GPSW-7 WELL, Sample 25 (Cretaceous to of Egypt)

Where: north Western Desert, Egypt (30.0° N, 28.0° E: paleocoordinates 9.8° N, 23.1° E)

• coordinate estimated from map

When: Classopollis brasiliensis pollen zone, F Member (Abu Roash Formation), Middle Cenomanian to Middle Cenomanian (99.6 - 93.5 Ma)

Environment/lithology: shallow subtidal; lithified, black, calcareous shale and lithified, black, calcareous shale

• The Cenomanian was terminated by the deposition of the Abu Roash F Member which took place in anoxic depositional phase. This may be the terminal global oceanic anoxic event known as the Bonarelli (OAE2) event, which was locally reported from north Sinai and the north Western Desert (Shahin, 1991, 2007; Ibrahim et al., 2006a). A relatively thin, exceptionally organic carbon-rich black shale horizon was located between 1803 and 1806 m. This horizon was composed exclusively of AOM, and also contained 3.17 wt% TOC. This confirms the deposition of the Abu Roash F Member in anoxic facies. This oxygen-deficient period corresponds to the IX field of Tyson (1993), and also corresponds to deposition in a distal suboxic–anoxic basin as reported by Roncaglia and Kuijpers (2006). The open marine nature portrayed for the Abu Roash F Member from the GPTSW-7 well, based on ostracodal evidence (GPC, 1994) is misleading. This controversial assumption cannot be supported palynologically, as evidenced by the presence of 100% AOM, in addition to the virtual absence of marine elements which signifies suboxic–anoxic conditions.

Size class: microfossils

Preservation: soft parts, original sporopollenin

Collection methods: core, chemical

Primary reference: S. El Beialy, H. S. El Atfy, M. S. Zavada, E. M. El Khoriby, and R. H. Abu-Zied. 2010. Palynological, palynofacies, paleoenvironmental and organic geochemical studies on the Upper Cretaceous succession of the GPTSW-7 well, North Western Desert, Egypt. Marine and Petroleum Geology 27:370-385 [C. Jaramillo/G. Doria/G. Doria]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 140403: authorized by Carlos Jaramillo, entered by Gabriela Doria on 09.03.2013

Creative Commons license: CC BY (attribution)

Taxonomic list

Pinopsida
 Pinales - Cheirolepidiaceae