Palynology of Some Cretaceous Mudstones from Southeast Aswan, Egypt: Signiﬁcance to Regional Stratigraphy

Journal of African Earth Sciences 47 (2007) 1–8 www.elsevier.com/locate/jafrearsci

Palynology of some Cretaceous mudstones from southeast Aswan, Egypt: signiﬁcance to regional stratigraphy

Magdy S. Mahmoud *, Mahmoud A. Essa

Geology Department, Faculty of Science, Assiut University, Assiut 71516, Egypt

Received 2 February 2006; received in revised form 5 October 2006; accepted 18 October 2006 Available online 30 November 2006

Abstract

The basal mudstones from the El-Nom borehole in the Gebel Abraq area in southern Egypt have yielded a diverse and relatively well preserved terrestrial palynoflora that includes Balmeisporites holodictyus, Crybelosporites pannuceus, Foveotricolpites gigantoreticulatus, Nyssapollenites albertensis, Retimonocolpites variplicatus and Rousea delicipollis. These suggest an Albian–Cenomanian age and deposition in a fluvio-deltaic environment; no marine phytoplankton is reported. The fern-dominated palynoflora and the overwhelming pres- ence of kaolinitic clays suggest a warm, humid palaeoclimate. According to available knowledge, the mudstones in the Gebel Abraq area, equivalents of the so-called ‘‘Timsah Formation’’, might be correlated with an older rock unit, the Maghrabi Formation, based on the new palynological age assessment. This new definition of local stratigraphy implies that the Bernice sheet of geological map of Egypt [Klitzsch, E., List, F., Po¨hlmann, G., 1987. Geological map of Egypt, sheet NF 36 NE Bernice, 1: 500000. Conoco and the Egyptian General Petroleum Corporation, Cairo] ought to be reconsidered. Ó 2006 Elsevier Ltd. All rights reserved.

Keywords: Terrestrial palynology; Stratigraphy; Cretaceous; Egypt

1. Introduction and geological setting The siliciclastics of the ‘‘Nubian Sandstone’’ rocks are of predominantly continental origin. They are widely exposed This study was conducted as part of a sustainable devel- in central and southern Egypt, and are mostly Cretaceous in opment project in southern Egypt in a trial to improve the age. These rocks are overlain by marine upper Cretaceous quality of living of the Ababda inhabitants in the Eastern rocks of the Duwi (phosphate) and Dakhla formations. A Desert of Egypt. One of the main objectives of this project formal subdivision of the ‘‘Nubian Sandstone’’ in central is to explore underground water for drinking and irrigation. and southern Egypt (Fig. 2) into six formations has been The El-Nom borehole was drilled in the Gebel Abraq area established (see Hermina et al., 1989 and references therein). (Fig. 1) for this purpose and oﬀered the opportunity to study These are, from base to top: the Six Hills (Basal Clastics), palynomorphs from fresh unweathered samples. The target Abu Ballas (Lingula Shale), Sabaya (Desert Rose Beds, of this study is threefold. Firstly, to elucidate the age of the Desert Rose Unit), Maghrabi (Plant Beds, Plant Bed Unit), palynomorph-productive rocks of the study area, for which Taref and Quseir (Variegated Shales, Mut) formations. biostratigraphic information is so far lacking; secondly, to Names in parentheses refer to commonly used informal syn- apply this biostratigraphic information in regional correla- onyms. The lithostratigraphy adopted in Aswan, including tion, and thirdly to use palynological and clay mineralogical the Gebel Abraq area as appearing in the Bernice map sheet data to determine depositional environments. NF 36 NE of Klitzsch et al. (1987), records Nubian units that are lateral time equivalents of the Taref–Quseir formations. These are the sand-dominated Abu Aggag Formation * Corresponding author. E-mail addresses: [email protected] (M.S. Mahmoud), maessa that rests unconformably over an eroded basement surface, [email protected] (M.A. Essa). the clay-dominated Timsah Formation and the overlying

Fig. 1. Geological map of Gebel Abraq area, SE Aswan (after Klitzsch et al., 1987; the Geological Map of Egypt 1: 500000). sand-dominated Umm Barmil Formation. However, rocks age, and may be diachronous, becoming younger from equivalent to the Maghrabi Formation have not previously the west (Dakhla) to the east (Kharga), with a shift in been recognized around Aswan. depocenters. Marine palynomorphs support a marginal Palynology has contributed significantly to the stratigra- marine environment for the Maghrabi Formation (Schrank phy and palaeoecology of the above-mentioned rock units and Mahmoud, 2000). In the Kharga Oasis area, well-pre- (e.g. Schrank, 1984, 1990, 1992, 2001; Schrank and Mah- served pollen and spores indicate an early Campanian age moud, 1998, 2000, 2002; Mahmoud, 2003; Mahmoud and for the base of the Quseir Formation (Mahmoud, 2003). Schrank, 2003) that were for a long time considered unfos- In the east Aswan area, in a location near to Gebel siliferous. Among contributions on the Dakhla area, pal- Abraq, a palynological association with Droseridites seno- ynofloras from the basal Six Hills were proved to be nicus dated the mudstone unit known as the ‘‘Timsah For- exclusively of early Cretaceous age (Schrank and Mah- mation’’ as Coniacian (Sultan, 1985). However, in Upper moud, 1998), as opposed to the previous late Jurassic Egypt the formation has been given a Coniacian to Santo- assumptions for the basal part of the formation. It is nian age based on the occurrence of the bivalves Inoce- now known that the Sabaya Formation may range down ramus balli and I. cycloides (Klitzsch, 1986), few floral into the Aptian and that the overlying Maghrabi Forma- remains such as angiosperm leaves and fruits, and some tion is of Albian-early Cenomanian to late Cenomanian ichnofossils, in highly bioturbated shallow-marine sand- M.S. Mahmoud, M.A. Essa / Journal of African Earth Sciences 47 (2007) 1–8 3

Fig. 2. Correlation of Cretaceous formations in central and southern localities of Egypt. See above listed references for more details. stones (Lejal-Nicol, 1987; Germann et al., 1987). The 2.1. Palynomorphs and palynofacies underlying Abu Aggag Formation contains poorly-preserved leaf remains and ichnofossils in the area of Bir Eighteen mudstone samples, between depths 30 and Sibrit, and is dated as Turonian (see Klitzsch and Hermina, 118 m, were productive and yielded palynofacies. Eight 1989). The Umm Barmil Formation, at the top, contains samples were productive of palynomorphs but only three small lamellibranches and Ostrea rouvillei and is dated in were found to be rich in palynomorphs. Seventy other sur- the areas southeast of Aswan as Santonian to early Camp- face samples were collected and processed, but proved to anian (Klitzsch, 1986; Hendriks et al., 1987). be palynologically barren. The samples were prepared To date, there is little palynostratigraphic information according to standard palynological preparation tech- concerning the strata of southeast Aswan in general and niques. Carbonates were first removed by reaction with the area of Gebel Abraq in particular, except for a few pal- HCl (35%) for approximately 24 h. Silicates were then ynofloras which were documented from a surface mud- removed from neutralized residues using HF (40%) for stone horizon in the Gebel Abraq area, as reported by approximately 24 h. No oxidation or ultrasonic treatments Mahmoud et al. (1995). Although the palynomorphs are were carried out. The digested residue was sieved using not well preserved, an angiosperm-dominated assemblage 10 lm polyamide nylon sieves. For each sample five perma- from mudstones equivalent to those studied here (previ- nent slides were prepared by using glycerine jelly as a ously named as the Abraq Formation, Mahmoud et al., mounting medium. From each productive sample at least 1995), with tricolporates and polyporates (Cretacaeiporites 200 grains were counted for semi-quantitative abundance polygonalis), is dated as late Albian to Cenomanian? The estimates. Additional slides were prepared from certain overlying sandstone-dominated unit, although also originally samples for qualitative studies and documentation of sig- misidentified as the Umm Sidida Formation (Mahmoud nificant or rare palynomorphs. et al., 1995), was allocated to the Cenomanian–Turonian? interval on the basis of regional correlation. As noted in the introduction, the main aim of this study 2.2. Clay mineralogy beside routine palynological investigations is to provide evidence for the age of the mudstone rocks encountered in the The clay fraction (<2 lm) was separated from seven El-Nom borehole and, consequently, to comment on its mudstone samples from the borehole taken at depths of lithostratigraphic setting with respect to other units shown 30, 54, 66, 86, 92, 100 and 114 m (see Fig. 3a). The samples on the Bernice map sheet NF 36 NE of Klitzsch et al. were disaggregated using ultrasonic treatment and washed (1987). Some palaeoenvironmental conclusions have also in distilled water until all soluble salts were removed, been drawn. before being dispersed with Calgon. Separation of the clay fraction was performed using the pipette method (Gale- 2. Materials and methods house, 1971). Oriented samples were mounted on glass slides and two X-ray diffractograms were made per sample The study is based on the description and analysis of 24 (one untreated and one heated at 550 °C for 3 h). The sam- cuttings samples collected from the El-Nom borehole, ples were run using a Philips X-ray diffractometer appara- drilled in the Gebel Abraq area of SE Aswan (Fig. 3a). tus with CuKa radiation, 45 KV and 35 mA and scanning 4 M.S. Mahmoud, M.A. Essa / Journal of African Earth Sciences 47 (2007) 1–8

Fig. 3. (a) The El-Nom borehole section in Gebel Abraq area, with sample positions and inferred lithostratigraphic units according to Klitzsch et al. (1987). (b) Percentage frequency pie diagrams of major palynomorph groups encountered in the Albian–Cenomanian interval of the El-Nom borehole section (1 – at sample depth 104 m, 2 – at sample depth 108 m, 3 – at sample depth 114 m).

between 2 and 40 2h at the rate of 1.2 2h/min. Mineral con- 4. Palynofacies of the mudstones and overlying sand- stituents in the clay fraction were identified using standard dominated interval tables for X-ray mineral identifications (Chen, 1977). Noticeable differences were found during the study of the organic debris, allowing the recognition of four major 3. Palynomorphs from the mudstones (so-called ‘‘Timsah palynofacies groups which display varying proportions of Formation’’) sedimentary organic matter (kerogen) types. These palynofacies are given numbers from 1 to 4 (see Fig. 3a). The palynomorph composition and frequency distribu- Well-preserved cuticle, opaque phytoclasts and amorphous tion in the three rich samples (at depths 104, 108 and organic matter (AOM) dominate facies 1–3, respectively. In 114 m) are similar. Representatives of five major pal- facies 4 diverse kerogen types and palynomorphs co-occur. ynomorph groups were recognized. The pie charts Palynofacies can be used successfully to make environmen- (Fig. 3b) display mean values of these major palynofloral tal and other interpretations (e.g. Batten, 1996). Their categories. The most striking aspect of the palynoflora at major characteristics are described below. depths 104 and 108 m is the dominance of spores, whereas in the 114 m sample diverse fungal palynomorphs occur in 4.1. Palynofacies 1 vast numbers. The fungal remains are dominated by multi- cellular forms, dicellular and unicellular representatives Sample depth: 30 m. and fruiting bodies being scarce. The pteridophytic spores Moderate to well-preserved cuticles, mostly of gymno- consist almost exclusively of Deltoidospora and Triplanosp- spermous origin (they are more resistant than angiosperm orites. Crybelosporites pannuceus (spore of a marsilean cuticles), and other membranous tissues dominate this pal- water fern), Balmeisporites and Ariadnaesporites (salvinea- ynofacies. The cuticles are mostly brown in colour but lean spores) were observed. Single grains of Cicatricosisp- sometimes dark brown. Cuticles and black wood (inerti- orites, foveolate and echinate spores were also found. nite/charcoal) form large phytoclasts more than 1 mm in Verrucate spores occur but are poorly preserved. Angio- diameter, although the latter also occur as small particles. sperm pollen such as Foveotricolpites gigantoreticulatus, The black phytoclasts are subrounded and possess mostly small monocolpates and tricolporates are major contribu- sharp outlines. AOM is not abundant. Degraded brown tors to the palynoflora. Rousea delicipollis, reticulate tricol- wood (vitrinite) phytoclasts are seen in the preparations, pate angiospermous grains, are rare. Gymnosperms are not and they are mostly moderately preserved. Fossil resin as common as angiosperms, despite the fact that the flakes found are similar to the modern Picea (spruce) resin organic debris contains abundant gymnospermous cuticles. (Batten, 1996). Palynomorphs are absent. M.S. Mahmoud, M.A. Essa / Journal of African Earth Sciences 47 (2007) 1–8 5

4.2. Palynofacies 2 Table 1 Semi-quantitative distribution of palynoflora encountered in the pal- Sample depth: 68 m. ynomorph-productive interval, El-Nom borehole, Gebel Abraq area, SE Aswan. For full reference to taxa see Ravn (1998) Opaque organic matter makes up more than 90% of this palynofacies, and is mostly equidimensional and can reach Taxa Sample depths (m) up to 1 mm in diameter. The particles show biological structures and occur either as large phytoclasts or dissem- 104 108 114 inated particles. Other organic debris such as degraded Spores ss wood phytoclasts, cuticles and membranous tissues are Ariadnaesporites sp. Balmeisporites holodictyus, Cookson and Dettmann dsd found, but resinous matter is rare. Palynomorphs are also (1958), Fig. 5 (15) absent except for a few freshwater algae (Pediastrum sp.). Cicatricosisporites sp. d Crybelosporites pannuceus (Brenner), Srivastava ss 4.3. Palynofacies 3 (1977), Fig. 5 (10, 13) Deltoidospora spp. m Echinate spores ds Sample depths: 86, 88, 90, 92, 94, 96, 100 and 102 m. Matonisporites equiexinus, Couper (1958) d AOM dominates this palynofacies with yellowish, Triplanosporites spp. jj brownish and dark brown to black colour. Other phyto- Verrucate spores ds clasts such as brown wood, tracheids and cuticles are rare Gymnospermous pollen and poorly preserved, and resinous matter is present. Araucariacites australis, Cookson (1947) mss Membranous structures are absent and palynomorphs are Balmeiopsis imbatus (Balme), Archangelsky (1979) dd sss extremely rare. The few specimens that have been identified Ephedripites spp. Equisetosporites ambiguous (Hedlund), Singh (1983), sss are Araucariacites spp., triporate pollen (very poorly pre- Fig. 5 (17) served) and freshwater algae (Pediastrum sp.). The sample Eucommiidites sp. sdd from 88 m contains abundant AOM, which could be of Spheripollenites sp. d freshwater or marine origin. Therefore, this sample was Angiospermous pollen also washed for foraminifera to check for possible marine cf. Cretacaeiporites scabratus, Herngreen (1973), d influence in the area, but it proved to be barren. Fig. 5 (12) Foveotricolpites gigantoreticulatus, Jardine´ and ssm 4.4. Palynofacies 4 Magloire (1965), Schrank (1987), Fig. 5 (1, 2, 5, 7) Monocolpopollenites sphaeroidites, Jardine´ and dd Magloire (1965), Fig. 5 (8) Sample depths: 104, 106, 108, 110, 112, 114, 116 and Monocolpopollenites sp. (smooth) ssm 118 m. Monocolpopollenites sp. (finely reticulate), Fig. 5 (3, md Black and brown wood phytoclasts dominate this pal- 16) d ynofacies, and they display different sizes and shapes. They Nyssapollenites albertensis, Singh (1971), Fig. 5 (14) Nyssapollenites spp., Fig. 5 (4, 9, 11) mss frequently occur as elongate laths or as equidimensional Retimonocolpites variplicatus Schrank and Mahmoud d particles with sharp angular outlines, showing evidence of (1998), Fig. 5 (18) biological structures. Other black matter with irregular Rousea delicipollis, Srivastava (1975), Fig. 5 (6) ss outlines is also present. Both black and brown wood phyt- Tricolpites sp. ds sds oclasts are mainly blocky to granular. The black particles Tricolpites spp. (small) show brown edges. At depths of 110 and 114 m, black Freshwater algae wood phytoclasts dominate the palynofacies. The brown Botryococcus braunii, Kutzing (1849) d Chomotriletes minor (Kedves), Pocock (1970) dd wood phytoclasts are moderately to poorly preserved. Ovoidites parvus (Cookson and Dettmann), Nakoman sss Cuticles are abundant in this palynofacies, and are also (1966) moderately to poorly preserved. However, the cuticle is Pediastrum sp. sm well-preserved in the sample located at 104 m. Other mem- Fungal spores branous tissues, AOM and resin also occur along with algal Unicellaesporites spp. mmd palynomorphs (Ovoidites and Pediastrum). The pal- Dicellaesporites spp. sss ynomorphs are derived from a diverse group of land plants Multicellaesporites spp. (uniserial and other varieties) mms ss although they are not as abundant as the palynodebris. In Multicellaesporites spp. (planspiral varieties) Fruiting bodies d general, the state of preservation of this palynofacies is rel- d s m j atively better than the other three. – Single specimen, – present (2–10), – common (10–20), – abundant (>20), – dominant (>50). 5. Palynological age of the mudstones

Several spore and pollen taxa (Table 1) are of late early (Schrank, 1992). Other taxa such as F. gigantoreticulatus to early late Cretaceous aspect. The first tricolporates are known to range into the early Senonian. A comprehen- (Nyssapollenites) appeared in the local record in the Albian sive range of the literature (see Ravn, 1998) has been used 6 M.S. Mahmoud, M.A. Essa / Journal of African Earth Sciences 47 (2007) 1–8 to infer ranges of the most significant palynomorphs ditions and coastal plain vegetation during late Albian to encountered in the present work (Fig. 4). Some taxa pos- early Cenomanian times (Schrank, 2001). sess overlapping ranges which point to an Albian–Cenoma- nian age for this unit. Based on this age assessment, it is 6. Palaeoenvironmental interpretation perhaps surprising that representatives of Afropollis pollen and elaterates (e.g. Elaterosporites and Elaterocolpites) are 6.1. Mineralogical implications missing, but on central Egypt, recent studies have documented the absence of elaterates from rocks of presumed The XRD analyses of the clay fractions (<2 l) in sam- Albian and Cenomanian ages (Schrank and Mahmoud, ples from 30 to 114 m reveal a kaolinitic composition, 1998, 2000). Elaterates are found in many contemporane- which reflects the prevalence of a warm, humid climate ous Albian–Cenomanian sections worldwide (see Hern- during deposition of the mud and sand-dominated part green et al., 1996). Their absence from Egyptian rocks of the succession. Kaolinite, a very stable weathering prod- was first interpreted by Schrank (1992) as being related uct, develops on nearly all types of rocks if rainfall is fre- to palaeoecological factors or to a still-inadequate data- quent and water flow and hydrolysis are sufficiently base. Later, Schrank (2001, p. 208), stated that ‘‘Afropollis strong (Chamley, 1989; Weaver, 1989). Such conditions (aff. Winteraceae) and elaterates (at least partly ephe- are easily established in tropical climates with heavy rain- droids) producers are mainly inhabitants of palaeotropical fall. However, kaolinite is also formed in subtropical and humid coastal plains’’. The absence of the marine influence humid temperate regions, but requires longer time periods in southern Egypt, where the El-Nom borehole section is to accumulate in appreciable amounts (Weaver, 1989). located, is thus perhaps responsible for the missing of both elaterates and Afropollis. In northern Sudan, exceptional 6.2. Implications of palynomorphs and palynofacies Afropollis/elaterates abundance peaks in the Dongola area are probably related to a short-term transgressive event in The mudstones are believed to have been deposited in a the largely non-marine sections, which brought humid con- non-marine (fluviatile) environment since marine pal-

Cretaceous

Lower Upper Cenomanian Maastrichtian Campanian Coniacian Santonian Neocomian in Africa Turonian Ranges Barremian Aptian Albian World range extension U M M U U M L L L

Balmeisporites holodictyus

Crybelosporites pannuceus

Equisetosporites ambiguus

Cretacaeiporites scabratus

Foveotricolpites gigantoreticulatus Nyssapollenites albertensis

N. Triangulus

Retimonocolpites variplicatus

Rousea delicipollis

Concurrent occurrence of taxa (i.e. Albian- Cenomanian age)

Fig. 4. Ranges of selected pollen and spores encountered in the Albian–Cenomanian interval of the El-Nom borehole (except of N. triangulus). Sources for ranges are taken from Ravn (1998). M.S. Mahmoud, M.A. Essa / Journal of African Earth Sciences 47 (2007) 1–8 7

Fig. 5. Albian–Cenomanian angiospermous pollen (1–9, 11, 12, 14, 16, 18), gymnospermous pollen (17) and spores (10, 13, 15) from the palynomorph- productive interval of the El-Nom borehole. 1, 2, 5, 7: Foveotricolpites gigantoreticulatus (1 – depth 108 m, diameter 41 lm, 2 – depth 114 m, diameter 48 lm, 5 – depth 108 m, diameter 39 lm, 7 – depth 114 m, diameter 41 lm). 3, 16: Monocolpopollenites sp., finely reticulate variety (3 – depth 104 m, diameter 21 lm, 16 – depth 114 m, diameter 37 lm). 4, 9, 11: Nyssapollenites spp. (4 – depth 114 m, diameter 20 lm, 9 – depth 114 m, diameter 23 lm, 11 – depth 108 m, diameter 23 lm). 6: Rousea delicipollis, depth 108 m, diameter 25 lm. 8: Monocolpopollenites sphaeroidites, depth 108 m, diameter 25 lm. 10, 13: Crybelosporites pannuceus (10 – depth 104 m, diameter 56 lm, 13 – depth 108 m, diameter 52 lm). 12: cf. Cretacaeiporites scabratus, depth 104 m, diameter 26 lm. 14: Nyssapollenites albertensis, depth 108 m, diameter 23 lm. 15: Balmeisporites holodictyus, depth. 17: Equisetosporites ambiguus, depth 108 m, length 52 lm. 18: Retimonocolpites variplicatus, depth 114 m, diameter 37 lm. ynomorphs such as dinoflagellate cysts are completely are well preserved, probably deposited in situ and not sub- absent. In the overlying sandy interval, palynomorphs are jected to distant transport. Despite the evidence that the absent but the palynofacies, as described earlier, comprises Tethyan shoreline reached as far south as Aswan during debris of terrestrial land plants, such as cuticles, wood Cenomanian times (Ward and McDonald, 1979), we argue phytoclasts and opaque organic matter. This implies that in favour of a non-marine origin for, at least, the this unit is also of terrestrial nature. The abundance of mudstones. pteridophytes and water ferns (45% and 43% of total palynoflora at depths of 104 and 108 m, respectively) supports humid palaeoclimate. Freshwater algae (e.g. Ovoidites, 7. Conclusions Pediastrum) are common constituents associated with the two samples containing ferns. At a depth of 114 m fungi An Albian–Cenomanian age is suggested for at least the are tremendously abundant, which may suggest lacustrine part represented by palynomorph-productive samples from sedimentation (Jansonius, 1976). The fungal palynomorphs the El-Nom borehole based on the overlapping ranges of 8 M.S. Mahmoud, M.A. Essa / Journal of African Earth Sciences 47 (2007) 1–8 the sporomorphs Balmeisporites holodictyus, C. pannuceus, egor, D.C. (Eds.), Palynology: Principles and Applications, vol. 3. F. gigantoreticulatus, Nyssapollenites albertensis, Retimono- American Association of Stratigraphic Palynologists Foundation, pp. colpites variplicatus and R. delicipollis. Palynofloral data 1157–1188. Jansonius, J., 1976. Palaeogene fungal spores and fruiting bodies of the indicated that terrestrial environments took place during Canadian Arctic. Geoscience and Man 15, 129–132. deposition of the so-called ‘‘Timsah Formation’’. Palyno- Klitzsch, E., 1986. Plate tectonics and cratonal geology in Northeast logical and clay mineralogical data suggest a warm-humid Africa (Egypt/Sudan). Geologische Rundschau 75 (3), 753–768. palaeoclimate, where the fern spores and the clay mineral Klitzsch, E., Hermina, M., 1989. The Mesozoic. In: Hermina, M., kaolinite dominate. A lack of humid coastal plains is Klitzsch, E., List, F. (Eds.), Stratigraphic Lexicon and Explanatory Notes to the Geological Map of Egypt 1:500000. Conoco Inc. and thought to be responsible for the absence of Albian–Ceno- Egyptian General Petroleum Corporation, Cairo, pp. 77–139. manian elaterates and Afropollis. A contradiction took Klitzsch, E., List, F., Po¨hlmann, G., 1987. Geological map of Egypt, sheet place based on the current investigation because the paly- NF 36 NE Bernice, 1: 500000. Conoco and the Egyptian General nological age of the mudstone unit equivalent to the so- Petroleum Corporation, Cairo. called Timsah Formation is proved to be as old as Lejal-Nicol, A., 1987. Flores nouvelles du Paleózoique et de Me´sozoique d’Egypte et du Sudan septentrional. Berliner Geowissenschaft Albian–Cenomanian and can be correlated with the Magh- Abhandlungen, A 75 (1), 151–248. rabi Formation. This implies that a revision of the units Mahmoud, M.S., 2003. Palynology and palaeoenvironment of the Quseir must be considered in the light of the new dating. Formation (Campanian) from central Egypt. Journal of African Earth Sciences 36, 135–148. Acknowledgements Mahmoud, M.S., Schrank, E., 2003. Early Cretaceous (Neocomian-early Barremian) spores and pollen grains from the Six Hills Formation, Kharga area, Egypt. Neues Jahrbuch fu¨r Geologie und Palaöntologie, Thanks go to Prof. Dr. M. Elhaddad (Assiut University) Abhandlungen 227 (2), 153–174. and the geology research team who allowed the authors to Mahmoud, M.S., Askalany, M.M., Abu Zeid, K.A., Thabit, G.K., 1995. study the present material, in the framework of the project New contributions to the geology of Gebel Abraq area, southeast entitled ‘‘The sustainable improvement in the quality of liv- Aswan (Egypt): recognition of mid-Cretaceous stratigraphic units. Neues Jahrbuch fu¨r Geologie und Palaöntologie, Abhandlungen 11, ing of the Ababda Inhabitants, Eastern Desert, Egypt’’. We 681–696. are grateful to Dr. I. Harding (University of Southampton, Ravn, R.L., 1998. Taxon.exe, v 3.2, Free Internet Database. http:// UK) for linguistic and scientific improvements of the man- www.palydisks.palynology.org/. uscript. Two anonymous reviewers are also thanked for Schrank, E., 1984. 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