High-altitude cushion peatlands can serve as high resolution climate archives for geoarchaeological and palaeoclimatological research in the central Andes. These unique ecosystems, dominated by juncaceous, peat-forming cushion plants, are characterized by high accumulation rates and therefore document rapid environmental changes, particularly at small time intervals.
Within the multidisciplinary project “Andean Transect – Climate Sensitivity of pre-Columbian Man-Environment-Systems” several sediment cores were retrieved from the Llamoca peatland in the western cordillera of southern Peru (Lucanas province) at 4.500 m a.s.l. and analyzed in a multi-proxy approach.
By means of electrical resistivity tomographies (ERT), which provided detailed information on both the thickness of the peat and the depth to bedrock, the most suitable sampling sites were identified.
A chronology based on almost 100 AMS 14C-datings gives first-time insights into climatic and environmental changes in the study area during the last 8.000 years.
Several periods of intense geomorphodynamic activity are documented by the heterogeneous granulometric composition of sediment layers. In contrast, geochemical analyses (humification degree, CNS measurements, XRF-scanning) of peat layers, which record stable environmental conditions, help identify even slight and short-term trends of landscape development. The results are substantiated by pollen, charred particles and plant macrofossils. Also, with terrestrial laser scanning data the ancient landscape can be reconstructed by generating subsurface models of the valley, and the stages of peat development – which coincide with pre-Columbian cultural eras – can be visualized.
With regard to a supraregional scale, our findings can ideally be linked to and verified by further records such as desert margin loess in the foot zone of the western Andes, river deposits from oases of the hyperarid Peruvian desert, as well as deep-sea cores form the southern Pacific.