peridotite interactions as LREE are known to be mobilized by such processes (‘‘lithospheric process’’) and the second trend as the signature of the initial mantle partial melting (‘‘asthenospheric process’’), with little or no overprint from melt/rock reaction events. |
|---|