Abstract This paper deals with characteristics of silicon isotope compositions and siliceous cathodoluminescence of host rocks, ores and hydrothermal silicified quartz of the Carlin-type ore deposits in the Yunnan-Gui...Abstract This paper deals with characteristics of silicon isotope compositions and siliceous cathodoluminescence of host rocks, ores and hydrothermal silicified quartz of the Carlin-type ore deposits in the Yunnan-Guizhou-Guangxi triangle area. The study shows that primary silicified quartz is nonluminescent but quartz in host rocks and secondary silicified quartz are luminescent by the action of cathode rays. Correspondingly, silicon isotope compositions of host rocks, ores and hydro6thermal quartz veins are clearly distinguished. In strata from the Middle Triassic to the “Dachang” host bed, δ30Si of the host rocks ranges from 0.0% ?0.3%, while that of primary ore-forming silicified fluids from ?0.1% to ?0.4%; in the Upper Permian and Lower Carboniferous strata and Indosinian diabase host beds, δ30Si of the host rocks is from ?0.1% to ?0.2% and that of the primary silicified quartz veins from 0.3 % ?0.5 %. This pattern demonstrates the following geochemical mineralization process, primary ore-forming siliceous fluids migrated upwards quickly along the main passages of deep-seated faults from mantle to crust and entered secondary faults where gold deposits were eventually formed as a result of permeation and replacement of the siliceous ore-forming fluids into different ore-bearing strata. This gives important evidence for the fact that ore-forming fluids of this type of gold deposits were mainly derived from upper mantle differentiation and shows good prospects for deep gold deposits and geochemical background for large and superlarge gold deposits.展开更多
The development of world economy has been heading for globalization and regionalization. In recent years, this tendency has born great impact on the rapid economic development of the Asian and Pacific countries, which...The development of world economy has been heading for globalization and regionalization. In recent years, this tendency has born great impact on the rapid economic development of the Asian and Pacific countries, which assumes the form of economic growth triangle as their major way for regional cooperation involving multiple nations. Among these, the Tumen River Triangle consisting of six countries' cooperation may have attracted great attention. Since 1991 when UNDP began to draw up plans for such a mammoth project which is called the Tumen River Area Development Project (or TRADP), the international economic cooperation in this area has been developing energetically. It is now necessary to assess the characteristics of geographical conditions and various economic resources from the viewpoints of economic geography and expound the mammoth benefits both in economy and to society. The demonstration would undoubtedly absorb more international capital to this area and enhance its economic and social development.展开更多
文摘Abstract This paper deals with characteristics of silicon isotope compositions and siliceous cathodoluminescence of host rocks, ores and hydrothermal silicified quartz of the Carlin-type ore deposits in the Yunnan-Guizhou-Guangxi triangle area. The study shows that primary silicified quartz is nonluminescent but quartz in host rocks and secondary silicified quartz are luminescent by the action of cathode rays. Correspondingly, silicon isotope compositions of host rocks, ores and hydro6thermal quartz veins are clearly distinguished. In strata from the Middle Triassic to the “Dachang” host bed, δ30Si of the host rocks ranges from 0.0% ?0.3%, while that of primary ore-forming silicified fluids from ?0.1% to ?0.4%; in the Upper Permian and Lower Carboniferous strata and Indosinian diabase host beds, δ30Si of the host rocks is from ?0.1% to ?0.2% and that of the primary silicified quartz veins from 0.3 % ?0.5 %. This pattern demonstrates the following geochemical mineralization process, primary ore-forming siliceous fluids migrated upwards quickly along the main passages of deep-seated faults from mantle to crust and entered secondary faults where gold deposits were eventually formed as a result of permeation and replacement of the siliceous ore-forming fluids into different ore-bearing strata. This gives important evidence for the fact that ore-forming fluids of this type of gold deposits were mainly derived from upper mantle differentiation and shows good prospects for deep gold deposits and geochemical background for large and superlarge gold deposits.
文摘The development of world economy has been heading for globalization and regionalization. In recent years, this tendency has born great impact on the rapid economic development of the Asian and Pacific countries, which assumes the form of economic growth triangle as their major way for regional cooperation involving multiple nations. Among these, the Tumen River Triangle consisting of six countries' cooperation may have attracted great attention. Since 1991 when UNDP began to draw up plans for such a mammoth project which is called the Tumen River Area Development Project (or TRADP), the international economic cooperation in this area has been developing energetically. It is now necessary to assess the characteristics of geographical conditions and various economic resources from the viewpoints of economic geography and expound the mammoth benefits both in economy and to society. The demonstration would undoubtedly absorb more international capital to this area and enhance its economic and social development.
