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The significance of giant seismites in the Plio‐Pleistocene Baza palaeo‐lake (S Spain)
Author(s) -
Alfaro Pedro,
Gibert Luis,
Moretti Massimo,
GarcíaTortosa Francisco J.,
Sanz de Galdeano Carlos,
GalindoZaldívar Jesús,
LópezGarrido Ángel C.
Publication year - 2010
Publication title -
terra nova
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.353
H-Index - 89
eISSN - 1365-3121
pISSN - 0954-4879
DOI - 10.1111/j.1365-3121.2010.00930.x
Subject(s) - geology , plio pleistocene , facies , sedimentary rock , structural basin , paleontology , magnitude (astronomy) , alluvium , geomorphology , sediment , geologic record , pleistocene , geochemistry , physics , astronomy
Terra Nova, 22, 172–179, 2010 Abstract Giant load‐type seismites, uncommon in the geological record, are described in Plio‐Pleistocene lacustrine deposits of the Baza Basin (Betic Cordillera, S Iberia). Deformed beds of the marginal lacustrine and distal alluvial facies of the Baza palaeo‐lake can be traced continuously for several kilometres. Soft‐sediment deformation is represented by load‐type structures of large dimensions (pillows around 4 m in width and 2 m in height). Three‐dimensional exposures show ellipsoidal pillows separated by fluidized channels without any preferred orientation. The final size of these load‐type seismites is strongly influenced by sedimentary factors such as the presence of a reverse density gradient in sediments and the bed thickness. The giant seismites of the Baza basin are located in a region, which is unlikely to have been subjected to high magnitude earthquakes (maximum around 7.0). Therefore, magnitude is not the main factor that controls the size of these load‐type structures.