Lineage of<i>Arxina schwageri</i>(Silvestri, 1928) new genus (Nummulitacea) from Middle Eocene of Egypt and Sultanate of Oman

Boukhary, Mohamed; Hussein, Aly I. M.; Al-Sayigh, Abdul Razak

doi:10.1080/08912963.2011.651468

Cited by 5 publications

(2 citation statements)

References 2 publications

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“…Based on Nummulites specimens found in the section, Bishay (1966) and Omara et al (1977) assigned the succession at Maghagha to the Late Lutetian and showed that this stage is represented by the Qarara Formation and part of El Fashn Formation. The stratigraphy and geology of the Qarara Formation has been reported in several studies (Boukhary and Abdulla 1985;Moulin, 2011, Lorraine, 2012, Boukhary et al, 2012. Boukhary and Abdulla (1985) that combined paleontological and petrological examination of the Eocene rocks at Maghagha and revealed that the succession belongs to the Nummulites gizehensis gizehensis Zone.…”

Section: Geological Backgroundmentioning

confidence: 81%

Characters ofNummulites multiplicutiospiralisn. sp. from the Qarara Formation, Maghagha, Nile Valley, Egypt

Safia

2021

Acta Geologica Sinica (Eng)

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Nummulites multiplicutiospiralis n. sp. is described and illustrated for both generations from a claystone of Lutetian age in the Middle Eocene Qarara Formation, Maghagha, Nile valley, Egypt. Previously considered to be Nummulites gizehensis, we describe this form as a new species based on diameter of the test and protoconch sizes, septal shape and granulations. The primary feature of this species is spiral multiplication, seen in spiral section. The species is also characterized morphologically by lenticular to flat tests with rounded periphery, wrinkled to broadly meandering septal filaments and few granules on the periphery in microspheric forms. The granules are spirally arranged on the septal filaments in megalospheric forms. Chambers are longer than high and the spire is irregular. The new taxon belongs to the Nummulites partschi Group, Subgroup N. gizehensis. Reflexive coiling in the spiral may develop through ontogeny as in N. rollandi, the species which was considered to be an index species in the southern Tethys (Boukhary et al., 1982 andBoukhary et al. 2010). The characters of the new species, as well as its retrogenesis and reflexive coiling, should be further studied in general in Nummulites spp., to understand the importance of such characters phylogenetically.

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Section: Geological Backgroundmentioning

confidence: 81%

Characters ofNummulites multiplicutiospiralisn. sp. from the Qarara Formation, Maghagha, Nile Valley, Egypt

Safia

2021

Acta Geologica Sinica (Eng)

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“…The limestone is characterized by Thalassinoides horizons and Nummulites gizehensis accumulation. Based on the previous studies, the index planktonic and benthic foraminifera, besides the occurrence of large benthic foraminifera represented by Nummulites gizehensis, assigned this rock unit to upper Lutetian [18,24,41,[50][51][52][53][54][55].…”

Section: Qarara Formationmentioning

confidence: 99%

Paleoclimate and Paleoenvironment Reconstructions from Middle Eocene Successions at Beni-Suef, Egypt: Foraminiferal Assemblages and Geochemical Approaches

et al. 2023

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The Eocene deposits of Egypt provide a wide variety of shallow marine facies and fossil assemblages, allowing paleoenvironmental reconstructions in this warmhouse climate interval. Forty-three rock samples have been collected from two middle Eocene sections, exposed at southeast Beni-Suef area in northern Egypt. The studied outcrops are lithologicsally subdivided into two rock units named from base to top as follows: (1) the Qarara Formation (Lutetian) and (2) the El Fashn Formation (Bartonian). Most investigated rock samples showed richness in benthic foraminiferal assemblages and only rare occurrences of index planktonic foraminifera. They yielded 160 foraminifera species which belong to 4 suborders, 19 superfamilies, 34 families, and 59 genera. The stratigraphic distribution of the identified species allowed us to define four local benthic bio-ecozones: (1) Bolivina carinata Lowest Occurrence Zone (Lutetian), (2) Cibicides mabahethi/Cancris auriculus primitivus Concurrent-Range Zone, (3) Nonion scaphum Lowest Occurrence Zone, and (4) Brizalina cooki/Nonionella insecta Concurrent-Range Zone (Bartonian). These biozones are described and discussed in detail and correlated to stratigraphic equivalents in Egypt. The rareness of index planktonic foraminifera through the studied sections does not allow a precise biostratigraphic and chronostratigraphic correlation. The shale samples show low TOC values, which may be related to low productivity, high sediment influx, and/or prevailing oxic conditions. Bulk rock geochemistry, consistent with the benthic foraminifera ecological preferences, indicated that the studied sections were deposited in moderate to high oxygen levels and warm climatic conditions in a typical shelf marine setting. The identified species showed strong similarities with nearby southern Tethys areas, reflecting migration via the trans-Sahara seaway, and minor similarities with those identified from the northwestern Tethys and the North Atlantic province attributed to the change in the environmental and climatic conditions, such as cooler, latitudinal zoned climatic conditions along the northwestern Tethys, which was unsuitable for their biological demands. The warming trend identified from Lutetian to Bartonian intervals corresponds to the onset of the Middle Eocene Climatic Optimum (MECO).

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Larger benthic foraminiferal turnover across the Eocene–Oligocene transition at Siwa Oasis, Western Desert, Egypt

Orabi¹,

Beshtawy²,

Osman³

et al. 2015

Journal of African Earth Sciences

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Lineage ofArxina schwageri(Silvestri, 1928) new genus (Nummulitacea) from Middle Eocene of Egypt and Sultanate of Oman

Cited by 5 publications

References 2 publications

Characters ofNummulites multiplicutiospiralisn. sp. from the Qarara Formation, Maghagha, Nile Valley, Egypt

Characters ofNummulites multiplicutiospiralisn. sp. from the Qarara Formation, Maghagha, Nile Valley, Egypt

Paleoclimate and Paleoenvironment Reconstructions from Middle Eocene Successions at Beni-Suef, Egypt: Foraminiferal Assemblages and Geochemical Approaches

Larger benthic foraminiferal turnover across the Eocene–Oligocene transition at Siwa Oasis, Western Desert, Egypt

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