| Autor: |
Charles W. Jefferson, T. Mark Harrison, Tony D. Peterson, Susan M. Swapp, Norbert G. Swoboda-Colberg, Kevin R. Chamberlain, Axel K. Schmitt, Wouter Bleeker, Andrei K. Khudoley |
| Rok vydání: |
2010 |
| Předmět: |
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| Zdroj: |
Precambrian Research. 183:379-387 |
| ISSN: |
0301-9268 |
| DOI: |
10.1016/j.precamres.2010.05.004 |
| Popis: |
An in situ U–Pb SIMS (IN-SIMS) method to date micro-baddeleyite crystals as small as 3 μm is presented with results from three samples that span a variety of ages and geologic settings. The method complements ID-TIMS geochronology by extending the range of dateable crystals to sizes smaller than can be recovered by physical separation. X-ray mapping and BSE imaging are used to locate target grains in thin section, followed by SIMS analysis on a CAMECA ims 1270, using the field aperture in the transfer column to screen out ions from host phases. Internal age precisions for the method are anticipated to range from 0.1% for Precambrian rocks to 3–7% for Phanerozoic rocks. Results establish a 2689 ± 5 Ma age for mafic dikes in the Wyoming craton, USA, a 1540 ± 30 Ma age for a subaerial lava flow from the Thelon Basin of northern Canada, and a 457 ± 34 Ma age for mafic dikes in the platform sequence of southeastern Siberia. The method is ideal for relatively non-destructive dating of small samples such as extraterrestrial rocks and precious terrestrial samples. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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Full Text from ScienceDirect