New 230Th/U and 14C ages from Lake Lahontan carbonates, Nevada, USA, and a discussion of the origin of initial thorium

Lin, Jo Chiu-Fang; Broecker, Wallace S.; Anderson, Robert F.; Hemming, S. R.; Rubenstone, J.L.; Bonani, Georges

doi:10.1016/0016-7037(96)00136-6

Cited by 78 publications

(42 citation statements)

References 34 publications

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“…To correct for detrital contamination, the main problem in age dating authigenic carbonates (Kaufman 1993;Debaene 2003), we chose the isochron method with several sub-samples (cf. Ludwig and Titterington 1994;Lin et al 1996;Frank et al 2000;Geyh 2001Geyh , 2005Mallick and Frank 2002) plotted in 230 Th/ 232 Th versus 234 U/ 232 Th activity diagrams (Rosholt 1976) (Rosholt diagrams). In the Rosholt diagrams, the plotted 230 Th/ 232 Th-234 U/ 232 Th activity ratios of sub-samples then are connected, or approximated, by a regression line that can be considered as an isochron.…”

Section: Methodsmentioning

confidence: 99%

Aragonite and calcite cementation in “boulder-controlled” meteoric environments on the Fern Pass rockslide (Austria): implications for radiometric age dating of catastrophic mass movements

Ostermann

Sanders

Prager³

et al. 2007

Facies

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On the Fern Pass rockslide (Eastern Alps, Austria), projecting boulders collected surface runoV and delayed percolation of water into the rockslide mass, leading to decimetre-scale, Xuctuating, phreatic/ vadose diagenetic systems along their contact. In these systems, aragonite and calcite precipitation were nourished mainly by dissolution of carbonate-rock Xour. Cement precipitation was limited to southern-and eastern-exposed "runoV haloes" of boulders and mainly resulted in cemented breccias. Aragonite precipitation was related to dissolved Mg 2+ and/or to high CaCO 3 supersaturation in evaporative-concentrated pore waters. Early aragonite cement yielded a 234 U/ 230 Th age of 4,150 § 100 years. Relative to other radiometric ages ( 36 Cl, 14 C; by other authors) for the rockslide event, the U-Th age of the aragonite is the most precise proxy of depositional age. Carbonate cements are present in other rockslide and rockfall deposits also. U-Th dating of such cements is thus a comparatively rapid and inexpensive method of minimum-age dating catastrophic mass movements.

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Section: Methodsmentioning

confidence: 99%

Aragonite and calcite cementation in “boulder-controlled” meteoric environments on the Fern Pass rockslide (Austria): implications for radiometric age dating of catastrophic mass movements

Ostermann

Sanders

Prager³

et al. 2007

Facies

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“…We will show that this uncertainty is the main source of error in the 230 Th age for most deep-sea corals. In general one might expect two possible sources of initial thorium: one from the water column, similar to the "hydrogenous" component of Lin et al (1996), and one from continentially derived detrital particles. Both dissolved and particulate sea water 230 Th/ 232 Th generally increase with depth and water mass age.…”

Section: Initial 230 Thmentioning

confidence: 99%

U-Th dating of deep-sea corals

Cheng

Adkins

Edwards

et al. 2000

Geochimica et Cosmochimica Acta

209

162

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Abstract- 230 Th, 232 Th, 234 U and 238 U compositions of several deep-sea solitary corals, mainly the species Desmophyllum cristagalli, were determined by thermal ionization mass spectrometry (TIMS). It is possible to obtain high precision ages on modern pristine corals that have low [ 232 Th] (5 to a few hundred ppt). However, because older deep-sea corals tend to have higher [ 232 Th] compared to surface corals, and the initial 230 Th/ 232 Th ratio is uncertain, older deep-sea corals have larger age uncertainties (Ϯseveral hundred years for samples with a few thousand ppt 232 Th). Therefore, the key hurdle for precise U-Th dating is to remove or account for contaminants which contain elevated 232 Th and associated 230 Th not due to closed system decay within the coral lattice. A modification of the trace metal cleaning methods used for foraminifera and surface corals can significantly reduce this contamination. By counting the visible growth bands and measuring the mean age of a single septum, the extension rate of D. cristagalli was estimated to be between 0.1 and 3.1 mm/year. In a mean sense, bands appear to be precipitated annually, but this estimate has a large uncertainty. If appropriate tracer calibrations can be established, these corals are therefore suitable to record decadal or sub-decadal oceanographic changes over the course of their lifetime. The ␦ 234 U values of all modern samples from different localities and different depths are similar (mean 145.5 Ϯ 2.3‰) and indistinguishable from the data obtained from surface corals. At a precision of about Ϯ2‰, we find no structure in the oceanic profile of ␦ 234 U ratios over the top 2000 m of the water column.

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“…Some difficulties of applying radiocarbon method for carbonate concretions dating have been previously discussed (Aitken, 1990 andBowman, 1995). Problems of radiocarbon age measurements for lacustrine carbonate samples from the Pleistocene Lake Lahontan, Nevada, USA are presented by Lin and coauthors (Lin et al, 1996). They reported systematically younger ages and suggest it arises as result of problems of contamination with secondary calcite and the local reservoir age correction.…”

Section: Discussionmentioning

confidence: 99%

Pleistocene glaciations of the SE Altai, Russia, based on geomorphological data and absolute dating of glacial deposits in Chagan reference section

Агатова

Непоп

2017

Geochronometria

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Geomorphological evidence of at least two Pleistocene glacial epochsis noted within the Chagan-Uzun river basin, SE Altai. A review and analysis of all available absolute dates for reference Chagan section is presented. The highest correlation amongst all TL dates is observed for the lens of glacio-lacustrine sediments -the most suitable among glacial deposits for luminescence dating, and indicates its possible Middle Pleistocene age. IRSL dates obtained from feldspar indicate a Middle Pleistocene age of moraines already in the upper part of the section. The small number of obtained IRSL dates does not allow making geochronological reconstructions of the Pleistocene glaciations, but gives the possibility for further experiments with different variation of OSL (IRSL) techniques. Strong low temperature peak in TL signal and strong response to IR stimulation are specific regional quartz features, which could be explained by combination of short transportation distance and low number of depositional cycles for mineral grains. Available radiocarbon dates of carbonate concretions from this section are not related to the age of moraine sedimentation and most likely indicate the period of the Chagan river incision into the ancient glacial deposits. This study has shown that TL method is not valid for dating glacial sediments and TL dates cannot be utilized as chronostratigraphic markers. Generally, the Chagan section could hardly serve as a reference section for the Altai stratigraphy; available depositional correlation schemes for the Russian Altai and Siberia which are based on several TL dates obtained in the last century needs to be improved.

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New 230Th/U and 14C ages from Lake Lahontan carbonates, Nevada, USA, and a discussion of the origin of initial thorium

Cited by 78 publications

References 34 publications

Aragonite and calcite cementation in “boulder-controlled” meteoric environments on the Fern Pass rockslide (Austria): implications for radiometric age dating of catastrophic mass movements

Aragonite and calcite cementation in “boulder-controlled” meteoric environments on the Fern Pass rockslide (Austria): implications for radiometric age dating of catastrophic mass movements

U-Th dating of deep-sea corals

Pleistocene glaciations of the SE Altai, Russia, based on geomorphological data and absolute dating of glacial deposits in Chagan reference section

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