Current models of the peopling of the higher-elevation zones of the Tibetan Plateau postulate that permanent occupation could only have been facilitated by an agricultural lifeway at ~3.6 thousand calibrated carbon-14 years before present. Here we report a reanalysis of the chronology of the Chusang site, located on the central Tibetan Plateau at an elevation of ~4270 meters above sea level. The minimum age of the site is fixed at ~7.4 thousand years (thorium-230/uranium dating), with a maximum age between ~8.20 and 12.67 thousand calibrated carbon-14 years before present (carbon-14 assays). Travel cost modeling and archaeological data suggest that the site was part of an annual, permanent, preagricultural occupation of the central plateau. These findings challenge current models of the occupation of the Tibetan Plateau.

This article describes a new capability for high-precision 14 C measurement of CO 2 from air at the Rafter Radiocarbon Laboratory, GNS Science, New Zealand. We evaluate the short-term within-wheel repeatability and long-term between-wheel repeatability from measurements of multiple aliquots of control materials sourced from whole air. Samples are typically measured to 650,000 14 C counts, providing a nominal accelerator mass spectrometry (AMS) statistical uncertainty of 1.3‰. No additional uncertainty is required to explain the within-wheel variability. An additional uncertainty factor is needed to explain the long-term repeatability spanning multiple measurement wheels, bringing the overall repeatability to 1.8‰, comparable to other laboratories measuring air materials to high precision. This additional uncertainty factor appears to be due to variability in the measured 14 C content of OxI primary standard targets, likely from the combustion process. We observe an offset of 1.4‰ in our samples relative to those measured by the University of Colorado INSTAAR, comparable to interlaboratory offsets observed in recent intercomparison exercises.

Rapid ground accelerations during earthquakes can trigger landslides which disturb mountain forests and harvest carbon from soils and vegetation. While infrequent over human timescales, these co-seismic landslides can set the rates of geomorphic processes over centuries to millennia. However, the long-term impacts of earthquakes and landslides on carbon export from the biosphere remain poorly constrained. Here, we examine the sedimentary fill of Lake Paringa, New Zealand, which is fed by a river draining steep mountains proximal to the Alpine Fault. Carbon isotopes reveal enhanced accumulation rates of biospheric carbon after four large earthquakes over the last ~1100 years, likely reflecting delivery of soil-derived carbon eroded by deep-seated landslides. Cumulatively these pulses of earthquake-mobilized carbon represent 23 ± 5% of the record length,

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Lakes are becoming degraded at an accelerating rate owing to human activity, and understanding their past ecology is necessary for lake management and rehabilitation. Palaeolimnology provides numerous methods that enable the historical state of lakes to be determined. New Zealand provides an ideal setting in which to do this as human modification of the landscape occurred later here than in most regions of the world (approx. 1300 CE). Lake Oporoa is a shallow lake that is highly significant to the local indigenous Māori community. This study used multiple proxy palaeolimnology to explore how lake ecology shifted following Māori and European settlement in the catchment, and how palaeolimnological data can be used to inform lake rehabilitation and conservation measures, alongside the desires of the indigenous community. Sedimentary pollen, diatoms, bacterial communities, and elemental and hyperspectral imaging scanning were used to infer ecological changes in the lake and catchment from pre‐human times to present. Following Māori settlement (approx. 1620 CE) there was gradual vegetation change and a rapid shift in diatom and bacterial assemblages, but not in phytoplankton pigments or sediment geochemistry. An increasing abundance of diatom taxa Discostella stelligera and Staurosirella cf. ovata indicates early nutrient enrichment. European pastoralism from approximately 1840 CE resulted in further deforestation, and all proxies show evidence for enhanced primary productivity driven by a combination of nutrient enrichment and changing lake levels, particularly since the 1960s. This has caused degradation in water quality and is likely to have contributed to the decline in populations of tuna (eel, Anguilla spp.). Conversations with local Māori, together with the palaeolimnological results, indicate that a culturally acceptable and realistic rehabilitation target for Lake Oporoa aligns with ecological conditions in the 1950s. The palaeoecological data provide information to guide catchment and lake revegetation and other methods of nutrient abatement, with the eventual aim of restoring culturally important tuna and native fish populations.