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Geologische Rundschau

, Volume 87, Issue 3, pp 477–494 | Cite as

Terrigenous sediment supply along the Chilean continental margin: modern regional patterns of texture and composition

  • F. Lamy
  • D. Hebbeln
  • G. Wefer
ORIGINAL PAPER

Abstract

The regional patterns of texture and composition of modern continental slope and pelagic sediments off Chile between 25°S and 43°S reflect the latitudinal segmentation of geological, morphological, and climatic features of the continental hinterland. Grain-size characteristics are controlled by the grain-size of source rocks, the weathering regime, and mode of sediment input (eolian off northern Chile vs fluvial further south). Bulk-mineral assemblages reveal a low grade of maturity. Regional variations are governed by the source-rock composition of the different geological terranes and the relative source-rock contribution of the Coastal Range and Andes, as controlled by the continental hydrology. The relative abundance of clay minerals is also predominantly influenced by the source-rock composition and partly by continental smectite neoformation. Latitudinal variations of illite crystallinities along the Chilean continental slope (and west of the Peru–Chile trench) clearly reflect modifications of the weathering regime which correspond to the strong climatic zonation of Chile.

Key words Chile Modern continental margin sedimentation Marine sediments Clastic sediments Granulometry Mineralogy Clay mineralogy 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1998

Authors and Affiliations

  • F. Lamy
    • 1
  • D. Hebbeln
    • 1
  • G. Wefer
    • 1
  1. 1.Fachbereich Geowissenschaften, Universität Bremen, Postfach 33 04 40, D-28334 Bremen, Germany Fax: ++49 421 218 3114 e-mail: frankl@allgeo.uni-bremen.deDE

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