scholarly journals Moving beyond the age-depth model paradigm in deep sea palaeoclimate archives: dual radiocarbon and stable isotope analysis on single foraminifera

2017 ◽  
Author(s):  
Bryan C. Lougheed ◽  
Brett Metcalfe ◽  
Ulysses S. Ninnemann ◽  
Lukas Wacker
Keyword(s):  
Stable Isotope ◽  
Deep Sea ◽  
Isotope Analysis ◽  
Late Glacial ◽  
Valuable Insight ◽  
14C Dating ◽  
Deep Sea Sediment ◽  
Rapid Changes ◽  
Novel Method ◽  
Opening Up

Abstract. Late-glacial palaeoclimate reconstructions from deep-sea sediment archives provide valuable insight into past rapid changes in ocean chemistry, but only a small proportion of the ocean floor is suitable for such reconstructions using the existing state-of-the-art using the age-depth approach. We employ ultra-small radiocarbon (14C) dating on single microscopic foraminifera to demonstrate that the longstanding age-depth method conceals large age uncertainty caused by post-depositional sediment mixing, meaning that existing studies may underestimate total geochronological error. To overcome these problems, we use dual 14C and stable isotope (δ18O and δ13C) analysis on single microscopic foraminifera to produce a palaeoclimate time series independent of the age-depth paradigm. This new and novel method will address large geographical gaps in late-glacial benthic palaeoceanographic reconstructions by opening up vast areas of previously disregarded deep-sea archives, leading to improved understanding of the global interaction between oceans and climate.

scholarly journals Moving beyond the age–depth model paradigm in deep-sea palaeoclimate archives: dual radiocarbon and stable isotope analysis on single foraminifera

2018 ◽  
Vol 14 (4) ◽  
pp. 515-526 ◽  
Author(s):  
Bryan C. Lougheed ◽  
Brett Metcalfe ◽  
Ulysses S. Ninnemann ◽  
Lukas Wacker
Keyword(s):  
Stable Isotope ◽  
Deep Sea ◽  
Accumulation Rate ◽  
Isotope Analysis ◽  
Sediment Accumulation ◽  
Late Glacial ◽  
Valuable Insight ◽  
14C Dating ◽  
Deep Sea Sediment ◽  
Ocean Chemistry

Abstract. Late-glacial palaeoclimate reconstructions from deep-sea sediment archives provide valuable insight into past rapid changes in ocean chemistry. Unfortunately, only a small proportion of the ocean floor with sufficiently high sediment accumulation rate (SAR) is suitable for such reconstructions using the long-standing age–depth model approach. We employ ultra-small radiocarbon (14C) dating on single microscopic foraminifera to demonstrate that the long-standing age–depth model method conceals large age uncertainties caused by post-depositional sediment mixing, meaning that existing studies may underestimate total geochronological error. We find that the age–depth distribution of our 14C-dated single foraminifera is in good agreement with existing bioturbation models only after one takes the possibility of Zoophycos burrowing into account. To overcome the problems associated with the age–depth paradigm, we use the first ever dual 14C and stable isotope (δ18O and δ13C) analysis on single microscopic foraminifera to produce a palaeoclimate time series independent of the age–depth paradigm. This new state of the art essentially decouples single foraminifera from the age–depth paradigm to provide multiple floating, temporal snapshots of ocean chemistry, thus allowing for the successful extraction of temporally accurate palaeoclimate data from low-SAR deep-sea archives. This new method can address large geographical gaps in late-glacial benthic palaeoceanographic reconstructions by opening up vast areas of previously disregarded, low-SAR deep-sea archives to research, which will lead to an improved understanding of the global interaction between oceans and climate.

scholarly journals Re-evaluating 14C dating accuracy in deep-sea sediment archives.

2019 ◽  
Author(s):  
Bryan Lougheed ◽  
Philippa Ascough ◽  
Andrew Dolman ◽  
Ludvig Löwemark ◽  
Brett Metcalfe
Keyword(s):  
Deep Sea ◽  
14C Dating ◽  
Deep Sea Sediment

scholarly journals Magdalenian and Epimagdalenian chronology and palaeoenvironments at Kůlna Cave, Moravia, Czech Republic

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Hazel Reade ◽  
Sonja B. Grimm ◽  
Jennifer A. Tripp ◽  
Petr Neruda ◽  
Zdeňka Nerudová ◽  
...  
Keyword(s):  
Czech Republic ◽  
Stable Isotope ◽  
Environmental Conditions ◽  
Late Glacial ◽  
Rapid Changes ◽  
Archaeological Materials ◽  
Gradual Development ◽  
Two Phases ◽  
Grassland Habitats ◽  
The Relationship

AbstractKůlna Cave is the only site in Moravia, Czech Republic, from which large assemblages of both Magdalenian and Epimagdalenian archaeological materials have been excavated from relatively secure stratified deposits. The site therefore offers the unrivalled opportunity to explore the relationship between these two archaeological phases. In this study, we undertake radiocarbon, stable isotope (carbon, nitrogen and sulphur), and ZooMS analysis of the archaeological faunal assemblage to explore the chronological and environmental context of the Magdalenian and Epimagdalenian deposits. Our results show that the Magdalenian and Epimagdalenian deposits can be understood as discrete units from one another, dating to the Late Glacial between c. 15,630 cal. BP and 14,610 cal. BP, and c. 14,140 cal. BP and 12,680 cal. BP, respectively. Stable isotope results (δ13C, δ15N, δ34S) indicate that Magdalenian and Epimagdalenian activity at Kůlna Cave occurred in very different environmental settings. Magdalenian occupation took place within a nutrient-poor landscape that was experiencing rapid changes to environmental moisture, potentially linked to permafrost thaw. In contrast, Epimagdalenian occupation occurred in a relatively stable, temperate environment composed of a mosaic of woodland and grassland habitats. The potential chronological gap between the two phases, and their associations with very different environmental conditions, calls into question whether the Epimagdalenian should be seen as a local, gradual development of the Magdalenian. It also raises the question of whether the gap in occupation at Kůlna Cave could represent a change in settlement dynamics and/or behavioural adaptations to changing environmental conditions.

Characterizing the Distribution of Methane Sources and Cycling in the Deep Sea via in Situ Stable Isotope Analysis

2013 ◽  
Vol 47 (3) ◽  
pp. 1478-1486 ◽  
Author(s):  
Scott D. Wankel ◽  
Yi-wen Huang ◽  
Manish Gupta ◽  
Robert Provencal ◽  
J. Brian Leen ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Deep Sea ◽  
Isotope Analysis
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