A high-altitude peatland record of environmental changes in the NW Argentine Andes (24 ° S) over the last 2100 years

Abstract

Abstract. High-altitude cushion peatlands are versatile archives for high-resolution palaeoenvironmental studies, due to their high accumulation rates, range of proxies, and sensitivity to climatic and/or human-induced changes. Especially within the Central Andes, the knowledge about climate conditions during the Holocene is limited. In this study, we present the environmental and climatic history for the last 2100 years of Cerro Tuzgle peatland (CTP), located in the dry Puna of NW Argentina, based on a multi-proxy approach. X-ray fluorescence (XRF), stable isotope and element content analyses (δ13C, δ15N, TN and TOC) were conducted to analyse the inorganic geochemistry throughout the sequence, revealing changes in the peatlands' past redox conditions. Pollen assemblages give an insight into substantial environmental changes on a regional scale. The palaeoclimate varied significantly during the last 2100 years. The results reflect prominent late Holocene climate anomalies and provide evidence that in situ moisture changes were coupled to the migration of the Intertropical Convergence Zone (ITCZ). A period of sustained dry conditions prevailed from around 150 BC to around AD 150. A more humid phase dominated between AD 200 and AD 550. Afterwards, the climate was characterised by changes between drier and wetter conditions, with droughts at around AD 650–800 and AD 1000–1100. Volcanic forcing at the beginning of the 19th century (1815 Tambora eruption) seems to have had an impact on climatic settings in the Central Andes. In the past, the peatland recovered from climatic perturbations. Today, CTP is heavily degraded by human interventions, and the peat deposit is becoming increasingly susceptible to erosion and incision.

Late Holocene environmental changes reconstructed from stable isotope and geochemical records from a cushion‐plant peatland in the Chilean Central Andes (27°S)

“…However, over centennial timescales the record reveals no clear oscillation. In accordance with our record, high Mn/Fe ratios of the Cerro Tuzgle cushion peatland, located in the Puna of northwest Argentina (24˚S, 67˚W, SASM-influenced), indicate increasing humidity between 300 and 100 cal a BP (Schittek et al, 2016;Fig. 7c).…”

“…Another distinct phase with lower d 18 O cell values in our record occurs between 1530 and 1270 cal a BP, indicating wetter conditions at the LP. Slightly increased humidity during that time is also evident in the Cerro Tuzgle peatland (Schittek et al, 2016). Whether increasing d 18 O cell values in the uppermost peat section (since around À30 cal a BP/1980 ad) mark a trend towards increased aridity remains unclear.…”

Two Thousand Years of Land-Use and Vegetation Evolution in the Andean Highlands of Northern Chile Inferred from Pollen and Charcoal Analyses

“…The formation of the Andean wetland occurred approximately around 1400 calendar year BP and reached its maximum extension between 600 calendar year BP and modern times, as indicated by the abundance of Eleocharis pollen and organic matter. The establishment of a permanently inundated wetland coincides with an increase in moisture levels during the late Holocene, reported extensively in South America, including the central Altiplano [57], northern and central Chile [67][68][69][70][71], and eastern and northwestern Argentina [72,73].…”

Multi‐Centennial‐Scale Variations of South American Summer Monsoon Intensity in the Southern Central Andes (24–27°S) During the Late Holocene

“…Master core halves from LP and CTP were cut into 1‐cm slices and sampled for radiocarbon dating and cellulose extraction. Bulk peat samples were used for radiocarbon dating by Accelerator Mass Spectrometry (Poznan Radiocarbon Laboratory, Poznan, Poland) (Kock, Schittek, Wissel, et al, ; Schittek et al, ). Radiocarbon ages were calibrated to calendar ages (cal.…”