摘要
In recent years, a considerable amount of microscopic spherules have been found in concentrates recovered from some stratabound gold deposits occurring in Middle-Upper Triassic turbidite series in northwestern Sichuan. Study indicates that these spherules are cosmic dust. It is the first time that cosmic dust of extraterrestrial origin has been found in hydrothermal gold deposits in China.The spherules are steel-grey in colour and show metallic luster. Their grain size is commonly less than 100 μm. According to their composition, they belong to chromium-rich iron cosmic dust. The spherules have complex and diverse microscopic structures and textures, i.e. they show a very distinct Widmanstaten structure.The variation of cosmic dust content in gold deposits exhibits a positive correlation with the mineralization intensities and hydrothermal alteration. Such a relation indicates that the ore sub- stances may transport not only mechanically but also may chemically in hydrothermal solutions.
In recent years, a considerable amount of microscopic spherules have been found in concentrates recovered from some stratabound gold deposits occurring in Middle-Upper Triassic turbidite series in northwestern Sichuan. Study indicates that these spherules are cosmic dust. It is the first time that cosmic dust of extraterrestrial origin has been found in hydrothermal gold deposits in China.The spherules are steel-grey in colour and show metallic luster. Their grain size is commonly less than 100 μm. According to their composition, they belong to chromium-rich iron cosmic dust. The spherules have complex and diverse microscopic structures and textures, i.e. they show a very distinct Widmanstaten structure.The variation of cosmic dust content in gold deposits exhibits a positive correlation with the mineralization intensities and hydrothermal alteration. Such a relation indicates that the ore sub- stances may transport not only mechanically but also may chemically in hydrothermal solutions.
基金
This study was supported by National Natural Science Foundation of China Grant 4880099
