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Kumphawapi, which is Thailand’s largest natural freshwater lake, contains a >10,000-year-long climatic and environmental archive. New data sets (stratigraphy, chronology, hydrogen isotopes, plant macrofossil and charcoal records) for two sedimentary sequences are here combined with earlier multi-proxy studies to provide a comprehensive reconstruction of past climatic and environmental changes for Northeast Thailand. Gradually higher moisture availability due to a strengthening of the summer monsoon led to the formation of a large shallow lake in the Kumphawapi basin between >10,700 and c. 7000 cal. BP. The marked increase in moisture availability and lower evaporation between c. 7000 and 6400 cal. BP favoured the growth and expansion of vegetation in and around the shallow lake. The increase in biomass led to gradual overgrowing and infilling, to an apparent lake level lowering and to the development of a wetland. Multiple hiatuses are apparent in all investigated sequences between c. 6500 and 1400 cal. BP and are explained by periodic desiccation events of the wetland and erosion due to the subsequent lake level rise. The rise in lake level, which started c. 2000 cal. BP and reached shallower parts c. 1400 cal. BP, is attributed to an increase in effective moisture availability. The timing of hydroclimatic conditions during the past 2000 years cannot be resolved because of chronological limitations.

Hundsalm ice cave located at 1520 m altitude in a karst region of western Austria contains up to 7-m-thick deposits of snow, firn and congelation ice. Wood fragments exposed in the lower parts of an ice and firn wall were radiocarbon accelerator mass spectrometry (AMS) dated. Although the local stratigraphy is complex, the 19 individual dates – the largest currently available radiocarbon dataset for an Alpine ice cave – allow to place constraints on the accumulation and ablation history of the cave ice. Most of the cave was either ice free or contained only a small firn and ice body during the ‘Roman Warm Period’; dates of three wood fragments mark the onset of firn and ice build-up in the 6th and 7th century ad. In the central part of the cave, the oldest samples date back to the 13th century and record ice growth coeval with the onset of the ‘Little Ice Age’. The majority of the ice and firn deposit, albeit compromised by a disturbed stratigraphy, appears to have been formed during the subsequent centuries, supported by wood samples from the 15th to the 17th century. The oldest wood remains found so far inside the ice is from the end of the Bronze Age and implies that local relics of prehistoric ice may be preserved in this cave. The wood record from Hundsalm ice cave shows parallels to the Alpine glacier history of the last three millennia, for example, the lack of preserved wood remains during periods of known glacier minima, and underscores the potential of firn and ice in karst cavities as a long-term palaeoclimate archive, which has been degrading at an alarming rate in recent years.

Holocene vegetation records are presented from palaeochannels in the southern Kelabit Highlands, at Pa’Dalih (PDH 212) and at Pa’Buda (BPG), and from a peat bog in the northern Kelabit Highlands, at Bario (Ba). Results are based on changes in the sediment lithology, loss-on-ignition, magnetic susceptibility, pollen, phytoliths and other palynomorphs. At Pa’Buda, possible clearance occurred ~6500 cal. BP, perhaps for arboriculture. More pronounced signatures of clearance are at PDH 212 by ~3100 cal. BP, and at Ba by 1300 cal. BP. Propagation/cultivation of the sago palm, Eugeissona, may have been taking place by ~2800 cal. BP at site PDH 212 and was probably taking place by at least 1300 cal. BP at Ba. Rice cultivation may have been taking place between 2800 and 1200 cal. BP at PDH 212, but this remains speculative, due to the morphological features of the Oryza bulliforms, but it was likely taking place at Pa’Dalih by 530–490 cal. BP, where Oryza bulliforms, with characteristics similar to domesticated ty...

Rice and sago are today important staples for many subsistence farmers and nomadic hunter-gatherers living in interior Borneo, but the cultural antiquity of these staples remains poorly understood. This study examines a 2300 yr sedimentary record from a palaeochannel near the village of Pa’Dalih in the southern Kelabit Highlands. Pollen and phytolith evidence indicate significant use of the sago palm Eugeissona near the channel during this period. Oryza phytoliths likely belonging to domesticated rice varieties are also recorded, although rice may have been used to a lesser extent than the sago palms. A rise in cultural activity takes place between c. 1715 and 1600 cal. BP, shown by increased frequency of fires.

In order to calibrate radiocarbon ages based on samples with a marine carbon component it is important to know the marine carbon reservoir correction or ΔR value. This study measured the ΔR on both known-age pre-bomb marine shells and paired marine and terrestrial samples from two regions on the west coast of South Africa: the southwestern Cape and Namaqualand. Pooling the data by region produces ΔR values that are similar enough to use a west coast weighted mean ΔR of 146 ± 85 14C years to correctly calibrate marine shell or mixed marine and terrestrial 14C ages. There are however temporal differences in ΔR throughout the Holocene, which we compare with proxy data for upwelling and sea surface temperatures.

The time dependency of the regional difference ΔR in the marine radiocarbon reservoir correction is an important issue for the calibration of marine radiocarbon ages and also provides information about past ocean circulation changes. Few measurements of Holocene reservoir corrections are available for the climatically important North Atlantic. We determined ΔR for intervals during the past 6100 years before present (BP) by comparing radiocarbon ages of 31 marine and terrestrial sample pairs from 14 archaeological sites from the coast of Ireland, Scotland and the Orkney Islands. We find that, while a time dependency in ΔR for this region cannot be ruled out, within the error of the determinations, the ΔR appears to have been constant for at least the last 2000 and possibly the last 6000 years. This work results in a recommendation for ΔR of 33 +93 for the region.