Seasonal deposition processes and chronology of a varved Holocene lake sediment record from Lake Chatyr Kol (Kyrgyz Republic)

Abstract. A finely laminated lake sediment record with a basal age of 11,619 ± 603 years BP was retrieved from Lake Chatyr Kol (Kyrgyz Republic). Microfacies analysis reveals the presence of seasonal laminae (varves) from the sediment basis to ~ 360 ± 40 years BP. The Chatvd19 floating varve chronology covers the time span from 360 ± 40 years BP to the base and relies on replicate varve counts on overlapping petrographic thin sections with an uncertainty of ± 5 %. The uppermost non-varved interval was chronologically constrained by 210Pb and 137Cs γ-spectrometry and interpolation based on varve thickness measurements of adjacent varved intervals with an assumed uncertainty of 10 %. Six varve types were distinguished, are described in detail and show a changing predominance of clastic-organic, clastic-calcitic or -aragonitic, calcitic-clastic, organic-clastic and clastic-diatom varves throughout the Holocene. Variations in varve thickness and the number and composition of seasonal sublayers are attributed to 1) changes in the amount of summer or winter/spring precipitation affecting local runoff and erosion and/or to 2) evaporative conditions during summer. Radiocarbon dating of bulk organic matter, daphnia remains, aquatic plant remains and Ruppia maritima seeds reveal reservoir ages with a clear decreasing trend up core from ~ 6,150 years in the early Holocene, to ~ 3,000 years in the mid-Holocene, to ~ 1,000 years and less in the late Holocene and modern times. In contrast, two radiocarbon dates from terrestrial plant remains are in good agreement with the varve-based chronology.

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Seasonal deposition processes and chronology of a varved Holocene lake sediment record from Chatyr Kol lake (Kyrgyz Republic)

Geochronology ◽

10.5194/gchron-2-133-2020 ◽

2020 ◽

Vol 2 (1) ◽

pp. 133-154

Author(s):

Julia Kalanke ◽

Jens Mingram ◽

Stefan Lauterbach ◽

Ryskul Usubaliev ◽

Rik Tjallingii ◽

...

Keyword(s):

Kyrgyz Republic ◽

Sediment Record ◽

Spring Precipitation ◽

Radiocarbon Dates ◽

Thin Sections ◽

Varve Thickness ◽

210Pb And 137Cs ◽

Plant Remains ◽

Bulk Organic Matter ◽

Deposition Processes

Abstract. Microfacies analysis of a sediment record from Chatyr Kol lake (Kyrgyz Republic) reveals the presence of seasonal laminae (varves) from the sediment base dated at 11 619±603 BP (years Before Present) up to ∼360±40 BP. The Chatvd19 floating varve chronology relies on replicate varve counts on overlapping petrographic thin sections with an uncertainty of ±5 %. The uppermost non-varved interval was chronologically constrained by 210Pb and 137Cs gamma spectrometry and interpolation based on varve thickness measurements of adjacent varved intervals with an assumed maximum uncertainty of 10 %. Six varve types were distinguished, are described in detail, and show a changing predominance of clastic-organic, clastic-calcitic or clastic-aragonitic, calcitic-clastic, organic-clastic, and clastic-diatom varves throughout the Holocene. Variations in varve thickness and the number and composition of seasonal sublayers are attributed to (1) changes in the amount of summer or winter/spring precipitation affecting local runoff and erosion and/or to (2) evaporative conditions during summer. Radiocarbon dating of bulk organic matter, daphnia remains, aquatic plant remains, and Ruppia maritima seeds reveals reservoir ages with a clear decreasing trend up core from ∼6150 years in the early Holocene, to ∼3000 years in the mid-Holocene, to ∼1000 years and less in the late Holocene and modern times. In contrast, two radiocarbon dates from terrestrial plant remains are in good agreement with the varve-based chronology.

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Seasonal deposition processes and chronology of a varved Holocene lake sediment record from Lake Chatyr Kol (Kyrgyz Republic) by Kalanke et al.

10.5194/gchron-2019-18-rc2 ◽

2020 ◽

Author(s):

Anonymous

Keyword(s):

Lake Sediment ◽

Kyrgyz Republic ◽

Sediment Record ◽

Seasonal Deposition ◽

Deposition Processes

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Supplementary material to "Seasonal deposition processes and chronology of a varved Holocene lake sediment record from Lake Chatyr Kol (Kyrgyz Republic)"

10.5194/gchron-2019-18-supplement ◽

2020 ◽

Author(s):

Julia Kalanke ◽

Jens Mingram ◽

Stefan Lauterbach ◽

Ryskul Usubaliev ◽

Achim Brauer

Keyword(s):

Lake Sediment ◽

Kyrgyz Republic ◽

Sediment Record ◽

Seasonal Deposition ◽

Supplementary Material ◽

Deposition Processes

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'Seasonal deposition processes and chronology of a varved Holocene lake sediment record from Lake Chatyr Kol (Kyrgyz Republic) by Kalanke et al.' Reviewer 2 comments.

10.5194/gchron-2019-18-rc3 ◽

2020 ◽

Author(s):

Anonymous

Keyword(s):

Lake Sediment ◽

Kyrgyz Republic ◽

Sediment Record ◽

Seasonal Deposition ◽

Deposition Processes

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First Holocene floating varve chronology in Central Asia from the Lake Chatyr Kol sediment record (Kyrgyz Republic)

10.5194/egusphere-egu2020-22554 ◽

2020 ◽

Author(s):

Julia Kalanke ◽

Jens Mingram ◽

Stefan Lauterbach ◽

Ryskul Usubaliev ◽

Achim Brauer

Keyword(s):

Central Asia ◽

Mountain Lake ◽

Lake Basin ◽

High Mountain ◽

Kyrgyz Republic ◽

Sediment Record ◽

Thin Sections ◽

The Holocene ◽

Sediment Profile ◽

Varve Chronology

We present the first floating varve chronology in arid Central Asia of a finely laminated lake sediment record from the high-mountain Lake Chatyr Kol (Kyrgyz Republic). The record was retrieved from the deepest part (~20m) of the lake basin and comprises seasonal laminations (varves) from 11,619 &#177; 603 years BP to 360 &#177; 40 BP years. The identification of varves is based on seasonal deposition models established from continuous thin section analyses of the entire sediment profile. The varves comprise a complex pattern of six different micro-facies types throughout the Holocene. All varve types include a pronounced clastic-detrital sublayer, but the composition of their summer sublayers varies between organic, diatom, calcite, and aragonite sublayers. Based on replicate varve counts on overlapping petrographic thin sections an uncertainty of &#177; 5 % has been calculated for the varve chronology. The chronology is floating because in the uppermost part of the sediment profile varves have been only occasionally formed or preserved which prevented from continuous varve counting in this interval. Instead, the non-varved interval has been dated with 210Pb and 137Cs &#947;-spectrometry providing an age for anchoring the floating chronology to the absolute time scale. The resulting chronology is supported by two 14C ages obtained from terrestrial plant macrofossils. In contrast, radiocarbon dating of aquatic materials showed significantly older ages and prove reservoir effects. Through comparison with the varve chronology changes in reservoir effects throughout the Holocene have been determined. We find a stepwise decline of reservoir ages from up to ~6150 years in the early Holocene to lowest reservoir ages of less than 1000 years in the late Holocene. In addition to their value as chronological tool, changes in varve thickness and seasonal sublayer composition are used as proxies for hydro-climatological reconstruction of Holocene climate evolution.This is a contribution to the CAHOL project, part of the BMBF-funded and integrated project CAME II.

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ON THE TIMING OF THE OLD COPPER COMPLEX IN NORTH AMERICA: A COMPARISON OF RADIOCARBON DATES FROM DIFFERENT ARCHAEOLOGICAL CONTEXTS

Radiocarbon ◽

10.1017/rdc.2021.7 ◽

2021 ◽

pp. 1-19

Author(s):

David P Pompeani ◽

Byron A Steinman ◽

Mark B Abbott ◽

Katherine M Pompeani ◽

William Reardon ◽

...

Keyword(s):

Native American ◽

Lake Sediment ◽

Copper Complex ◽

Lake Superior ◽

Copper Mining ◽

Radiocarbon Dates ◽

Copper Mines ◽

Tool Technology ◽

High Lead ◽

Old Copper Complex

ABSTRACT The Old Copper Complex (OCC) refers to the production of heavy copper-tool technology by Archaic Native American societies in the Lake Superior region. To better define the timing of the OCC, we evaluated 53 (eight new and 45 published) radiocarbon (14C) dates associated with copper artifacts and mines. We compared these dates to six lake sediment-based chronologies of copper mining and annealing in the Michigan Copper District. 14C dates grouped by archaeological context show that cremation remains, and wood and cordage embedded in copper artifacts have ages that overlap with the timing of high lead (Pb) concentrations in lake sediment. In contrast, dates in stratigraphic association and from mines are younger than those from embedded and cremation materials, suggesting that the former groups reflect the timing of processes that occurred post-abandonment. The comparatively young dates obtained from copper mines therefore likely reflect abandonment and infill of the mines rather than active use. Excluding three anomalously young samples, the ages of embedded organic material associated with 15 OCC copper artifacts range from 8500 to 3580 cal BP, confirming that the OCC is among the oldest known metalworking societies in the world.

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Climate influence on organic carbon burial efficiency as revealed from a multi-proxy lake sediment record in Croatia

10.1002/essoar.10504565.1 ◽

2020 ◽

Author(s):

Ivan Razum ◽

Petra Bajo ◽

Dea Brunović ◽

Nikolina Ilijanić ◽

Ozren Hasan ◽

...

Keyword(s):

Organic Carbon ◽

Lake Sediment ◽

Sediment Record ◽

Carbon Burial ◽

Organic Carbon Burial ◽

Burial Efficiency

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Using a lake sediment record to infer the long-term history of cyanobacteria and the recent rise of an anatoxin producing Dolichospermum sp.

Harmful Algae ◽

10.1016/j.hal.2020.101971 ◽

2021 ◽

Vol 101 ◽

pp. 101971

Author(s):

William O. Hobbs ◽

Theo W. Dreher ◽

Edward W. Davis ◽

Rolf D. Vinebrooke ◽

Siana Wong ◽

...

Keyword(s):

Lake Sediment ◽

Sediment Record ◽

History Of

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The First Holocene Varve Chronology for the UK: based on the integration of varve counting, radiocarbon dating and tephrostratigraphy from Diss Mere (UK).

10.5194/egusphere-egu21-7314 ◽

2021 ◽

Author(s):

Celia Martin-Puertas ◽

Amy A. Walsh ◽

Simon P.E Blockley ◽

Poppy Harding ◽

George E. Biddulph ◽

...

Keyword(s):

Laminated Sediments ◽

Seasonal Patterns ◽

Sediment Record ◽

Radiocarbon Dates ◽

Varve Chronology ◽

Counting Error ◽

Tephra Layers ◽

Core Depth ◽

The Uk ◽

Varve Counting

This paper reports the first Holocene varved chronology for the lacustrine sediment record of Diss Mere in the UK. The record of Diss Mere is 15 m long, and shows 4.2 m of finely-laminated sediments, which are present between ca. 9 and 13 m of core depth. The microfacies analysis identified three major seasonal patterns of deposition, which corroborate the annual nature of sedimentation throughout the whole interval. The sediments are diatomaceous organic and carbonate varves with an average thickness of 0.45 mm. A total of 8473 varves were counted with maximum counting error of up to &#160;40 varves by the bottom of the varved sequence. To tie the resulting floating varve chronology to the IntCal 2020 radiocarbon timescale, we used a Bayesian Deposition model (P_Sequencewith outlier detection) on all available chronological data from the core. The data included five radiocarbon dates, two known tephra layers (Glen Garry and OMH-185) with calendar ages based on Bayesian modelling of sequences of radiocarbon ages, and the relative varve counts between dated points. The resulting age-depth model (DISSV-2020) dates the varved sequence between ca. 2100 and 10,300 cal BP and age&#160;uncertainties are decadal in scale (95% confidence).&#160;

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