In the 1990s, some median-large gold deposits have been discovered in several lead-zinc metallogenetic belts (e.g. the Qinling lead-zinc metallogenetic belt, Shanxi Province and Gansu Province and the Qingchengzi lead...In the 1990s, some median-large gold deposits have been discovered in several lead-zinc metallogenetic belts (e.g. the Qinling lead-zinc metallogenetic belt, Shanxi Province and Gansu Province and the Qingchengzi lead-zinc ore field, Liaoning Province) in China. Gold deposits and lead-zinc deposits spatially co-exist in the same tectonic setting; lead-zinc orebodies are commonly located below gold ore bodies. The host rocks of lead-zinc ore-bodies are conformably overlain by those of gold ore bodies. The age of gold mineralization is obviously younger than that of lead-zinc mineralization. Preliminary geochemical research has demonstrated the following: lead-zinc mineralization took place in a marine sedimentary-exhalative system, which had the characteristics of a high fluid/rock ratio, a high salinity and a high halide activity; meanwhile, most of gold was transported into the low-temperature hydrothermal plume and primarily enriched in sediments. During later (magmatism-) metamorphism- tectonism, gold was remobilized and transported into the metamorphic fluid which had the characteristics of medium- high temperatures, a low fluid/rock ratio and a low activity of halide, and precipitated at a favourable structural site. Therefore, the co-existence of gold and lead-zinc deposits and the separation of gold from lead-zinc result from the differences of chemical composition and circulation of ore fluids in the same tectonic unit. This phenomenon can be used as an important criterion in exploration.展开更多
The formation, development and evolution of the Qinling orogenic belt can be divided into three stages: (1) formation and development of Precambrian basement in the Late Archaean-Palaeoproterozoic (3.0–1.6 Ga), (2) p...The formation, development and evolution of the Qinling orogenic belt can be divided into three stages: (1) formation and development of Precambrian basement in the Late Archaean-Palaeoproterozoic (3.0–1.6 Ga), (2) plate evolution (0.8–0.2 Ga), and (3) intracontinental orogeny and tectonic evolution in the Mesozoic.展开更多
文摘In the 1990s, some median-large gold deposits have been discovered in several lead-zinc metallogenetic belts (e.g. the Qinling lead-zinc metallogenetic belt, Shanxi Province and Gansu Province and the Qingchengzi lead-zinc ore field, Liaoning Province) in China. Gold deposits and lead-zinc deposits spatially co-exist in the same tectonic setting; lead-zinc orebodies are commonly located below gold ore bodies. The host rocks of lead-zinc ore-bodies are conformably overlain by those of gold ore bodies. The age of gold mineralization is obviously younger than that of lead-zinc mineralization. Preliminary geochemical research has demonstrated the following: lead-zinc mineralization took place in a marine sedimentary-exhalative system, which had the characteristics of a high fluid/rock ratio, a high salinity and a high halide activity; meanwhile, most of gold was transported into the low-temperature hydrothermal plume and primarily enriched in sediments. During later (magmatism-) metamorphism- tectonism, gold was remobilized and transported into the metamorphic fluid which had the characteristics of medium- high temperatures, a low fluid/rock ratio and a low activity of halide, and precipitated at a favourable structural site. Therefore, the co-existence of gold and lead-zinc deposits and the separation of gold from lead-zinc result from the differences of chemical composition and circulation of ore fluids in the same tectonic unit. This phenomenon can be used as an important criterion in exploration.
基金This project was supported by grants from the Ministry of Science and Technology(969140104)the General Bureau of Geology and Exploration under theformer CNNC(98-D-1).
文摘The formation, development and evolution of the Qinling orogenic belt can be divided into three stages: (1) formation and development of Precambrian basement in the Late Archaean-Palaeoproterozoic (3.0–1.6 Ga), (2) plate evolution (0.8–0.2 Ga), and (3) intracontinental orogeny and tectonic evolution in the Mesozoic.
