University of Plymouth PEARL https://pearl.plymouth.ac.uk 04 University of Plymouth Research Theses 01 Research Theses Main Collection 1989 Mid- to late Cretaceous Microbiostratigraphy, Palaeo-ecology and Palaeogeography of the Sergipe Basin, northeastern Brazil Koutsoukos, Eduardo Apostolos Machado http://hdl.handle.net/10026.1/2016 University of Plymouth All content in PEARL is protected by copyright law. Author manuscripts are made available in accordance with publisher policies. Please cite only the published version using the details provided on the item record or document. In the absence of an open licence (e.g. Creative Commons), permissions for further reuse of content should be sought from the publisher or author. Mió- to late Cretaceous Microbiostratigraphy/ Palaeo-ecology and Palaeogeography of the Sergipe Basin, northeastern Brazil Eduardo Apostólos Hachado Koutsoukos B.Sc. Geology Ihesis submitted in partial fulfilment of the requireménts for the Degree of.Doctor of Philosophy. to tbe Council for National Acndemic Awards Research oonducted at the Departuaent of Gecflogical Sciences oC Pofyfcedinic South West^ dymoutfa, in ooDabacatìon with IMxfileo BrasDeiro SJV. (EGTROBRAS), Rio de Janeiro December 1989 V O I. D M E 1 PCI.YTECKN:O£CUTHV/:3T U3RARY SERVICES Item NO. 5500611-fc Class NO. Conti No. HZD- TO LATE CBETACEOUS MICROBIOSTHATIGRAHT, PALAEO-ECOLOGY AHD PALAEOGEOGRAPHY OF THE SERGIPE BASIN, NORTHEASTERN BRAZIL by Eduardo Apostólos Hachado Koutsoukos The palaeo-ecology and biostratigrajdiy of foraminiferal, radiolarian and diatom assesii^lages have been studied throu^ the i^iper Aptian to Maastrichtian sedimentary successicxi of the Sergipe Basin, northeastern Brazil, The systematic taxonomy of the microfauna studied is documented and conpletely revised. Palaeo-environmental models, nostly derived from micropalaeontological and sedimentological criteria, are proposed for the distribution of the foraminiferal morphogroups. The palaeogeographic reconstructicn of the studied area, frcsn the upper Aptian to Maastrichtian, is presented. A refined raicrobiostratigraphic zonation scheme, based on ali secticns studied, is proposed and primarily defined for regional applicatici. Ihe conposition and distribution patterns of the foraminiferal assanblages (diversity and abundance of norphogrOLÇJs) are shown to be a direct respcxise to overall palaeoceanographic conditicns and to conmunity strategies of exploitation of the trophic resources in the microhabitats. The foraminifera recovered - from the oldest, late i^tian, marine sediments reveal a characteristic Tethyan affinity and suggest that this area had at least minimal surface water exchange with low latitude central North fttlantic-western Tethyan bicprovinces, even possibly at intermediate (epi- to mesopelagic) water depths. A shallow Calcite Conpensaticn D^th within Upper mesopelagic depths (c. 3Q0~500m) is inferred for the Upper Aptian-Albian. Twelve foraminiferal palaeocoitnoinities can be recognised in the succession. These are characterised by the relative dorainance of the major foraminiferal groups and related to variations in trophic structures. Iheir palaeo-environnental distributicn is proposed as a model with référence to the Sergipe Cretaceous séquence. Radiolarians and diatoms are documented for the first time from the mid-Cretaceous succession of the Sergipe Basin. Prevailing palaeoceanograj*iic conditicns are inferred for the épisodes of siliceous radiolarian and diatcsn bicBtiineralization/preservaticn. The study indicates that intermittent hypoxic/anoxic events occurred in the basin, most likely associated with the Interplay of various processes. Three nexima in oxygen depletiíMi (dysaerobic-anaerobic conditicns) are recorded in the succession : Ist) in the iipper Äptian-lowernost Albian; 2nd) in the lower Cenomanian; 3rd) in the uppermost Cenomanian-lowermost Turonian. Waning low-oxygen conditiois (dys^robic to aérobic) are apparent in the middle-içjper Albian and middle-ufper Turonian to Ccniacian. - I - DECLARATION I hereby dedare that the work submitted in partiaL fiilfilment of the requirements fot the Degree of Doctor oE PhilosofAiy under the tibie "MID- TO LATE CRETACEOUS MICROHEOSTRATEGRAPHY, PALAEO-ECOLOGY AND PALAEOGEOGRAPHY OF THE SERGIPE BASIN, NORTHEASTERN BRAZIL" is the true result of my own independent originai research. AH authors and'wrarks consulted are acknowledged and referred in fuIU No part of this wcrk has been accepted in suhstance far any ofcher degree nor is it being currentiy submitted for candidature for any other degree. During the course of this research the following papers have been published or submitted for publicati£»i ai the results obtained : 1) "Late Cretaceous anoxic events in the Brazilian continental margin", by M.R. Hello, EJV.M. Koutsoukos, M.B. Hart, S.C. BrasseU & J.R MaxweU - Organic Geochemistry, 14 (5): 529-542 (1989). 2) "Favus^a Michael (1972): evidence of ecof^ienotypic adaptation of a planktcmc fcaramirafer to shallow-water carbonate envìronments during the mid-Cretaceous", by E.A.M. Koutsoukos, P.N. Leary & M.B. Hart - Journal of Foraminiferal Research, 19 (4): 324-336 (1989). 3) "Latest Cenomanian-earliest Turonian low-oxygen tdlerant benthcaiic fcrarainifera: a case study from the Sergipe Basin (NE Brazil) and the western Anglo-Paris Basin Southern England)", by E.A.M. Koutsoukos, P.N. Leary & M.B. Hart - Palaeogeography, PalaeoclimatcQogy, Palaeoecology (in press). 4) "The upp^ Aptian-Albian succession of the Sergipe Basin, Brazib an integrated palaeo-environmental assessment", by E.A.M. Koutsoukos, M.R, Hello, N.C. de Azambu^ Filho, M.B, Hart & J.R. Maxwell - American Assocdation of Petroleum Geologìsts Bulletin (in press). - II - 5) "Radiolarians and diatoms froiii the mid-Cretaceous successdon a£ äie Sergipe Basin, northeastem Brazili palaeoceanograftóc assessment", by E.A.M. Koutsoukos & M.B. Hart - Journal of Micropalaeontology - Loidon (in press). 6) "Cretaceous fcraminiferal morphogroup disbdbution patterns, paJaeocommunities and troEtóo strucbjres: a case study from the Sergipe Basin, arazil", by EJV.M. Koutsoukos & M.B. Hart - Transactims of the Royal Society of Edinburgh: Barth Sciences ^bmitted). 7) "Late Aptian to Maastrichtian fcrarainiferal biogeography and palaeoceanography of the Sergipe Basin, Brazü", by E.A.M. Koutsoukos - Proceedings of the Symposium on "Biogeographic Pattems in the Cretaceous Ocean" (Strasbourg, France, 20-23rd M arch, 1989), European Union of Gecsciences - Palaeogeografhy, Palaeoclimatology, Palaeoecology ^bmitted). 8) "MicropalaeontolDgical and geochemical evidence of mid-Cretaceous hypoxic/anoxic envircnments in the Sergipe Basin, NE Brazü", by E.A.M. Koutscxikos, M.R. MeUo & N.C. de Azambup Filho - Proceedings of the Meeting on "Modem and Andent Coitinental Shelf Anoxia" (Lcndon, 17-19th May, 1989), Special PutÜcatirHTs of the Geological Society of Loidon (submitted). Copies of the published p^iers are bound into this thesis as Appendix 3. EDUARDO A. M. KOUTSOUKOS MALCOLM B. HART (Research Supervisor) - III - TO TANIA, KARINA AND VICTOR WITH LOVE - IV ACKNOffLEDGNENTS I am deeply grateful for the advixx and financiali Support of Peträleo BrasÜeiro SA. (PETROBRAS), Rio de Janeiro, ftrazil, without whose support this research woold not have been accompli^ed, and to Professor Malcolm B. Hart {POLYTECHNIC SOüTH WEST), fear his supervisión and guidance during the research. My sincere gratítude is also due to the EoEowing people; F-T. FetjS (PETROBRAS/DINIER-Aracaji), foc the assistance and support given during the Visit and sampling of outcrop locaüties in Sergipe and in sampling core sections of onshore wells stcced in Aracaji. Alexandre J. Ric^iter (PETROBRAS/CENPES/DIVEX-SEBIPE, Rio de Janeiro), fcr his inestimable hélp in the planning of the fíeld work in Sergipe, mapping guidance and location of several impoctant outcrops of the Riachuelo Formation, lang forgotten in distant areas. Luiz CS. Freitas (CENPES/DIVEX), fca: his feUowship and assistance in the field work, Reginalde P.M. Campcs and Nivaldo Lima (CENPESAiIVEX-SEHIPE), for the high guality microfossa picking they have achieved. Mario G. da Silva and Werceny Cardoso (CENPES/EiEVEX-SEaiPE), for the sample processing. The personnel of the 'Setca: de Preparacäo de Amostras" (CENPES/tJIVEX-SEPRAM), for the preparation of the petrografáiic thin secticsis. Ihe 'Setra: de Geoquímica' (CENPES/DIVEX-SEGEQ), far the geochemical weE lo^ they provided. Hildeberto A. O^da y Ojsòa. (PETROBRAS/DEPEX-SECASU ), Ubirapra Mello and aU coUeagues of the 'Setor de Sergipe-Alagoas" (DEPEX-SESEA), fca: their assistance and guidance in the selectdiMi of ofcrpctive weil sections fcc the research . and the interpreted seismo-stratigraphic profües they suppUed, Walmyr S. de Abceu (CENPES/DIVEX-SEHIPE), fcc his sincere friendship and assistance. Ali cdDeagues and friends cf the 'Setor de Bioestratigrafia e Paleoecologia' (SEHTPE) and CENPES/PETROBRAS, fcc their sincere support and friendship during several years of working together, which has contributed to the strengthening of this research. My thanks also go to the draft section of CENPES/PETROBRAS for providing the excellent final versions of figures 1.2, 1.4, 2.4, 5.3-6, 5.13{A-E), 7.1-2, 8.1-11, 8.13-19, 8.23-24 and 8.27. John Abraham (POLYTECHNIC SOUTH WEST) fa: drawing the final versions of figures 6.1-3. Antony Smith and Francis Reis (Media Service/POLYTECHNIC - V SOüTH WEST) for assistance and excellent quaUty wc»:k in the jAiotographic processing and reproduction