کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4729973 1640347 2016 13 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Using detrital zircons from river sands to constrain major tectono-thermal events of the Cathaysia Block, SE China
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات زمین شناسی
پیش نمایش صفحه اول مقاله
Using detrital zircons from river sands to constrain major tectono-thermal events of the Cathaysia Block, SE China
چکیده انگلیسی


• Detrital zircon U–Pb–Hf isotopes from major rivers in Cathaysia Block are analyzed.
• 1.6–2.0 Ga and 2.6–3.0 Ga are two principal periods of continental crustal growth.
• 90% of the present crust in the northeastern Cathaysia Block was formed by 1.6 Ga.
• 80% of the present crust in the southwestern Cathaysia Block was formed by 1.6 Ga.
• Cretaceous zircons have εHf(t) values less variable than Jurassic zircons.

Detrital zircons from the Minjiang and Zhujiang Rivers in SE China have been analyzed for U/Pb ages and Lu–Hf isotopic compositions to constrain their provenance and the growth history of the continental crust of the Cathaysia Block. Zircon U/Pb ages show five major populations at 90–250 Ma, 400–500 Ma, 0.7–1.2 Ga, 1.6–2.0 Ga and 2.3–2.6 Ga. Proterozoic zircons have Hf isotopic signatures consistent with the remelted ancient crust and the involvement of juvenile crust. However, Phanerozoic zircons have Hf isotopic signatures indicative of reworked or recycled ancient crust. Crustal growth rates based on the two-stage Hf model ages of the detrital zircons indicate that 30% and 90% of present crust in the northeastern Cathaysia Block was formed by 2.5 Ga and 1.6 Ga, respectively, whereas <20% continental crust was formed by 2.5 Ga, and 80% by 1.6 Ga in the southwestern Cathaysia Block. Therefore, Neoarchean and Paleoproterozoic were two major periods of crustal growth of the Cathaysia Block. Our results also reveal that the tectono-thermal events at ∼370 Ma and ∼117 Ma may have occurred to the Wuyishan terrane in the northeastern Cathaysia Block. Jurassic zircon grains have Hf isotopic compositions more variable than Cretaceous grains, which may have been derived from different source rocks. The 140–120 Ma tectono-thermal events were likely related to the change of the subduction direction of the Paleo-Pacific plate from northward to northwestward at 140 Ma. The 112–90 Ma tectono-thermal events may be correlated with the rollback of the subducted paleo-Pacific plate at ∼110 Ma.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Asian Earth Sciences - Volume 124, 1 July 2016, Pages 1–13
نویسندگان
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