Universität zu Köln

Luecke, Andreas, Kock, Sebastian, Wissel, Holger, Kulemeyer, Julio J., Lupo, Liliana C., Schaebitz, Frank and Schittek, Karsten (2022). Hydroclimatic record from an Altiplano cushion peatland (24 degrees S) indicates large-scale reorganisation of atmospheric circulation for the late Holocene. PLoS One, 17 (11). SAN FRANCISCO: PUBLIC LIBRARY SCIENCE. ISSN 1932-6203

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Abstract

The hydroclimate of South America is characterized by the South American summer monsoon (SASM), a tropical atmospheric circulation that induces a summer precipitation regime, and the Southern Hemisphere Westerlies (SHW), an extratropical atmospheric circulation that induces a winter precipitation regime. Stretched between these two systems is a NW-SE-oriented region dominated by descending air masses, resulting in the South American subtropical dry zone (SASDZ), also known as the arid diagonal. We investigated the Cerro Tuzgle cushion peatland (CTP) located on the Argentine Altiplano, north of the present-day SASDZ. Previous work revealed that the CTP was consistently in the SASM regime during the last 2900 cal yr BP. Here, we extend the CTP record to the middle Holocene covering the last 7200 cal yr BP to gain further knowledge of the Holocene development of the SASM and potential modulations of the SASDZ. The prominent feature of the entire record is a distinct and lasting transition centred around 3100 cal yr BP characterized by declining minerogenic content, increasing organic carbon content, rising stable carbon isotope values of organic matter and cellulose, and increasing stable oxygen isotope values of cellulose. We interpret this specific proxy pattern as a hydroclimatic transition towards less arid conditions at the CTP after 3100 cal yr BP. The transition corresponds with the end of the continuous Holocene strengthening of the SASM between 3500 cal yr BP and 3000 cal yr BP indicated by proxy records from north and east of the CTP. The CTP does not reflect this strengthening of the SASM and rather exhibits a threshold response indicating the effective establishment of the SASM summer precipitation regime at 24 degrees S. This suggests that moisture supply during a more arid middle Holocene was provided by isotopically depleted precipitation, while moisture supply after the transition originated from isotopically enriched SASM summer precipitation. Concurrent hydroclimatic changes in the SHW winter precipitation regime south of the SASDZ are documented in a distinct lake level rise of Laguna Aculeo (33 degrees 50 ' S) around 3200 cal yr BP. These coinciding hydrological changes of the SASM and the SHW precipitation regimes indicate larger scale reorganisations of atmospheric circulation components, potentially connected to major modulations of the SASDZ. Thus, our CTP record sheds light on the middle to late Holocene development of the SASM at its southern limit and corroborates connections between the tropical and extratropical hydroclimate of South America.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Luecke, Andreas UNSPECIFIED UNSPECIFIED UNSPECIFIED Kock, Sebastian UNSPECIFIED UNSPECIFIED UNSPECIFIED Wissel, Holger UNSPECIFIED UNSPECIFIED UNSPECIFIED Kulemeyer, Julio J. UNSPECIFIED UNSPECIFIED UNSPECIFIED Lupo, Liliana C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Schaebitz, Frank UNSPECIFIED UNSPECIFIED UNSPECIFIED Schittek, Karsten UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-671679
DOI:	10.1371/journal.pone.0277027
Journal or Publication Title:	PLoS One
Volume:	17
Number:	11
Date:	2022
Publisher:	PUBLIC LIBRARY SCIENCE
Place of Publication:	SAN FRANCISCO
ISSN:	1932-6203
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language CARBON-ISOTOPE DISCRIMINATION; AMERICAN MONSOON HISTORY; CAL YR BP; STABLE-ISOTOPE; CENTRAL ANDES; HIGH-RESOLUTION; PRECIPITATION DELTA-O-18; ENVIRONMENTAL-CHANGES; HADLEY CIRCULATION; CONVERGENCE ZONE Multiple languages Multidisciplinary Sciences Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/67167