Publication Date:
2024-01-29
Description:
A multiproxy record from a stalagmite collected from Torgashinskaya Cave (Southern Siberia, Russia) and
growing between ca. 6 and 3.8 ka shows evidence for regional climatic changes occurring at ca. 5 ka. Interpretation
of stable isotope ratios (δ18O and δ13C) and fluorescence data (intensity and wavelength of the emitted
fluorescence) suggests that the interval between ca. 5 and 4.2 ka was generally warmer and drier than the interval
between ca. 6 and 5 ka. The observed bipartitioning of the climate, attributable to the so-called ‘middlelate
Holocene transition’, has a striking similarity to changes in K+ and Na+ concentration of Greenland ice cores
(taken as indicators of the strength of the Siberian High and Icelandic Low, respectively), in the abundance of
hematite-stained grains in subpolar North Atlantic sediments and, to lesser extent, in the summer Asian monsoon
intensity deduced by δ18O from Chinese speleothems. In particular, the δ18O record at Torgashinskaya Cave can
be interpreted as mostly driven by temperature changes. Besides several episodes of drift towards higher temperatures,
it also strongly suggests the presence of short cooling events centered at 4.1+0.08/-0.07, 4.85+0.05/-0.06,
5.1+0.09/-0.09, 5.3+0.08/-0.07 and 5.8+0.12/-0.13 ka. Notably, the last three such events are in very good correspondence
with spikes in the K+ and Na+ concentration of Greenland ice cores. Instead, the cooling around 4.1 ka
could be the local response to the 4.2 event, a cold/dry episode identified in several records in the Northern
Hemisphere. This suggests that δ18O of speleothem calcite from this area could be a useful proxy for defining the
evolution of the Siberian High and its effect on the wider regional climate.
Description:
Published
Description:
108355
Description:
OSA2: Evoluzione climatica: effetti e loro mitigazione
Description:
JCR Journal
Keywords:
Stable isotopes
;
Fluorescence
;
Speleothems
;
Siberian high
;
Holocene
;
Permafrost
;
Paleoclimate
;
4.2 event
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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