کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5785674 1640179 2017 14 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Paleoproterozoic plume-related basaltic rocks in the Mana gold district in western Burkina Faso, West Africa: Implications for exploration and the source of gold in orogenic deposits
ترجمه فارسی عنوان
سنگهای بازالتی مرتبط با پالئوپروتروزیوئیک در منطقه منا طلای غربی بورکینافاسو، غرب آفریقا: پیامدهای اکتشاف و منبع طلا در ذخایر ارگوژن
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات زمین شناسی
چکیده انگلیسی


- Basaltic rocks formed in an oceanic plateau setting above plume-head.
- Gold endowment interpreted to be linked with plume-related basaltic rocks.
- Two geochemical diagrams using Zr, Y, Nb and Th for establishing the gold fertility of belts.

Birimian volcanic rocks of the Mana District are located in the an important gold-mineralized segment of the Paleoproterozoic Houndé greenstone belt, western Burkina Faso, which contains cumulative resources of ∼11 Moz. Five orogenic gold deposits (∼8 Moz) are hosted in or close to basaltic rocks. Theses rocks were studied to investigate their possible role as a gold source in younger orogenic gold deposits. They are Fe-rich tholeiitic basalts with flat REE patterns, with (La/Yb)N = 0.96-1.3 and without negative Eu anomaly (Eu/Eu* = 0.92-1.26). The basalts also have low initial Sr isotopic ratios (0.693612-0.702190) and positive εNd values (+2.25 to +3.14). Using a Ce/Nb vs. Th/Nb diagram and various plume-related basalts worldwide for comparison, the Mana basalts are shown to be plume-related. In addition, using Zr/Nb vs. Nb/Th and Nb/Y vs. Zr/Y binary diagrams and reference fields, the Mana basaltic rocks appear to have formed directly above the plume head. Because plume-related basalts tend to be enriched in gold relative to MORB, we propose that the gold endowment of the Mana district is mostly related to the occurrence of plume-related basaltic rocks, which may have served as an important metal stock during subsequent remobilization for forming the orogenic gold deposits. We also propose that for gold exploration, two simple geochemical diagrams involving Zr, Y, Nb and Th could be used at an early stage to test the origin of the basaltic rocks and hence indirectly establish the fertility of a specific belt for hosting orogenic gold deposits.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of African Earth Sciences - Volume 129, May 2017, Pages 17-30
نویسندگان
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