The238U spontaneous fission decay constant re-determined by fission tracks

Thiel, K.; Herr, W.

doi:10.1016/0012-821x(76)90007-8

Cited by 40 publications

(8 citation statements)

References 25 publications

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“…Two decay constants are currently being used in fission-track dating-one at about 8.4XI0-1 7 yr-1 (Spadavecchia and Hahn, 1967;Wagner and others, 1975;and Thiel and Herr, 1976), and the second near 7.0XI0-1 7 yr-1 • There is a difference of about 17 percent between these two constants. The second decision involves a choice between two calibration values (Cu or Au) used to determine the uranium content of a material to be dated.…”

Section: Discussion Of Zircon Fission-track Agesmentioning

confidence: 99%

Fission-track and K-Ar ages of natural glasses

Naeser¹,

Izett²,

Obradovich³

1980

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Section: Discussion Of Zircon Fission-track Agesmentioning

confidence: 99%

Fission-track and K-Ar ages of natural glasses

Naeser¹,

Izett²,

Obradovich³

1980

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“…If we consider a sample containing evenly distributed 238%j atoms, then the total number of decays of 238%j of a given volume in time t is given by: (Note: 238%] decays by both alpha emission and spontaneous nuclear fission with individual decay constants and Xf. These are usually summed together to provide the total decay constant for 238%]^ symbolised by ^d-Since is known to be six orders of magnitude lower than X^^ (Wagner et al, 1975;Theil and Hur, 1976) it can be assumed that Xo -…”

Section: Derivation O F the Fission Track Age Equationmentioning

confidence: 99%

Thermotectonics of the Calabrian Arc, Southern Italy constraints from fission track analysis

Thomson¹

1993

Nuclear Tracks and Radiation Measurements

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This study uses fission track analysis to provide temperature and time constraints on the cooling and exhumation history of the basement rocks of the Calabrian Arc of southern Italy. Fission track analysis also provides information on the provenance and burial history of the terrigenous Oligo-Miocene Stilo-Capo d 'Orlando Formation.65 samples from the basement rocks have yielded 57 apatite fission track ages, 54 zircon fission track ages and 25 apatite track length distributions. 9 samples from the Stilo-Capo d 'Orlando Formation have yielded 8 apatite fission track ages, 8 zircon fission track ages and 6 apatite track length distributions.Qualitative and quantitative analysis of the fission track data reveals that the majority of the basement rocks underwent a phase of increased cooling related to exhumation between about 35 Ma (Early Oligocene) and 15 Ma (Middle Miocene). Evidence from the local sedimentary record indicates that erosion played an important role in the exhumation process. Extensional tectonism also contributes to some of the increased exhumation. Analysis of the fission track results obtained from the Stilo-Capo d 'OrlandoFormation confirm a Calabrian basement provenance for the sediments. The previously debated origin of volcanic conglomerate clasts from the formation is also resolved. Finally apatite fission track analysis indicates post-depositional burial at the base of the formation to temperatures greater than 80*C.The final part of this thesis uses the fission track age and temperature constraints to produce an improved tectonic model for the Oligo-Miocene tectonic evolution of the Calabrian Arc. This model proposes that increased exhumation is a consequence of the dynamics of an overthickened orogenic wedge. The model is related to the overall plate dynamics of the western Mediterranean orogeny. Ill A CKNO W LED G EM ENTSThis project was supervised by Dr. Robert Hall, who has provided much advice and encouragement, when not away in the field, and whose valuable criticisms of the initial drafts of this thesis were much appreciated. I must also thank Professor Claudio Vita-Finzi, who proposed southern Italy as the field area after problems developed with the original project proposal. Finally, I am greatly indebted to Dr. Tony Hurford for allowing the use of the facilities of the London Fission Track Research Group. Funding for this project was provided by the Natural Environment Research Council. Financial assistance from the London Fission Track Research Group and Eurotrack was also greatly received.Samples were collected from throughout Calabria and Sicily, and special recommendation must go to Le Pensione Sirene, in Scilla. Assistance and company in the field from Bill Murphy, Dr. Robert Hall, Professor Claudio and Penelope Vita-Finzi and Mark Ferry was invaluable. Also, thanks to Gert Jan Weltje for a valuable discussion in the field, and for providing a pre-print of his work on the Stilo-Capo d 'Orlando Formation.Finally thanks to the FIAT garage at Villa san Giovanni for keeping the...

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“…Wagner et al 1976). It is based on h a. determinations from U-rich man-made glasses of known ages (Wagner et al 1975;Thiel and Herr 1976) as well as on geological calibrations with K-Ar dated impact and volcanic glasses (Storzer 1970b;Storzer and Popeau 1973b). Recently, Carpenter (1980) showed that, provided uranium isotopic composition and content in glass dosimeters are well known (which is the ease of the NnS standards), the measure of the neutron fluence can be avoided.…”

Section: Toward a Standardization In Ft Dating?mentioning

confidence: 99%

Precision, accuracy and meaning of fission track ages

Poupeau

1981

J Earth Syst Sci

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The precision, meaning, and accuracy of the fission track (Fr) dating method are reviewed from an examination of the recent literature as well as previously unpublished data from the author's laboratory. It is concluded that for apparent FT ages (i.e. ages derived from the canonical age equation) a precision (2~r level) of the order of 4-4 ~o to 4-5 Yo can be reached provided that (i) uranium is sufficiently homogeneously distributed in the dated samples, at least locally; and (ii) a large enough number of tracks can be counted. Model r'r ages, i.e. ages for which partial geological track annealing is taken into account, have variable degrees of precision. While model ages obtained with the track-size method seem, as evaluated from the literature, to have usually a limited precision of the order of 4-30yo (2~), plateau ages usually have a precision better than 4-5 ~0 at a 2~r confidence level. Because it provides an objective test on the accuracy of track identification, as well as some insight of the variability of closing temperatures between various samples of a given mineral phase, the Isochroua'l Plateau (icp) method, when applicable, will be preferred (Poupean et al 1980a). However, for phases which.could be damaged by heating at relatively high temperatures, as for example hydrated glass shards from tephra, an Isothermal Plateau (ITP) approach is to be preferred. Due to uncertainties about the value of the 28sU spontaneous fission decay constant ,~y, as well as difficulties inherent in the dosimetry of thermal neutrons in nuclear reactors, the rT method of dating is not an independent one. Presently, it relies on the existence of geological standards (volcanic rocks) of known age, allowing to determine an operational 'Ay' value (Naeser et al 1980). Accordingly, the accuracy of an FT age is limited by the accuracy on the age of the standard. It should be better than ,~ 5 Yo. For volcanic, hypovolcunic rocks, and shallow intrusives, the rr method dates the time of formation, provided they were not further reheated. More generally, the track method provides cooling ages. Closing temperatures calculated from laboratory experiments vary from ~ 300"C to 100~ according to minerals, for slow cooling rates (,~ l~ For apatites, recent geological calibrations (Naeser et al 1980; Gleadow and Duddy 1980) confirmed laboratory extrapolations. The association of the rT method with other geochronometers is therefore critical to the study of the cooling history of old cratons as well as to the evaluation of uplift/erosion rates in recent belts, Keywords. Fission tracks; fission track dating; track annealing; fission decay constant; neutron dosimetry; model ages; plateau ages; cooling and uplift rates.

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The238U spontaneous fission decay constant re-determined by fission tracks

Cited by 40 publications

References 25 publications

Fission-track and K-Ar ages of natural glasses

Fission-track and K-Ar ages of natural glasses

Thermotectonics of the Calabrian Arc, Southern Italy constraints from fission track analysis

Precision, accuracy and meaning of fission track ages

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