Carbon and oxygen isotope stratigraphy of Jurassic platform carbonates from Saudi Arabia: Implications for diagenesis, correlations and global paleoenvironmental changes

摘要: Abstract Major carbon cycle disturbances reflected by isotope excursions (CIE) have been reported in the Jurassic successions of Euro-Boreal and Mediterranean basins. However, sedimentary geochemical data from other domains are still required to unravel global or regional nature paleoenvironmental identify potential triggers. Here, we present biostratigraphically well-constrained (middle Toarcian lower Kimmeridgian) bulk-rock δ13C δ18O central Saudi Arabia. Five major negative identified back-reef facies below sequence boundaries disconformities (Aalenian-Bajocian boundary, upper Bajocian, middle Bathonian, Callovian Kimmeridgian), suggesting that these carbonates underwent intense meteoric diagenesis during partial subaerial exposures Arabian Platform. The record is less altered shows correlations with relative sea-level changes influencing productivity levels inflows fluvial (12C-enriched) oceanic (12C-depleted) waters onto platform. Overall, most variations recorded at scale Platform within agreement NW Tethyan data. Among variations, increase values Toarcian, Bathonian zigzag Zone indicate a considerable 12Corg burial concomitant rises. Conversely, occurrence but diachronous CIEs Aalenian-Bajocian boundary around lower-upper Bajocian transition interpreted as accelerations terrestrial transfer ocean atmosphere linked widespread emergences landmasses. Whether (eustatic) (tectonic), all transfers could be distal consequences successive episodes Pangean breakup.