Tephra anchored floating varve chronology covering ca. 19.0-11.0 ka BP in new core from Lake Lago Grande di Monticchio: preliminary results

The high-resolution Monticchio (MON) sediment record has been demonstrated to be a key archive for reconstructing climate and environmental changes in the central Mediterranean for the last glacial-interglacial cycle. New sediment cores have been retrieved in April 2016 to investigate particularly the transition from the Last Glacial Maximum into the Holocene with a new high-resolution methodological approach. A floating varve chronology spanning ca. 8,000 years has been established by varve counting on thin sections using a petrographic microscope and layer thickness based sedimentation rate estimates for non- or poorly varved intervals. Varve counting is based on detailed seasonal deposition models of five different varve types. The resulting floating chronology consist of 66.6% individually counted varves and 33.4% interpolated years. The uncertainty estimate of the floating chronology has been determined by double counting and amounts to &#177;5.8%.The floating chronology is anchored to an absolute chronology using the Agnano Pomici Principali tephra, dated at 11,999&#177;52 cal yrs BP from paleosols overlying proximal tephra (Bronk Ramsey et al. 2015), is a suitable anchoring point to cross correlation. The resulting varve-based chronology has been compared with several other marker tephras dated elsewhere including the Soccavo 4 tephra (11,700&#177;150 cal yrs BP), the Neapolitan Yellow Tuff (NYT; 14,194&#177;172 cal yrs BP) and the Greenish tephra (19226&#177;104 cal yrs BP). Further comparison with published (Hajdas et al. 1997) and new radiocarbon dates from different terrestrial macro remains are discussed in this paper. This study presents an independent chronology for the last glacial/interglacial transition for a comparison of MON data with high-resolution lake records western and central Europe.ReferencesBronk Ramsey, C., P. G. Albert, S. P. E. Blockley, M. Hardiman, R. A. Housley, C. S. Lane, S. Lee, I. P. Matthews, V. C. Smith & J. J. Lowe (2015) Improved age estimates for key Late Quaternary European tephra horizons in the RESET lattice. Quaternary Science Reviews, 118, 18-32.Hajdas, I., G. Bonani, B. Zolitschka, A. Brauer & J. Negendank (1997) 14C Ages of Terrestrial Macrofossils from Lago Grande Di Monticchio (Italy). Radiocarbon, 40, 803-807.

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Lake Torfadalsvatn: a high resolution record of the North Atlantic ash zone I and the last glacial-interglacial environmental changes in Iceland

Boreas ◽

10.1111/j.1502-3885.1992.tb00009.x ◽

2008 ◽

Vol 21 (1) ◽

pp. 15-22 ◽

Cited By ~ 109

Author(s):

SVANTE BJÖRCK ◽

ÓLAFUR INGÓLFSSON ◽

HAFLIDI HAFLIDASON ◽

MARGRÉT HALLSDÖTTIR ◽

N. JOHN ANDERSON

Keyword(s):

High Resolution ◽

North Atlantic ◽

Environmental Changes ◽

Last Glacial ◽

The North ◽

The North Atlantic ◽

The Last Glacial

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Depositional environments in the northern Barents Sea, from the last glacial to the present — preliminary results

10.5194/egusphere-egu21-12617 ◽

2021 ◽

Author(s):

Vårin Trælvik Eilertsen ◽

Rydningen Tom Arne ◽

Matthias Forwick ◽

Monica Winsborrow ◽

Jan Sverre Laberg

Keyword(s):

Sea Ice ◽

Environmental Changes ◽

Barents Sea ◽

Ice Sheet ◽

Depositional Environments ◽

Radiocarbon Dates ◽

Future Evolution ◽

Last Glacial ◽

Minimum Age ◽

The Last Glacial

The Eurasian Ice Sheet Complex was the world&#8217;s third largest ice mass during the last glacial maximum (LGM), and included the British, Fennoscandian and Svalbard&#8211;Barents Sea ice sheets. Of these three, the mostly marine-based Svalbard-Barents Sea Ice Sheet (SBIS) is the least well constrained in terms of ice sheet dynamics and deglacial retreat patterns. Improving the understanding of the behavior and decay of this marine paleo-ice sheet can provide knowledge that is relevant to understanding the future evolution of the marine terminating ice margins in Greenland and Antarctica, which are today undergoing rapid retreat and thinning.We present high-resolution TOPAS sub-bottom profiler data and multi-proxy analyses of four sediment gravity cores (1.15 to 5.05 m long) retrieved from water depths of c. 250-550 m in a trough south of Kvit&#248;ya, NW Barents Sea. The data were collected during the Nansen Legacy (https:/arvenetternansen.com/) Paleo-cruise in 2018, with the aim of reconstructing the patterns and timing of deglaciation of the SBIS and postglacial environmental changes in the northern Barents Sea. The data show a succession of up to 10 m high and 400 m wide ridges, interpreted to be recessional push-moraines, representing small still-stands or re-advances of the ice front during its retreat in southwesterly direction. An up to 40 m high and 20 km long sedimentary wedge in the central and western part of the study area buries some of these moraines. This wedge is interpreted to be a grounding zone wedge representing a major still-stand or re-advance during the deglaciation.The gravity cores are located distal to, on the distal slope and on top of the grounding zone wedge. A muddy diamict defines the lowermost unit in each core. It is interpreted to be primarily subglacial till. This till is covered by laminated mud, interpreted to represent sedimentation from meltwater plumes that emanated from the nearby ice margin. Massive marine mud containing scattered clasts (the clasts are interpreted to be ice rafted debris) define the uppermost unit in all cores. This is suggested to represent deposition from suspension settling and ice rafting in a glacier-distal environment at the end of the last glacial, as well as during modern conditions.Radiocarbon dates (submitted for dating) will provide a minimum age for the formation of the grounding zone wedge and the recessional moraines in front of it. This will improve the chronology on the deglacial events forming these deposits and landforms. Together with detailed multi-proxy analyses of the sedimentary units, this will also provide new knowledge about the development from glacial conditions to a glacier-proximal and &#8211;distal, and an open marine environment from the last glacial to the present.

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High-resolution record of environmental changes and tephrochronological markers of the Last Glacial-Holocene transition at Lake Lautrey (Jura, France)

Journal of Quaternary Science ◽

10.1002/jqs.873 ◽

2004 ◽

Vol 19 (8) ◽

pp. 797-808 ◽

Cited By ~ 20

Author(s):

Boris Vannière ◽

Gilles Bossuet ◽

Anne-Véronique Walter-Simonnet ◽

Pascale Ruffaldi ◽

Thierry Adatte ◽

...

Keyword(s):

High Resolution ◽

Environmental Changes ◽

Last Glacial ◽

The Last Glacial

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Late Quaternary climate-driven environmental change in the Larsemann Hills, East Antarctica, multi-proxy evidence from a lake sediment core

Quaternary Research ◽

10.1016/j.yqres.2005.04.002 ◽

2005 ◽

Vol 64 (1) ◽

pp. 83-99 ◽

Cited By ~ 69

Author(s):

Dominic A. Hodgson ◽

Elie Verleyen ◽

Koen Sabbe ◽

Angela H. Squier ◽

Brendan J. Keely ◽

...

Keyword(s):

Environmental Changes ◽

Accumulation Rate ◽

Late Quaternary ◽

East Antarctica ◽

Algal Community ◽

Data Set ◽

Last Glacial ◽

Larsemann Hills ◽

Quaternary Climate ◽

The Last Glacial

AbstractLittle is known about the response of terrestrial East Antarctica to climate changes during the last glacialâ€“interglacial cycle. Here we present a continuous sediment record from a lake in the Larsemann Hills, situated on a peninsula believed to have been ice-free for at least 40,000 yr. A mutli-proxy data set including geochronology, diatoms, pigments and carbonate stable isotopes indicates warmer and wetter conditions than present in the early part of the record. We interpret this as Marine Isotope Stage 5e after application of a chronological age-depth model and similar ice core evidence. Dry and cold conditions are inferred during the last glacial, with lake-level minima, floristic changes towards a shallow water algal community, and a greater biological receipt of ultraviolet radiation. During the Last Glacial Maximum and Termination I the lake was perennially ice-covered, with minimal snowmelt in the catchment. After ca. 10,500 cal yr B.P., the lake became seasonally moated or ice-free during summer. Despite a low accumulation rate, the sediments document some Holocene environmental changes including neoglacial cooling after ca. 2450 cal yr B.P., and a gradual increase in aridity and salinity to the present.

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Paleoenvironments from robust loess stratigraphy using high-resolution color and grain-size data of the last glacial Krems-Wachtberg record (NE Austria)

Quaternary Science Reviews ◽

10.1016/j.quascirev.2020.106602 ◽

2020 ◽

Vol 248 ◽

pp. 106602

Author(s):

Tobias Sprafke ◽

Philipp Schulte ◽

Simon Meyer-Heintze ◽

Marc Händel ◽

Thomas Einwögerer ◽

...

Keyword(s):

Grain Size ◽

High Resolution ◽

Last Glacial ◽

Size Data ◽

The Last Glacial

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Absence of Last Glacial Maximum Records in Lowland Tropical Forests

Quaternary Research ◽

10.1006/qres.1997.1953 ◽

1998 ◽

Vol 49 (2) ◽

pp. 233-237 ◽

Cited By ~ 104

Author(s):

Marie-Pierre Ledru ◽

Jacques Bertaux ◽

Abdelfettah Sifeddine ◽

Kenitiro Suguio

Keyword(s):

South America ◽

Tropical Forests ◽

Last Glacial Maximum ◽

Sedimentation Rate ◽

Glacial Maximum ◽

Radiocarbon Dates ◽

Last Glacial ◽

The Last Glacial Maximum ◽

Pollen Records ◽

The Last Glacial

Environmental conditions of the lowland tropical forests during the last glacial maximum (LGM) between ca 20,000 and 18,000 14C yr B.P., are reevaluated in terms of dating control and lithology analyzed in seven pollen records from South America. The reevaluation shows that probably in none of the published records are LGM sediments present or abundant. This conclusion is based on the occurrence of abrupt lithologic changes coupled with changes in sedimentation rate interpolated from radiocarbon dates. These findings suggest that the LGM was represented probably by a hiatus of several thousand years, indicative of drier climates than before or after.

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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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