DFG-Leibniz Center for Surface Process and Climate Studies

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Plateau Evolution and Paleoclimate in the Southern Central Andes

Funding: Deutsche Forschungsgemeinschaft (DFG), Alexander von Humboldt Foundation (AvH), German Academic Exchange Service (DAAD), National Science Foundation (NSF)
Starting date: Jan 1, 2005
Duration: 7 years

Gregory Hoke and Manfred R. Strecker (PI’s)

Collaborating researchers (PI’s only)

Richard W. Allmendinger (Cornell), Ricardo N. Alonso (UN Salta, Argentina), Bodo Bookhagen (UC Santa Barbara), Federico Dávila (UN Córdoba), George E. Hilley (Stanford), Phoebe Judge (Cornell), Carolina Montero (UN Salta), Andreas Mulch (Leibniz Universität Hannover), Edward Sobel (Universität Potsdam), José Sosa (UN Tucumán), Cornelius Uba (Universittät Potsdam)


Description

Next to Tibet, the Andean Altiplano/Puna Plateau is the second largest plateau province on Earth. Processes linked with the development of the plateau have had a sustained influence on the tectonic evolution of the plateau margins, the non-plateau southernmost central Andes, and adjacent regions in the broken foreland of the Andes and the Subandean foreland fold-and-thrust belt. In addition, uplift of the plateau and the subsequent uplift of ranges to the east have fundamentally influenced atmospheric circulation and rainfall patterns, and consequently surface processes.

Several mechanisms accounting for the creation of the Altiplano/Puna Plateau have been proposed, but the onset and overall mode of plateau formation, i.e. whether it occurred in increments or as a wholesale event, are still not well understood. In addition, the effects of climate on the formation and limited conservation of the plateau surface and adjacent intermontane basins and their sedimentary fills, calls for a detailed analysis. Through a multidisciplinary study of the Southern Central Andes we may thus learn about general plateau-forming and range-forming mechanisms as well as the complex relationships between climate and tectonics in the growth and demise of mountain belts. The major part of our study focuses on the transition between the Eastern Cordillera, the Subandean thrust belt, the Santa Barbara tectonic inversion province, the northernmost Sierras Pampeanas, and the Puna Plateau.

In our studies we

    1. analyze the role of climatic change on plateau formation in the
      southern central Andes of Bolivia and Argentina;
    2. determine the onset of humid vs. arid climate conditions along the
      eastern flanks of the Andean plateau margin;
    3. assess the role of tectonic versus climatic forcing in the filling and
      evacuation of intermontane sedimentary basin fills; and
    4. determine paleo-elevations using O isotopes measured on paleosols
      and volcanic glass in Tertiary volcanic ash layers.

More specifically, we are studying the effects of plateau formation with respect to the evolution of climate and the asymmetric spatial distribution of surface processes and resulting differences in mass-flux in intermontane basins due to orographic barrier uplift. We assess the sedimentary history and geomorphic evolution of selected intermontane basins using cosmogenic nuclides and Ar/Ar dating, investigate sedimentary provenance and paleosols, and quantify ages and rates of differential uplift/denudation of the basin margins using the apatite fission-track and apatite (U-Th)/He methods. The complementary analysis of stable isotopes of carbon and oxygen will unravel progressively changing paleo-ecologic conditions during intermontane basin formation and the break-up of the foreland through basement uplifts. With emerging data sets we hope to differentiate between competing processes of plateau formation and destruction in the spatiotemporal context of non-collisional mountain belt.

Thematically related to these investigations is a pilot study in the Pre and frontal cordilleras of San Juan in western Argentina carried out in cooperation with Rick Allmendinger and Phoebe Judge of Cornell University. In this project we are evaluating the relationships between the deposition of transient sedimentary valley fills and their subsequent erosion. These processes are temporally and spatially analyzed with respect to the history of thrust-belt advance and the common reactivation of major range-bounding faults within the mountain belt.


Selected publications

2008

Bookhagen, B. and Strecker, M.R. High-resolution TRMM rainfall, hillslope angles, and relief along the eastern Andes, Geophysical Research Letters, 35, L06403.

Carrapa, B. Hauer, J., Schoenbohm, L., Strecker, M.R., Schmitt, A., Villanueva, A., and Sosa Gomez, J. Dynamics of deformation and sedimentation in the northern Sierras Pampeanas: an integrated study of the Neogene Fiambalá basin, NW Argentina. Geological Society of America Bulletin, 120, 1518‐1543 doi:10.1130/B26111.1

Bookhagen, B. and Strecker, M.R., Modern rainfall variation during ENSO cycles and ist impact on the Amazon basin. In: Amazonia, landscapes and species evolution: a look into the past, Hoorn, C., Vonhof, H. and Wesselingh, F. (eds.) Blackwell Publishing, Oxford, UK, in press.

Schoenbohm, L. and Strecker, M.R., Late Pliocene reactivation of thrust and reverse faults as normal faults along the southern margin of the Puna Plateau, NW Argentina. Tectonics (in revision)

2007

Mortimer, E., Schoenbohm, L., Carrapa, B., Sobel, E.R. Sosa Gomez, J., and Strecker, M.R. Compartmentalization of a foreland basin in response to plateau growth and diachronous thrusting: El Cajón – Campo Arenal basin, NW Argentina. Geological Society of America Bulletin, 119, 637-665.

Strecker, M.R. , Alonso, R., Bookhagen, B., Carrapa. B., Hilley, G.E., Sobel, E.R., Trauth, M.H., Tectonics and climate of the southern central Andes. Annual Reviews in Earth and Planetary Sciences, 35, 747-787.

Uba, C.E., Strecker, M.R., Schmitt, A.K. Increased sediment accumulation rates in the Central Andes during the late Miocene due to climate forcing. Geology, 35, 979 - 982.

2006

Coutand, I., Carrapa, B., Deeken, A., Schmitt, A.K., Sobel. E.R., Strecker, M.R. Orogenic plateau formation and lateral growth of compressional basins and ranges: insights from sandstone petrography and detrital apatite fission-track thermochronology in the Angastaco Basin, NW-Argentina. Basin Research, 18, 1-26, doi: 10.1111/j.1365-2117.2006.00283.x

Carrapa, B., Strecker, M.R., and Sobel, E. Cenozoic orogenic growth in the Central Andes: Evidence from sedimentary rock provenance and apatite fission track thermochronology in the Fiambala Basin, southernmost Puna Plateau margin (NW Argentina). Earth and Planetary Science Letters, 247, 82-100

Deeken, A., Sobel, E.R., Haschke, M.R., Strecker, M.R., and Riller, U. Age of Initiation and Growth Pattern of the Puna Plateau, NW-Argentina, Constrained by AFT thermochronology. Tectonics, 25:TC6003, doi:10.1029/2005TC001894

2005

Hilley, G. and Strecker, M.R., Processes of oscillatory basin filling and excavation in a tectonically active orogen: Quebrada del Toro Basin, NW Argentina. Geological Society of America Bulletin, 117, 887-901.

Hilley, G., Blisniuk, P.M. and Strecker, M.R., Mechanics and erosion of thick-skinned and basement-cored uplift provinces. Journal of Geophysical Research, 110, doi:10.1029/2005 JB003704.

Carrapa, B., Adelmann, D., Hilley, G.E., Mortimer, E., Sobel, E., and Strecker, M.R. Oligocene uplift and development of plateau morphology in the southern Central Andes. Oligocene uplift and development of plateau morphology in the southern Central Andes. Tectonics, 24, doi:10.1029/2004TC001762.

2004

Hilley, G. and Strecker, M.R. Steady-state erosion of critical Coulomb wedges. J. Geophysical Research, 109, B1, B01411 10.1029/2002 JB002284.

Hilley, G., Strecker, and Ramos, V. Erosional growth of critical Coulomb wedges applied to the Aconcagua Fold and Thrust Belt, Argentina. J. Geophysical Research, 109, B1, B01410 10.1029/2002 JB002282.

2003

Trauth, M., Bookhagen, B., Mueller, A., and Strecker, M.R.. Late Pleistocene climate change and erosion in the Santa Maria Basin, NW Argentina. Journal of Sedimentary Research, 73, 82-90.

Sobel, E. and Strecker, M.R. Uplift, exhumation, and precipitation: Tectonic and climatic control of Late Cenozoic landscape evolution in the northern Sierras Pampeanas, Argentina. Basin Research, 15, 431-451.

Sobel, E., Hilley, G.E., and Strecker, M.R. Formation of internally drained contractional basins by aridity-limited bedrock incision, 2003, J. Geophysical Research, 108. B7, 2344, doi:10.1029/2002JB001883.

 

shaded relief map

Fig. 1: Shaded relief map and precipitation in the central and southern Andes (WMO, 1975). Sediment-fill thickness in trench from Bangs and Cande, 1997)

 

major geolog. provinces

Fig. 2: Left, major geologic provinces of the southern central Andes superposed on shaded relief map derived from Shuttle Radar Topography Mission (SRTM). Boundaries of geologic provinces modified after Jordan et al. (1983).

Right, mean annual rainfall (m/yr) draped over shaded relief for the southern central Andes. Remotely-sensed rainfall data are derived from the TRMM (Tropical Rainfall Measurement Mission) satellite and have been calibrated using ground-control stations. Processing of the data is similar to the procedure described in Bookhagen and Burbank (2006). Note the pronounced high rainfall areas on the windward slopes in the Bolivian and Argentine Subandean belts, the Santa Barbara System and the Sierras Pampeanas vs. the interior and western flanks of the central Andes.

rainfall

Fig. 3: Digital elevation model of the NW Argentine Andes with superposed precipitation (Strecker et al., 2007). During episodes of increased climatic variability (La Niña years) rainfall penetrates farther westward through low-elevation outlets of intermontane basins in the region E of the Puna Plateau margin.

 

Puna

Fig. 4: Three-dimensional NW view of closed, fault-bounded sedimentary basins in the Puna and currently external-draining basins within the eastern border of the Puna at approximately 25º S lat. These transiently closed basins at the Puna border were subject to repeated cycles of tectonic activity that transformed the former foreland areas into intermontane basins. The basin-bounding faults to the east of the Puna Plateau have been repeatedly reactivated during the past 4 Ma, defeating the drainage system and leading to thick conglomeratic fills. Most of these intermontane fills have been incised due to headward erosion and a re-establishment of fluvial connectivity with the foreland. The uplifts in the broken foreland are highly disparate in time and space and are largely influenced by inherited extensional structures of the Cretaceous Salta Rift.

 

cordiliera san juan

Fig. 5: Thick conglomeratic valley fill covering paleo-topography in the intermontane Iglesia-Calingasta Valley (view W) of San Juán province.

 

anden panorama

Fig. 6: Anden panorama



 

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