Aglomerados volcánicos y conglomerados volcanogénicos estratificados del mioceno temprano en la base de las series cenozoicas del campo de talampaya: Interpretación estratigráfica y significado geológico

Translated title of the contribution: Early miocene stratified volcanic agglomerates and volcanogenic conglomerates at the base of the cenozoic series at campo de talampaya: Stratigraphic interpretation and geologic meaning

Ricardo A. Astini, Carina E. Colombi, Juan C. Candiani, Dennis Kent, Carl Swisher, Brent D. Turrin

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

The purpose of this work is to highlight an epoch of intense andesitic volcanism within the interior of the South American plate prior to the inception of the Bermejo foreland basin in the retroarc region of the southern Central Andes. Facies analysis and detailed mapping of the Campo de Talampaya area, located between the Sierras Pampeanas and the Precordillera between 29°30'-30°S in western Argentina, allow reconstruction of an important andesitic volcanic stage represented by a coarse-grained volcaniclastic unit that developed before the wide and asymmetric Bermejo foreland basin. The latter took place as a response of flexural loading associated to progressive Andean deformation and crustal thickening after the breakup of Farallon plate and initiation of orthogonal convergence along the Pacific margin. The studied volcanosedimentary stratigraphy (La Moradita Formation nov. nom.) unconformably overlies Cretaceous rocks and is erosively truncated by well-dated mid Miocene distal foreland series. Stratigraphic analysis and new 40Ar/39Ar dating allows reconstruction of the paleogeographic evolution. The results portray a regional correlation across the present foreland including the Precordillera thrust and fold belt and into the Famatina ranges (within the broken foreland) that shows a broad magmatic event that occurred between ca. 20-18 Ma (early Miocene). This episode built localized volcanic systems across the Andean retroarc associated with extension that together with the lithostatic load contributed to increase accommodation and allowed the preservation of this unique volcanic stage. This event is much younger than the volcanism associated with more recent (late Miocene-Pliocene) shallowing of subduction within this segment of the Andes and precedes the thick synorogenic stratigraphy within the foreland.

Translated title of the contributionEarly miocene stratified volcanic agglomerates and volcanogenic conglomerates at the base of the cenozoic series at campo de talampaya: Stratigraphic interpretation and geologic meaning
Original languageSpanish
Pages (from-to)423-448
Number of pages26
JournalRevista de la Asociacion Geologica Argentina
Volume74
Issue number4
StatePublished - 2017

All Science Journal Classification (ASJC) codes

  • Geology
  • Stratigraphy

Keywords

  • Central andes
  • Early neogene
  • Paleogeography
  • Retroarc foreland basin
  • Volcaniclastic deposits

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