40Ar-39Ar dating of rocks drilled at sites 60-458 and 60-459
Cobertura |
MEDIAN LATITUDE: 17.863775 * MEDIAN LONGITUDE: 147.026100 * SOUTH-BOUND LATITUDE: 17.862500 * WEST-BOUND LONGITUDE: 146.934300 * NORTH-BOUND LATITUDE: 17.864200 * EAST-BOUND LONGITUDE: 147.301500 * DATE/TIME START: 1978-04-18T00:00:00 * DATE/TIME END: 1978-04-25T00:00:00 |
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Data(s) |
09/10/1982
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Resumo |
40Ar-39Ar dating of a high-MgO bronzite andesite from near the top of basement drilled at Site 458 shows the characteristic symptoms of artificially disturbed samples - i.e., an inverse staircase-type age spectrum, approximate linearity on an isochron plot, and concordance between total fusion age and isochron age. From conclusions based on other artificially disturbed samples (Ozima et al., 1979), we suggest that the reference isochron age (33.6 Ma) approximates the age of the sample. A basalt from deeper in Hole 458 gives an isochron age of 19.1 ± 0.2 Ma, which is slightly younger than the plateau age of 21.4 ± 1.0 Ma. Both ages are, however, considerably younger than the age of fossils in the overlying sediments (30 - 34 Ma). The age discrepancy may be explained if the 40Ar-39Ar age represents the age of secondary minerals, which formed later. No useful age data were obtained from a basalt sample recovered from Hole 459B. |
Formato |
application/zip, 2 datasets |
Identificador |
https://doi.pangaea.de/10.1594/PANGAEA.820217 doi:10.1594/PANGAEA.820217 |
Idioma(s) |
en |
Publicador |
PANGAEA |
Direitos |
CC-BY: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted |
Fonte |
Supplement to: Takigami, Yutaka; Ozima, Minoru (1982): 40Ar-39Ar dating of rocks drilled at sites 458 and 459 in the Mariana fore-arc region during Leg 60. In: Hussong, DM; Uyeda, S; et al. (eds.), Initial Reports of the Deep Sea Drilling Project (U.S. Govt. Printing Office), 60, 743-746, doi:10.2973/dsdp.proc.60.141.1982 |
Palavras-Chave | #-; # = Isochron age was calculated from 700, 800 and 900°C fractions; 37Ar/36Ar; 37Ar/36Ar e rel; 39Ar; 39Ar/36Ar; 39Ar/36Ar e rel; 40Ar/36Ar; 40Ar/36Ar e rel; 60-458; 60-459; Age, 40Ar/39Ar Argon-Argon; Age, dated; Age, dated standard deviation; Age dated; Age std dev; Apparent; Apparent; 1 sigma; Argon-37/Argon-36; Argon-37/Argon-36, error, relative; Argon-39; Argon-39/Argon-36; Argon-39/Argon-36, error, relative; Argon-40/Argon-36; Argon-40/Argon-36, error, relative; Coeff; Coefficient; Deep Sea Drilling Project; DRILL; Drilling/drill rig; DSDP; Event; Fraction; Glomar Challenger; Isochron; Isochron intercept; J = [exp(lambda-ts) -l]/(40Ar/39Ar)S; ts is age of a standard sample (JGl-biotite), S refers to a standard sample, lambda is total decay constant of 40K; Label; Leg60; MSUM = SUMS/n - 2. n = number of fractions (Brooks et al., 1972). # = cutoff values for the 95% significance level (cutoff value); North Pacific/SEDIMENT POND; North Pacific/TRENCH; ODP sample designation; Plateau; r = Correlation coefficient (York, 1969); Sample code/label; Standard deviation; Std dev; Sum; Temperature, technical; Total fusion; T tech |
Tipo |
Dataset |