New stratigraphic data on the Aptian of the Persian Gulf

During Aptian times the northeastern corner of the African plate, the Arabian craton, was in the tropics. Two-thirds of it was covered by a broad epeiric sea opening eastward into the Tethys Ocean. Carbonate sedimentation recorded several environmental perturbations caused by changes in relative sea-level and by interconnected coeval global events. A well in offshore Abu Dhabi was used as the reference because it was drilled through the whole of the interval of interest and cored strata dated Gargasian (middle Aptian sensu gallico, early late Aptian sensu anglico) downward to beds of Late Barremian age. The holostratigraphic approach employing biostratigraphy, lithostratigraphy and sequence stratigraphy, along with basic well log interpretation and δ13C-based chemostratigraphy, facilitated correlation with outcrops in Iran and Oman, and with other wells in Iraq, Qatar and the United Arab Emirates, over distances of several hundreds of kilometers. This approach made possible refinement of our regional model for this interval and the identification of a set of events that included several forced regressions, transgressions of varying importance (by extension in the literature those floodings of greatest magnitude have been called “drownings”), the Oceanic Anoxic Sub-Event 1a and a microbial Bacinella “bloom”.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Review of the regional stages in countries surrounding the Persian Gulf. ► Correlation of these former “operational units” between these countries. ► Relative datings of three Aptian “drowning” events and of segments of the δ13C curve. ► Relative datings of these events, of “the” Bacinella facies, and of the OAE1a.