The magnitude of change in climatic conditions and vegetation response to the last deglaciation in various parts
of tropical Amazonia is poorly understood and controversial. Analysis of a sediment core e.g. fossil pollen, X-ray
Fluorescence (XRF) and charcoal from Lake Malachite on the Hill of Six Lakes in northwestern Brazil provided a
deglacial history of climate, vegetation change and fire. Pollen revealed a forested landscape throughout, with
shifts in composition that were driven by warming and changes in precipitation. The glacial cooling of c. 4–5 !C
had brought species characteristic of cooler climates into the Amazon lowlands and was followed by an initial
warming that began at least 19.5 thousand calibrated years before the present (cal kyr BP). Temperature oscillations
and changes in precipitation between (18–14.6 cal kyr BP) associated with Heinrich Stadial 1 were
observed as wet-dry-wet oscillations similar to some of the previous studies, and were evident in both pollen and
XRF data. The pollen spectra were consistent that of a mesic forest before and after the peak of the Last Glacial
Maximum. Cool-adapted taxa had previously been described from other cores from the Hill of Six Lakes, and
persisted in low abundances until c. 14.1 cal kyr BP. No distinct response to the Atlantic Cold Reversal was
evident in our proxy data. The early Holocene was marked by pollen, charcoal, and sedimentary changes that
could reflect a peak drought stress on the forest. The large occurrence of charcoal indicating an increase in fires
coincided with disturbance elements e.g. Cecropia and Alchornea, that could have been consistent with human
disturbance of the forest at c. 10.2 cal kyr BP.
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The Lake Paravani archive – a contribution to the late Quaternary landscape evolution of the Lesser Caucasus (Georgia)
Lake Paravani, located on the volcanic Javakheti Plateau in the central part of the Lesser Caucasus at 2073 m a.s.l., forms a unique geo‐bio‐archive for palaeoenvironmental reconstructions in this remote region. Based on sediment cores from the southwestern part of the lake we expand the existing palynological and sedimentological records beyond the Last Glacial Maximum (LGM). For the first time, it is possible to reconstruct the palaeoenvironment in this part of the Lesser Caucasus back to
- Award ID(s):
- 1854153
- PAR ID:
- 10525453
- Publisher / Repository:
- Wiley Online Library
- Date Published:
- Journal Name:
- Boreas
- ISSN:
- 0300-9483
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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