IGCP Project 381 
IGCP Project 381 "South Atlantic Mesozoic Correlations" (SAMC)
Project leaders
Eduardo A. M. Koutsoukos, Petrobrás, Rio de Janeiro, Brazil
Peter Bengtson, Geologisch-Paläontologisches Institut, Universität Heidelberg, Germany
Contents
IGCP Project 381 "South Atlantic Mesozoic Correlations", abbreviated SAMC, was accepted by the IGCP Scientific Board in February 1995 for a running period of five years. The project has as its primary objective to promote interdisciplinary and integrated international correlative studies of the Mesozoic basins of the South Atlantic Ocean. The project area embraces the entire South Atlantic from Antarctica to Mexico on the South and Central American margins and from South Africa to Morocco on the African margin. The Mesozoic succession of the South Atlantic offers an excellent opportunity for major interdisciplinary efforts aiming at improved understanding of processes of basin evolution on passive continental margins. With respect to global warming concerns, the South Atlantic, because of its size and the widespread occurrence of organic-rich lithologies, may also provide clues to the cause of the enhanced carbon dioxide content of the Cretaceous greenhouse atmosphere. Whereas considerable progress has recently been made in understanding the evolution of the South Atlantic, reliable regional correlation remains to be established. Despite half a century of intensive geological studies, few attempts have been made to integrate data from individual basins into a common geological framework. Consequently, a priority of SAMC is to establish a well-defined standard stratigraphical scale and correlation charts for the entire project area. Subsequently, the charts will be used to build sets of palaeogeographical and palaeoceanographical maps, together with hydrocarbon and mineral play maps.
Key topics of geological interest are the separation history of South Africa from South America, the changing influence with time of the Walvis-Rio Grande Ridge, the timing of the final separation of northeastern Brazil from the Gulf of Guinea region of Africa, and the separation history of South and North America. Global geological issues centre on determining how very large scale events in the separation history of Africa and South America influenced the Cretaceous warming event. For example, the dimensions and exact age of the South Atlantic flood basalt province remain to be established. The triggers for the abundant lacustrine and marine source rocks are also poorly understood, as are the origin and significance of the evaporite systems. The project area hosts 15% of the remaining global oil reserves and 8% of the remaining global gas reserves (Oil and Gas Journal, 26/12/94, pp. 42-43). Improved performance requires a comprehensive understanding of the workings of source rocks, reservoir and trap systems through time, both in the producing basins and the frontier regions. Mineral exploration lacks, in particular in western, equatorial and northern Africa, a systematic understanding of the igneous and thermal systems that operated during the Mesozoic.
Expected results of the Project are:
* fully integrated stratigraphical data sets, comprising biostratigraphical zonation schemes, magnetostratigraphy, sedimentary geochemistry (organic geochemistry, stable isotopes and trace elements), sedimentology, sequence stratigraphy and tectonostratigraphy.
* a high-resolution event stratigraphy (bioevents, long- and short-term chemostratigraphic events, eustatic fluctuations) for testing the synchroneity of regional and global events.
* integrated regional models of basin development and evolution.
* regional, evolutionary palaeogeographical maps, at 1:500,000 scale, from the last phase of Gondwana to the fully oceanic settings at the end of the Mesozoic.
* general palaeogeographical maps of the South Atlantic at 1:10,000,000 scale.
* palaeobiogeographical maps, at 1:10,000,000 scale, showing the patterns of distribution of key micro- and macrofossil groups.
* palaeoceanographical maps, at 1:10,000,000 scale, with inferred bottom and surface circulation patterns.
* detailed regional models of the setting and genesis of known and potential hydrocarbon and mineral resources, together with play and reserve maps at 1:500,000 scale.
The inaugural meeting of SAMC was held 24-25 July 1995 in Uberaba, a Brazilian university town half way between São Paulo and Brasília, in conjunction with the XIV Brazilian Palaeontological Congress. It was attended by 33 persons representing five countries (Argentina, Brazil, Germany, United Kingdom and the USA), including the project proposers (Eduardo Koutsoukos and Peter Bengtson) and four regional coordinators (Nick Cameron, Eduardo Musacchio, Eduardo Olivero and Peter Szatmari). The aims of the meeting were to launch the project formally and to introduce its research objectives to the Latin American scientific community, to identify key areas and research objectives, to promote integration and collaboration among participants (with presentation of status reports and research results), and to set up a schedule for project meetings (workshops and general meetings). The meeting was divided into two sessions: 24 July was utilised for introduction and technical presentations, 25 July comprised implementation work. Eleven papers were presented and discussed. The extended abstracts for the oral presentations were published in the July issue of the project newsletter SAMC News 2, together with some additional contributions. The minutes relating to the project implementation meeting were subsequently published in SAMC News 3. The following scientific points were made by the action groups formed for the meeting.
Cretaceous Continental Ecosystems. - It is now clear that the red-bed succession of the Brazilian basins is not barren as previously thought, but contains a very rich and diverse fauna and flora. It is also evident that the Cretaceous deposits are more widespread than previously mapped. Twelve topics were identified for study. They comprise:
(1) Aspects of the depositional environment of the Lower Cretaceous of the San Fransciscan Basin.
(2) Cretaceous insects.
(3) Palaeoecology of ostracods from northern Brazil.
(4) Systematics and palaeoecology of Cretaceous fishes from northern Brazil.
(5) Geochemical aspects of the marine transgression in the Araripe Basin (northeastern Brazil).
(6) Palaeoenvironmental significance of invertebrate ichniofossils.
(7) Palaeoenvironmental significance of vertebrate ichnofossils.
(8) Cretaceous vertebrate fauna of the Paraná Basin and its ties to other South American basins.
(9) Systematics and palaeoecology of Cretaceous gastropods and bivalves.
(10) Triassic and Jurassic plants from the Paraná Basin.
(11) Reconstruction of environments using palaeoflora for the Lima Campos and Araripe basins.
(12) Carbonate lacustrine facies. Contact will be made with French geoscientists working on the interior African basins. Work of this type is crucial to the project as the continental faunas appear to indicate a much later final separation of Africa from South America than do the marine faunas.
Southern South America. - The area of the South American margin from the Espirito Santo Basin in Brazil to southern Argentina is a key one for the project as it hosts the transition from the fully marine basins to the south of the Walvis-Rio Grande Ridge into the early Cretaceous lacustrine basins located to the north of these ridges. Five topics were found to require immediate attention:
(1) The relationship between the volcanic and lacustrine Jurassic units of Patagonia and South Africa.
(2) Improved correlations, using biostratigraphy, geochemistry and palaeoceanography, between the southernmost Brazilian basins and the equivalent basins in Africa (Namibia).
(3) Tying the biostratigraphy of the non-marine early, middle and late Cretaceous to the international chronostratigraphic scale.
(4) Once the third topic is completed, reviewing the evolution of the non-marine Cretaceous ecosystems.
(5) Correlation of the Neocomian marine facies of southernmost Africa and west central Patagonia. Progress can be achieved using a mixture of Petrobrás and Argentinian groups, and a new liaison between Argentinian universities and Petrobrás. Field workshops are considered to be important. The need for new correlation methods was emphasised. Magnetostratigraphy and isotopic techniques will be reviewed.
Southernmost Argentina (Austral Basin) and Antarctic Peninsula. - This area is characterised by Cretaceous and Jurassic marine successions of difficult access. Much of the geology, therefore, still remains poorly known. Key issues concern establishing a basic biostratigraphy for the region, for example:
(1) The establishment of a biostratigraphical timescale using ammonites and microfossils.
(2) Tying the local biostratigraphical scale to the international chronostratigraphical scale.
(3) Defining the Santonian, Campanian and Maastrichtian stage boundaries.
(4) Defining the palaeontological and sedimentological factors characterising the platform to deep-water transition in the James Ross and Austral basins. Chilean participation will be needed for the Austral Basin as exposures are better in Chile. Assistance will also be sought from collaboration with IGCP Project 322 "Correlation of Jurassic events in South America".
Northern Brazil. - Northern Brazil refers to the basins north of the Albrolhos Arch. Although this area is relatively well known, significant gaps in knowledge remain. Key objectives are, therefore, to fill these gaps. A firm biostratigraphical framework is needed before the topic-oriented studies listed below can commence. The decisions of the recently held "Second International Symposium on Cretaceous Stage Boundaries" in Brussels (September 1995) form a basis for this work. The following themes were identified as potential topics for Working Groups:
(1) Determination of the Aptian-Albian (opening of the South Atlantic) to Coniacian-Santonian (end of restricted phase) stage boundaries.
(2) Determination of a reliable date for the first marine transgression.
(3) Understanding of the origin of the dysoxic-anoxic events recorded in the South Atlantic.
(4) The nature and timing of the uplift in northeastern Brazil.
(5) South Atlantic evaporite events (including the Araripe Basin).
(6) Palaeobiogeographical syntheses. These will include lateral correlations and ties to the interior basins.
(7) Palaeoclimatology.
(8) New correlation techniques, such as palaeomagnetics, stable isotopes, chemostratigraphy and clay mineral typing.
(9) Platform-deep-water biostratigraphical correlations.
(10) Shallow carbonate platform correlations with Africa.
(11) Atlas of microfacies types.
(12) Phosphate events.
(13) The K-T boundary. Not all of the topics require immediate implementation. There is a need to search for global climatic markers in the lacustrine phase. Progress in understanding tectonic issues, such as the uplift history of northern Brazil, will be required.
Africa. - Although there is a wealth of new information on the African margin, much of the new results remains to be published. Furthermore, what modern literature there is tends to present results and not the underlying palaeontology used to achieve the results: this is because much of the original work was oil-company funded and the base palaeontological findings retain significant commercial value. Because of these problems, it is suggested that 1996 should be treated as a fact-finding year in which work will be concentrated on data collection and assembly. The recommended tool is the preparation of a chain of stratigraphical columns from South Africa to Morocco. Assistance from local experts, either from within the project or from known authorities on the area, will be sought for compiling the columns. The results will be used at the 1996 Annual Meeting in Salvador (SAMC I) to propose the multidisciplinary working groups for the region. Although a year will have been "lost" in relation to the other action group proposals, this approach will ensure that only those working groups with the maximum chance of success will be set up. In addition, ways will be sought during the first year to set up monodisciplinary groups to:
(1) begin to apply "depositional systems" concepts;
(2) begin to apply results to existing and developing models;
(3) begin to tie in onshore igneous events and their associated mineral resource systems;
(4) begin to incorporate geomorphology, palaeoclimate and palaeoceanographical circulation patterns;
(5) begin to add carbon, oxygen and strontium isotope data to the stratigraphical columns. Ways will also be sought to increase direct participation from Africa. The first step will be to initiate data flowage through letter and fax contact. These initial contacts will then be used to set an international correspondence and collaboration system with the aim of achieving, by the time of the Salvador meeting, the first joint presentations and papers. The goal will be to demonstrate that sufficient new geological worth is being added by the project to make it important that funds are found for African nationals to attend project meetings.
The wide variety of approaches adopted by the action groups reflect the diversity of geological understanding and needs within the project area.
Currently there are twelve Working Groups, approved in Uberaba after discussion of the findings of the action groups:
* Aptian-Albian and Albian-Cenomanian Stage Boundaries: Chairman Eduardo A.M. Koutsoukos (Petrobrás-CENPES, Rio de Janeiro, Brazil)
* Cenomanian-Turonian and Turonian-Coniacian Stage Boundaries: Chairman Peter Bengtson (University of Heidelberg, Germany)
* Coniacian-Santonian, Santonian-Campanian and Campanian-Maastrichtian Stage Boundaries: Chairman Eduardo Olivero (CADIC, Ushuaia, Argentina)
* Atlas of Carbonate Microfacies: Chairman Dimas Dias-Brito (IGCE-UNESP, Rio Claro, Brazil)
* Chemostratigraphical Correlations: Chairman René Rodrigues (Petrobrás- CENPES, Rio de Janeiro, Brazil)
* Cretaceous Continental Ecosystems: Chairman Ismar Carvalho (Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil)
* Dating of the First Marine Transgression: Chairman Eduardo A.M. Koutsoukos
* K-T Boundary: Chairman Eduardo A.M. Koutsoukos
* Biochronostratigraphy and Biogeography of Non-Marine Microfossil Assemblages: Chairman Eduardo Musacchio (Universidad Nacional de la Patagonia, Comodoro Rivadavia, Argentina)
* Palaeogeography: Chairmen Nick Cameron (Imperial College, London UK) in conjunction with Petrobrás-CENPES (Rio de Janeiro, Brazil)
* South Atlantic Evaporites: Chairman Peter Szatmari (Petrobrás-CENPES, Rio de Janeiro, Brazil)
* Regional Tectonics: Chairman Peter Szatmari
Working Groups for Africa, Venezuela, and Central America are being planned. Topic-specific Working Groups, including those handling igneous geology, mineral systems and palaeoclimatology, are at the formulation stage. For Africa much of the new results of the Atlantic margin basins has not been published. Discussions are in progress, initially with the state oil companies, to determine whether seismic and unpublished palaeontology can be made available.
Regional Coordinators for IGCP Project 381
Eleven Regional Coordinators and members of the Project Working Group were elected in Uberaba (listed below). They are responsible for liaison among participants, for disseminating information about the progress of the project and forthcoming meetings, and for stimulating and coordinating research in their fields of expertise.
Peter Bengtson - Geologisch-Paläontologisches Institut der Universität Heidelberg, Im Neuenheimer Feld 234, D-69120 Heidelberg, Germany. Tel.: +49-6221-568293, Fax: 563940 or 565503, E-mail: Peter.Bengtson@urz.uni-heidelberg.de
William D. Brumbaugh - Texas A & M University, Geochemical and Environmental Research Group, 833 Graham Road, College Station, TX 77845, USA. Tel.: +1-713 8708188, Fax: 5586531
Nick R. Cameron - Imperial College, London, UK. Tel./Fax: +44-149-4 774559, E-mail: jac@pcmail.nerc-bas.ac.uk
Victor N'da Loukou - Société Nationale d'Opérations Pétrolières (PETROCI), B.P.V. 194, Abidjan, Ivory Coast. Tel.: 221-466820 or 466816, Fax: 221-216824
Ivan de Klasz - "La Verdiane", 74 Av. du Mont Alban, F-06300 Nice, France. Tel.: +33-93-268843, Fax: 894820
Eduardo A. M. Koutsoukos - PETROBRAS-CENPES/Divex, Cidade Universitária, 21949-900 Rio de Janeiro, RJ, Brazil. Tel. +55-21-5986440, Fax 5986795, Tel. (home): 3258306, Fax (home): 3254982, E-mail: koutsoukos@cenpes.petrobras.gov.br
Jean Mascle - Laboratoire de Géodynamique Sous-Marine, BP no. 48, F-06230 Villefranche-sur-Mer, France. E-mail: mascle@ccrv.obs-vlfr.fr
Eduardo Musacchio - Lab. de Bioestratigrafía, Universidad Nacional de La Patagonia, Ciudad Universitaria km 4, 9000 Comodoro Rivadavia, Chubut, Argentina. Tel./Fax: +54-967-50339, E-mail: aldo@unpbib.edu.ar
Eduardo B. Olivero - Centro Austral de Investigaciones Científicas (CADIC), Av. Malvinas Argentinas s/n , C.C. 92, 9410 Ushuaia, Tierra del Fuego, Argentina. Tel.: +54-901-22 310/312/314, Fax: 30 644
Sunday W. Petters - Department of Geology, MOBIL/NNPC Chair of Petroleum Geology, University of Calabar, P.O. Box 3654, Calabar, Nigeria. Tel.: +234-84-224747 or 224748, ext. 350, Telex: 65103 UNICAL
Peter Szatmari - PETROBRAS-Cenpes/Divex/Setec, Cidade Universitária, 21949-900 Rio de Janeiro, RJ, Brazil. Tel.: +55-21-5986435, Fax: 5986792
Currently SAMC has 222 individual participants from 33 countries (* indicates activity in 1995): Angola(*), Argentina(*), Brazil(*), Cameroun, Central African Republic, Colombia, Congo, Cuba, Egypt, France(*), Germany(*), Guinea, Hungary, Italy, Ivory Coast(*), Libya, Malaysia, Mexico, Morocco, Niger, Nigeria(*), Portugal, Russia, Senegal(*), Slovakia, South Africa, Sweden, Switzerland, Tanzania, Togo, United Kingdom(*), United States of America(*), Venezuela.
Three project newsletters have been issued (SAMC News 1, 2 and 3) and a fourth is due in February 1996. SAMC News 2, July 1995, contains the extended abstracts of 11 papers presented at the Uberaba meeting, together with 4 additional contributions.
List of selected publications (September 1995):
Antunes, R. L., in press. Biozonas de nanofósseis do Cretáceo da margem continental brasileira: problemas e possíveis soluções. Boletim de Geocências da Petrobrás, Rio de Janeiro.
de Baldis, E. D. P., 1995. Santonian microflora of Rio Guanaco Formation (continental facies) from Rio Turbio profile, Santa Cruz province, Argentine. Southern hemisphere correlation. SAMC News 2, p. 20. Rio de Janeiro.
de Baldis, E. D. P., 1995. Santonian dinoflagellates of brackish-water facies from Rio Guanaco Formation (San Martin-C profile), Santa Cruz province, Argentina, and their relation with the Austral counterpart of the Williams Suite of temperate paleolatitudes. SAMC News 2, p. 20. Rio de Janeiro.
Bengtson, P., 1995. Ammonite and inoceramid biostratigraphy of northeastern Brazil: a status report. SAMC News 2, 11-12. Rio de Janeiro.
Bengtson, P. 1995. Biostratigraphie und Paläontologie des James-Ross-Beckens, Antarktische Halbinsel. Berichte zur Polarforschung 170, 153-156. Alfred-Wegener-Institut für Polar- und Meeresforschung, Bremerhaven.
Bengtson, P., Herrmann, A., Seeling, J., Übelaker, S. & Walter, S. 1995. The Cenomanian/Turonian boundary in northeastern Brazil: a progress report. Second International Symposium on Cretaceous Stage Boundaries [Brussels, 8-16 September 1995], Abstract volume, p. 19. Subcommission on Cretaceous Stratigraphy.
Concheyro, A., Robles-Hurtado, G.m. & Olivero, E.B., in press. Sedimentology and Calcareous Nannofossils from the Upper Cretaceous Paleocene of James Ross Island Area, Antarctica. Paper submitted to the International Symposium on Antarctic Earth Sciences (Siena, Italy, 1995).
Digbehi, Z. B. & Bourrouilh, in press. Séquences de plate-forme carbonatée-bassin en zone transformante: exemple du Cénomanien des marges sud-aquitaine, vallée d'Ossau, Pyrénées atlantiques. Bulletin de la Société Géologique, Annual Meetings.
The First Annual Meeting of SAMC (SAMC I) will be held 2-5 September 1996, in Salvador, Bahia, Brazil. The meeting includes field trips to the classical Jurassic and lower Cretaceous outcrops of the hydrocarbon-rich Recôncavo Basin, a typical rift-phase marginal basin, the richly fossiliferous marine, middle and upper Cretaceous and K-T boundary sections of the Sergipe, Pernambuco-Paraíba and Potiguar basins, and to the fish and dinosaur beds of the interior Araripe Basin. The Recôncavo Basin exposures present by far the best and most complete outcrops of the South Atlantic lacustrine rift succession. The K-T boundary section in the Pernambuco-Paraíba Basin is well exposed and includes spectacular tsunami beds. Finally, the Araripe Basin, because of its transitional marine and terrestrial assemblages, may hold the clue to solving the timing of the final break between northeastern Brazil and the Gulf of Guinea region.
The 1997 Annual Meeting (SAMC II) will be held in Cameroun, in conjunction with the "3è Colloque de Stratigraphie et de Paléogéographie de l'Atlantique Sud et du 13è Colloque Africain de Micropaléontologie", 8-13 March 1997.
In 1997 a European regional SAMC meeting will also be held in Heidelberg, Germany, simultaneously with the "Second European Round Table on the Palaeontology and Stratigraphy of South America", in conjunction with the "18th IAS Regional Meeting", 2-4 September.
Argentina will be the venue for the 1998 annual meeting. This meeting is likely to be split between two centres, Ushuaia in Tierra del Fuego and Comodoro Rivadavia in Patagonia, to allow for maximum opportunities for field geology.
The 1999 annual meeting will be held in Africa, either in Nigeria (Calabar) or the Ivory Coast. The final annual meeting of SAMC, in 2000, will take place in South Africa.
For additional information about SAMC, please contact the project leaders: Peter Bengtson or Eduardo A.M. Koutsoukos.
For English-speaking participants: Márcio R. Mello, Petrobrás-Cenpes/Divex/Segeq, Cidade Universitária, Quadra 7, 21949-900 Rio de Janeiro, RJ, BRAZIL. Tel: +55-21-5986460, Fax: 5986799, E-mail: bv77@c53000.petrobras.anrj.br
For French-speaking participants: Mitsuru Arai Petrobrás-Cenpes/Divex/Sebipe, Cidade Universitária, Quadra 7, 21949-900 Rio de Janeiro, RJ, BRAZIL. Tel.: +55-21-5986452, Fax: 5986795, E-mail: koutsoukos@cenpes.petrobras.gov.br
Full details of the aims, objectives and achievements of IGCP Project 381 SAMC is being provided at this URL address as part of the PaleoPages of the University of Heidelberg. The information is updated continuously. In addition, SAMC maintains a mailing list (i.e. a discussion group via e-mail), SAMC-Net, which is open to all registered or potential project participants.
Comments and suggestions about SAMC are welcome and should be sent to the project leaders (see above).
Link to the Heidelberg PaleoPages
This Page is maintained by Peter Bengtson and Jens Seeling