کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4685779 | 1635516 | 2010 | 8 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Constraining the physical-chemical conditions of Pleistocene cavernous weathering in Late Paleozoic granites
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
فرآیندهای سطح زمین
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چکیده انگلیسی
Cavernous weathering such as tafoni, alveoles and honeycomb structures have been recorded from a great variety of bedrocks and landforms. In the present study cavernous weathering from late Variscan granites was discussed as to its physical-chemical regime of formation. U/Pb dating yielded a maximum age of 1.52 ± 0.03 Ma. Supergene U mineralization is accompanied by kaolinite, nontronite and Fe(III) phosphates. Based upon Eh-pH diagrams calculated for U-Fe-P mineralization the physical-chemical conditions may be described as oxidizing with pH values fluctuating around neutral at near-ambient temperatures of 25 °C. Alteration occurs in two stages: dissolution of rock-forming minerals and neoformation of hydrosilicates under mildly acidic conditions, followed by phosphate precipitation under near-neutral conditions.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Geomorphology - Volume 121, Issues 3â4, 15 September 2010, Pages 283-290
Journal: Geomorphology - Volume 121, Issues 3â4, 15 September 2010, Pages 283-290
نویسندگان
Harald G. Dill, Berthold Weber, Axel Gerdes,