Universität zu Köln

Schittek, K., Forbriger, M., Maechtle, B., Schaebitz, F., Wennrich, V., Reindel, M. and Eitel, B. (2015). Holocene environmental changes in the highlands of the southern Peruvian Andes (14 degrees S) and their impact on pre-Columbian cultures. Clim. Past., 11 (1). S. 27 - 45. GOTTINGEN: COPERNICUS GESELLSCHAFT MBH. ISSN 1814-9332

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Abstract

High-altitude peatlands of the Andes still remain relatively unexploited although they offer an excellent opportunity for well-dated palaeoenvironmental records. To improve knowledge about climatic and environmental changes in the western Andes of southern Peru, we present a high-resolution record of the Cerro Llamoca peatland for the last 8600 years. The 10.5m long core consists of peat and intercalated sediment layers and was examined for all kinds of microfossils. We chose homogeneous peat sections for pollen analysis at decadal to centennial resolution. The inorganic geochemistry was analysed in 2mm resolution (corresponding > 2 years) using an ITRAX X-ray fluorescence core scanner. We interpret phases of relatively high abundances of Poaceae pollen in our record as an expansion of Andean grasslands during humid phases. Drier conditions are indicated by a significant decrease of Poaceae pollen and higher abundances of Asteraceae pollen. The results are substantiated by changes in arsenic contents and manganese/iron ratios, which turned out to be applicable proxies for in situ palaeoredox conditions. The mid-Holocene period of 8.6-5.6 ka is characterised by a series of episodic dry spells alternating with spells that are more humid. After a pronounced dry period at 4.6-4.2 ka, conditions generally shifted towards a more humid climate. We stress a humid/relatively stable interval between 1.8 and 1.2 ka, which coincides with the florescence of the Nasca culture in the Andean foothills. An abrupt turn to a sustained dry period occurs at 1.2 ka, which is contemporaneous with the demise of the Nasca/Wari society in the Palpa lowlands. Markedly drier conditions prevail until 0.75 ka, providing evidence of the presence of a Medieval Climate Anomaly. Moister but hydrologically highly variable conditions prevailed again after 0.75 ka, which allowed re-expansion of tussock grasses in the highlands, increased discharge into the Andean foreland and resettling of the lowlands during this so-called late Intermediate Period (LIP). On a supraregional scale, our findings can ideally be linked to and proved by the archaeological chronology of the Nasca-Palpa region as well as other high-resolution marine and terrestrial palaeoenvironmental records. Our findings show that hydrological fluctuations, triggered by the changing intensity of the monsoonal tropical summer rains emerging from the Amazon Basin in the north-east, have controlled the climate in the study area.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Schittek, K. UNSPECIFIED UNSPECIFIED UNSPECIFIED Forbriger, M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Maechtle, B. UNSPECIFIED UNSPECIFIED UNSPECIFIED Schaebitz, F. UNSPECIFIED UNSPECIFIED UNSPECIFIED Wennrich, V. UNSPECIFIED UNSPECIFIED UNSPECIFIED Reindel, M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Eitel, B. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-417377
DOI:	10.5194/cp-11-27-2015
Journal or Publication Title:	Clim. Past.
Volume:	11
Number:	1
Page Range:	S. 27 - 45
Date:	2015
Publisher:	COPERNICUS GESELLSCHAFT MBH
Place of Publication:	GOTTINGEN
ISSN:	1814-9332
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language OMBROTROPHIC PEAT BOGS; MODERN POLLEN RAIN; CLIMATE-CHANGE; LAKE TITICACA; BOLIVIAN ALTIPLANO; VEGETATION HISTORY; STABLE-ISOTOPE; TROPICAL ANDES; NORTHERN CHILE; LYNCHS CRATER Multiple languages Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/41737