کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5784974 | 1639836 | 2017 | 11 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Zircon U-Pb dating using LA-ICP-MS: Quaternary tephras in Boso Peninsula, Japan
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
ژئوشیمی و پترولوژی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Zircon U-Pb dating using LA-ICP-MS was applied to six Quaternary tephras in Boso Peninsula, central Japan: J1, Ks4, Ks5, Ks10, Ks11, and Ch2 in descending order. Accurate age determination of these tephras is of critical importance because they are widespread tephras in Japan and also relevant to a candidate site for the global boundary stratotype section and point of the early-middle Pleistocene boundary. Twenty grains were dated for each tephra and the following results were obtained. The J1 tephra had only 5 grains that yielded <2 Ma. The obtained age was â¼0.2 m.y. older than the stratigraphic age. No Quaternary ages were obtained from the Ks4 tephra. The Ks5 and Ks10 tephras had 10-12 grains that were â¼0.1-0.3 m.y. older than the stratigraphic age. The Ks11 tephra had 14 grains that yielded a weighted mean age of 0.52 ± 0.04 Ma (error reported as 95% confidence level), which was in agreement with the stratigraphic age. The Ch2 tephra had 16 grains that yielded a weighted mean age of 0.61 ± 0.02 Ma, which was also in agreement with the stratigraphic age. The good agreement between zircon U-Pb ages and the stratigraphy for Ks11 and Ch2 tephras validates the reliability of the established stratigraphy and our dating approach. The other tephras that yielded â¼0.1-0.3 m.y. older ages than the stratigraphy may indicate that the analyzed zircons were antecrysts that crystallized before eruption or they were detrital zircons incorporated during deposition.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Quaternary Geochronology - Volume 40, May 2017, Pages 12-22
Journal: Quaternary Geochronology - Volume 40, May 2017, Pages 12-22
نویسندگان
Hisatoshi Ito, Futoshi Nanayama, Hiroomi Nakazato,