Desert terrains in northern China are covered by widespread regolith sediments which mask geochemical signals from ore bodies and are major obstacles to mineral exploration. There is a critical need to study the verti...Desert terrains in northern China are covered by widespread regolith sediments which mask geochemical signals from ore bodies and are major obstacles to mineral exploration. There is a critical need to study the vertical distribution of elements in this regolith and to establish optimum sampling and analytical methods. The aim of this study is to understand the dispersion and variation of elements throughout the cover in a vertical profile. The results demonstrate that the main elements show a distribution pattern of enrichment in clay layers in the vertical profile, i.e., most elements tend to be enriched in the most upper part of the profile above the orebodies except for some elements like Cu, Ca and Ag. Meanwhile, both fine (-160 mesh) and coarse (+20 mesh) fraction samples from clay-rich horizons are favorable samples and selective leaching of the elements absorbed on clays or oxide coatings is effective for localizing buried deposits. The distribution of active Cu and Mo is quite different because chalcopyrite is weathered into Cu sulfate and CuCO3, and is precipitated in alkaline environments in a layer below close to the surface. Mo is soluble in the alkaline environment so it can penetrate the caliche layer and be enriched on the surface of soil enriched with weakly cemented clay.展开更多
The mineralization ages reported in the past in the Tuwu-Yandong copper district not only are different,but also fall into the Hercynian epoch.This study has achieved 9 zircon and 7 apatite fission track analysis resu...The mineralization ages reported in the past in the Tuwu-Yandong copper district not only are different,but also fall into the Hercynian epoch.This study has achieved 9 zircon and 7 apatite fission track analysis results.The zircon fission track ages range from 158 Ma to 289 Ma and the apatite ages are between 64 Ma and 140 Ma.The mineralization accords with the regional tectonics in the copper district.We consider that the zircon fission track age could reveal the mineralization age based on annealing zone temperature of 140―300℃ and retention temperature of ～250℃ for zircon fission track,and metallogenetic temperature of 120―350℃ in this ore district.Total three mineralization epochs have been identified,i.e.,289―276 Ma,232―200 Ma and 165―158 Ma,and indicate occurrence of the min-eralization in the Indosinian and Yanshan epochs.Corresponding to apatite fission track ages,the three tectonic-mineralizing epochs are 140―132 Ma,109―97 Ma and 64 Ma,which means age at about 100℃ after the mineralization.The three epochs lasted 146 Ma,108 Ma and about 100 Ma from ～250℃ to ～100℃ and trend decrease from early to late.It is shown by the fission track modeling that this district underwent three stages of geological thermal histories,stable in Cretaceous and cooling both before Cretaceous and after 20 Ma.展开更多
利用卫星数据快速提取矿化岩性信息,是目前矿产资源勘查的重要技术手段之一。文章以新疆东天山土屋斑岩型铜矿区为研究区,基于该地区出露岩体相关矿物的可见光近红外波段(VNIR)至短波红外波段(SWIR)的光谱特征分析,对ASTER多光谱包括以...利用卫星数据快速提取矿化岩性信息,是目前矿产资源勘查的重要技术手段之一。文章以新疆东天山土屋斑岩型铜矿区为研究区,基于该地区出露岩体相关矿物的可见光近红外波段(VNIR)至短波红外波段(SWIR)的光谱特征分析,对ASTER多光谱包括以热红外(TIR)波段在内的全谱域数据进行处理,分别采用主成分分析(PCA)、波段比值(BR)、矿物指数算法识别和提取了研究区地表侵入体的岩性信息。同时,对ASTER 15 m DEM数据进行E-W方向滤波处理,提取和解译出土屋矿区控矿断裂构造信息,结合岩性信息分析控矿条件。最后,对遥感信息提取结果分别进行了矿物镜下与野外验证。展开更多
基金supported by Department of Science and Technology of Shanxi Province (Project No. 2009021007-1)National Natural Science Foundation of China (Project No. 41103052/D0309)
文摘Desert terrains in northern China are covered by widespread regolith sediments which mask geochemical signals from ore bodies and are major obstacles to mineral exploration. There is a critical need to study the vertical distribution of elements in this regolith and to establish optimum sampling and analytical methods. The aim of this study is to understand the dispersion and variation of elements throughout the cover in a vertical profile. The results demonstrate that the main elements show a distribution pattern of enrichment in clay layers in the vertical profile, i.e., most elements tend to be enriched in the most upper part of the profile above the orebodies except for some elements like Cu, Ca and Ag. Meanwhile, both fine (-160 mesh) and coarse (+20 mesh) fraction samples from clay-rich horizons are favorable samples and selective leaching of the elements absorbed on clays or oxide coatings is effective for localizing buried deposits. The distribution of active Cu and Mo is quite different because chalcopyrite is weathered into Cu sulfate and CuCO3, and is precipitated in alkaline environments in a layer below close to the surface. Mo is soluble in the alkaline environment so it can penetrate the caliche layer and be enriched on the surface of soil enriched with weakly cemented clay.
基金Supported by the National Basic Research Priorities Program (Grant No 2001CB409804)the National Natural Science Foundation of China (Grant Nos 10475093,10175076 and 40072068)
文摘The mineralization ages reported in the past in the Tuwu-Yandong copper district not only are different,but also fall into the Hercynian epoch.This study has achieved 9 zircon and 7 apatite fission track analysis results.The zircon fission track ages range from 158 Ma to 289 Ma and the apatite ages are between 64 Ma and 140 Ma.The mineralization accords with the regional tectonics in the copper district.We consider that the zircon fission track age could reveal the mineralization age based on annealing zone temperature of 140―300℃ and retention temperature of ～250℃ for zircon fission track,and metallogenetic temperature of 120―350℃ in this ore district.Total three mineralization epochs have been identified,i.e.,289―276 Ma,232―200 Ma and 165―158 Ma,and indicate occurrence of the min-eralization in the Indosinian and Yanshan epochs.Corresponding to apatite fission track ages,the three tectonic-mineralizing epochs are 140―132 Ma,109―97 Ma and 64 Ma,which means age at about 100℃ after the mineralization.The three epochs lasted 146 Ma,108 Ma and about 100 Ma from ～250℃ to ～100℃ and trend decrease from early to late.It is shown by the fission track modeling that this district underwent three stages of geological thermal histories,stable in Cretaceous and cooling both before Cretaceous and after 20 Ma.
文摘利用卫星数据快速提取矿化岩性信息,是目前矿产资源勘查的重要技术手段之一。文章以新疆东天山土屋斑岩型铜矿区为研究区,基于该地区出露岩体相关矿物的可见光近红外波段(VNIR)至短波红外波段(SWIR)的光谱特征分析,对ASTER多光谱包括以热红外(TIR)波段在内的全谱域数据进行处理,分别采用主成分分析(PCA)、波段比值(BR)、矿物指数算法识别和提取了研究区地表侵入体的岩性信息。同时,对ASTER 15 m DEM数据进行E-W方向滤波处理,提取和解译出土屋矿区控矿断裂构造信息,结合岩性信息分析控矿条件。最后,对遥感信息提取结果分别进行了矿物镜下与野外验证。
