The Dababiya corehole, Upper Nile Valley, Egypt : preliminary results

of the CLIMATE & BIOTA EARLY PALEOGENE Volume 105/1 Austrian Journal of Earth Sciences Vienna 2012 The Dababiya corehole, Upper Nile Valley, Egypt: Preliminary results____________________________________________ William A. BERGGREN 1)2)*) , Laia ALEGRET , Marie-Pierre AUBRY , Ben S. CRAMER , Christian DUPUIS , Sijn GOOLAERTS , 3) 1) 4) 5) 6) Dennis V. KENT , Christopher KING , Robert W. O’B. KNOX , Nageh OBAIDALLA , Silvia ORTIZ , Khaled A. K. OUDA , 1)7) 8) Ayman ABDEL-SABOUR , Rehab SALEM 10) 9) 1)12) 10) , Mahmoud M. SENOSY , Mamdouh F. SOLIMAN 10) 11) 10) & Ali SOLIMAN 1) Department of Earth and Planetary Sciences, Rutgers University 610 Taylor Rd., Piscataway, NJ 08854-8066, USA; 2) Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA; 3) Universidad de Zaragoza, Calle Pedro Cerbuna, E-50009 , Zaragoza, Spain; 4) Theiss Research, Eugene, Oregon, USA; 5) UMONS-GFA, rue de Houdain, 9- B 7000 Mons, Belgium; 6) Royal Belgian Institute of Natural Sciences, Vautierstraat 29, 1000 Brussels, Belgium; 7) Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10964 USA; 8) 16A Park Rd., Bridport DT6 5DA, UK; 9) British Geological Survey, Keyworth NG12 5GG, UK; 10) 11) Universidad del País Vasco, PO Box 644, 48080 Bilbao, Spain; Geology Department, Faculty of sciences, Tanta University, 31527-Tanta, Egypt; 13) Karl-Franzens, University of Graz, Institute of Earth Sciences, Heinrichstrasse 26 A-8010 Graz, Austria; Corresponding author, [email protected] 12)13) KEYWORDS Department of Geological Sciences, University of Assiut, Assiut, Egypt; 12) *) 10) Dakhla and Esna Shale Formations Upper Cretaceous and Paleocene Dababiya Quarry Tarawan Chalk stratigraphy Abstract The Dababiya corehole was drilled in the Dababiya Quarry (Upper Nile Valley, Egypt), adjacent to the GSSP for the Paleocene/ Eocene boundary, to a total depth of 140 m and bottomed in the lower Maastrichtian Globotruncana aegyptiaca Zone of the Dakhla Shale Formation. Preliminary integrated studies on calcareous plankton (foraminifera, nannoplankton), benthic foraminifera, dinoflagellates, ammonites, geochemistry, clay mineralogy and geophysical logging indicate that: 1) The K/P boundary lies between 80.4 and 80.2 m, the Danian/Selandian boundary between ~ 41 and 43 m, the Selandian/Thanetian boundary at ~ 30 m (within the mid-part of the Tarawan Chalk) and the Paleocene/Eocene boundary at 11.75 m (base [planktonic foraminifera] Zone E1 and [calcareous nannoplankton] Zone NP9b); 2) the Dababiya Quarry Member (=Paleocene/Eocene Thermal Maximum interval) extends from 11.75 to 9.5 m, which is ~1 m less than in the adjacent GSSP outcrop.; 3) the Late Cretaceous (Maastrichtian) depositional environment was nearshore, tropical-sub tropical and nutrient rich; the latest Maastrichtian somewhat more restricted (coastal); and the early Danian cooler, low(er) salinity with increasing warmth and depth of water (i.e., more open water); 4) the Paleocene is further characterized by outer shelf (~ 200 m), warm water environments as supported by foraminifera P/B ratios > 85% (~79-28 m), whereas benthic foraminifera dominate (>70%) from ~27-12 m (Tarawan Chalk and Hanadi Member) due, perhaps, in part to increased dissolution (as observed in nearby outcrop samples over this interval); 5) during the PETM, enhanced hydrodynamic conditions are inferred to have occurred on the sea-floor with increased river discharge (in agreement with sedimentologic evidence), itself a likely cause for very high enhanced biological productivity on the epicontinental shelf of Egypt; 6) correlation of in situ measured geophysical logs of Natural Gamma Ray (GR), Single-Point Resistance (PR), Self-Potential (SP), magnetic susceptibility (MS), and Resistivity, and Short Normal (SN) and Long Normal (LN) showed correspondence to the lithologic units. The Dababiya Quarry Member, in particular, is characterized by very high Gamma Ray and Resistivity Short Normal values.________________ 1. Introduction The GSSP for the base of the Eocene Series is located at related also on the basis of 1) the mass extinction of abyssal 1.58 m above the base of Section DBH in the Dababiya Quar- and bathyal benthic foraminifera (Stensioeina beccariiformis ry, on the east bank of the Nile River, about 35 km south of microfauna), and reflected at shallower depths by a minor ben- Luxor, Egypt (Aubry et al., 2007). It is the base of Bed 1 of thic foraminiferal turnover event; 2) the transient occurrence of the Dababyia Quarry Beds of the El Mahmiya Member of the the excursion taxa among the planktonic foraminifera (Acari- Esna Shale Formation, interpreted as having recorded the ba- nina africana, A. sibaiyaensis, Morozovella allisonensis); 3) sal inflection of the carbon isotope excursion (CIE), a promi- the transient occurrence of the Rhomboaster spp. – Discoas- nent (3 to 5‰) geochemical signature which is recorded in ter araneus (RD) nannoplankton assemblage); 4) an acme of marine (deep and shallow) and terrestrial settings around the the dinoflagellate Apectodinium complex. The GSSP-defined world. The Paleocene/Eocene (P/E) boundary is thus truly a Paleocene/Eocene boundary is approximately 0.8 Myr older globally correlatable chronostratigraphic level. It may be cor- than the base of the stratotypic Ypresian Stage in epiconti- The Dababiya corehole, Upper Nile Valley, Egypt: Preliminary results nental northwestern Europe. We retain the term Sparnacian Stage for the interval separated by these two stratigraphic horizons. Calcareous and organic-walled microfossils in Paleogene 3. Lithostratigraphy and sedimentology The core consists of, in stratigraphic order, the Dakhla Shale Formation (140 to 39 m), the Tarawan Chalk (39 to 22 m; Fig. 2), and the Hanadi (22 to 11.40 m), Dababiya Quarry (11.40 and Upper Cretaceous outcrops in most of Egypt are poorly to 9.5 m) and El Mahmiya (9.5 to 0 m) members of the Esna to only moderately well preserved as a result of post-depositi- Shale Formation. The Dakhla Shale Formation is provisionally onal carbonate recrystallization. The Dababiya Quarry micro- divided into five informal lithologic units. A phosphate-rich bed fossils are no exception and, indeed, both calcareous nanno- at 136 m separates units 1 and 2. A strongly burrowed surface plankton and planktonic foraminifera suffered from dissolution/ at 111 m separates units 2 and 3. The latter extends up to 83 recrystallization and no dinoflagellates were preserved. Benthic m marked by a bioturbated surface at the base of a phospha- foraminifera fared somewhat better. Additionally, no paleomag- tic bed. Unit 5 is thin (4 m) and topped by a pyritized horizon netic stratigraphy was possible in outcrop because 1) stable marking the K/P boundary. Unit 4 extends to the base of the magnetizations are carried by hematite with no evidence of a Tarawan Chalk, marked by a sharp increase in CaCO3 content. primary magnetic mineral such as magnetite, 2) the magnetic Bioturbation is conspicuous between ~73 and 78 m (Lower polarity stratigraphy is inconsistent with patterns expected Danian) and between ~42 and 47 m (in the vicinity of the Da- from the geomagnetic time scales, and 3) directions corres- nian/Selandian boundary). The interval from 9.4 m to 6.0 m in pond to late Cenozoic directions and are far from those ex- the corehole is readily correlated with the interval from 5.4 m pected from early Cenozoic directions for Africa (Kent and to 9.0 m in the DBH (outcrop) subsection and the interval Dupuis, 2003).______________________________________ from 0.0 m to 3.5 m in the DBD subsection.______________ In the hope of obtaining material of better preservation and The clay mineral content (chlorite, illite, illite-smectite [R0 reliable magnetostratigraphy we obtained funding to drill a type], kaolinite) varies in the core. The interval from 140 to 80 corehole in the vicinity of the outcrop section(s). We describe m (unit 4) contains chlorite with illite and kaolinite, indicating below some of the preliminary results of our studies while no- detrital input. The interval from 80 m to 15/20 m is characte- ting that microfossil preservation has proved only marginally rized by smectitic mixed layers with lesser amounts of illite better, except for the dinoflagellates, and paleomagnetic mea- and kaolinite. This may reflect reduced detrital input into the surements have again been found to be unreliable with occur- basin. From 15/20 m to the top of the core, kaolinite and illite rences of hematite remanence carriers, suggesting that che- are abundant, indicating continental erosion. The peak in kao- mical alteration and remagnetization are not simply due to linite and illite at the P/E boundary likely reflects an episode surficial weathering._________________________________ of runoff associated with global warming, as supported by geo- 2. Background regarded as anchimetamorphic minerals. However, conside- chemical analysis (see below). Chlorite and illite are broadly The Dababiya corehole (25° 30’09.9” N, 32° 31’27.1” E) was ring the shallow burial depth (~350 to 500 m) of the lower Pa- drilled in February 2004. It is located ~200 m east of the Eo- leogene sediments at Dababyia, such an origin is not possi- cene GSSP DBH section (Aubry et al., 2007; Fig. 1). It was ble. As is often case in sedimentary successions, illite and spudded in the El Mahmiya Member of the Esna Shale For- chlorite are of detrital origin in the core. Kaolinite is typically a mation, ~9.5 m above the Dababiya Quarry Member. It pene- product of continental weathering associated with acidic lea- trated to a total depth of 140.2 m, and bottomed in ammonite ching processes. Smectites and particularly the IS-mixed lay- –nuculid–bearing phosphatic shales of the Dakhla Shale For- ers may form in sea water by aggradation, but they may also mation in the lower Maastrichtian Globotruncana aegyptiaca form in soils. Their detrital origin is thus blurred by marine ag- Zone. Recovery was generally good but the upper/initial ~ 6 m gradation processes, as might be the case here. For a com- of the corehole were poorly recovered.__________________ prehensive discussion on the origin of clays we refer the reader to Thiry and Jacquin (1993).___ A high-resolution mineralogical and geochemical study of the Dababiya Quarry Member in the Dababiya core was carried out by Soliman et al. (2011) complementing the studies of Dupuis et al. (2003), Ernst et al. (2006), Soliman et al. (2006) and Schulte et al. (2011) on the adjacent Gabal Dababiya (PaleoceneEocene GSSP) outcrop section. The sediments of the Dababiya Quarry Member are distinctive in containing Figure 1: Geographic location of the Dababyia Corehole._______________________________ relatively high amounts of phosphatic William A. BERGGREN, Laia ALEGRET, Marie-Pierre AUBRY, Ben S. CRAMER, Christian DUPUIS, Sijn GOOLAERTS, Dennis V. KENT, Christopher KING, Robert W. O’B. KNOX, Nageh OBAIDALLA, Silvia ORTIZ, Khaled A. K. OUDA, Ayman ABDEL-SABOUR, Rehab SALEM, Mahmoud M. SENOSY, Mamdouh F. SOLIMAN & Ali SOLIMAN components (fish debris and coprolites), bacterial pyrite fram- and Morozovella allisonensis). The greater part of the Hanadi boids and organic matter. Strong positive anomalies in the Member corresponds to Subzone P4c (21.15–14.25 m) and trace elements Zn, V, Mo, Ni, Cr, Cu, P and S are present at Zone P5 (14.25–11.75 m). The P4a-b/P4c subzonal boundary the top of Bed 1 (clay bed) and in Bed 2 (bone-bearing bed), is placed at the contact between the Tarawan Chalk and Ha- corresponding to the core of the CIE. These geochemical and nadi Member (= lowest occurrence [LO] of Acarinina soldado- mineralogical signatures indicate deposition during a period of ensis at ~21 m); the E1/E2 zonal boundary corresponds with upwelling and high productivity, with the development of su- the Dababiya Quarry/El Mahmiya boundary at 9.5 m._______ boxic to anoxic conditions at or just above the sediment-water The Cretaceous/Paleogene (K/P) boundary is located at ~ interface. High Ti/Al ratios indicate increased river discharge 80 m. Sediments between 81 and 80 m are characterized by, at this time, most probably in response to climatic warming. i.al., Pseudotextularia deformis, Peudoguembelina costulata, The sediments of the recovery phase of the CIE reflect a gra- P. kempensis, P. palpebra and Globigerinelloides aspera de- dual return to open marine environments similar to those that noting the uppermost Maastrichtian P. palpebra Zone. Zone prevailed during the Late Paleocene.____________________ Pα spans the interval between 80 and 79 m. Zone P1 extends 4. Biostratigraphy P1a (up to 76.4 m), P1b (to 72.40 m) and P1c (up to 68.35 m). 4.1 Planktonic foraminifera Zone P3 extends from 56.60 m to 39.60 m. The LO of Igorina from 79 to 68.35 m (~11 m) and can be divided into Subzones Zone P2 extends from 68.35 m to 56.60 m (LO of M. angulata). The core spans from lower Eocene (Zone E2) to lower Maast- albeari (P3a/b subzonal boundary) occurs at 49.45 m below a richtian (Globotruncana aegyptiaca Zone) (Figure 2). Planktonic black layer at 46.5 m. The highest occurrence (HO) of Prae- foraminifera are generally rare and moderately preserved. The murica carinata is at this level. The Danian/Selandian boundary biostratigraphy of the Tarawan Chalk to El-Mahmiya Member is placed at ~46.5 m on this basis. Zone P4 is denoted by the is the same as in the nearby GSSP section (see Berggren and LO of Gl. pseudomenardii just below the Tarawan Chalk/Dakhla Ouda, 2003; Chapter 4) with predominantly morozovellid and Shale contact at ~ 39 m. The P4a/b boundary is denoted by acarininid taxa and subordinate numbers of subbotinids. The the HO of Parasubbotina variospira at 34 m in the lower part Dababiya Quarry Member (11.75–9.5 m) contains a mixed aca- of the Tarawan Chalk.________________________________ rininid-morozovellid assemblage with subordinate subbotinids Assemblages from 137 to 140 m (base of the corehole) are and the excursion taxa (Acarinina africana, A. sibaiyaensis characterized by Globotruncana arca, G. aegyptiaca, G. lin- Figure 2: Lithology, biostratigraphy, geochemistry and mineralogy of Dababya Corehole. Formation and Member names shown in left column. Cretaceous/Paleogene (K/P) boundary lies at ~80 m; Paleocene/Eocene (=Thanetian/Sparnacian) boundary lies at 11.75 m (= [PF] P5/E1 and [CN] NP9a/b) zonal boundaries). PETM=11.75–9.5 m. See text for discussion/explanation of P/B ratios, carbonate and clay mineralogy data; DBM: Dababiya Quarry Member._______________________________________________________________________________________________________ The Dababiya corehole, Upper Nile Valley, Egypt: Preliminary results neiana, G. ventricosa, Archeoglobigerina cretacea, Heterohelix and H. anartios). The youngest beds belong to Zone NP9b, globulosa, H. moremani and H. reussi indicative of the lower and lie very close to the NP9/NP10 zonal boundary. The Tara- Maastrichtian G. aegyptiaca Zone. Maastrichtian samples be- wan Chalk is extremely difficult to date, encompassing Zone tween 137 and 81 m were not examined with few exceptions NP5 to NP9a (39 to 22 m).____________________________ and will form the subject of future studies.________________ The bulk of the Dakhla Shale belongs to Zone NP4 (69 m to 33 m). The Neo-Duwi beds (see Aubry et al., this volume) are 4.2 Calcareous Nannoplankton predicted to occur in the interval between 43.15 and 41 m. The Coccoliths are common to abundant at most levels through- LO of Diantholitha mariposa at 47.05 m, those of D. alata, D. out the section, but preservation varies greatly. Assemblages magnolia, Lithoptychius collaris and L. felis at 43.15 m, and are of rather low diversity, and some markers are unexpec- the HO of Diantholithus spp. at 41 m constitute a characteris- tedly rare. Species of Heliodiscoaster and Heliolithus were tic sequence in the vicinity of the Neo-Duwi beds at Gebel generally rare, causing difficulties in determining the presence Qreyia (Aubry et al., this volume). The radiation of Lithopty- and /or extent of Zones NP6, NP7 and NP8 (Figure 2). For chius (first radiation of the fasciculiths, Romein, 1979; second this preliminary study only the zonal markers of Martini (1971) radiation of the fasciculiths, Bernaola et al., 2009) that marks and Sissingh (1977) are considered.____________________ the Danian/Selandian boundary begins at 43.15 m. The LO of The Paleocene/Eocene boundary lies at the base of Bed 1 Sphenolithus primus was noted at 35 m. The Selandian/Tha- of the Dababyia Quarry Member, with the upper part of the netian boundary is extremely difficult to delineate. It possibly Hanadi Member belonging to Subzone NP9a, and the Daba- corresponds to a burrowed surface between 23 and 24 m, byia Quarry Member Bed 2 belonging to the older part of Sub- and a substantial stratigraphic gap is inferred. Zonal bounda- zone NP9b as characterized by the so-called RD assemblage ries are difficult to delineate below 69 m because of the scar- (which consists of Rhomboaster spp., Helio-discoaster araneus city of the marker species. The NP3/NP4 zonal boundary lies Figure 3: Benthic foraminiferal assemblages in the Cretaceous Dakhla Shales Formation through lowermost Eocene Esna Shales Formation. DQM: Dababiya Quarry Member._____________________________________________________________________________________________________ William A. BERGGREN, Laia ALEGRET, Marie-Pierre AUBRY, Ben S. CRAMER, Christian DUPUIS, Sijn GOOLAERTS, Dennis V. KENT, Christopher KING, Robert W. O’B. KNOX, Nageh OBAIDALLA, Silvia ORTIZ, Khaled A. K. OUDA, Ayman ABDEL-SABOUR, Rehab SALEM, Mahmoud M. SENOSY, Mamdouh F. SOLIMAN & Ali SOLIMAN between 70.5 m and 72.5 m. The base of Zone NP2 occurs The uppermost Paleocene assemblages from the El Hanadi between 77.85 and 78.40 m. The K/P boundary is denoted by Member of the Esna Shale Formation contain abundant buli- the LO of B. sparsus at 80.20 m. The interval between 80.40 m minids (Bulimina callahani), which may indicate an abundant and 84 m is characterized by the occurrence of Nephrolithus flux of food to the seafloor and partially dissolved tests that frequens and belongs to Zone CC26. The occurrence of Micula may be indicative of corrosive bottom waters._____________ prinsii at 80.40 and 80.60 characterizes Subzone CC26b. No The HOs of species such as Anomalinoides rubiginosus, Ci- samples were studied between 84 m and 139.90 m. A sample bicidoides hyphalus and Gyroidinoides globosus in the Daba- from 139.90 m belongs to Zone CC24 or older.____________ biya Corehole can be correlated with the Benthic Foraminiferal Extinction Event (BEE) that occurred in deep-water set- 4.3 Dinoflagellates Diverse and well-preserved dinoflagellate cyst assemblages tings during the PETM. Less than 10% of the benthic foraminiferal species disappeared at the Paleocene/Eocene boun- were recovered from the Dakhla Formation. The interval be- dary in the section, confirming that the BEE was less promi- tween 70 and 140 m is Upper Cretaceous–Lower Paleocene, nent in shallow epicontinental environments compared to the but there is no sharp qualitative changes in the dinoflagellate deep sea (Alegret and Ortiz, 2006)._____________________ cyst associations that would help in precisely delineating the Lowermost Eocene assemblages (Dababiya Quarry Member) K/P boundary. The LOs of Damassadinium californicum and contain abundant pyritized molds and dissolved tests. Low di- Carpatella coronata (80.25 m), Senoniasphaera inornata (81 versity assemblages are mainly dominated by uniserial taxa, m), Membranilarnacia?, Tenella and Kallosphaeridium yoru- trochamminids, Lenticulina, Anomalinoides cf. zitteli, C. pseu- baense (80.75 m), Palynodinium grallator (80.75 m) and Ken- doperludicus, Globocassidulina subglobosa and Oridorsalis leyia leptocerata (81 m) and the HOs of Dinogymnium spp. umbonatus. Samples available from the Dababiya Quarry Mem- (80.75 m), Damassadinium fibrosum (82.1 m) and Alisogym- ber were insufficient to assess in detail the paleoenvironmental nium euclaense (84 m) are significant markers around the turnover across the PETM in comparison to earlier high reso- Maastrichtian/Danian boundary (e.g., Slimani et al., 2010). lution studies (e.g., Alegret and Ortiz, 2006). Available data Thus the K/P boundary is between 80 m and 81 m or, possi- confirm the previous pattern of recovery documented by these bly, at 81.75 m._____________________________________ authors. In particular, the presence of abundant pyritzed moulds 4.4 Ammonites Quarry Beds suggest carbonate dissolution during the PETM. of benthic foraminifera and dissolved tests in the Dababiya In the Cretaceous part of the core, ammonites are observed at several levels between 80.42 and 139.27 m. They are al- 5.2 Ratio planktonic/benthic foraminifera most all heteromorph ammonites such as scaphitids and ba- The ratio of planktonic to benthic foraminifera in the 125- culitids. The presence of the stratigraphically restricted sca- 250 µm size fraction varies considerably in the interval 81 phitid species Indoscaphites pavana (Forbes, 1846), previ- m–12 m and characterizes three markedly different intervals. ously only known from southern India, Algeria and Tunisia Between 81 and 80 m the planktonic foraminifera are in very (Goolaerts et al., 2004; Goolaerts, 2010), suggests that the low proportions (< 10% compared with 60% at 82 m). This interval from ~100 to 80 m represents the latest 420 kyr of prominent event between 81 and 82 m is latest Maastrichtian. the Maastrichtian. This is supported by the presence of the Between 79 and 28.5 m the planktonic foraminifera occur in latest Maastrichtian planktonic foraminifer Abathomphalus very high proportions (mostly > 85%). This is typical for outer mayaroensis in the same interval.______________________ neritic to upper bathyal open marine environments. Between 5. Paleoenvironments This abrupt drop in the abundance of the planktonic foramini- 28.0 and 12.0 m the benthic foraminifera dominate (>70%). fera occurs in the upper part of the Tarawan Chalk and low 5.1 Benthic foraminifera abundances persist through the Hanadi Member.__________ Benthic foraminiferal assemblages are dominated by taxa These abrupt changes clearly indicate major oceanographic typical of the Midway-type fauna and of outer shelf environ- events and need to be calibrated with other environmental ments, and indicate deposition at about 200 m depth for most parameters. part of the studied section (Fig. 3)._____________________ Significant changes in composition have been observed, with 5.3 Dinoflagellates very low diversity assemblages characteristic of low-oxygen en- Dinoflagellate assemblages indicate that environmental vironments in the Cretaceous dark-colored levels of the Dakhla changes occurred through the Maastrichtian and Danian. The Shale Formation, followed by the typical Paleocene assembla- interval between 140 and 86 m is marked by the abundance ges dominated by the Midway–type fauna (e.g., Angulogaveli- of peridinioid cysts such as Palaeocystodinium, Phelodinium, nella avnimelechi, Bulimina midwayensis, Cibicidoides alleni, Cerodinium and Deflandrea. This is indicative of near-shore, Cibicidoides succeedens, Loxostomoides applinae, Osangu- tropical-subtropical and nutrient-rich environments (Lentin and laria plummerae, Siphogenerinoides eleganta; Berggren and Williams, 1980). Based on the abundance of Manumiella the Aubert, 1975) in the Dakhla Shale and Tarawan Formations._ interval between 86 and 80 m corresponds to a restricted, low The Dababiya corehole, Upper Nile Valley, Egypt: Preliminary results salinity and cold environment (Habib and Saeedi, 2007). A gra- CGS units), GR values (72-101 API), PR (51-53 Ohm), SN dual increase in water depth from a near shore to open marine (75-80 Ohm-m), and SP values (-2328 to -2082 mV), while (warm) environment is inferred for the interval between 80 and LN values are high (49-50 Ohm.m). This geophysical zone 70 m based on the abundance of gonyaulacoid cysts such as corresponds to the El-Mahmiya Member. The second geophy- Glaphyrocysta, Areoligera, Operculodinium and Spiniferites sical zone extends from 9.7 to 11.75 m and has moderate to (Brinkhuis and Zachariasse, 1988)._____________________ low MS (1.0-4.0 CGS units) while characterized by very high 6. Geophysical logging values change from 51-53 Ohm and the SP values from - values of GR (79-460 API) and SN (72-87 Ohm.m). The PR The geophysical logging was carried out by the Egyptian 2536 to -2262 mV; LN is high (50-52 Ohm-m). This zone cor- Geological Survey and Mining Authority (EGSMA). It included responds to the Dababyia Quarry Member. The third geophy- Natural Gamma Ray (GR), Single-Point Resistance (PR), sical zone extends from 11.75 to 21.35 m. It is characterized Self-Potential (SP), and Resistivity, Short Normal (SN) and by moderate to very low values of MS (0.4-4.0 CGS units) Long Normal (LN). The magnetic susceptibility of the core and moderate to low values of GR (52-94 API), SN (50-77 was measured in Assiut University._____________________ Ohm-m) and SP from -2282 to -1784 mV. PR values change The geophysical logs were correlated with each other as well from 49 to 53 Ohm and the LN from 2 to 52 Ohm-m. This as the magnetic susceptibility. From this correlation it was easy zone corresponds to the El-Hanadi Member. The fourth geo- to separate five geophysical zones. These zones are descri- physical zone extends from 21.35 to 39 m, and is characteri- bed from top to bottom as follows (Figure 4). The first geo- zed by moderate to very low values of MS (0.7-5 CGS units), physical zone extends from the ground surface to 9.7 m. This with high GR (24-101 API) and SP values (-2499-1740 mV). zone is characterized by high to moderate MS values (2.0-7.0 The PR ranges between 49 and 57 Ohm, the SN values be- Figure 4: Geophysical logging of Dababiya corehole. See text for further explanation.________________________________________________ William A. BERGGREN, Laia ALEGRET, Marie-Pierre AUBRY, Ben S. CRAMER, Christian DUPUIS, Sijn GOOLAERTS, Dennis V. KENT, Christopher KING, Robert W. O’B. KNOX, Nageh OBAIDALLA, Silvia ORTIZ, Khaled A. K. OUDA, Ayman ABDEL-SABOUR, Rehab SALEM, Mahmoud M. SENOSY, Mamdouh F. SOLIMAN & Ali SOLIMAN tween 50 and 73 Ohm-m, and the LN between 2 and 5 Ohm- marine (warm) environment.________________________ m). This zone is encountered in the Tarawan Chalk Forma- 6) Five geophysical zones were identified, which clearly reflect tion. The fifth geophysical zone extends from 39 m to the different lithologies. The main chronostratigraphic boun- bottom of the well. It has very high to very low values of MS daries were also marked by sharp peaks in the GR. PR (0.1-11 CGS units) and SN (25-94 Ohm-m) and high to low and MS. values of GR (34-224 API) and PR (46-53 Ohm). The SP values range between -5748 and -1676 mV, and the LN values Acknowledgements between 0.4-5 Ohm-m). This zone encompasses the Dakhla This paper is an outgrowth of a poster presented at the Cli- Shale Formation.____________________________________ mate and Biota of the Early Paleogene Conference (CBEP 8) The geophysical zones clearly reflect different lithologies. In held in Salzburg, June 5-8, 2011. We are grateful to Hans Eg- addition, the biostratigraphically identified P/E and K/P boun- ger (Geological Survey of Austria) for organizing the confe- daries are marked by sharp peaks in all logs particularly in rence and to Michael Wagreich (University of Vienna) for his the GR and PR as well as in the magnetic susceptibility. Of editing the proceedings volume of the conference. We thank special interest are the major GR peaks associated with the the many colleagues who were kind enough to offer comments Dababiya Quarry Member and the Neo-Duwi beds. These on the poster during the course of the meeting, and to Werner peaks are associated with relatively high concentrations of Piller and Peter Schulte for reviewing the paper. We are grate- phosphate and organic matter, both of which are commonly ful to Dave Bord for assistance with the preparation of the enriched in uranium and other radioactive elements._______ figures. The Dababiya corehole was made possible by the financial support of the National Geographic Society. RK pub- 7. Conclusions The Dababiya Corehole provides basic information on the lishes with the approval of the Executive Director, British Geological Survey (NERC)._______________________________ litho-, bio- and chemostratigraphy of the Late Cretaceousearliest Eocene (~70-56 Ma) of the Upper Nile Valley. This will be expanded in a more thorough analysis as a monograph in the near future.___________________________________ At this stage of our work we can cite the following (prelimi- References Alegret, L. and Ortiz, S., 2006. Global extinction event in ben- nary) conclusions:___________________________________ thic foraminifera across the Paleocene/Eocene boundary at 1) The Dababiya corehole recovered ~ 80 m of lower Eocene- the Dababiya Stratotype section. Micropaleontology, 52(5), Paleocene shales and chalk, and ~60 m of Upper Cretaceous (Maastrichtian) black shales._____________________ 2) The Dababiya corehole recovered a relatively complete succession of Paleocene and lowermost Eocene planktonic foraminiferal and calcareous nannoplankton zones. The hole terminated in the Lower Cretaceous Globotruncana aegyptiaca Zone._____________________________ 3) Assemblages characteristic of low-oxygen environments in the Cretaceous dark levels of the Dakhla Shale Formation 48-63. Aubry, M.-P., Rodriguez, O., Bord, D., Godfrey, l., Schmitz, B. and Knox, R. W. O’B., 2011. Paleocene evolution of the Order Discoasterales (Coccolithophores): biostratigraphic and paleoceanographic implications. In: H. Egger (ed.), Climate and Biota of the Early Paleogene. Conference Program and Abstracts, 5-8 June 2011, Salzburg, Austria. Berichte der Geologischen Bundesanstalt, 85, 36.________________________ are followed by typical Midway-type Paleocene assembla- Aubry, M.-P., Ouda, Kh., Dupuis, C., Berggren, W. A., Van Cou- ges. The latter suggests deposition at upper bathyal to vering, J. A., and the Members of the Working Group on the outer neritic depths (~200 m) which is supported by P:B Paleocene/Eocene Boundary, 2007. Global Standard Strato- ratio studies._____________________________________ type-section and Point (GSSP) for the base of the Eocene Se- 4) The presence of the stratigraphically restricted scaphitid spe- ries in the Dababiya Section (Egypt). Episodes, 30(4), 271-286. cies Indoscaphites pavana suggests that the interval from 100 to 80 m represents the latest 420 kyr of the Maestrichtin. This is supported by the presence of the latest Maestrichtian planktonic foraminifera Abathomphalus mayorensis in the Berggren, W. A. and Aubert, J., 1975. Paleocene benthonic foraminiferal biostratigraphy, paleobiogeography and paleoecology of Atlantic-Tethyan regions: Midway-type fauna. Palaeo- same interval.____________________________________ geography, Palaeoclimatology, Palaeoecology, 18, 73-192.__ 5) Dinoflagellate assemblages indicate notable environmen- Berggren, W.A. and Ouda, Kh., 2003. Upper Paleocene-lower tal changes from Late Maestrichtian to earliest Paleocene. An abundance of peridinoid cysts indicates a near-shore, (sub)tropical, nutrient-rich environment during the Late Cretaceous; the presence of Manumiella indicates a cold, restricted, low salinity environment in the latest Maestrichtian, and an abundance of Gonyaulacoid cysts indicates a gradual increase in water depth from a nearshore to open Eocene planktonic foraminiferal biostratigraphy of the Dababiya section, Upper Nile Valley (Egypt). In: Kh. Ouda and M.P. Aubry (eds.), The Upper Paleocene-Lower Eocene of the Upper Nile Valley: Part 1, Stratigraphy. 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P., 2006. to rift activity, sea-level changes and paleoceanography in the Environmental perturbation in the southern Tethys across the Cretaceous of the Atlantic Ocean. Clay Minerals, 28, 61-84._ Paleocene/Eocene boundary (Dababiya, Egypt): Foraminiferal and clay mineral records. Marine Micropaleontology, 60, 89–111. Goolaerts, S., 2010. Late Cretaceous ammonites from Tunisia: chronology and causes of their extinction and extrapolation to other areas. Aardkundige Mededelingen 21, xii + 220pp._____ Received: 21 October 2011 Accepted: 15 March 2012 Goolaerts, S., Kennedy, W.J., Dupuis, C. and Steurbaut, E., 2004. Terminal Maastrichtian ammonites from the CretaceousPaleogene Global Stratotype Section and Point, El Kef, Tunisia. Cretaceous Research 25, 313-328._____________________ Habib D. and Saeedi F. 2007. The Manumiella seelandica global spike: Cooling during regression at the close of the Maastrichtian. Palaeogeography, Palaeoclimatology, Palaeoecology, 255, 87–97. William A. BERGGREN 1)2)*) , Laia ALEGRET 3) , Marie-Pierre AUBRY1), Ben S. CRAMER 4), Christian DUPUIS 5), Sijn GOOLAERTS6), Dennis V. KENT1)7), Christopher KING8), Robert W. O’B. KNOX9), Nageh OBAIDALLA 10), Silvia ORTIZ11), Khaled A. K. OUDA10), Ayman ABDEL-SABOUR10), Rehab SALEM1)12), Mahmoud M. SENOSY 10), Mamdouh F. SOLIMAN 10) & Ali SO- Kent, D.V. and Dupuis, C., 2003. Paleomagnetic study of the LIMAN12)13) Paleocene-Eocene Tarawan Chalk and Esna Shale: Dual po- 1) larity remagnetizations of Cenozoic sediments in the Nile Valley (Egypt). In: Kh. Ouda and M.-P. Aubry, (eds.), The Upper 2) Paleocene-Lower Eocene of the Upper Nile Valley: Part 1: Stratigraphy. Micropaleontology, 49, supplement 1, 139-146._ Department of Earth and Planetary Sciences, Rutgers University 610 Taylor Rd., Piscataway, NJ 08854-8066, USA;__________________ Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA;______________________ 3) Universidad de Zaragoza, Calle Pedro Cerbuna, E-50009 , Zaragoza, Spain; Lentin, J. and Williams, G .L., 1980. Dinoflagellate provin- 4) 4 cialism with emphasis on Campanian Peridiniaceans. Ameri- 5) can Association of Stratigraphic Palynologists, Contributions, UMONS-GFA, rue de Houdain, 9- B 7000 Mons, Belgium; 6) Royal Belgian Institute of Natural Sciences, Vautierstraat 29, 1000 7) Lamont-Doherty Earth Observatory of Columbia University, Palisades, Series, 7, 1-4. Romein, A.T.J., 1979. Lineages in Early Paleogene calcareous Theiss Research, Eugene, Oregon, USA; Brussels, Belgium;________________________________________ NY 10964 USA; nannoplankton. Utrecht Micropaleontological Bulletins, 22, 1-231. 8) Schulte, P., Scheibner, C. and Speijer, R. P., 2011. Fluvial dis- 16A Park Rd., Bridport DT6 5DA, UK; 9) British Geological Survey, Keyworth NG12 5GG, UK; charge and sea-level changes controlling black shale deposi- 10) tion during the Paleocene–Eocene Thermal Maximum in the Department of Geological Sciences, University of Assiut, Assiut, Egypt; 11) Dababiya Quarry section, Egypt. Chemical Geology, 285, 167– Universidad del País Vasco, PO Box 644, 48080 Bilbao, Spain; 12) 183. Sissingh, W., 1977. Biostratigraphy of Cretaceous calcareous nannoplankton. Geologie in Mijnbouw, 56, 37-65.__________ Geology Department, Faculty of sciences, Tanta University, 31527Tanta, Egypt;_____________________________________________ 13) Karl-Franzens, University of Graz, Institute of Earth Sciences, Heinrichstrasse 26 A-8010 Graz, Austria;__________________________ *) Corresponding author, [email protected]___________________