Lake formation, characteristics and evolution in retroarc deposystems: A synthesis of data from the modern Andean orogen and its associated basins

By: , and 
Edited by: Peter G. DeCellesMihai N. DuceaBarbara Carrapa, and Paul Kapp

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Abstract

Lake deposystems are commonly associated with retroarc mountain belts in the geological record. These deposystems are poorly characterized in modern retroarcs, placing limits on our ability to interpret environmental signals from ancient deposits. To address this problem, we have synthesized our existing knowledge about the distribution, morphometrics, and sedimentary geochemical characteristics of tectonically formed lakes in the central Andean retroarc. Large, active mountain belts such as the Andes frequently create an excess of sediment, to the point that modeling and observational data both suggest their adjacent retroarc basins will be rapidly overfilled by sediments. Lake formation, requiring topographic closure, demands special conditions such as topographic isolation and arid climatic conditions to reduce sediment generation, and bedrock lithologies that yield little siliciclastic sediment.

Lacustrine deposition in the modern Andean retroarc has different characteristics in the six major morphotectonic zones discussed. (1) High-elevation hinterland basins of the arid Puna-Altiplano Plateau frequently contain underfilled and balanced-filled lakes that are potentially long-lived and display relatively rapid sedimentation rates. (2) Lakes are rare in piggyback basins, although a transition zone exists where basins that originally formed as piggybacks are transferred to the hinterland through forward propagation of the thrust belt. Here, lakes are moderately abundant and long-lived and display somewhat lower sedimentation rates than in the hinterland. (3) Wedge-top and (4) foredeep deposystems of the Andean retroarc are generally overfilled, and lakes are small and ephemeral. (5) Semihumid Andean back-bulge basins contain abundant small lakes, which are moderately long-lived because of underfilling by sediment and low sedimentation rates. (6) Broken foreland lakes are common, typically underfilled, large, and long-lived playa or shallow systems.

Additional publication details

Publication type Book chapter
Publication Subtype Book Chapter
Title Lake formation, characteristics and evolution in retroarc deposystems: A synthesis of data from the modern Andean orogen and its associated basins
DOI 10.1130/2015.1212(16)
Volume 212
Year Published 2015
Publisher Geological Society of America
Contributing office(s) Central Energy Resources Science Center
Description 27 p.
Larger Work Type Book
Larger Work Title Geodynamic of a cordilleran orogenic system: The central Andes of Argentina and northern Chile
First page 309
Last page 335
Other Geospatial Andes Mountains