Simulating foreland basin response to mountain belt kinematics and climate change in the Eastern Cordillera and Subandes: An analysis of the Chaco foreland basin in southern Bolivia

Todd M. Engelder, Jon D. Pelletier

Research output: Chapter in Book/Report/Conference proceedingChapter

2 Scopus citations

Abstract

The relative importance of crustal thickening, lithospheric delamination, and climate change in driving surface uplift and the associated changes in accommodation space and depositional facies in the adjacent foreland basin in the central Andes has been a topic of vigorous debate over the past decade. Interpretation of structural, geochemical, geomorphic, and geobiologic field data has led to two proposed endmember Tertiary surface uplift scenarios for the Eastern Cordillera and Subandes in the vicinity of the Bolivian orocline. A "gradual uplift" model proposes that the rate of surface uplift has been relatively steady since deformation propagated into the Eastern Cordillera during the late Eocene. In this scenario, the mean elevation of the region was >2 km above mean sea level (msl) by the late Miocene or earlier. Alternatively, a "rapid uplift" model suggests that the mean elevation of the Altiplano was <1 km above msl, and the peaks of the Eastern Cordillera were more than 2 km below their modern elevations until rapid uplift began ca. 10 Ma. Determining which of these uplift scenarios is most consistent with the stratigraphic record is complicated by the potentially confounding effects of global climate changes and lithospheric delamination in the stratigraphic record. In this study, we use a coupled mountain-belt-sediment-transport model to predict the foreland basin stratigraphic response to these end-member surface uplift scenarios. Our model results indicate that the location and height of the migrating deformation front play the dominant roles in controlling changes in accommodation space and grain size within the foreland basin. Changes in accommodation space and rates of sediment supply related to climate change and lithospheric delamination play secondary roles. Our results support the conclusion that the Eastern Cordillera likely gained most of its modern elevation prior to 10 Ma, in contrast with recent proposals that most of the modern elevation was obtained during the late Miocene. This conclusion is consistent with the most comprehensive paleoaltimetric analysis of the region to date.

Original languageEnglish (US)
Title of host publicationGeodynamics of a Cordilleran Orogenic System
Subtitle of host publicationThe Central Andes of Argentina and Northern Chile
EditorsMihai N. Ducea, Mihai N. Ducea, Peter G. DeCelles, Paul A. Kapp, Barbara Carrapa
PublisherGeological Society of America
Pages337-357
Number of pages21
ISBN (Electronic)9780813712123
DOIs
StatePublished - Jan 1 2015

Publication series

NameMemoir of the Geological Society of America
Volume212
ISSN (Print)0072-1069

ASJC Scopus subject areas

  • Geology

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    Engelder, T. M., & Pelletier, J. D. (2015). Simulating foreland basin response to mountain belt kinematics and climate change in the Eastern Cordillera and Subandes: An analysis of the Chaco foreland basin in southern Bolivia. In M. N. Ducea, M. N. Ducea, P. G. DeCelles, P. A. Kapp, & B. Carrapa (Eds.), Geodynamics of a Cordilleran Orogenic System: The Central Andes of Argentina and Northern Chile (pp. 337-357). (Memoir of the Geological Society of America; Vol. 212). Geological Society of America. https://doi.org/10.1130/2015.1212(17)