32Si in limestone aquifers

Morgenstern, Uwe; Gellermann, R.; Hebert, D.; Börner, I.; Stolz, Werner; Vaikmäe, Rein; Rajamäe, R; Putnik, Goran D.

doi:10.1016/0009-2541(94)00115-o

Cited by 15 publications

(4 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Gas tracers such as helium-3, chlorofluorocarbons, and sulphur hexafluoride equilibrate with air once groundwaters have entered the stream and thus have very limited use for streamwater dating. For improved understanding of older water components beyond the tritium method with mean transit times of up to 1000 years, silicon-32, another non-gaseous tracer, has potential for dating of water within various types of aquifer if the exchange processes of the silica in the groundwater with the aquifer material can be better understood (Morgenstern et al, 1995(Morgenstern et al, , 1996Fifield and Morgenstern, 2009). …”

Section: Water Datingmentioning

confidence: 99%

Dating of streamwater using tritium in a post nuclear bomb pulse world: continuous variation of mean transit time with streamflow

Morgenstern

Stewart

Stenger³

2010

Hydrol. Earth Syst. Sci.

Self Cite

178

184

View full text Add to dashboard Cite

Abstract. Tritium measurements of streamwater draining the Toenepi catchment, a small dairy farming area in Waikato, New Zealand, have shown that the mean transit time of the water varies with the flow rate of the stream. Mean transit times through the catchment are 2-5 years during high baseflow conditions in winter, increasing to 30-40 years as baseflow decreases in summer, and then dramatically older water during drought conditions with mean transit time of more than 100 years. Older water is gained in the lower reaches of the stream, compared to younger water in the headwater catchment. The groundwater store supplying baseflow was estimated from the mean transit time and average baseflow to be 15.4 × 10 6 m 3 of water, about 1 m water equivalent over the catchment and 2.3 times total annual streamflow. Nitrate is relatively high at higher flow rates in winter, but is low at times of low flow with old water. This reflects both lower nitrate loading in the catchment several decades ago as compared to current intensive dairy farming, and denitrification processes occurring in the older groundwater. Silica, leached from the aquifer material and accumulating in the water in proportion to contact time, is high at times of low streamflow with old water. There was a good correlation between silica concentration and streamwater age, which potentially allows silica concentrations to be used as a proxy for age when calibrated by tritium measurements. This study shows that tritium dating of stream water is possible with single tritium measurements now that bomb-test tritium has effectively disappeared from hydrological systems in New Zealand, without the need for time-series data.

show abstract

Section: Water Datingmentioning

confidence: 99%

Dating of streamwater using tritium in a post nuclear bomb pulse world: continuous variation of mean transit time with streamflow

Morgenstern

Stewart

Stenger³

2010

Hydrol. Earth Syst. Sci.

Self Cite

178

184

View full text Add to dashboard Cite

show abstract

“…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). Artificially produced 32 Si (via spallation of Vanadium) was first used to study biogenic silica production rates in the Weddell-Scotia Seas by Tréguer et al (1991).…”

Section: Introductionmentioning

confidence: 99%

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

Rahman

Aller

Cochran

2017

Global Biogeochemical Cycles

View full text Add to dashboard Cite

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.

show abstract

“…The extent of the infiltration and the resulting 32 Si accumulation levels will depend on local geologic details specific to the rock formation. As an example, studies of 32 Si concentrations in limestone aquifers show 32 Si transport from the surface down to depths of several tens of meters [41]. There is no current economic driver for significant quantities of "deep" industrial silica or quartz mining that could produce silicon segregated from surface waters carrying 32 Si.…”

Section: Vector 1: Si-32 In the Source Materialsmentioning

confidence: 99%

Naturally occurring 32Si and low-background silicon dark matter detectors

Orrell

Arnquist

Bliss

et al. 2018

Astroparticle Physics

View full text Add to dashboard Cite

The naturally occurring radioisotope 32 Si represents a potentially limiting background in future dark matter directdetection experiments. We investigate sources of 32 Si and the vectors by which it comes to reside in silicon crystals used for fabrication of radiation detectors. We infer that the 32 Si concentration in commercial single-crystal silicon is likely variable, dependent upon the specific geologic and hydrologic history of the source (or sources) of silicon "ore" and the details of the silicon-refinement process. The silicon production industry is large, highly segmented by refining step, and multifaceted in terms of final product type, from which we conclude that production of 32 Si-mitigated crystals requires both targeted silicon material selection and a dedicated refinement-through-crystal-production process. We review options for source material selection, including quartz from an underground source and silicon isotopically reduced in 32 Si. To quantitatively evaluate the 32 Si content in silicon metal and precursor materials, we propose analytic methods employing chemical processing and radiometric measurements. Ultimately, it appears feasible to produce silicon detectors with low levels of 32 Si, though significant assay method development is required to validate this claim and thereby enable a quality assurance program during an actual controlled silicon-detector production cycle.

show abstract

32Si in limestone aquifers

Cited by 15 publications

References 7 publications

Dating of streamwater using tritium in a post nuclear bomb pulse world: continuous variation of mean transit time with streamflow

Dating of streamwater using tritium in a post nuclear bomb pulse world: continuous variation of mean transit time with streamflow

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

Naturally occurring 32Si and low-background silicon dark matter detectors

Contact Info

Product

Resources

About

32Si in limestone aquifers

Cited by 15 publications

References 7 publications

Dating of streamwater using tritium in a post nuclear bomb pulse world: continuous variation of mean transit time with streamflow

Dating of streamwater using tritium in a post nuclear bomb pulse world: continuous variation of mean transit time with streamflow

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

Naturally occurring 32Si and low-background silicon dark matter detectors

Contact Info

Product

Resources

About

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