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| Titel |
Nature of the crust in the northern Red Sea |
| VerfasserIn |
Marco Ligi, Enrico Bonatti, William Bosworth, Yue Cai, Anna Cipriani, Camilla Palmiotto, Sara Ronca, Monique Seyler |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250144167
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| Publikation (Nr.) |
 EGU/EGU2017-7961.pdf |
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| Zusammenfassung |
| We present here 3D seismic reflection and gravity data obtained from an off-axis area of the NW Red Sea, as well as results of a study of gabbroic rocks recovered in the same area both from an oil well below a thick evaporitic-sedimentary sequence, and from a layered mafic complex exposed on the Brothers islets. We show that magmatism can play an important role in the evolution of narrow rifts, and that our results can help to solve the controversy on the nature of the crust in the northern/central Red Sea, i.e., the crust outside the axial oceanic cells is either oceanic or it consists of melt-intruded extended continental crust. The studied gabbros show petrologic and geochemical signatures similar to those of mid-ocean ridge basalts (MORB) and are compatible with their having been emplaced either in a continental or in an oceanic context. We explored the different hypotheses proposed to explain the lack of magnetic anomalies in presence of oceanic crust in the northern Red Sea. Our results combined with a review of all the geophysical and geological data in the area point to a stretched and thinned continental crust with few isolated sites of basaltic injections, in line with a model whereby asthenospheric melt intrusions contribute to weaken the lower crust enabling some decoupling between upper and lower crust, protracting upper crust extension and delaying crustal breakup. Our findings show that continental rupture in the northern Red Sea is preceded by intrusion of basaltic melts with MORB-type elemental and isotopic signature, that cooled forming gabbros at progressively shallower crustal depths as rifting progressed towards continental separation. |
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