Paleoenvironmental proxy records from Lake Hovsgol, Mongolia, and a synthesis of Holocene climate change in the Lake Baikal watershed

Abstract

Here we discuss paleoenvironmental evolution in the Baikal region during the Holocene using new records of aquatic (diatom) and terrestrial vegetation changes from Hovsgol, Mongolia's largest and deepest lake. We reconcile previous contradictory Baikal timescales by constraining reservoir corrections of AMS dates on bulk sedimentary organic carbon. Synthesis of the Holocene records in the Baikal watershed reveals a northward progression in landscape/vegetation changes and an anti-phase behavior of diatom and biogenic silica proxies in neighboring rift lakes. In Lake Baikal, these proxies appear to be responsive to annual temperature increases after 6 ka, whereas in Lake Hovsgol they respond to higher precipitation/runoff from 11 to 7 ka. Unlike around Lake Baikal, warmer summers between 6 and 3.5 ka resulted in the decline, not expansion, of forest vegetation around Lake Hovsgol, apparently as a result of higher soil temperatures and lower moisture availability. The regional climatic proxy data are consistent with a series of 500-yr time slice Holocene GCM simulations for continental Eurasia. Our results allow reevaluation of the concepts of ‘the Holocene optimum’ and a ‘maximum of the Asian summer monsoon’, as applied to paleoclimate records from continental Asia.

Climate in continental interior Asia during the longest interglacial of the past 500 000 years: the new MIS 11 records from Lake Baikal, SE Siberia

“…These proxies at both sites are consistent with BioSi/diatom responses in indicating a prolonged interval of high primary production and accumulation of organic matter (OM) in the lake. By analogy with Holocene (TOC 1-3% dry sediment weight, Prokopenko et al, 1999Prokopenko et al, , 2007 and the last interglacial (TOC 1.5-2%, Prokopenko and Williams, 2003), sustained high OM accumulation during MIS 11 (TOC 1-2%, Figs. 3, 4) may be interpreted as an indication of high lake productivity characteristic of "full-scale" interglacial conditions, not unlike those during MIS 1 and MIS 5e intervals.…”

“…Previously, the close temporal relationship between BioSi/diatom and arboreal pollen proxies for warm regional climate has been established for the radiocarbondated Holocene interval (e.g. Prokopenko et al, 2007) and for the paleointensity-dated last interglacial interval, as seen from the comparison of diatom (Rioual and Mackay, 2005) and pollen records. For older interglacial and interstadial intervals, the apparent durations (thicknesses) agree in pollen and BioSi/diatom records as well (Table 1).…”

Quantitative reconstructions of mid- to late holocene climate and vegetation in the north-eastern altai mountains recorded in lake teletskoye

“…3A). This effect is well known and has been described for the large lakes in different parts of the world (e.g., Moreton et al, 2004;Prokopenko et al, 2007;Watanabe et al, 2009;Zhou et al, 2015).…”

Continental Erosion/Weathering Changes in Central Asia Recorded in the Holocene Sediment from Lake Hovsgol, Northwest Mongolia, by Synchrotron μ-XRF Mapping Analyses

“…Evidences and suggestions supporting our hypothesis are provided by studies on the sediment from Lake Hovsgol. Prokopenko et al (2007) showed that the early Holocene diatom/biogenic silica (bioSi) peaks correlated with the humidity maximum (Fig. 6f) reconstructed by the pollen fossil analyses and from predictions of GCMs (Bush, 2005).…”

“…6f) reconstructed by the pollen fossil analyses and from predictions of GCMs (Bush, 2005). Based on these observations, Prokopenko et al (2007) regarded that the early Holocene increase of diatom abundance in Lake Hovsgol was caused by increased nutrient supply with high precipitation and surface runoff. The early Holocene diatom/bioSi peaks correspond to the increased Br contents in core HDP-06 (Fig.…”