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Climate of the Past An interactive open-access journal of the European Geosciences Union
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Volume 11, issue 1
Clim. Past, 11, 27–44, 2015
https://doi.org/10.5194/cp-11-27-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.

Special issue: Past environmental and climatic stress during modern human's...

Clim. Past, 11, 27–44, 2015
https://doi.org/10.5194/cp-11-27-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 07 Jan 2015

Research article | 07 Jan 2015

Holocene environmental changes in the highlands of the southern Peruvian Andes (14° S) and their impact on pre-Columbian cultures

K. Schittek1, M. Forbriger2, B. Mächtle3, F. Schäbitz1, V. Wennrich4, M. Reindel5, and B. Eitel3 K. Schittek et al.
  • 1Seminar of Geography and Geographical Education, University of Cologne, Germany
  • 2Institute of Geography, University of Cologne, Germany
  • 3Geographical Institute, University of Heidelberg, Germany
  • 4Institute of Geology and Mineralogy, University of Cologne, Germany
  • 5German Archaeological Institute, Commission for Archaeology of Non-European Cultures (KAAK), Bonn, Germany

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 10.5 m 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 2 mm 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.

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