A review of coastal palaeoclimate and relative sea-level reconstructions using δ13C and C/N ratios in organic material

Lamb, Angela L.; Gitau, Wilson; Leng, Melanie J.

doi:10.1016/j.earscirev.2005.10.003

Cited by 933 publications

(721 citation statements)

References 115 publications

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“…Encouragingly, these data suggest that environmental conditions play a large role in influencing the isotopic signature although the processes leading to these values are likely to be diverse. The highest  13 C diatom values, observed in the Southern Ocean, show a similar range to other carbon isotope studies of marine algae that have reported values of -16 to -25‰ [33] .…”

Section: Prospects For the Application Of δ 13 C Diatom In Lakes Andsupporting

confidence: 85%

Developing a methodology for carbon isotope analysis of lacustrine diatoms

Hurrell

Barker

Leng

et al. 2011

Rapid Comm Mass Spectrometry

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Stable isotope analysis of sedimentary carbon in lakes can help reveal changes in terrestrial and aquatic carbon cycles. A method based on a single, photosynthetic organism, where host effects are minimised, should offer more precision than carbon isotope studies of bulk lake sediments. Here we systematically develop a method for use on fossil lacustrine diatom frustules, adapted from previous studies in marine environments. A step-wise cleaning experiment on diatomaceous lake sediments from Lake Challa, Mt, Kilimanjaro, was made to demonstrate the necessary treatment stages to remove external sedimentary carbon. Changes in soluble carbon compounds during these cleaning experiments were measured using GC/MS. Mass spectrometry methods were refined to measure the small percentage carbon of these samples and details of these methods are presented.Samples of cleaned diatoms containing <1% carbon yielded robust results. Carbon isotope analysis of diatom samples containing different species mixtures were performed and showed suggestive differences, although the effects lay within current experimental error and require further work.Unlike work on oxygen and silicon isotopes from diatom frustules, mineral contamination had no discernable impact on the diatom carbon isotope ratios from these sediments. The range of values found in the lakes investigated thus far can be interpreted with reference to the supply and nature of carbon from the catchment as well as demand generated from lake primary productivity.3

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Section: Prospects For the Application Of δ 13 C Diatom In Lakes Andsupporting

confidence: 85%

Developing a methodology for carbon isotope analysis of lacustrine diatoms

Hurrell

Barker

Leng

et al. 2011

Rapid Comm Mass Spectrometry

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“…Enhanced supply of reworked, fossil terrestrial organic substance may be identified by a C org /N tot ratio >12 and a strongly depleted d 13 C org ratio (e.g. Meyers, 1997;Lamb et al, 2006). The C org contents of the dated samples from the southern Bellingshausen Sea shelf range from 0.04 to 0.70 wt.% (Table 1).…”

Section: Ams 14 C Down-core Agesmentioning

confidence: 99%

“…The d 13 C org composition of marine particulate organic substance typically ranges from À18& to À27& (e.g. Harden et al, 1992;Meyers, 1997;Lamb et al, 2006;Smith et al, 2006). More depleted d 13 C org values down to À29.4& were reported for the organic material in sediments from the Ross Sea shelf Domack et al, 1999).…”

Section: Ams 14 C Down-core Agesmentioning

confidence: 99%

“…C org /N tot ratios of marine organisms typically range from w4 to w10 and those in terrestrial plants from w12 to w45 (e.g. Meyers, 1997;Lamb et al, 2006). C org /N tot ratios up to 30 have been reported from Holocene Antarctic shelf sediments and were attributed to enhanced supply of terrestrial organic material or (lipid-rich) organic matter from marine benthic algae in combination with limited nitrogen availability under sea-ice cover (e.g.…”

Section: Contents Of Inorganic and Organic Carbon And C Org /N Tot Ramentioning

confidence: 99%

“…2), because such ratios are typical for marine phytoplankton production in open water (e.g. Meyers, 1997;Lamb et al, 2006). At site GC359 the lower part of the middle lithological unit differs from the upper part by maxima in gravel content and MS, high WBD variability, a minimum in water content and a stratified interval (Fig.…”

Section: Distal Sub-ice Shelf/sub-sea Ice Faciesmentioning

confidence: 99%

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The sedimentary legacy of a palaeo-ice stream on the shelf of the southern Bellingshausen Sea: Clues to West Antarctic glacial history during the Late Quaternary

Hillenbrand

Larter

Dowdeswell

et al. 2010

Quaternary Science Reviews

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a b s t r a c tA major trough ("Belgica Trough") eroded by a palaeo-ice stream crosses the continental shelf of the southern Bellingshausen Sea (West Antarctica) and is associated with a trough mouth fan ("Belgica TMF") on the adjacent continental slope. Previous marine geophysical and geological studies investigated the bathymetry and geomorphology of Belgica Trough and Belgica TMF, erosional and depositional processes associated with bedform formation, and the temporal and spatial changes in clay mineral provenance of subglacial and glaciomarine sediments.Here, we present multi-proxy data from sediment cores recovered from the shelf and uppermost slope in the southern Bellingshausen Sea and reconstruct the ice-sheet history since the last glacial maximum (LGM) in this poorly studied area of West Antarctica. We combined new data (physical properties, sedimentary structures, geochemical and grain-size data) with published data (shear strength, clay mineral assemblages) to refine a previous facies classification for the sediments. The multi-proxy approach allowed us to distinguish four main facies types and to assign them to the following depositional settings: 1) subglacial, 2) proximal grounding-line, 3) distal sub-ice shelf/sub-sea ice, and 4) seasonal open-marine. In the seasonal open-marine facies we found evidence for episodic currentinduced winnowing of near-seabed sediments on the middle to outer shelf and at the uppermost slope during the late Holocene.In addition, we obtained data on excess 210 Pb activity at three core sites and 44 AMS 14 C dates from the acid-insoluble fraction of organic matter (AIO) and calcareous (micro-) fossils, respectively, at 12 sites. These chronological data enabled us to reconstruct, for the first time, the timing of the last advance and retreat of the West Antarctic Ice Sheet (WAIS) and the Antarctic Peninsula Ice Sheet (APIS) in the southern Bellingshausen Sea. We used the down-core variability in sediment provenance inferred from clay mineral changes to identify the most reliable AIO 14 C ages for ice-sheet retreat. The palaeo-ice stream advanced through Belgica Trough after w36.0 corrected 14 C ka before present (B.P.). It retreated from the outer shelf at w25.5 ka B.P., the middle shelf at w19.8 ka B.P., the inner shelf in Eltanin Bay at w12.3 ka B.P., and the inner shelf in Ronne Entrance at w6.3 ka B.P. The retreat of the WAIS and APIS occurred slowly and stepwise, and may still be in progress. This dynamical ice-sheet behaviour has to be taken into account for the interpretation of recent and the prediction of future mass-balance changes in the study area. The glacial history of the southern Bellingshausen Sea is unique when compared to other regions in West Antarctica, but some open questions regarding its chronology need to be addressed by future work.

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Distribution and sources of organic matter in surface sediments of the eastern continental margin of India

et al. 2013

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[1] The sources and distribution of organic matter (OM) in surface sediments of the eastern continental margin of India, including the region influenced by river discharge, were investigated using content, molar C:N ratios and stable isotopes of carbon and nitrogen. Despite relatively high water column integrated chlorophyll-a concentrations were found in the continental shelf than the slope; however, the lower sediment organic carbon (SOC) was found in the former than the latter region suggesting that in situ production did not play significant role on preservation of SOC in the coastal Bay of Bengal. The broad range of δ 13 C of SOC (À23.2 to À16.7‰) suggests that OM is a broad mixture of terrestrial and marine OM. Relative contributions from terrestrial C 3 and C 4 plants and marine sources are quantified as 34%, 23%, and 43%, respectively, indicating that dominant source of allochthonous OM (~57%) in the coastal Bay of Bengal. Relatively higher contribution of OM from C 4 plants was found in the sediments at off river Krishna indicating that this region received detritus of agricultural crops such as jowar, bajra, and sugar cane, which are dominant in its drainage basin, during SW monsoon. This study revealed that relatively high OM preserved in the slope than shelf region along the coastal Bay of Bengal and the composition of OM is primarily controlled by the type of agricultural crops and vegetation in the drainage basin of the river.

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A review of coastal palaeoclimate and relative sea-level reconstructions using δ13C and C/N ratios in organic material

Cited by 933 publications

References 115 publications

Developing a methodology for carbon isotope analysis of lacustrine diatoms

Developing a methodology for carbon isotope analysis of lacustrine diatoms

The sedimentary legacy of a palaeo-ice stream on the shelf of the southern Bellingshausen Sea: Clues to West Antarctic glacial history during the Late Quaternary

Distribution and sources of organic matter in surface sediments of the eastern continental margin of India

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