PUMA
Istituto di Geoscienze e Georisorse     
Ellero A., Malasoma A., Marroni M., Pandolfi L., Urbani F. Tectono-metamorphic history of the Tacagua ophilitic unit (Cordillera de la Costa, Venezuela): Insights in the evolution of the southern margin of the Caribbean plate. In: Island Arc, vol. 16 (1) pp. 105 - 123. Blackwell, 2007.
 
 
Abstract
(English)
The southern margin of the Caribbean Plate is well exposed in the Cordillera de la Costa of northern Venezuela, where amalgamated terranes consisting of continental and oceanic units occur. In the Cordillera de la Costa, metamorphosed oceanic units crop out along the coast near Caracas. Among them, the Tacagua unit is characterized by metaserpen-tinites and metabasites showing mid-oceanic ridge basalt geochemical affinity. These lithologies, representative of a disrupted ophiolite sequence, are associated with metasediments consisting of calcschists alternating with pelitic and psammitic schists, whose protoliths were probably represented by deep-sea hemipelagic and turbiditic deposits. In the Tacagua unit, a polyphase deformation history has been reconstructed, consisting of four folding phases from D1 to D4. Geological setting suggests an involvement of the Tacagua unit in the processes connected with a subduction zone. The following deformations (from D2 to D4) observed in the field might be related to the exhumation history of the Tacagua unit. The late deforma-tion history consists of an alternation of deformation phases characterized by displacement parallel (D2 and D4 phases) and normal (D3 phase) to plate boundary between the Caribbean and South America Plates. All lines of geological evidence suggest that the whole evolution of the Tacagua unit was acquired in a setting dominated by oblique convergence, in which alternation of strike-slip and pure compressional or pure extensional tectonics occurred through time.
URL: http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1440-1738
Subject Caribbean plate
oblique convergence
ophiolite
Tacagua unit
Venezuela


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