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. Inter- pretation 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 in- terval between ca. 6 and 5 ka. The observed bipartitioning of the climate, attributable to the so-called ‘middle- late 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 18 18 intensity deduced by δ O from Chinese speleothems. In particular, the δ O record at Torgashinskaya Cave can be interpreted as mostly driven by temperature changes. Besides several episodes of drift towards higher tem- peratures, 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 corre- spondence 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.
A mid-Holocene stalagmite multiproxy record from southern Siberia (Krasnoyarsk, Russia) linked to the Siberian High patterns
A. Columbu
Primo
;G. Zanchetta;
2023-01-01
Abstract
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. Inter- pretation 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 in- terval between ca. 6 and 5 ka. The observed bipartitioning of the climate, attributable to the so-called ‘middle- late 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 18 18 intensity deduced by δ O from Chinese speleothems. In particular, the δ O record at Torgashinskaya Cave can be interpreted as mostly driven by temperature changes. Besides several episodes of drift towards higher tem- peratures, 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 corre- spondence 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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
