The half-life of 32Si: a new estimate based on varved lake sediments

Nijampurkar, V. N.; Rao, D. K.; Oldfield, Frank; Renberg, Ingemar

doi:10.1016/s0012-821x(98)00186-1

Cited by 18 publications

(8 citation statements)

References 14 publications

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“…The cosmogenic radionuclide 32 Si (half-life c. 140 -178 years) is being actively researched as a dating tool for waters and sediments of late Holocene age (Morgenstern et al, 1996;Nijampurkar et al, 1998). Silicon also possesses three stable isotopes, 28 Si, 29 Si and 30 Si, which are fractionated by chemical and biological processes.…”

Section: New Analytical Techniques For the Study Of Si Biogeochemistrymentioning

confidence: 99%

“…Silicon isotopes hold great potential as tracers of the terrestrial Si cycle and its influence on the marine Si cycle (Douthitt, 1982;Lucas et al, 1993;Ding et al, 1996;De La Rocha, 2002Basile-Doelsch et al, 2005;Basile-Doelsch, 2006;Georg et al, 2006). The cosmogenic radionuclide 32 Si (half-life c. 140 -178 years) is being actively researched as a dating tool for waters and sediments of late Holocene age (Morgenstern et al, 1996;Nijampurkar et al, 1998). Silicon also possesses three stable isotopes, 28 Si, 29 Si and 30 Si, which are fractionated by chemical and biological processes.…”

Section: New Analytical Techniques For the Study Of Si Biogeochemistrymentioning

confidence: 99%

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Biogenic silica: a neglected component of the coupled global continental biogeochemical cycles of carbon and silicon

Street-Perrott

Barker

2008

Earth Surf Processes Landf

208

140

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On geological time-scales (≥ ≥ ≥ ≥ ≥10 6 years), the global geochemical cycles of carbon and silicon are coupled by the drawdown of atmospheric CO 2 through chemical weathering of Ca-and Mg-silicate minerals in continental rocks. Rivers transport the soluble products of weathering (cations, alkalinity and silicic acid) to the oceans, where they are utilized by marine ecosystems. On decadal to glacial-interglacial time-scales, however, large biotic fluxes and storages of Si within terrestrial and freshwater ecosystems need to be taken into account. Recent studies have emphasized the importance of Si-accumulating plants, which deposit significant amounts of amorphous hydrated silica in their tissues as opal phytoliths. These include grasses, sedges, palms, some temperate deciduous trees and conifers, and many tropical hardwoods. Landscapes dominated by accumulator plants, such as tropical rainforests, grasslands, herbaceous wetlands and bamboo forests, act as 'silica factories'. Important 'silica bioengineers' in freshwater ecosystems comprise diatoms, sponges and chrysophytes. This paper reviews the biological role of Si in higher plants, the impact of vegetation on rates of chemical weathering, the fluxes of Si through catchment ecosystems, lakes and rivers, and the potential contribution of new geochemical and isotopic tracers to Si biogeochemistry. Multiproxy investigations of lake sediments will provide novel insights into past variations in Si biocycling from terrestrial to aquatic realms on 10-10 6 year time-scales.

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Section: New Analytical Techniques For the Study Of Si Biogeochemistrymentioning

confidence: 99%

Section: New Analytical Techniques For the Study Of Si Biogeochemistrymentioning

confidence: 99%

Biogenic silica: a neglected component of the coupled global continental biogeochemical cycles of carbon and silicon

Street-Perrott

Barker

2008

Earth Surf Processes Landf

208

140

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“…To date, given its very low activity and the difficult analytical procedures necessary for measurement, the use of natural 32 Si as a tracer has been limited. It has been used to determine particle mixing rates in the deep sea (DeMaster & Cochran, 1982), sedimentation rates in deltas and lakes (Nijampurkar et al, 1998;Morgenstern et al, 2001Morgenstern et al, , 2013Suckow et al, 2001), and ages of glacier ice (Nijampurkar et al, 1982(Nijampurkar et al, , 1985Morgenstern et al, 1996Morgenstern et al, , 2000. It has also been used as a tracer of stable silicon inputs into various water masses (Nijampurkar et al, 1966(Nijampurkar et al, , 1983Lal et al, 1970Lal et al, , 1976DeMaster, 1980;Morgenstern et al, 1995) and to date groundwater ages in aquifers (Nijampurkar et al, 1966;Lal et al, 1970;Franke et al, 1988;Fröhlich et al, 1988;Morgenstern et al, 1995).…”

Section: Introductionmentioning

confidence: 99%

The Missing Silica Sink: Revisiting the Marine Sedimentary Si Cycle Using Cosmogenic ³²Si

Rahman

Aller

Cochran

2017

Global Biogeochemical Cycles

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Burial of biogenic silica (bSitotal) in high sedimentation rate continental margins remains highly uncertain. Cosmogenic 32Si (t1/2~140 years) can be used to trace the fates of bSitotal postdeposition, including as opal (bSiopal) and diagenetically altered opal (bSialtered), the latter dominantly authigenic clay (bSiclay). To determine the magnitude and form of bSitotal storage in coastal sediments, conventional operational leaches targeting bSiopal and bSialtered (including bSiclay) were modified for large‐scale samples necessary for measurement of 32Si. The 32Si activity was used to estimate total biogenic silica burial (bSitotal = bSiopal + bSialtered) in several depositional settings: Gulf of Papua, Gulf of Mexico, Long Island Sound, and in the previously studied Amazon‐Guianas deltaic system. In subtropical and temperate regions, 32Si was detected in both traditional biogenic silica leaches (bSiopal) and residual authigenic clays. Traditional bSiopal and modified operational leaches designed to target the most reactive authigenic silicates (~bSialtered) consistently underestimate authigenic clay formation (bSiclay) and thus the magnitude of bSitotal burial in temperate coastal zones and subtropical deltas by 2–4‐fold. In tropical deltas, 32Si activities in the residual fraction after removal of bSiopal demonstrate rapid and almost complete alteration of initial bSiopal to new forms, most likely bSiclay. Globally, 4.5–4.9 Tmol/yr Si may be trapped in marine nearshore deposits as rapidly formed clay (bSiclay), 100% of the “missing silica sink” in the marine silica budget.

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“…Here, a number of radiometric methods have been used to date sediment sequences including 14 C dating of Holocene sedimentary records, luminescence dating, where particles of 12.4 RECONSTRUCTING ENVIRONMENTAL CHANGE appropriate size and mineralogy are preserved in the sediments, and the use of cosmogenic 32 Si dating (half life c. 178 years) in sediments rich in biogenic silica (e.g. Likens and Davis, 1975;Nijampurkar et al, 1998;Banerjee, Murray and Foster, 2001;Reimer et al, 2004;Pittam, Foster and Mighall, 2009). Despite the appeal of 32 Si to bridge the gap between dates provided by 14 C and 210 Pb dating, the lengthy preparation procedure, long count times and the high cost of analysis has precluded its widespread application (Morgenstern, personal communication, 2004).…”

Section: Dating Sedimentary Sequencesmentioning

confidence: 99%

Lakes and Reservoirs in the Sediment Cascade

Foster

2010

Sediment Cascades

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The half-life of 32Si: a new estimate based on varved lake sediments

Cited by 18 publications

References 14 publications

Biogenic silica: a neglected component of the coupled global continental biogeochemical cycles of carbon and silicon

Biogenic silica: a neglected component of the coupled global continental biogeochemical cycles of carbon and silicon

The Missing Silica Sink: Revisiting the Marine Sedimentary Si Cycle Using Cosmogenic ³²Si

Lakes and Reservoirs in the Sediment Cascade

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The half-life of 32Si: a new estimate based on varved lake sediments

Cited by 18 publications

References 14 publications

Biogenic silica: a neglected component of the coupled global continental biogeochemical cycles of carbon and silicon

Biogenic silica: a neglected component of the coupled global continental biogeochemical cycles of carbon and silicon

The Missing Silica Sink: Revisiting the Marine Sedimentary Si Cycle Using Cosmogenic 32Si

Lakes and Reservoirs in the Sediment Cascade

Contact Info

Product

Resources

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The Missing Silica Sink: Revisiting the Marine Sedimentary Si Cycle Using Cosmogenic ³²Si