الفهرس 
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Abstract
The lower Paleogene succession in the Abu Gharadig Field (wells: AG- 22 / AG-32), Western Desert, Egypt is differentiated into two formations of wide distribution. These units are arranged from base to top into: the Apollonia Formation (Early Paleocene to Middle Eocene), which has been subdivided into four informal members D, C, B, A, and Daba’a Formation (Middle Eocene to Early Oligocene). Biostratigraphically, 21 planktonic foraminiferal zones and biozones were recognized; these are from older to younger as follows: - Globanomalina compressa subzone (P1c) - Paramurica uncinata Zone (P2) - Morozovella angulate Zone (P3) - Igorina pusilla Subzone (P3a) - Igorina albeari Subzone (P3b) - Morozovella velascoensis Zone (P5) - Acarinina sibaiyaensis Zone (E1) - Pseudohastigerina wilcoxensis / M. velascoensis Zone (E2) - Morozovella formosa Zone (E4) - Morozovella aragonensis / M. subbotinae Zone (E5) - Acarinina pentacamerata Zone (E6) - Acarinina cuneicamerata Zone (E7) - Guembelitrioides nuttalli Zone (E8) - Globigerinatheka kugleri (E9) Zone - Acarinina topilensis Zone (E10) - Morozovella lehneri Zone (E11) - Orbulinoides beckmanni Zone (E12) - Globigerinatheka kugleri Zone (E13) 119 - Globigerinatheka semiinvoluta Zone (E14) - Globigerinatheka index Zone (E15) - Pseudohastigrina naguewchiensis Zone (O1). For calcareous nannofossils, the stratigraphic ranges of the recorded taxa have been utilized to recognize 17 biostratigraphic zones arranged from older to younger as follows: - Chiasmolithus Danicus Zone (NP3) - Ellipsolithus macellus Zone (NP4) - Fasciculithus tympaniformis Zone (NP5) - Discoaster multiradiatus Zone (NP9) - Tribrachiatus contortus Zone (NP10) - Discoaster binodosus Zone (NP11) - Tribrachiatus orthostylus Zone (NP12) - Discoaster lodoensis Zone (NP13) - Discoaster sublodoensis zone (NP14) - Nannoterina fulgens zone (NP15) - Discoaster tanii zone (NP16) - Discoaster saipanensis Zone (NP17) - Chiasmolithus oamarunsis Zone (NP18) - Isthmolithus. recurvus – sphenolithus pseudoradians Zone (NP19 /NP20) - Ericsonia subdisticha Zone (NP21) - Helicopontosphaera reticulate Zone (NP22) - Sphenolithus predistentus Zone (NP23). Within the Paleocene, two prominent major gaps are recognized comprising (a) The basal hiatus covers most of the Early Paleocene (NP1 to NP2 nannofossil Zones) which corresponds to the absence of planktonic foraminiferal zones of P0, Pα, P1a & lowermost part of P1b. (b) The second hiatus comprises mainly Late Paleocene (NP6 to NP7/8 nannofossil Zones) which corresponds to the absence of planktonic foraminiferal Zone of P4. The Paleocene sediments of 111 wells AG-32 and AG22 are attributed to nannofossil zones NP3 to NP5 equivalent to the planktonic foraminifers zones of P1c to the lowermost part of Zone of P4. Whereas nannofossils Zone NP9 is equivalent to the planktonic foraminifers Zone of P5. These hiatuses are thought to be related to compressional tectonic phases, eustatic sea–level falls, or a combination of the two processes. The Danian/Selandian boundary is tentatively placed within calcareous nannofossil Zone NP4 which is located within the Apollonia (D) Formation and at the top of the planktonic foraminifera Subzone I. pusilla (P3a(. It is placed at the level of the first appearance of Fasciculithus pileatus, F. involutusulii, and F. janii. The Paleocene/Eocene boundary is drawn tentatively at the base of Foraminifera Zone E1 where Acarinina Africana, Ac. sibaiyaensis and M. allinsoensis recoded their first appearance. For calcareous nannofossils, this boundary, as drawn, occurs between calcareous nannofossil zones NP9 (Thanetian) and NP10 (Ypresian). This level can be traced as defined by the first appearance of Rhomboaster spp. In addition, the FO of D. diastypus co-occurs with the FO of R. bramletti. The Paleocene/Eocene boundary interval in the studied wells is marked by several events: • The relative abundance of Fasciculithus taxa decreased dramatically around the P/E boundary (F. tympaniformis, F. involutus) and F. billatus have their highest occurrences in several horizons during the NP9 Zone (around the P/E boundary). • The increase in the relative abundance of Neochiastozygus junctus before this boundary. 111 • The first appearance of Rhomboastercuspis, Pontosphaera multipora, and Campylosphaera eodela / dela above this boundary. • The abundance of warm-water species (Discoaster, Sphenolithus, Rhomboaster, Tribrachiatus and Pontosphaera) before the P/E boundary indicates warm-water pale temperatures at this interval. The rapid increase of Discoaster spp. and Chiasmolithus spp. during the P/E boundary also, reflects elevated water temperatures throughout this interval. • Three genera; Acarinina, Morozovella, and Subbotinae dominate the planktonic foraminiferal assemblages of the Late Paleocene - Early Eocene of the studied wells and suggest the presence of tropicalsubtropical surface waters in the Late Paleocene-Early Eocene interval. It corresponds to the uppermost part of the NP12 Zone the uppermost part of NP13 and the lowermost part of the NP14 Zone. This zone comprises samples 4500 in well AG-22 &5200 in well AG-32. • The Eocene/Oligocene boundary in terms of foraminifers and calcareous nannofossils appears to be complete, it occurs within the lowermost part of Daba’a formation in the studied wells and could be placed at extinction of Late Eocene index fossil turborotalids (Turborotalia cerroazulensis, and Tur. cunialensis) followed by a significant size reduction of the genus Pseudohastigerina and the extinction of the hantkeninids (Hantkenina alabamensis), which mark the Eocene/Oligocene boundary. • Furthermore, the Eocene/Oligocene boundary in terms of calcareous nannofossils appears to be complete; it occurs within the lowermost part of Daba’a formation in the studied wells and could be placed at the extinction of rosette-shaped discoasters such as Discoaster saipanensis and D. barbadiensis at the top of zones NP19/20 or CP15 and /or the LO 112 of C. reticulatum has been consistently found slightly below the LO of D. saipanensis.