Determination of sediment volumes, accumulation rates and turbidite emplacement frequencies on the Madeira Abyssal Plain (NE Atlantic): a correlation between seismic and borehole data

The sedimentary infill history of the Madeira Abyssal Plain (MAP) is established from correlation of ODP Leg 157 drillsites (Sites 950–952) with an almost regular grid of ∼7000 km of intermediate-resolution seismic reflection profiles covering the central part of the abyssal plain. The most conspicuous seismic reflectors bounding the seismostratigraphic units have been identified and mapped. Correlation between seismic and borehole data using synthetic seismograms allows the lithological attribution and dating of the reflectors and seismostratigraphic units. Lateral mapping and correlation of seismic units also allows both the volumes and rates of accumulation of sediments within each seismostratigraphic unit and equivalent time periods of deposition to be determined. These calculations have been corrected for the effect of compaction, calculated at around 40% at the base of the drillholes. Three main turbidite types have been identified at the drillsites and their emplacement frequency has been calculated for each site and time period. Our results show that Cretaceous oceanic crust was draped with red pelagic clays, and the fracture-zone valleys were completely infilled and levelled in a geologically rather short time, probably during the latest Oligocene and Early Miocene, by organic-rich turbidites derived from the NW African continental margin. At 16 Ma, the topography was levelled enough to allow large turbidity current flows to cover the entire plain. During the Middle and Late Miocene (16–5.9 Ma), organic-rich turbidites were emplaced on the abyssal plain at a low rate of accumulation (∼12 m/my). In the uppermost Miocene–Early Pliocene (5.9–3.6 Ma), turbidite emplacement increased markedly in both frequency and accumulation rate (e.g., ∼26 m/my for organic-rich turbidites). During this time, period emplacement of volcanic-rich turbidites also increased in volume and frequency, a trend that continued into the Pliocene. Increased volcanic-rich turbidite emplacement correlates well with increased volcanic activity on the Canary Islands, and increased organic-rich turbidite emplacement may correlate with periods of erosion on the NW African continental margin. These erosional periods may be related to global cooling and falling sea level, intensification of bottom-water currents, and enhanced upwelling on the margin.

[1]  P. Weaver,et al.  Seismic facies of the Madeira Abyssal Plain: a correlation between seismic reflection profile and borehole data , 1998 .

[2]  N. Shackleton,et al.  Paleotemperature History of the Cenozoic and the Initiation of Antarctic Glaciation: Oxygen and Carbon Isotope Analyses in DSDP Sites 277, 279 and 281 , 1975 .

[3]  R. Embley.  Anatomy of Some Atlantic Margin Sediment Slides and Some Comments on Ages and Mechanisms , 1982 .

[4]  R. G. Rothwell,et al.  Sedimentation on the Madeira Abyssal Plain over the last 300 000 years , 1987, Geological Society, London, Special Publications.

[5]  P. Raven,et al.  Late Cretaceous and Tertiary vegetation history of Africa , 1978 .

[6]  P. Weaver,et al.  Saharan Continental Rise: Facies Distribution and Sediment Slides , 1992 .

[7]  M. Sarnthein,et al.  Late Neogene events of atmospheric and oceanic circulation offshore Northwest Africa: High-resolution record from deep-sea sediments , 1984 .

[8]  K. Pickering.  Atlas of deep water environments : architectural style in turbidite systems , 1995 .

[9]  H. Chamley,et al.  Oligocene and Post-Oligocene History of Sedimentation and Climate off Northwest Africa (DSDP Site 369) , 1982 .

[10]  D. Schnitker.  Quaternary Deep-Sea Benthic Foraminifers and Bottom Water Masses , 1980 .

[11]  I. Jarvis,et al.  Neogene turbidite sequence on the Madeira abyssal plain: basin filling and diagenesis in the deep ocean , 1998 .

[12]  Joan Martí,et al.  Stratigraphy, structure and geochronology of the Las Cañadas caldera (Tenerife, Canary Islands) , 1994, Geological Magazine.

[13]  A. Kuijpers,et al.  Turbidite deposition and the origin of the Madeira Abyssal Plain , 1986, Geological Society, London, Special Publications.

[14]  O. Pilkey.  Sedimentology of basin plains , 1987, Geological Society, London, Special Publications.

[15]  A. Kuijpers,et al.  Climatic control of turbidite deposition on the Madeira Abyssal Plain , 1983, Nature.

[16]  M. Sarnthein,et al.  Late Neogene submarine erosion events along the north-east Atlantic continental margin , 1986, Geological Society, London, Special Publications.

[17]  R. Hiscott,et al.  Deep Marine Environments: Clastic sedimentation and tectonics , 1989 .

[18]  C. Payton.  Seismic Stratigraphy — Applications to Hydrocarbon Exploration , 1977 .

[19]  Antonio Cendrero,et al.  Constructive and destructive episodes in the building of a young Oceanic Island, La Palma, Canary Islands, and genesis of the Caldera de Taburiente , 1994 .

[20]  P. Weaver,et al.  Correlation, frequency of emplacement and source directions of megaturbidites on the Madeira Abyssal Plain , 1992 .

[21]  J. V. Hinte,et al.  Geohistory Analysis--Application of Micropaleontology in Exploration Geology , 1978 .

[22]  W. Berger,et al.  Cretaceous and Cenozoic Sediments from the Atlantic Ocean , 1972 .

[23]  Martin Williams,et al.  The Sahara and the Nile. , 1980 .

[24]  M. Cita,et al.  The Origin of the Mediterranean Evaporite , 1973 .

[25]  P. Weaver,et al.  Geology and geochemistry of abyssal plains , 1987 .

[26]  I. Jarvis,et al.  The Geology and Geochemistry of Madeira Abyssal Plain Sediments: A Review , 1989 .

[27]  P. Weaver,et al.  Calculating erosion by deep-sea turbidity currents during initiation and flow , 1993, Nature.

[28]  A. Cendrero,et al.  K-Ar chronology of the volcanic eruptions in the Canarian archipelago: Island of La Gomera , 1984 .

[29]  J. Martí,et al.  Stratigraphy and K-Ar ages of the Diego Hernández wall and their significance on the Las Cañadas Caldera formation (Tenerife, Canary Islands) , 1990 .

[30]  I. Jarvis,et al.  Composition and provenance of turbidite sands: Late quaternary, Madeira Abyssal Plain , 1992 .

[31]  Antonio Cendrero,et al.  Evolution of the eastern volcanic ridge of the Canary Islands based on new KAr data , 1992 .

[32]  J. Fritsch,et al.  The Continental Margin of Morocco: Seismic Sequences, Structural Elements and Geological Development , 1982 .

[33]  R. Searle.  Regional setting and geophysical characterization of the Great Meteor East area in the Madeira Abyssal Plain , 1987, Geological Society, London, Special Publications.

[34]  J. H. Mercer,et al.  Major late cainozoic climatic events and palaeoenvironmental changes in Africa viewed in a world wide context , 1986 .

[35]  B. J. Collette.  Fracture zones in the North Atlantic: morphology and a model , 1986, Journal of the Geological Society.

[36]  C. Summerhayes,et al.  Oceanography: An Illustrated Guide , 1996 .

[37]  J. Kennett.  Cenozoic evolution of Antarctic glaciation the Circum-Antarctic Ocean and their impact on global paleoceanography , 1977 .

[38]  E. Hailwood,et al.  Non-biostratigraphical Methods of Dating And Correlation , 1995 .

[39]  D. Masson,et al.  Sediment mass wasting in the Canary Basin , 1995 .

[40]  I. Jarvis,et al.  High-resolution chemostratigraphy of Quaternary distal turbidites: a case study of new methods for the analysis and correlation of barren sequences , 1995, Geological Society, London, Special Publications.

[41]  B. Haq,et al.  Chronology of Fluctuating Sea Levels Since the Triassic , 1987, Science.

[42]  Antonio Cendrero,et al.  Volcanic evolution of the island of Tenerife (Canary Islands) in the light of new K-Ar data , 1990 .

[43]  P. Weaver,et al.  Late Quaternary evolution of the Madeira Abyssal Plain, Canary Basin, NE Atlantic , 1992 .

[44]  U. Rad,et al.  Cretaceous-Cenozoic History of the West Saharan Continental Margin (NW Africa): Development, Destruction and Gravitational Sedimentation , 1982 .

[45]  D. Masson.  Late Quaternary turbidity current pathways to the Madeira Abyssal Plain and some constraints on turbidity current mechanisms , 1994 .

[46]  E. Jones,et al.  Late Quaternary mass movement on the lower continental rise and abyssal plain off Western Sahara , 1991 .

[47]  R. Huene,et al.  Initial reports of the deep sea drilling project: National Science Foundation, Washington, D.C., 1969, 672 pp., U.S. $ 10.25 , 1971 .

[48]  D. Hodell,et al.  Late Miocene to Earliest Pliocene (9.84.5 Ma) Paleoceanography of the Subantarctic Southeast Atlantic: Stable Isotopic, Sedimentologic, and Microfossil Evidence , 1991 .

[49]  M. Badley,et al.  Practical seismic interpretation , 1985 .

[50]  R. Wood,et al.  The geology of the angareb ring dike complex, northwestern ethiopia , 1976 .

[51]  John B. Anderson,et al.  Glacial Eustasy During the Cenozoic: Sequence Stratigraphic Implications , 1998 .

[52]  C. Poag,et al.  Geologic Evolution of Atlantic Continental Rises , 1992 .

[53]  I. McDougall,et al.  Geochronology of Gran Canaria, Canary Islands: Age of shield building volcanism and other magmatic phases , 1976 .

[54]  I. Jarvis,et al.  Geochemical characteristics and provenance of late Quaternary sediments from the Madeira Abyssal Plain, N Atlantic , 1987, Geological Society, London, Special Publications.

[55]  R. Searle,et al.  Sonar acoustic facies and sediment distribution on an area of the deep ocean floor , 1985 .

[56]  D. Masson,et al.  Catastrophic collapse of the volcanic island of Hierro 15 ka ago and the history of landslides in the Canary Islands , 1996 .

[57]  C. Summerhayes,et al.  North Atlantic Paleoceanography , 1987 .