A reassessment of late glacial – Holocene diatom oxygen isotope record from Lake Baikal using a geochemical mass‐balance approach

Abstract

We present a new palaeoenvironmental record of hydrological variability in Lake Baikal, based on re-modelled d 18 O diatom values of diatom silica (d 18 O modelled ), where the residual contaminants are identified and compensated for using electron optical imaging and whole-sample geochemistry. d 18 O modelled interpretations are based on the balance between rivers with high d 18 O values and rivers with low d 18 O values. Isotopic variability is related to latitudinal differences in precipitation which feed these rivers. The d 18 O modelled record suggests that rather moist conditions prevailed in the Lake Baikal region during the latter stages of the Younger Dryas. Throughout the Holocene, episodes of low d 18 O modelled values are, in general, in good agreement with increases in percentage haematite-stained grains in North Atlantic sediments (indicative of ice-rafted debris events). Rivers with southerly catchments dominate fluvial input especially between c. 3.3 and 2 cal ka BP, concurrent with high precipitation in the Lake Baikal region.

Environmental change and cultural dynamics of Holocene hunter–gatherers in Northeast Asia: Comparative analyses and research potentials in Cis-Baikal (Siberia, Russia) and Hokkaido (Japan)

“…To be sure, all these works contribute new and important insights on middle Holocene climates and environments but not of the kind that would necessitate revision of the empirical challenges described above (e.g., Tarasov et al, 2009;Bezrukova et al, 2010Bezrukova et al, , 2011Mackay et al, 2011). Rather, they strengthen our points which, unsurprisingly, resonate well with those made recently in a broader review of interactions between middle Holocene climate change and cultural transitions (Anderson et al, 2007).…”

“…The extensive program of bioarchaeological work completed to date on the Cis-Baikal materials has been published in numerous research papers summarized recently in an edited volume (Weber et al, 2010a) with new studies appearing regularly (e.g., Bezrukova et al, 2011;WatersRist et al, 2010;Katzenberg et al, In Press;Losey et al, 2011;Mackay et al, 2011;Scharlotta et al, 2011;Waters-Rist et al, 2011;Weber et al, 2011;Shepard, In Press;Weber and Goriunova, In Press). Clearly, our current views on the subject (Weber and Bettinger, 2010) are different from those presented earlier (Weber, 1995;Weber et al, 2002;Weber and McKenzie, 2003).…”

Lake Baikal isotope records of Holocene Central Asian precipitation

“…Isotope measurements were made on a Finnigan MAT 253 and converted to the Vienna Standard Mean Ocean Water (VSMOW) scale using the within-run laboratory diatom standard BFCmod calibrated against NBS28. Where necessary, samples were corrected for oxygen bearing contaminants using a geochemical mass balance approach developed for Lake Baikal (Mackay et al, 2011). The issue of contaminants can be problematic in Lake Baikal due to aluminosilicates trapped within the cylindrical frustules of Aulacoseira species (Brewer et al, 2008).…”

“…The issue of contaminants can be problematic in Lake Baikal due to aluminosilicates trapped within the cylindrical frustules of Aulacoseira species (Brewer et al, 2008). To account for this, contaminants were calculated using XRF Al2O3 concentrations following the mass-balance approach in Mackay et al (2011) in which samples are corrected for an assumed diatom bound Al concentration of 0.3 wt%, and used to model contaminant oxygen using Lake Baikal end-members in which aluminosilicates contain 17.2% Al with a δ 18 O composition of 11.7‰ ± 0.3‰ (Brewer et al, 2008).…”

“…To date, this interpretation has been applied to interglacial records from Lake Baikal spanning the Holocene, MIS 5e and MIS 11 to constrain temporal variations in the penetration of weste rlies into Central Asia and regional atmospheric circulation involving the Siberian High (Mackay et al, , 2011(Mackay et al, , 2013. However, no empirical relationship has been demonstrated between hydroclimate variability and down-core records of δ 18 Odiatom.…”