Evolución tectonosedimentaria de la cuenca Miocena de "Piggy-Back" de Rodeo-Iglesia (San Juan, Argentina)

• M. Gagliardo ^[1] ; F. Colombo ^[2] ; A. Caselli ^[1] ; A. Tripaldi ^[3] ; C. Limarino ^[1]
  1. [1] Universidad de Buenos Aires

     Universidad de Buenos Aires

     Argentina

     
  2. [2] Universitat de Barcelona

     Universitat de Barcelona

     Barcelona, España

     
  3. [3] CONICET

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• Localización: Geotemas (Madrid), ISSN 1576-5172, Nº. 2, 2000 (Ejemplar dedicado a: IV Congreso del Grupo Español del Terciario (Tremp, 19-21 septiembre, 2000)), págs. 77-79
• Idioma: español
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• Resumen

  • The Rodeo-Iglesia Basin (northwest Argentina) is a narrow piggy-back depositional area which formed during the uplift of the Andean Cordillera (Miocene). Five hundred meters of continental sediments belonging to the Rodeo Formation were deposited in this basin. The Rodeo Formation is divided in 7 sedimentary facies in accordance with lithological and sedimentological features. Facies I (25 m thick) is composed of matrix and clast-supported breccias and represents talus deposits. Facies 2 (30 m thick) comprises tuffs, ignimbrites and tuffaceous mudstones, indicating volcanic activity in the area. Facies 3 (55 m) corresponds to fluvial (braided) conglomerates and sandstones that pass upward to fine sandstones deposited in distal ephemeral braided plains (facies 4, 150 m). Facies 5 (100 m) is made up of amalgamated sandy channels, interbedded with thick intervals of massive and laminated mudstones deposited in a muddy plain of a playa lake environment. Facies 6 (35 m) reflects marked changes in sedimentary environments and provenance conditions. This unit corresponds to braided fluvial systems and shows large amounts of clasts of Andean granites. The top of the sequence is formed by a thick lacustrine interval (150 m) including sand flats (facies 7), mud flats (facies 8), saline mud flats (facies 10) and minor sandy mouth-bars and microdeltas deposits (facies 9). All these facies define four depositional sequences that describe the tectonosedimentary evolution of this pyggy-back basin.