R. M. STAINFORTH
Tropical Oil Company, Bogotá, Colombia
Reproduced from the
JOURNAL OF PALEONTOLOGY
Vol. 23, No. 4, July, 1949
with the kind permission of SEPM Society for Sedimentary Geology, February 2003
Abstract—A condensed summary is presented on the distribution of Foraminifera in Egyptian sediments of Oligocene, Miocene and Pliocene age.
The following brief notes are based on a six-month research study of the post-Eocene washed residues in the collection of The Standard Oil Company of Egypt, S. A. Lack of any detailed papers on the subject since Macfadyen’s of 1930 is considered to justify publication of the main conclusions reached.
Most of the upper Tertiary rocks of Egypt lie transgressively on Eocene or older beds, but locally some lower Oligocene shales are preserved below the unconformity. At such places the top of the Eocene is marked by abrupt disappearance of Bulimina jacksonensis, Hantkenina spp., Globorotalia cocoaensis although the bulk of the fauna passes with little change into the overlying Oligocene. Of particular interest are the following pelagic species which range above the top of the Eocene:
Globigerina cf. wilsoni
Globorotalia centralis var.
There is a remarkable similarity to the group of pelagic species which characterize the lower Oligocene of Ecuador and neighboring countries (Stainforth 1948).
Beds basal to the first post-Eocene transgression probably include Chattian and Aquitanian elements, judging from he geological history of the eastern Mediterranean (cf. Little 1945, pp. 59, 60, bibliography: Sandford 1944: Arni 1940). Macfadyen (l. c.) only hesitantly admits the presence of pre‑Burdigalian, post‑Eocene beds in the Gulf of Suez, but his conclusions are based partly on paleogeographic correlation with rather remote parts of the Mediterranean, and partly on echinoid determinations by R. Fourtau (1920) which tend to have been dated younger than in more recent studies by the Italian school of geologists in Libya (fide M. Marchetti, private report).
The Foraminifera do not assist in settling the age of the basal transgressive beds. The appearance of large‑apertured species of Globigerinoides may be taken as evidence of post‑mid‑Oligocene age, but this is already fully apparent from other evidence. With very few exceptions the Miocene species of small Foraminifera are long-ranging and the assemblages reflect predominantly the facies in which they lived. Macfadyen (1930, p. 41) recognized this as the reason underlying his inability to establish a rigid foraminiferal zonation within the Globigerina Marls of the Gulf of Suez. The principal facies‑variants are:
(i) A moderately deep marine facies with a rich microfauna characterized by plentiful Lagenidae and nodosarians and the presence of Pullenia spp., Plectofrondicularia spp., Baggina indica, Technitella nitida, Nonion pompilioides, etc.
(ii) A shallower fades with a more limited fauna. Species tending to be conspicuous include Cibicides praecinctus, Uvigerina barbatula and U. bononiensis.
(iii) Littoral and reefal facies with specialized forms such as Miogypsina, Heterostegina, Peneroplidae and Alveolinellidae.
As one criterion of his locally recognizable upper zone Macfadyen (l. c., p. 38) noted the presence in some abundance of Candorbulina universa and Globigerinoides rubra. This observation can be included in a zonation based on pelagic species only, and the present writer has found that with one exception all sections of the Globigerina Marls can be grouped under two zonal units on this basis. The faunal characteristics of the two zones are:
Globigerinoides rubra and/or Candorbulina universa conspicuous.
Globigerina concinna, Globigerina aff. venezuelana and Globigerinoides conglobata absent or inconspicuous.
Globorotalia cf. barissanensis absent.
Globigerinoides rubra and Candorbulina universa absent or inconspicuous.
Globigerina concinna, G. aff. venezuelana and Globigerinoides conglobata. One or more of these generally conspicuous.
Globorotalia aff. barissanensis. Sporadically present, occasionally common.
Globigerina bulloides, Globigerinoides triloba and Globigerinella aequilateralis liable to occur in abundance at all levels.
The exception referred to above is in the Ayun Musa area of Sinai, some 20 miles southwest of Suez, especially at Macfadyen’s Locality No. 14 in Wadi el Bir. The marl at this point contains a remarkably rich fauna which includes an abundance of the pelagic marker‑species of both zones. This anomaly is not fully explained, but tentatively it is suggested that the faunal change used in defining the zones is affected by facies conditions. The value of pelagic organisms as age indicators normally lies in their freedom from facies control, but this generalization applies only to open‑sea deposits. The Gulf of Suez was an unusual form of basin, rather an elongate trough with only a narrow connection to the open Mediterranean. The zonal boundary under discussion falls in the upper Burdigalian and coincides with the beginning of the phase of isolation which culminated in desiccation and the formation of thick Helvetian evaporites. These end‑of‑cycle conditions indicate steadily increasing salinity and surface temperatures, factors which might well have caused a change in the upper Burdigalian pelagic faunas, especially in the southern part of the Gulf. The anomaly near Ayun Musa could then be attributed to its northern position and proximity to the main Mediterranean province, but an obstacle to accepting this is the validity of the pelagic zonation still farther north at Habashi.
In the Western Desert the age‑equivalents of the Globigerina Marls and overlying evaporites of the Gulf of Suez are mainly shallow marine limestones. Microfaunas are sparse, consisting of a Rotalia‑Elphidium‑Discorbis suite of no zonal value. The appearance of Borelis melo characterizes upper Vindobonian levels. Pelagic Foraminifera are seldom encountered, but Globigerinoides conglobata appears to range definitely higher than in the Gulf of Suez marls, a factor with a slight bearing on the foregoing discussion.
At the surface near Dishet el Dhaba, a few miles south of Hurghada, and in some wells a rich foraminiferal fauna has been found in sediments directly overlying the Miocene evaporites. The assemblage contains few of the forms abundant in the underlying Miocene and includes fresh genera and species‑groups such as large Robulus sp. with umbilical nodes, large Rotalia sp., Globigerinoides elongata, a lofty species of Cymbaloporetta, and other distinctive forms. This fauna is considered to be of Pliocene age, representing the second post‑Eocene subsidence of the region, and it may include Indian Ocean forms.
Original descriptions are designated only by name and date, since further details are readily obtainable from the Catalogue of Foraminifera (Ellis and Messina).
Technitella nitida Heron‑Allen and Earland 1932. The Egyptian specimens are usually flattened but appear closest to this species.
Nonion pompilioides (Fichtel and Moll). See Nautilus pompilioides F. and M. 1798. This is recorded by Macfadyen as Nonionina pompilioides (l. c. p. 104)
Borelis melo (Fichtel and Moll). See Nautilus melo F. and M. 1798, Borelis melonoides de Montfort 1808.
Bulimina jacksonensis Cushman 1925. The Egyptian specimens appear identical with this well-known American species. Macfadyen records a single broken specimen of B. sculptilis or jacksonensis from Miocene Marls (l. c. p. 55) but this occurrence is not confirmed by the present studies. Reworked Eocene and Cretaceous microfossils frequently occur near the transgressive base of the Miocene beds.
Uvigerina barbatula Macfadyen 1930 (l. c. p. 92, pl. 3, f. 26).
Uvigerina bononiensis Fornasini 1888. This species is noted by Macfadyen (I.e. p. 93, pl. 3, f. 29).
Baggina indica (Cushman). See Pulvinulina indica Cushman 1921. This species is noted by Macfadyen (l. c. p. 101, pl. 4, f. 13).
Globigerina bulloides d’Orbigny 1826. This species is noted by Macfadyen (l. c. p. 94, pl. 4, f. 2). The form seems close to the original type, cf. topotypes figured by Cushman (1941, p. 38, pl. 10, ff. 1-13).
Globigerina concinna Reuss 1850. See also Cushman (1936, p. 20, pl. 4, ff. 11-15). This species ranges much higher in Egypt than in the Caribbean region.
Globigerina dissimilis Cushman and Bermúdez 1937. Egyptian specimens seem identical with the form figured from Ecuador (Stainforth 1948, p. 119, p1. 25, ff. 29-31) in all respects except that the supplementary chamber bridging the aperture is often lacking.
Globigerina “triloculinoides” Beck 1943, non Plummer 1926. Reference to the occurrence of this species in America has been made by Stainforth (1948, p. 117, pl. 25, ff. 32, 33). It may be the species mentioned in the type description of G. triloculinoides Plummer but distinguished as being larger, having a less conspicuous umbilical lip, and occurring in higher Eocene than Midway and in Oligocene strata in Texas.
Globigerina aff. venezuelana Hedberg 1937. This species was recorded by Macfadyen (l. c. p. 101, pl. 4, f. 14) as “Pulvinulina crassa” (Rotalina crassa d’Orbigny 1840) but it bears little resemblance to the type figure of that Cretaceous species. The aperture indicated by Macfadyen is considered to be an accidental feature of loosely coiled specimens, since it is absent in the numerous more compactly coiled individuals. The gaping square umbilicus is the most constant feature. It seems to belong to the C. venezuelana group, but is closer to specimens figured from Jamaica (Cushman and Jarvis 1930, p. 366, pl. 34, f. 5), Trinidad (Cushman and Stainforth 1945, p. 67, pl. 12, f. 13) and Ecuador (Stainforth 1948, p. 119, pl. 25, ff. 26-28) than to the type figure from Venezuela.
Globigerina cf. wilsoni Cole 1927. An identical species is described from the upper Eocene and lower Oligocene of Ecuador (Stainforth 1948, p. 117, pl. 26, ff. 1-3).
Globigerinoides conglobata (Brady). See Globigerina conglobata Brady 1879. This species is recorded in the American upper Tertiary (Stainforth 1948, p. 121, pl. 26, f. 4).
Globigerinoides elongata (d’Orbigny). See Globigerina elongata d’Orbigny 1826. This distinctive species is readily recognized from the topotypes figured by Cushman (1941, pl. 10, ff. 16-18).
Globigerinoides rubra (d’Orbigny). See Globigerina rubra d’Orb. 1839. The Egyptian form is figured by Macfadyen (l. c. p1. 4, f. 3) but the rate of increasing size of successive chambers is often lower than in the specimen chosen.
Globigerinoides triloba (Reuss). See Globigerina triloba Reuss 1850. This is figured from the Globigerina Marls by Macfadyen (l. c. pl. 4, f. 4). Topotypes have been figured by Cushman, who notes synonymy with Globigerinoides trilocularis (d’Orb.) (1946, pp. 20, 21, pl. 4, ff. 16‑18).
Globigerinella aequilateralis (Brady). See Globigerina aequilateralis Brady 1879. This species is figured by Macfadyen under Globigerina cretacea, though he mentions similarity to the form named here (l. c. p. 94, pl. 4, f. 1).
Candorbulina universa Jedlitschka 1933. Macfadyen (l. c. p. 96) lists Orbulina universa from the Egyptian Miocene, but all the specimens seen in the present study fall under Candorbulina. The bilobate form is present.
Globorotalia aff. barissanensis LeRoy 1939. The species from the lower zone of the Globigerina Marls belongs to this group but is slightly smaller and more regularly constructed dorsally.
Globorotalia centralis Cushman and Bermúdez 1937 var. The variety in question is an inflated form noted from Eocene and lower Oligocene beds in the Caribbean region (Stainforth 1948, p. 118, pl. 26, ff. 27-29).
Globorotalia cocoaensis Cushman 1928. This is probably the unfigured G. crassaformis (G. and W.) of Henson (1938, p. 231 and chart, p. 229), but Globigerina crassaformis Galloway and Wissler 1927 was described from Pleistocene material. G. cocoaensis is widely distributed in the American Upper Eocene and has been recorded in the Eocene of Morocco (Ostrowsky 1938, pp. 344, 345).
Cibicides praecinctus (Karrer). See Rotalia praecincta Karrer 1868. Macfadyen (l. c. p. 98) records this species under Truncatulina.
—, and Stainforth, R. M., 1945, The Foraminifera of the Cipero Marl Formation of Trinidad, B.W.I. Cushman Lab. Foram. Res., Spec. Publ. 14, pp. 1-91, Sharon, Mass.
Ostrowsky, V., 1938, Note Préliminaire sur la Répartition Stratigraphique des Petits Foraminifères dans le Nummulitique du Prérif (Maroc). Soc. Géol. de France, Bull. 5e Ser., tome 8, nos. 5‑6, pp. 341‑353, Paris.
Stainforth, R. M., 1948, Applied Micropaleontology in Coastal Ecuador. Jour. Paleontology, Vol. 22, no. 2, pp. 113-151.
 Originally published by permission of The Standard Oil Company of Egypt, S.A. Cordial acknowledgment is made to D. B. Eicher and others of the company’s geological staff in Cairo for guidance and assistance in the research.
 The writer here expresses his personal opinion as to age, based on the suite of pelagic Foraminifera which defines the Eo‑Oligocene boundary in the Caribbean region. The term Lower Oligocene is thus used in the American sense, which may not be strictly synchronous with European and Mediterranean usage. The Geological Department of Anglo‑Egyptian Oilfields Ltd. kindly reviewed the manuscript and expressed the opinion that the absence of the three Caribbean Eocene species listed is not, in Egypt, evidence of post‑Eocene age, especially since “the principal occurrences of the undoubted Eocene species Nummulites contortus Deshayes and N. striatus Bruguière are found above the level of disappearance of all these species.” The problem thus raised deserves further attention: on the one hand the writer may have generalized too far on the results of a brief study; on the other hand the value of pelagic Foraminifera in long‑range correlation should not be dismissed too lightly, especially in a case where Tethyan communication can be postulated.
 Henson (1938, p. 231, 232 and chart) indicates the appearance of Globigerinoides as early as the Eocene, but from private reports it seems that he included forms with the same chamber arrangement but with supplementary apertures insignificant or lacking (cf. Globigerinoides triloba and Globigerina “triloculinoides”). The present writer applies Globigerinoides only to forms with conspicuous supplementary apertures, as in the original designation of the genus (Cushman 1927, p. 87).