Dolomite formation in breccias at the Musandam Platform border, Northern Oman Mountains, United Arab Emirates |
| |
| Authors: | L Breesch R Swennen B Vincent |
| |
| Institution: | aGeologie, K.U.Leuven, Celestijnenlaan 200E, B-3001 Heverlee, Belgium;bInstitut Français du Pétrole, Géologie-Géochimie, 1-4 Avenue de Bois-Préau, 92852 Rueil-Malmaison Cedex, France |
| |
| Abstract: | The presence of dolomite breccia patches along Wadi Batha Mahani suggests large-scale fluid flow causing dolomite formation. The controls on dolomitization have been studied, using petrography and geochemistry. Dolomitization was mainly controlled by brecciation and the nearby Hagab thrust. Breccias formed as subaerial scree deposits, with clay infill from dissolved platform limestones, during Early Cretaceous emergence. Cathodoluminescence of the dolostones indicates dolomitization took place in two phases. First, fine-crystalline planar-s dolomite replaced the breccias. Later, these dolomites were recrystallized by larger non-planar dolomites. The stable isotope trend towards depleted values (δ18O: − 2.7‰ to − 10.2‰ VPDB and δ13C: − 0.6‰ to − 8.9‰ VPDB), caused by mixing dolomite types during sampling, indicates type 2 dolomites were formed by hot fluids. Microthermometry of quartz cements and karst veins, post-dating dolomites, also yielded high temperatures. Hot formation waters which ascended along the Hagab thrust are invoked to explain type 2 dolomitization, silicification and hydrothermal karstification. |
| |
| Keywords: | Dolomite formation Breccias Fluid flow Northern Oman Mountains |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
