Dirty calcites 1. Uranium-series dating of contaminated calcite using leachates alone

Schwarcz, Henry P.; Latham, Alfred

doi:10.1016/0168-9622(89)90046-8

Cited by 111 publications

(83 citation statements)

References 8 publications

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“…Age es ti ma tion is im pos si ble since the 230 Th/ 234 U ac tiv ity ra tio is over 1 (see Ivanovich and Harmon, 1992 caused by U mi gra tion. The con tent of 232 Th, which is an in di cator of de tri tal Th, is at the level of 68 ppb and the 230 Th/ 232 Th activ ity ra tio is >20 which is ac cepted as a "thresh old value" (see Schwarcz and Latham, 1989).…”

Section: Isotopic Compositionmentioning

confidence: 99%

New data on pre-Eocene karst in the Tatra Mountains, Central Carpathians, Poland

Jach

Gradziński

Hercman

2016

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1 Jagiellonian Uni ver sity, In sti tute of Geo log i cal Sci ences, Oleandry 2a, 30-063 Kraków, Po land 2 Pol ish Acad emy of Sci ences, In sti tute of Geo log i cal Sci ences, Twarda 51/55, 00-818 Warszawa, Po land Jach, R., Gradziński, M., Hercman, H., 2016. New data on pre-Eocene karst in the Tatra Moun tains, Cen tral Carpathians, Po land. Geo log i cal Quar terly, 60 (2): 291-300, doi: 10.7306/gq.1281Sparry lime stone, ferruginous muddy lime stone and lime stone brec cia have been found in the West ern Tatra Mts. They occur within Ju ras sic rocks of the Choč Nappe just be low red con glom er ates of prob a ble Eocene age. The de pos its found bear strong re sem blance to the infill of sub ter ra nean karst forms. They dif fer sig nif i cantly from Qua ter nary karst de pos its of the Tatra Mts. The d 18 O val ues of spelean car bon ates sug gest crystallisation at rel a tively high tem per a tures (over 20°C) whereas their rel a tively neg a tive d 13 C val ues im ply the pres ence of soil-de rived CO 2 linked with veg e ta tion dom i nated by C3 path way plants. The karst forms and their infill were formed be fore the Eocene trans gres sion, which shows un equiv o cally that the Tatra Mts. were sub jected to karstification at that time.

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Section: Isotopic Compositionmentioning

confidence: 99%

New data on pre-Eocene karst in the Tatra Mountains, Central Carpathians, Poland

Jach

Gradziński

Hercman

2016

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“…A few of the analyzed samples had significant non-radiogenic Th contamination but most of them were clean enough with 230 Th/ 232 Th activity ratio above 20 (cf. Schwarcz and Latham, 1989). Based on the dating results, the speleo- Table 2 (see also Figs 3 and 4).…”

Section: Methodsmentioning

confidence: 99%

Evolution of Brestovská Cave Based on U-Series Dating of Speleothems

2008

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Abstract:The U-series dating indicates five episodes of flowstone growth in Brestovská Cave, namely: ca. 200 ka, ca. 128-88 ka, ca. 82-65 ka, ca. 64-50 ka, and during the Holocene. The age of flowstones and their spatial distribution within the cave prove that the upper storey of the cave was dewatered before 200 ka. At that time the lower storey also existed and was able to carry the whole water flowing through the cave. It suggests that 200 ka ago the water-table was at similar level as it is at present. Hence, one should accept that the valley bottom was then also at the present level. During at least a part of the MIS 6 the growth of speleothems was possible in the cave. It suggests that the cave was located outside the permafrost zone then. Between 50 ka and Holocene, Brestovská Cave was flooded by invasion waters originating from the melting of the Würm glacier; the water-table was additionally raised due to the blockage of a resurgence by glacifluvial sediments. The flooding event caused the destruction of older deposits, including speleothems, and deposition of fine-grained clastics on the cave walls.

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“…Strong acid could in principle attack these particles, which are most likely carbonate and clay, and thereby contaminate the digest with non-authigenic U and Th. This is linked to the wellestablished allogenic 230 Th contamination problem of so-called "dirty" calcites (Przbylowicz et al, 1991;Schwarcz, 1980;Schwarcz & Latham, 1989). It is therefore necessary to find a compromise between risking authigenic 230 Th to plate out (at high pH) and contamination of non-authigenic 230 Th to dissolve from detrital surfaces (at low pH).…”

Section: Yield Experiments In Gypsum Dissolutionmentioning

confidence: 99%

Uranium-series dating of gypsum speleothems: methodology and examples

Sanna¹,

Saez²,

Simonsen³

et al. 2010

IJS

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The analytical problems of dating gypsum speleothems with the U-series technique are reviewed. Gypsum speleothems are, in general, very low in U content, challenging the limits of detection methods. Various approaches to dissolving gypsum and isolation of actinides from the matrix include ion-pairing dissolution with magnesium salts and using nitric acid. The most precise dating technique is Thermal Ionization Mass Spectrometry (TIMS), combined with Fe(OH) 3 scavenging and anionic exchange chromatography. Less satisfactory, but much quicker, is direct retention of actinides from HNO 3 by means of TRU resin and MC-ICP-MS detection. We have tested these methods on gypsum speleothems from the Sorbas karst in Spain and from the Naica caves in Mexico. be successfully dated, a potentially excellent source of palaeoenviromental and geomorphic information. For instance, many gypsum karsts, like Sorbas in southern Spain (Calaforra, 1998), the Gypsum area near Bologna in Italy (Forti & Rossi, 2003) and the New Mexico gypsum karst (Calaforra & Forti, 1994) contain gypsum speleothems (Klimchouk et al., 1997). There is also a great variability in gypsum speleothems with regards to their size, external shape, internal structure and development. Davis (2000) reports from Lechuguilla Cave (New Mexico, USA) gypsum stalactites, columns, hairs, "Candelieres" (up to 6 m long), flowers and needles (>1 m long). Korshunov and Shavrina (1998) focus on cryogenic gypsum speleothems and describe gypsum powder (formed after ice sublimation), gypsum yozh (with spherical, hemispherical, flat or amorphous shape, with development closely related to clay deposits), and spherical porous yozh with an unclear genesis. Gypsum trays have been reported by Calaforra & Forti (1994) and Doran & Hill (1998) as clusters of popcorn or grape coralloids ending in a flat surface. Gypsum nests has been described by Maltsev (1997) at Geophysicheskaya Cave, Turkmenistan, as a funnel-shaped mass of thousands of oriented gypsum needles with a hollow interior. Gypsum crusts in lava tubes have recently been dated by U-series technique (Dillon, 2009). Also, northern caves, even in relatively cold and wet regions like north Norway, contain evaporitic gypsum crusts (Lauritzen, 2002;Onac & Lauritzen, 1995 Keywords: Uranium series dating, gypsum, cave, methodology

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Dirty calcites 1. Uranium-series dating of contaminated calcite using leachates alone

Cited by 111 publications

References 8 publications

New data on pre-Eocene karst in the Tatra Mountains, Central Carpathians, Poland

New data on pre-Eocene karst in the Tatra Mountains, Central Carpathians, Poland

Evolution of Brestovská Cave Based on U-Series Dating of Speleothems

Uranium-series dating of gypsum speleothems: methodology and examples

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