کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6442279 | 1639628 | 2014 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
40Ar/39Ar dating of exceptional concentration of metals by weathering of Precambrian rocks at the Precambrian-Cambrian boundary
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موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
ژئوشیمی و پترولوژی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
The sub-Cambrian surface, including diverse metalliferous deposits, shows evidence of intense weathering of Precambrian rocks to form supergene-enriched ores and metalliferous placers, followed by widespread peneplanation. Much of the metal would have been flushed to the Cambrian ocean during peneplanation. An 40Ar/39Ar age of 542.62 ± 0.38 Ma (1 sigma, full external precision, Renne et al., 2011) for metalliferous alteration clays in Scotland shows that this event occurred immediately prior to the Precambrian-Cambrian boundary. A negative δ53Cr isotopic signature for the clay is consistent with mobilization on land of redox sensitive metals by oxidative terrestrial weathering. This unprecedented flushing of metals from the weathered Precambrian surface would have contributed to the chemistry of the earliest Cambrian ocean at a time of marked faunal evolution.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Precambrian Research - Volume 246, June 2014, Pages 54-63
Journal: Precambrian Research - Volume 246, June 2014, Pages 54-63
نویسندگان
John Parnell, Darren F. Mark, Robert Frei, Anthony E. Fallick, Rob M. Ellam,