Elsevier

Aeolian Research

Volume 10, September 2013, Pages 89-102
Aeolian Research

Dunes and dunefields in the Bolivian Chaco as potential records of environmental change

https://doi.org/10.1016/j.aeolia.2013.04.002Get rights and content

Highlights

  • Extensive dunefields mapped in the Bolivian Chaco.

  • Dunefields express long-term fluvial-aeolian interactions.

  • Wide spectrum of landforms records diverse aeolian processes.

  • Reconstruction of late Quaternary environmental changes relies on geomorphic context.

Abstract

Eastern Bolivia is situated along the southern margin of the Amazon basin where climate is characterized by the strong hydroclimatic seasonality and high wind speeds related to the South American Low Level Jet (SALLJ). In this setting, this paper explores the geomorphology and environmental significance of the aeolian record in the Bolivian Chaco. Based on the analysis of remote sensing imagery, 10 dunefields were mapped. Their size, topography and geomorphic setting reflect long-term interactions with the fluvial system in the Andean foreland. Preserved aeolian morphology includes different types of linear sand streaks and ridges, parabolic and elongate parabolic morphologies, source-bordering dunes, sandsheets, and transverse dunes and/or mega-ripples. This detailed local to regional-scale geomorphic dataset thus provides the necessary base for the establishment of a chronological framework of dune activity versus stability, and the mapping results reflect the spatial and temporal variations of aeolian processes and their environmental controls such as wind, vegetation, and sediment supply. Compared to the extensive area covered by inactive aeolian features, the localized modern dune activity implies that environmental conditions were more conducive for the expansion of dunefields during some periods in the late Quaternary, while the predominance of parabolic forms reflects the variable but persisting control of vegetation on dune formation in the Bolivian Chaco.

Introduction

The lowlands of the Bolivian Chaco are situated along the southern margin of the Amazon basin, where the effects of late Quaternary latitudinal changes in vegetation and climate are clearly manifest in a wide range of relict landforms (Iriondo, 1993, Latrubesse et al., 2012, May, 2006, May, 2011, Werding, 1977a), alluvial stratigraphy (May et al., 2008a, May and Veit, 2009, May et al., 2008b, Servant et al., 1981), and pollen records (Burbridge et al., 2004, Mayle et al., 2000, Mourguiart and Ledru, 2003, Whitney et al., 2011). Further north – in the Amazon basin of inland Brazil and Venezuela – late Quaternary environmental changes have been inferred from studies of aeolian system, which are expressed in numerous forest covered palaeodunes and dunefields (Carneiro Filho et al., 2002, De Oliveira et al., 1999, Latrubesse and Nelson, 2001, Parolin and Stevaux, 2006, Tatumi et al., 2002, Tricart, 1974). Luminescence based chronologies for late Quaternary aeolian activity have also been published from dunefields and sand seas in the Argentinean Pampas (Kruck et al., 2011, Tripaldi and Forman, 2007, Tripaldi et al., 2011, Zárate and Tripaldi, 2012) and the Paraguayan Chaco (Kruck, 1996, Kruck et al., 2011). In the Bolivian Chaco, a number of studies have focused on problems related to recent aeolian activity (Derpsch, 1974, Herzog, 1914, Jordan, 1981, Jordan, 1982), whereas the only available information on type and controls of longer-term aeolian activity still relies on a very limited set of localized radiocarbon and luminescence ages (Latrubesse et al., 2012, Servant et al., 1981). Thus, much of the aeolian geomorphology in the extensive dunefields of eastern Bolivia remains to be explored (Iriondo, 1993, May, 2006), and has therefore been overlooked in hemispheric and continent-scale reviews on the Quaternary aeolian record (Muhs and Zárate, 2001, Munyikwa, 2005a). Despite the lack of detailed studies, the Bolivian Chaco has been suggested as an important source area for the widespread Quaternary loess cover across northern Argentina (Iriondo, 1990, Iriondo, 1997, Schellenberger and Veit, 2006, Zárate, 2003), and aeolian activity has generally been associated with dry climatic intervals in the Last Glacial Maximum (LGM) and/or the mid-Holocene (Clapperton, 1993, Latrubesse, 2003). Such generalized interpretation of the aeolian record as a proxy for regional to global-scale aridity (e.g. Sarnthein, 1978), however, has recently been debated (Chase, 2009, Kocurek and Lancaster, 1999, Munyikwa, 2005b, Thomas, 2013, Tsoar, 2005). As the development of sand dunes is mainly controlled by sediment supply, wind strength, and vegetation (Kocurek and Lancaster, 1999, Pye and Tsoar, 2009), a detailed knowledge of dune morphology and setting is required for a sound palaeoenvironmental – and even palaeoclimatic – interpretation of the aeolian record (Chase, 2009, Thomas, 201313). Consequently, this paper attempts the first comprehensive documentation of aeolian geomorphology in the Bolivian Chaco by mapping dunes, palaeodunes and dunefields from remote sensing data, and will thus provide the base to reconstructing mechanisms and controls of dune formation over late Quaternary timescales.

Section snippets

Study area

The evolution of the modern Andean foreland in eastern Bolivia is closely related to the Cenozoic uplift and deformation history of the Central Andes, and can be regarded as the consequence of crustal thickening, eastward propagation of the Andes and topographic loading (Allmendinger et al., 1997, Horton and DeCelles, 1997, Isacks, 1988). The Gran Chaco – a ∼850 000 km2 large area dominated by xerophytic deciduous forest (Riveros, 2004) – occupies much of the foreland basin in southeastern

Methods

To provide a comprehensive and detailed overview of aeolian landforms and processes in eastern Bolivia, data acquired on different spatial scales have been combined (Breed and Grow, 1979). (i) The analysis of regional-scale aeolian geomorphology in the Bolivian Chaco mainly relies on the visual interpretation (Hugenholtz et al., 2012, Rosenfeld, 1984, Verstappen, 1977) of freely available remote sensing data (source: US Geological Survey, http://earthexplorer.usgs.gov) such as Landsat imagery

Regional aeolian geomorphology

A variety of aeolian depositional landforms were mapped in the study area between approximately 17.5–20.5°S and 60–63°W (Fig. 2b). Depending on the spatial pattern and density of dunes, they were grouped into 10 dunefields, and then further classified according to the three main geomorphic settings (Fig. 2b) of the piedmont (A1 and A2), the foreland megafans (B1.1, B1.2, B1.3, B2, B3.1, and B3.2), and the erosional uplands of the Altos de Izozog in the eastern study area (C1 and C2).

The areas,

Discussion

The presented dataset is the first attempt to document, quantify and explain the information stored in the extensive dunes and dunefields of the Chaco in eastern Bolivia. It forms the base for the following discussion of three major issues related to the interpretation of the aeolian record: (i) what does the geomorphology of dunefields reveal about the long-term controls on their formation, (ii) what geomorphic and environmental information is stored in the spectrum of active and inactive

Conclusions

In conclusion, the detailed mapping of aeolian dunefields in eastern Bolivia has provided the first in-depth overview of the different types of aeolian landforms preserved in the Bolivian Chaco. The location and size of the dunefields generally show a dominant role of the fluvial system in the longer-term formation and preservation of the dunefields. The dominance of parabolic dunes in the Bolivian Chaco also indicates that, similar to today, vegetation and varying wind regimes were also

Acknowledgements

This research has been funded by SNF-project ‘Palaeoecology of Eastern Bolivia’ (200020-105228/1). Haim Tsoar is thanked for kindly providing Fig. 2a. The author would also like to thank Tim Cohen, Luke Gliganic, Nick Lancaster, Edgardo Latrubesse, Frank Preusser, Haim Tsoar, Heinz Veit, and Xiaoping Yang for fruitful discussions on aeolian geomorphology in the Chaco. The comments of two anonymous reviewers helped to improve the quality of this paper. Also, the logistical support of the Museo

References (121)

  • C.H. Hugenholtz et al.

    Remote sensing and spatial analysis of aeolian sand dunes: a review and outlook

    Earth-Science Reviews

    (2012)
  • C.H. Hugenholtz et al.

    Biogeomorphic model of dunefield activation and stabilization on the northern Great Plains

    Geomorphology

    (2005)
  • M. Iriondo

    Geomorphology and late Quaternary of the Chaco (South America)

    Geomorphology

    (1993)
  • M.H. Iriondo

    Models of deposition of loess and loessoids in the upper Quaternary of South America

    Journal of South American Earth Sciences

    (1997)
  • M.H. Iriondo

    Last glacial maximum and hypsithermal in the southern hemisphere

    Quaternary International

    (1999)
  • N. Lancaster

    How dry was dry? Late Pleistocene palaeoclimates in the Namib Desert

    Quaternary Science Reviews

    (2002)
  • E.M. Latrubesse et al.

    Evidence for late Quaternary aeolian activity in the Roraima–Guyana Region

    CATENA

    (2001)
  • E.M. Latrubesse et al.

    Late Quaternary megafans, fans and fluvio-aeolian interactions in the Bolivian Chaco, Tropical South America

    Palaeogeography, Palaeoclimatology, Palaeoecology

    (2012)
  • L. Marín et al.

    Twentieth century dune migration at the Great Sand Dunes National Park and Preserve, Colorado, relation to drought variability

    Geomorphology

    (2005)
  • T. Maxwell et al.

    Sand sheet dynamics and Quaternary landscape evolution of the Selima Sand Sheet, southern Egypt

    Quaternary Science Reviews

    (2001)
  • J.-H. May et al.

    Holocene landscape evolution along the Andean piedmont, Bolivian Chaco

    Palaeogeography, Palaeoclimatology, Palaeoecology

    (2008)
  • J.-H. May et al.

    Late Quaternary paleosols and their paleoenvironmental significance along the Andean piedmont, Eastern Bolivia

    CATENA

    (2009)
  • J.-H. May et al.

    Late Quaternary paleosol-sediment-sequences and landscape evolution along the Andean piedmont, Bolivian Chaco

    Geomorphology

    (2008)
  • D.R. Muhs et al.

    Evidence of Active Dune Sand on the Great Plains in the 19th Century from Account of Early Explorers

    Quaternary Research

    (1995)
  • D.R. Muhs et al.

    Late Quaternary eolian records of the Americas and their Paleoclimatic significance

  • R. Müller et al.

    Spatiotemporal modeling of the expansion of mechanized agriculture in the Bolivian lowland forests

    Applied Geography

    (2011)
  • K. Munyikwa

    Synchrony of southern hemisphere late Pleistocene arid episodes: a review of luminescence chronologies from arid aeolian landscapes south of the equator

    Quaternary Science Reviews

    (2005)
  • A. Schellenberger et al.

    Pedostratigraphy and pedological and geochemical characterization of Las Carreras loess-paleosol sequence, Valle de Tafi, NW-Argentina

    Quaternary Science Reviews

    (2006)
  • Agrar- und Hydrotechnik GmbH, 1974. Proyecto de desarrollo agroindustrial Abapo-Izozog. – Hidrología,...
  • AGTECA, 2010. Climate. Available from: <http://www.agteca.com/climate.htm>...
  • R.W. Allmendinger et al.

    The evolution of the Altiplano-Puna Plateau of the Central Andes

    Annual Review of Earth and Planetary Sciences

    (1997)
  • P. Baby et al.

    Geometry and kinematic evolution of passive roof duplexes deduced from crosssection balancing: example from the foreland thrust system of the southern Bolivian Subandean zone

    Tectonics

    (1992)
  • C.S. Breed et al.

    Regional studies of sand seas, using Landsat (ERTS) Imagery

  • C.S. Breed et al.

    Morphology and distribution of dunes in sand seas observed by remote sensing

  • J.E. Bullard et al.

    Aeolian-fluvial interactions in dryland environments: examples, concepts and Australia case study

    Progress in Physical Geography

    (2003)
  • C.M. Campetella et al.

    The influence of the Andes Mountains on the South American low-level flow

    Geophysical Research Letters

    (2002)
  • A. Carneiro Filho et al.

    Amazonian paleodunes provide evidence for drier climate phases during the late Pleistocene–Holocene

    Quaternary Research

    (2002)
  • Cooke R.U., Warren A., Goudie A.S., Desert Geomorphology, UCL Press, London, UK,...
  • P.P. David

    Stabilized dune ridges in northern Saskatchewan

    Canadian Journal of Earth Sciences

    (1981)
  • R.W. Derpsch

    Estudio sobre la erosión eolica en la región integrada del departamento de Santa Cruz y medidas practicas para su control

    (1974)
  • O. Durán et al.

    Vegetation against dune mobility

    Physical Review Letters

    (2006)
  • S.L. Forman et al.

    Large-scale stabilized dunes on the High Plains of Colorado: understanding the landscape response to Holocene climates with the aid of images from space

    Geology

    (1992)
  • S.G. Fryberger et al.

    Origin, sedimentary features, and significance of low-angle eolian “sand sheet” deposits, Great Sand Dunes National Monument and vicinity, Colorado

    Journal of Sedimentary Petrology

    (1979)
  • R.D. Garreaud

    Cold air incursions over subtropical South America: mean structure and dynamics

    Monthly Weather Review

    (2000)
  • R.D. Garreaud et al.

    Atmospheric circulation and climatic variability

  • G. Gerold

    Untersuchungen zur Badlandentwicklung in den wechselfeuchten Waldgebieten Südboliviens

    Geoökodynamik

    (1985)
  • Gerold, G., 1988. Die Bedeutung von Ariditätswandel und Vegetationsdegradation für die fluviale Morphodynamik in den...
  • Geyh, M.A., Grosjean, M., Kruck, W., Schotterer, U., 1996. Sincronopsis del desarollo morfológico y climatológico del...
  • T. Herzog

    Dünen und Wald in den Savannen von Santa Cruz (Ostbolivien)

    Petermann’s Mittheilungen

    (1914)
  • P.P. Hesse

    The Australian Desert Dunefields: Formation and Evolution in an Old, Flat, Dry Continent

    (2010)
  • Cited by (0)

    View full text