Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
PALYNOFACIES ANALYSIS OF SEDIMENTS FROM THE COTE-DIVOIRE GHANA TRANSFORM MARGIN - PRELIMINARY CORRELATION WITH SOME REGIONAL EVENTS IN THE EQUATORIAL ATLANTIC
Autore:
OBOHIKUENOBE FE; YEPES O; MASCLE J; LOHMANN GP; CLIFT P; ALLERTON S; ASK M; BARRERA E; BARTON E; BASILE C; BELLIER JP; BENKHELIL J; BRANTUOH E; EDWARDS R; EWERT E; GONCALVES C; JANIK AG; HOLMES MA; HISADA K; LOHMANN KC; MORITA S; MONTERAGUTIERREZ CA; NORRIS RD; PLETSCH T; PICKETT EA; RAVIZZA G; SHAFIK S; STRAND KO; WAGNER T; WATKINS D;
Indirizzi:
UNIV MISSOURI,DEPT GEOL & GEOPHYS,125 MCNUTT HALL ROLLA MO 65409 LAB GEODYNAM SOUS MARINE VILLEFRANCHE MER FRANCE WOODS HOLE OCEANOG INST WOODS HOLE MA 02543 UNIV OXFORD OXFORD OX1 2JD ENGLAND ROYAL INST TECHNOL S-10044 STOCKHOLM SWEDEN UNIV AKRON AKRON OH 44325 UNIV GRENOBLE 1 GRENOBLE FRANCE UNIV PARIS 06 PARIS FRANCE UNIV PERPIGNAN F-66025 PERPIGNAN FRANCE UNIV CAMBRIDGE CAMBRIDGE CB2 1TN ENGLAND UNIV LEICESTER LEICESTER LE1 7RH LEICS ENGLAND UNIV MIAMI CORAL GABLES FL 33124 UNIV NEBRASKA LINCOLN NE 00000 UNIV TSUKUBA TSUKUBA IBARAKI 305 JAPAN UNIV MICHIGAN ANN ARBOR MI 48109 UNIV TOKYO,OCEAN RES INST TOKYO JAPAN TEXAS A&M UNIV COLLEGE STN TX 77843 UNIV MISSOURI ROLLA MO 65401 CHRISTIAN ALBRECHTS UNIV KIEL D-24098 KIEL GERMANY UNIV EDINBURGH EDINBURGH EH8 9YL MIDLOTHIAN SCOTLAND AUSTRALIAN GEOL SURVEY ORG CANBERRA ACT AUSTRALIA UNIV OULU OULU FINLAND UNIV BREMEN D-2800 BREMEN 33 GERMANY
Titolo Testata:
Palaeogeography, palaeoclimatology, palaeoecology
fascicolo: 3-4, volume: 129, anno: 1997,
pagine: 291 - 314
SICI:
0031-0182(1997)129:3-4<291:PAOSFT>2.0.ZU;2-C
Fonte:
ISI
Lingua:
ENG
Soggetto:
NORTH-ATLANTIC; PETROLEUM; TEMPERATURE;
Keywords:
PALYNOFACIES; PALYNOMORPHS; THERMAL ALTERATION; TRANSFORM MARGIN;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
40
Recensione:
Indirizzi per estratti:
Citazione:
F.E. Obohikuenobe et al., "PALYNOFACIES ANALYSIS OF SEDIMENTS FROM THE COTE-DIVOIRE GHANA TRANSFORM MARGIN - PRELIMINARY CORRELATION WITH SOME REGIONAL EVENTS IN THE EQUATORIAL ATLANTIC", Palaeogeography, palaeoclimatology, palaeoecology, 129(3-4), 1997, pp. 291-314

Abstract

Analyses of the palynofacies and sporomorph thermal alteration indices (TAI) of sediments from Ocean Drilling Program (ODP) Sites 959 to 962 in the Cote d'Ivoire-Ghana Transform Margin, West Africa were undertaken to (1) determine the source and depositional conditions of the organic matter in the sediments, (2) refine a paleobathymetric curve derived from other data for Site 959, which drilled the most continuous sedimentary sequence from Pleistocene to Albian and (3) interpret the paleothermal history of the area. Twelve types of dispersed organic matter were identified: amorphous organic matter (AOM), marine palynomorphs, algae, resins; black debris, yellow-brown fragments, black-brown fragments, cuticles, plant tissue, wood, sporomorphs and fungi. The relative abundances of these organic matter components at each site were analyzed using cluster analysis, resulting in the identification of seven palynofacies assemblages at Sire 959, five each at sites 960 and 961, and four at Site 962. Amorphous organic matter (which is chiefly marine derived), black debris and wood have played the most significantrole in defining palynofacies assemblages. The palynofacies assemblages show some correlation with lithologic units, sediment sources and depositional environments. Previous palynofacies studies in passive margins have demonstrated that changes in the ratio of AOM to terrestrialorganic matter are related primarily to proximal-distal positions of depositional environments relative to the shoreline. However, this assumption does not always hold true for a transform margin where tectonic factors play an important role in the organic matter distribution, at least in the early stages of evolution. Lithofacies, CCD paleodepthsfor the North Atlantic, trace fossil association, benthic foraminifera and palynofacies data were the criteria used for reconstructing a paleobathymetric curve for Site 959. A cyclicity in the organic matter distribution of the Upper Miocene to Lower Pliocene pelagic sediments could be related to fluctuations in productivity of biosiliceous and calcareous organisms, and sedimentation rates. A drastic increase in theamount of AOM and a decrease in black debris and wood in the carbonate and elastic rocks (Lithologic Unit IV) overlying the tectonized Albian sediments (Lithologic Unit V) at Sites 959 and 960 coincide with the presence of an unconformity. Qualitative color analysis of palynomorphs was undertaken for all sites: although the main focus was on Site 959 where detailed organic geochemical data were available. At Site 959, TAI values indicate an immature stage of organic maturation (<2) down to the black claystones of Lithoiogic Unit III at about 918.47 mbsf. Below this, samples show an increase with depth to a moderately mature stage (>2 except for the claystone samples between 1012.52 and 1036.5 mbsf. and one limestone sample at 1043.4 mbsf), reaching peak levels of 2.58 to 3.0 in the tectonized Albian sediments below the unconformity. These TAI values show a positive correlation with the T-max values derived from Rock-Eval pyrolpsis data. The highest values recorded in the basal tectonized units at all the sites (Sites 960-962 have mean values between 2.25 and 3.13) may be related to high heat flow during the intracontinental to syntransform basin stage in the region. (C) 1997 Elsevier Science B.V.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 25/09/20 alle ore 00:39:05