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Ar-40/-Ar-39 geochronology at the Instituto de Geociencias, USP: instrumentation, analytical procedures, and calibration
Vasconcelos, PN, Onoe, AT, Kawashita, K, Soares, AJ and Teixeira, W (2002) Ar-40/-Ar-39 geochronology at the Instituto de Geociencias, USP: instrumentation, analytical procedures, and calibration. Anais Da Academia Brasileira De Ciencias, 74 2: 297-342.
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| Author(s) |
Vasconcelos, PN
Onoe, AT
Kawashita, K
Soares, AJ
Teixeira, W
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| Title |
Ar-40/-Ar-39 geochronology at the Instituto de Geociencias, USP: instrumentation, analytical procedures, and calibration
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| Journal name |
Anais Da Academia Brasileira De Ciencias
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| Publication date |
2002
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| Volume number |
74
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| Issue number |
2
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| ISBN |
0001-3765
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| ISSN |
0001-3765
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| Start page |
297
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| End page |
342
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| Total pages |
46
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| Editor(s) |
Leny A Cavalcante
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| Place of publication |
Brazil
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| Publisher |
Academia Brasileira de Ciencias
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| Collection year |
2002
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| Language |
eng
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| Subject |
C1
260109 Geochronology
780104 Earth sciences
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| Abstract |
Laser heating Ar-40/Ar-39 geochronology provides high analytical precision and accuracy, mum-scale spatial resolution. and statistically significant data sets for the study of geological and planetary processes, A newly commissioned Ar-40/Ar-39 laboratory at CPGeo/USP, Sao Paulo, Brazil, equips the Brazilian scientific community with a new powerful tool applicable to the study of geological and cosmochemical processes. Detailed information about laboratory layout, environmental conditions, and instrumentation provides the necessary parameters for the evaluation of the CPGeo/USp Ar-40/Ar-39 suitability to a diverse range of applications. Details about analytical procedures, including mineral separation, irradiation at the IPEN/CNEN reactor at USP, and mass spectrometric analysis enable potential researchers to design the necessary sampling and sample preparation program suitable to the objectives of their study. Finally, the results of calibration tests using Ca and K salts and glasses, international mineral standards, and in-house mineral standards show that the accuracy and precision obtained at the Ar-40/Ar-39 laboratory at CPGeo/USP are comparable to results obtained in the most respected laboratories internationally. The extensive calibration and standardization procedures under-taken ensure that the results of analytical studies carried out in our laboratories will gain immediate international credibility, enabling Brazilian students and scientists to conduct forefront research in earth and planetary sciences.
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| Keyword(s) |
Geochronology
40ar/39ar Method
Irradiation
Calibration
Multidisciplinary Sciences
Ar-40/ar-39 Method
Tertiary Boundary Tektites
Ar-40/ar-39 Laser-probe
K-ar
Weathering Processes
Koobi Fora
Ar-40-ar-39
Age
Ar-40
California
Intercalibration
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