A new occurrence of carbonatites associated with intrusive ijolite and syenite has been discovered within the Hawasina Complex underlying the Semail Ophiolite Complex at the southern part of the Rawda-Masfut ridge, Northern Oman Mountains. The carbonatites occur as dikes and sills with lengths of several hundreds of meters and range in composition from calciocarbonatites to ferruginous calciocarbonatites. The carbonatites intruded the ijolite and the associated radiolarian cherts of the Early Cretaceous Sid'r Formation. The close spatial association of carbonatite, ijolite, syenite and radiolarian cherts along with geological, petrographical and geochemical data indicates that these rocks are of intra-oceanic origin. Petrological and field relationships between the carbonatite and associated alkaline silicate intrusives from the Masfut area are consistent with the carbonatites being generated as derivative magmas through liquid immiscibility. They appear to represent magmas related to the volcanism associated with regional crustal extension that preceded the genesis of the Semail Ophiolite.
ASJC Scopus subject areas
- Geochemistry and Petrology