Academic Journal
39 Ar‐ 40 Ar chronology of the enstatite chondrite parent bodies
| العنوان: | 39 Ar‐ 40 Ar chronology of the enstatite chondrite parent bodies |
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| المؤلفون: | Hopp, Jens, Trieloff, Mario, Ott, Uli, Korochantseva, Ekaterina V., Buykin, Alexey I. |
| المصدر: | Meteoritics & Planetary Science ; volume 49, issue 3, page 358-372 ; ISSN 1086-9379 1945-5100 |
| بيانات النشر: | Wiley |
| سنة النشر: | 2014 |
| المجموعة: | Wiley Online Library (Open Access Articles via Crossref) |
| الوصف: | Ar‐Ar isochron ages of EL chondrites suggest closure of the K‐Ar system at 4.49 ± 0.01 Ga for EL 5 and 6 chondrites, and 4.45 ± 0.01 Ga for EL 3 MAC 88136. The high‐temperature release regimes contain a mixture of radiogenic 40 Ar* and trapped primordial argon (solar or Q‐type) with 40 Ar/ 36 Ar TR ~ 0 , which does not affect the 40 Ar budget. The low‐temperature extractions show evidence of an excess 40 Ar component. The 40 Ar/ 36 Ar is 180–270; it is defined by intercept values of isochron regression. Excess 40 Ar is only detectable in petrologic types >4/5. These lost most of their primordial 36 Ar from low‐temperature phases during metamorphism and retrapped excess 40 Ar. The origin of this excess 40 Ar component is probably related to metamorphic Ar mobilization, homogenization of primordial and in situ radiogenic Ar, and trapping of Ar by distinct low‐temperature phases. Ar‐Ar ages of EH chondrites are more variable and show clear evidence of a major impact‐induced partial resetting at about 2.2 Ga ago or alternatively, prolonged metamorphic decomposition of major K carrier phases. EH impact melt LAP 02225 displayed the highest Ar‐Ar isochron age of 4.53 ± 0.01 Ga. This age sets a limit of about 25–45 Ma for the age bias between the K‐Ar and U‐Pb decay systems. |
| نوع الوثيقة: | article in journal/newspaper |
| اللغة: | English |
| DOI: | 10.1111/maps.12243 |
| الاتاحة: | http://dx.doi.org/10.1111/maps.12243 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fmaps.12243 https://onlinelibrary.wiley.com/doi/pdf/10.1111/maps.12243 |
| Rights: | http://onlinelibrary.wiley.com/termsAndConditions#vor |
| رقم الانضمام: | edsbas.BEB512C8 |
| قاعدة البيانات: | BASE |
| DOI: | 10.1111/maps.12243 |
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