Clay mineralogy of South Atlantic surface sediments, supplement to: Petschick, Rainer; Kuhn, Gerhard; Gingele, Franz (1996): Clay mineral distribution in surface sediments of the South Atlantic: sources, transport, and relation to oceanography. Marine Geology, 130(3-4), 203-229


Surface samples, mostly from abyssal sediments of the South Atlantic, from parts of the equatorial Atlantic, and of the Antarctic Ocean, were investigated for clay content and clay mineral composition. Maps of relative clay mineral content were compiled, which improve previous maps by showing more details, especially at high latitudes. Large-scale relations regarding the origin and transport paths of detrital clay are revealed. High smectite concentrations are observed in abyssal regions, primarily derived from southernmost South America and from minor sources in Southwest Africa. Near submarine volcanoes of the Antarctic Ocean (South Sandwich, Bouvet Island) smectite contents exhibit distinct maxima, which is ascribed to the weathering of altered basalts and volcanic glasses. The illite distribution can be subdivided into five major zones including two maxima revealing both South African and Antarctic sources. A particularly high amount of Mg- and Fe-rich illites are observed close to East Antarctica. They are derived from biotite-bearing crystalline rocks and transported to the west by the East Antarctic Coastal Current. Chiorite and well-crystallized dioctaedral illite are typical minerals enriched within the Subantarctic and Polarfrontal-Zone but of minor importance off East Antarctica. Kaolinite dominates the clay mineral assemblage at low latitudes, where the continental source rocks (West Africa, Brazil) are mainly affected by intensive chemical weathering. Surprisingly, a slight increase of kaolinite is observed in the Enderby Basin and near the Filchner-Ronne Ice shelf.The investigated area can be subdivided into ten, large-scale clay facies zones with characteristic possible source regions and transport paths. Clay mineral assemblages of the largest part of the South Atlantic, especially of the western basins are dominated by chlorite and illite derived from the Antarctic Peninsula and southernmost South America and supported by advection within the Circumantarctic Deep Water flow. In contrast, the East Antarctic provinces are relatively small. Assemblages of the eastern basins north of 30°S are strongly influenced by African sources, controlled by weathering regimes on land and by a complex interaction of wind, river and deep ocean transport. The strong gradient in clay mineral composition at the Brazilian slope indicate a relatively low contribution of tropically derived assemblages to the western basins.

Related Identifier
Metadata Access
Creator Petschick, Rainer; Kuhn, Gerhard; Gingele, Franz
Publisher PANGAEA - Data Publisher for Earth & Environmental Science
Publication Year 1996
Rights Creative Commons Attribution 3.0 Unported
OpenAccess true
Language English
Resource Type Supplementary Collection of Datasets
Format application/zip
Size 2 datasets
Discipline Earth System Research
Spatial Coverage (-98.001W, -78.254S, 40.868E, 29.095N); Southern Ocean; Walvis Ridge; Angola Basin; Guinea Basin; Equatorial Atlantic; Brazil Basin; Romanche fracture zone; Cape Blanc; Cape Basin; Hunter Channel; Eastern Rio Grande Rise; Kongo delta; Northern Guinea Basin; Southwest Guinea Basin; West Angola Basin; Mid Atlantic Ridge; East Brazil Basin; Amazon Fan; off Gran Canaria; Congo Fan; off Kunene; Namibia Continental Margin; Namibia continental slope; South African margin; Argentine Basin; Slope off Argentina; Uruguay continental margin; Rio Grande Rise; Santos Plateau; Northern Brasil-Basin; Western Equatorial Atlantic; South of Cape Verde Islands; off Cape Blanc; Filchner Trough; Filchner Shelf; King George Island, Antarctic Peninsula; South Orkney; Weddell Sea; Bransfield Strait; Atlantic Ridge; Halley Bay; Gould Bay; Camp Norway; Atka Bay; Lyddan Island; Eastern Weddell Sea, Southern Ocean; Kapp Norvegia; Cape Fiske; Argentine Islands; Maud Rise; Vestkapp; Barents Sea; Wegener Canyon; Hope Bay; Drake Passage; Antarctic Peninsula; Adelaide Island; Anvers Island; Atlantic Indik Ridge; Van Heesen Ridge; Agulhas Basin; Meteor Rise; Shona Ridge; Indian-Antarctic Ridge; South Sandwich Basin; South Sandwich Islands; South Sandwich Trough; Fram Strait; Greenland Slope; Lazarev Sea; Astrid Ridge; Polarstern Kuppe; Discovery Seamount; South Atlantic; South Atlantic Ocean; Scotia Sea, southwest Atlantic; Agulhas Ridge; Islas Orcadas; South Sandwich; Falkland Islands; Riiser-Larsen Sea; Cosmonaut Sea; Conrad Rise; Southeast Pacific
Temporal Coverage Begin 1983-02-13T00:00:00Z
Temporal Coverage End 1995-05-10T21:07:00Z