Geophysical, magmatic, and metallogenic manifestations of a mantle plume in the upper reaches of the Aldan and Amur Rivers

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• 作者：A.M. Petrishchevsky ; ^{petris2010@mail.ru" class="auth_mail} ; Yu.P. Yushmanov
• 关键词：gravity modeling ; plumes ; metallogeny ; Amur region
• 刊名：Russian Geology and Geophysics
• 出版年：April, 2014
• 年：2014
• 卷：55
• 期：4
• 页码：443-462
• 全文大小：2582 K

文摘

Gravity models of the crust and upper mantle to a depth of 100 km are analyzed to study structural relationships of tectonic and tectonophysical media of different rigidities with the distribution of shallow ore deposits above the Aldan-Zeya plume. The spatial correlation of ore clusters and districts with high crustal viscosity inhomoheneities at depths of 10, 20, and 35 km shows distinct stepwise behavior. On the other hand, media of decreased viscosity are observed in the lower crust (at depths of 25-30 km), subcrustal (40-50 km) layers, and asthenosphere (at a depth below 70 km). They are related to chambers of the complete or partial melting (heat sources) of magmatic and ore occurrences near the Earth鈥檚 surface. Lateral metallogenic zoning in the spatial distribution of the ore deposits is due to the spread and redistribution of magmas and ore-forming fluids, shielded by rigid plates in the lower crust. A naturally determined series of ore parageneses is observed from center to flanks of the plume: Au, Mo 鈫?#xA0;Au, Ag, Pb, Zn 鈫?#xA0;Au, Pb, Zn 鈫?#xA0;Au, W 鈫?#xA0;Au, Sb 鈫?#xA0;W, Sn 鈫?#xA0;Sn. The mutual position of the tectonomagmatic structures of different ranks within the plume head obeys hierarchical and fractal laws.