Abstract
The sedimentology and chemostratigraphy (δ13Ccarb, δ13Corg, Sr concentrations) of the Triassic-Jurassic (Tr-J) boundary interval has been investigated in detail in sections of the Ghalilah Formation exposed in Wadi Ghalilah, Wadi Milaha and Wadi Naqab, northeastern United Arab Emirates. The sequence of events recorded across the Tr-J boundary interval in Ras Al Khaimah reflects significant environmental change that can ultimately be related to CAMP volcanism. Uppermost Triassic limestones of the Sumra Member rich in coral, calcareous sponges and large-size bivalves are interbedded with siliciclastic mudstones and deposited in an open lagoonal environment. These are abruptly followed by oolites with intercalated calcareous mudstones of the Sakhra Member that are devoid of macrofossil. Thrombolitic microbialites that occur in the lowermost Sakhra Member are interpreted to reflect the demise of hypercalcifying marine biota during the Tr-J boundary interval. The oolites of the Sakhra Member are capped by a subaerial exposure surface, followed by peritidal deposits of the Shuba Member. The available, sparse biostratigraphic data of the Ghalilah Formation are critically discussed and support a position of the Tr-J boundary at the base of the Sakhra Member. A negative excursion in δ13Corg occurs in the upper Sumra Member and possibly correlates with the Late Triassic Spelae carbon-isotope event. The δ13Ccarb and δ13Corg values increase across the boundary interval, and an extended positive excursion in δ13Ccarb occurs in the oolites of the Sakhra Member. Sr concentrations increase in the bioclastic limestones of the uppermost Sumra Member and peak in the oolites of the upper Sakhra Member. High Sr concentrations also occur at correlative stratigraphical levels in the Lombardy Basin (Italy), and are interpreted as an Early Hettangian seawater signal, reflecting the global-scale reduction of biological aragonite precipitation and an increased continental weathering flux.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
