Compressional Features Across the Caribbean Margin of Colombia
J.W. Ladd, M. Truchan, 1983. "Compressional Features Across the Caribbean Margin of Colombia", Seismic Expression of Structural Styles: A Picture and Work Atlas. Volume 1–The Layered Earth, Volume 2–Tectonics Of Extensional Provinces, & Volume 3–Tectonics Of Compressional Provinces, A. W. Bally
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Lamont-Doherty seismic Line &130 is one of a suite of seismic lines shot by R/V ROBERT D. CONRAD across the Caribbean margin of Colombia. This margin, which Case (1974) called the South Caribbean basin, is part of a zone of convergence between the oceanic Colombian basin and the continent of South America. This zone of northwest to southeast convergence extends to the southeast onshore where thrusting and uplift of the Sierra Santa Marta occurs (Kellogg and Bonini, 1982). While there is great variability in detail from one seismic section to another, the main features of this margin are illustrated by Line C-130 — the continental slope is underlain by a thick, mildly deformed sediment section. Near the toe of the slope a highly deformed wedge of sediments which forms the South Caribbean Deformed Belt abuts the deep undeformed oceanic sediments of the Colombia basin. A map view of this region is best depicted on the Caribbean tectonic map by Case and Holcombe (1980).
Whereas other seismic sections more clearly show oceanic crust beneath the deformed toe of the slope, Line C-130 is particularly expressive of the similarity of this region to more generally recognized subduction zone complexes. The setting and internal structure of the deformed toe with the numerous diffraction hyperbolae suggesting landward dipping reflectors is similar to many accretionary prisms around the world. Adjacent seismic sections confirm the imbricate nature of the landward dipping reflectors. The thick, mildly deformed sediments of the Rancheria basin are similar to accumulations in basins that form the forearc regions of many subduction zones worldwide.