High-resolution magnetostratigraphy of late quaternary sediments from Lake Baikal, Siberia: timing of intracontinental paleoclimatic responses

Demory, François; Nowaczyk, Norbert R; Witt, Annette; Oberhänsli, Hedi

doi:10.1016/j.gloplacha.2004.09.016

Cited by 57 publications

(24 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…4±2 cm/kyr (BDP Members, 1997;2001). The relative stability of sedimentation rates in this area is independently confirmed by radiocarbon dating Nakamura et al, 2003) and magnetic paleointensity age models of the late Pleistocene Demory et al, 2005). Because of the dramatic variations in Lake Baikal diatom production in response to climate, the Pleistocene glacial-interglacial cycles at Academician Ridge are represented by a distinct pattern of variations in biogenic silica content (BioSi) in sediments.…”

Section: Age Model and Glacial-interglacial Cycles In The Baikal Recordmentioning

confidence: 77%

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

et al. 2010

View full text Add to dashboard Cite

Abstract.A synthesis of paleoclimate responses from Lake Baikal during the MIS 11 interglacial is presented based on proxy records from two drill sites 245 km apart. BDP-99 is located in vicinity of the delta of the major Baikal tributary, whereas the BDP-96 site represents hemipelagic setting distant from riverine influence. The comparison of thicknesses of interglacial intervals in these contrasting depositional settings confirms the extended ca. 33-kyr duration of the MIS 11 interglacial. The new BDP-99 diatom biostratigraphic record matches that of the BDP-96-2 holostratotype and thus allows establishing establishes robust correlation between the records on the same orbitally-tuned timescale.The first detailed MIS 11 palynological record from the BDP-99 drill core indicates the dominance of boreal conifer (taiga) forest vegetation in the Baikal region throughout the MIS 11 interglacial, since at least 424 ka till ca. 396 ka. The interval ca. 420-405 ka stands out as a "conifer optimum" with abundant Abies sibirica, indicative of climate significantly warmer and less continental than today. The closest Baikal analog to this type of vegetation in the history of the current Holocene interglacial is at ca. 9-7 ka. The warm conifer phase lasted for ca. 15 kyr during MIS 11 interrupted by two millennial-scale cooling episodes at ca. 411-410 and 405-404 ka. Reconstructed annual precipitation of 450-550 mm/yr during the MIS 11 interglacial is by ca. 100 mm higher than during the Holocene; regional climate was less continental with warmer mean temperatures both in summer and in winter.Correspondence to: A. A. Prokopenko (sasha@geol.sc.edu) At both drill sites, the two-peak structure of the MIS 11 diatom abundance profiles reflects the orbital signature of precession in the interglacial paleoclimate record of continental Eurasia. MIS 11 interglacial was characterized by the sustained high level of primary production and accumulation of autochthonous organic matter at both study sites. The responses of paleoclimate-sensitive indices in the mineralogy of the MIS 11 sediments in BDP-96-2 are consistent with those during the Holocene. Illitization of secondary clay minerals in the Baikal watershed was an important process, but it appears to have been subdued during the first half of the MIS 11, apparently due to elevated humidity and muted seasonality of regional climate. Past interglacials as potential analogs to modern and future climatesThe ability to predict future changes in global climate is essential for policymaking today and for human well-being in future, it relies on the ability to successfully model climatic conditions known to have existed in the past. Instrumental and even historic records of past climates do not extend beyond the very late portion of the current Holocene interglacial, which lasted since ca. 11.7 ka. To gain a better understanding of the climate of earlier periods, different geologic archives are studied for paleoclimate proxy records.The dominant paradigm in paleoclimate research recognizes...

show abstract

Section: Age Model and Glacial-interglacial Cycles In The Baikal Recordmentioning

confidence: 77%

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

et al. 2010

View full text Add to dashboard Cite

show abstract

“…Note the consistency between the palynological zonation, the radiocarbon and palaeomagnetic (Demory et al, 2005) …”

Section: Chronostratigraphymentioning

confidence: 84%

“…The age models were derived from magnetic susceptibility and anhysteretic remanent magnetisation measured on the Continent Ridge and Posolsky Bank pilot cores (Demory et al, 2005). Geomagnetic palaeointensities of Lake Baikal sediments were tuned to the ODP 984 reference site (Channell, 1999).…”

Section: Chronostratigraphymentioning

confidence: 99%

Clay-mineral record in Lake Baikal sediments: The Holocene and Late Glacial transition

Fagel

Boës

2008

Palaeogeography, Palaeoclimatology, Palaeoecology

View full text Add to dashboard Cite

Abstract:We analyse the clay-mineralogical composition of two 1-m long cores from elevated plateaus in the southern and northern basins of Lake Baikal. Our aim is to test the limits of classically used clay proxies for climate reconstructions. Mineralogical signature is determined by X-ray diffraction on oriented aggregates from Holocene and Late Glacial sediments. Mineralogical results are presented on a palaeomagnetic-derived time scale. Sampling at a centimeter resolution allows for a sub-millenial order reconstruction. The evolution of clayderived climate proxies (smectite/illite peak intensity ratio, S/I) is compared between the two locations, with respect to other climate reconstructions for the Lake Baikal area and Siberia. During the Late Glacial punctual increases of S/I are related to changes of particle source rather than any climate change. At both sites the most intense chemical weathering conditions occured during the Subboreal, lagging the Eurasian middle Atlantic climate optimum. S/I follows a gradual but irregular increase through the Holocene, probably related to slow warming favourable to the development of the Siberian soils. The different sensitivity to hydrolysing conditions in northern and southern sites can be explained by a combination of local lithological and topographical parameters.

show abstract

“…The chronology of core CON01-603-2 is based on palaeomagnetic data tuned to a reference curve (Demory et al, 2005) from ODP Site 984 (Channell, 1999). The palaeomagnetic-derived age model was constrained by seven correlation points between 603 and 731 cm.…”

Section: Lithology and Chronologymentioning

confidence: 99%

“…The illite abundance is low (mean value 34% ±5 at lσ standard deviation), with an upcore decreasing trend. (Demory et al, 2005), core CON01-603-2 from the northern basin of Lake Baikal. The bold curve represents the 5-point running average.…”

Section: Kazantsevo and Transition Clay Recordmentioning

confidence: 99%

Weathering in the Lake Baikal watershed during the Kazantsevo (Eemian) interglacial: Evidence from the lacustrine clay record

Fagel

Mackay

2008

Palaeogeography, Palaeoclimatology, Palaeoecology

View full text Add to dashboard Cite

Abstract:The clay-mineralogical record of a piston core recovered on an elevated plateau in the northern basin of Lake Baikal has been investigated for the Kazantsevo interglacial period (i.e., Eemian s.s. equivalent in northern Europe). The age model (as inferred from palaeomagnetic intensity) suggests that this stage spans ca. 128 to 117 kyr BP. Relative clay mineral abundances and clay-mineral ratios are used to reconstruct the weathering conditions within the Baikal watershed at a sub-millennial resolution, and suggest that the clay record is highly variable. A bimodal clay-data distribution is in agreement with different clay sources and/or formation between the studied glacial and interglacial periods. High amounts of smectites in the Taz glacial samples (128.7-136.4 kyr BP) may be explained by an additional source of neoformed smectites during the glacial stage. In addition to the classically used smectite/illite ratio, the mineralogical results are integrated by the calculation of a hydrolysis index that takes into account the abundance of all clay species and their sensitivity to chemical weathering. A principal components analysis (PCA) of the Baikal clay minerals allows the comparison of the clay parameters with regard to weathering conditions. Clay data are further compared (i) with diatom and pollen profiles, (ii) with pollen-based quantitative reconstructions for the same core material, and (iii) with other climate reconstructions for the Lake Baikal region and Siberia. Several features of our record are highlighted here. During the early period of the Kazantsevo interglacial (128.4-125.2 kyr BP), weathering processes remain controlled by physical reworking for more than 2 kyr after the initial transition from cold to warm conditions. Inception of chemical weathering starts only after ca. 125 kyr BP, a period coincident with the warmest conditions according to both the pollen record and by the strongest chernozem development in Siberian soils. Within the interglacial interval, the hydrolysis index displays a two-step increase, punctuated by a minimum value ca. 122 kyr BP. The increasing but irregular trend persists after the transition from the Kazantsevo interglacial to the Zyryanka glacial (~ 117 kyr BP). Peak chemical weathering, as inferred by clay changes, lags the interglacial/ glacial transition by at least 2 kyr. This suggests that pedogenesis remains active after the interval of surface stabilization. Lake Baikal clay minerals trace the nature of the main weathering conditions within the watershed. We note any increase in physical weathering is rapidly recorded in sedimentary clay assemblages but the mineral imprint to chemical weathering changes is more gradual, lagging reconstructed climate conditions over the lake by ca. 2 kyr.

show abstract

High-resolution magnetostratigraphy of late quaternary sediments from Lake Baikal, Siberia: timing of intracontinental paleoclimatic responses

Cited by 57 publications

References 42 publications

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

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

Clay-mineral record in Lake Baikal sediments: The Holocene and Late Glacial transition

Weathering in the Lake Baikal watershed during the Kazantsevo (Eemian) interglacial: Evidence from the lacustrine clay record

Contact Info

Product

Resources

About