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Neogene to Quaternary broken foreland formation and sedimentation dynamics in the Andes of NW Argentina (25°S)

Neogene to Quaternary broken foreland formation and sedimentation dynamics in the Andes of NW Argentina (25°S)
Neogene to Quaternary broken foreland formation and sedimentation dynamics in the Andes of NW Argentina (25°S)
The northwest Argentine Andes constitute a premier natural laboratory to assess the complex interactions between isolated uplifts, orographic precipitation gradients, and related erosion and sedimentation patterns. Here we present new stratigraphic observations and age information from intermontane basin sediments to elucidate the Neogene to Quaternary shortening history and associated sediment dynamics of the broken Salta foreland. This part of the Andean orogen, which comprises an array of basement-cored range uplifts, is located at ?25°S and lies to the east of the arid intraorogenic Altiplano/Puna plateau. In the Salta foreland, spatially and temporally disparate range uplift along steeply dipping inherited faults has resulted in foreland compartmentalization with steep basin-to-basin precipitation gradients. Sediment architecture and facies associations record a three-phase (?10, ?5, and <2 Ma), east directed, yet unsystematic evolution of shortening, foreland fragmentation, and ensuing changes in precipitation and sediment transport. The provenance signatures of these deposits reflect the trapping of sediments in the intermontane basins of the Andean hinterland, as well as the evolution of a severed fluvial network. Present-day moisture supply to the hinterland is determined by range relief and basin elevation. The conspiring effects of range uplift and low rainfall help the entrapment and long-term storage of sediments, ultimately raising basin elevation in the hinterland, which may amplify aridification in the orogen interior.
foreland, broken foreland, climate, intermontane basin, sediment trapping, sediment routing
0278-7407
TC2006
Hain, M.P.
d31486bc-c473-4c34-a814-c0834640876c
Strecker, M.R.
43615303-06ca-4739-a8d5-1bd189c79a05
Bookhagen, B.
89d94b44-b9e4-486b-aba3-7218924f58c0
Alonso, R.N.
c3a9696e-1603-4e28-8e37-730a0f37b5ae
Pingel, H.
ed4e4574-8939-4d7f-b64a-c8f554a42b43
Schmitt, A.K.
67c35843-bf93-4546-a91c-d03e53a89677
Hain, M.P.
d31486bc-c473-4c34-a814-c0834640876c
Strecker, M.R.
43615303-06ca-4739-a8d5-1bd189c79a05
Bookhagen, B.
89d94b44-b9e4-486b-aba3-7218924f58c0
Alonso, R.N.
c3a9696e-1603-4e28-8e37-730a0f37b5ae
Pingel, H.
ed4e4574-8939-4d7f-b64a-c8f554a42b43
Schmitt, A.K.
67c35843-bf93-4546-a91c-d03e53a89677

Hain, M.P., Strecker, M.R., Bookhagen, B., Alonso, R.N., Pingel, H. and Schmitt, A.K. (2011) Neogene to Quaternary broken foreland formation and sedimentation dynamics in the Andes of NW Argentina (25°S). Tectonics, 30 (2), TC2006. (doi:10.1029/2010TC002703).

Record type: Article

Abstract

The northwest Argentine Andes constitute a premier natural laboratory to assess the complex interactions between isolated uplifts, orographic precipitation gradients, and related erosion and sedimentation patterns. Here we present new stratigraphic observations and age information from intermontane basin sediments to elucidate the Neogene to Quaternary shortening history and associated sediment dynamics of the broken Salta foreland. This part of the Andean orogen, which comprises an array of basement-cored range uplifts, is located at ?25°S and lies to the east of the arid intraorogenic Altiplano/Puna plateau. In the Salta foreland, spatially and temporally disparate range uplift along steeply dipping inherited faults has resulted in foreland compartmentalization with steep basin-to-basin precipitation gradients. Sediment architecture and facies associations record a three-phase (?10, ?5, and <2 Ma), east directed, yet unsystematic evolution of shortening, foreland fragmentation, and ensuing changes in precipitation and sediment transport. The provenance signatures of these deposits reflect the trapping of sediments in the intermontane basins of the Andean hinterland, as well as the evolution of a severed fluvial network. Present-day moisture supply to the hinterland is determined by range relief and basin elevation. The conspiring effects of range uplift and low rainfall help the entrapment and long-term storage of sediments, ultimately raising basin elevation in the hinterland, which may amplify aridification in the orogen interior.

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More information

Published date: April 2011
Keywords: foreland, broken foreland, climate, intermontane basin, sediment trapping, sediment routing
Organisations: Paleooceanography & Palaeoclimate

Identifiers

Local EPrints ID: 358638
URI: http://eprints.soton.ac.uk/id/eprint/358638
ISSN: 0278-7407
PURE UUID: 670501e6-5f85-4e61-b797-3f1b6f2a4834

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Date deposited: 09 Oct 2013 14:27
Last modified: 14 Mar 2024 15:07

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Contributors

Author: M.P. Hain
Author: M.R. Strecker
Author: B. Bookhagen
Author: R.N. Alonso
Author: H. Pingel
Author: A.K. Schmitt

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