Middle Eocene–early Miocene planktonic foraminiferal biostratigraphy, chronostratigraphy, sea‐level reconstruction and sequence biostratigraphy at N. ElFaras‐1Xwell, Qattara Depression, Western Desert, Egypt

Abstract

The planktonic foraminiferal assemblages are tracked in the middle Eocene–early Miocene succession within N. El Faras‐1X Well, Qattara Depression, Egypt. This succession is composed mainly of three lithostratigraphic units the upper part of the Apollonia Formation (middle to late Eocene), Dabaa Formation (late Eocene and Oligocene) and the lower part of the Moghra Formation (early Miocene). Biostratigraphically, the recorded 77 planktonic foraminiferal species enabled the recognition of 12 planktonic foraminiferal biozones; 4 biozones belong to middle to late Eocene, 7 biozones belong to the Oligocene and 1 belongs to the early Miocene. The proposed biozones were compared with their equivalents in other Egyptian regions and other schemes. Eleven Lowest Occurrence and two Highest Occurrence planktonic foraminiferal bioevents were also recognized and correlated all over the world. The chronostratigraphy and the stage boundaries were mainly delineated according to the diagnostic planktonic foraminifera. The middle–late Eocene boundary (Bartonian–Priabonian boundary), The Eocene–Oligocene boundary (Priabonian–Rupelian boundary), the early Oligocene–late Oligocene boundary (Rupelian–Chattian boundary) and the Oligocene–Miocene boundary (Chattian–Aquitanian boundary) were accurately determined. Based on the % P, the palaeobathymetry was estimated and hence the sea‐level fluctuation. The reconstructed sea‐level curve revealed two major transgressive–regressive cycles with minor oscillation within them. These events were globally correlated and match in most parts with that of the worldwide sea‐level curves. The sequence stratigraphy framework consists mainly of two transgressive–regressive (T–R) depositional sequences (DS1 and DS2). The DS1 includes the TST1 below which is capped by mfs1 and the HST1 above. The DS2 involves the TST2 below that was capped by mfs2 and the HST2 above.