The mechanisms and time scale of alteration halos in vein-type tungsten deposits in southern China
The mechanisms and time scale of alteration halos in vein-type tungsten deposits in southern China
复制标题
中国南方脉型钨矿床蚀变晕的机制和时间尺度
DOI：
10.1016/j.oregeorev.2017.07.024
复制
发表时间：
2017-10
影响因子：
3.3
通讯作者：
Zhang Dehui
中科院分区：
文献类型：
--
作者：
Liu Xiangchong;Xing Huilin;Zhang Dehui
蚀变晕是岩石中热液流动留下的指纹，表明成矿过程。中国南方的南岭山脉是世界级的钨矿省。然而，人们对为什么该地区许多钨矿床的正常矿脉蚀变晕随着深度的增加以及形成晕所需的时间而减少的原因知之甚少。进行了基于有限元的数值实验，以研究钨矿床中从裂缝到邻近围岩的热液流动和物质扩散过程。蚀变晕的垂直分布受围岩孔隙度、裂缝渗透率和裂缝中热液流动持续时间的影响。当热液向上流动时，当围岩在一公里左右的深度内具有恒定的孔隙度时，在更深的层面上会形成更宽的蚀变晕。这与我国南方钨矿床蚀变晕特征不符。当围岩孔隙度随深度增加而减小时，钨矿床中可能会形成蚀变晕。钨矿床的硅化和灰岩化可能需要数十年至数千年的时间才能形成。这样一个周期比现有等时年龄的不确定性要短得多，并且可能代表矿化脉冲的持续时间，而不是与钨矿化相关的所有地质事件。钨从裂缝向邻近围岩的扩散无法在如此短的时间内产生大规模的浸染式钨矿化。
Alteration halos are the fingerprints left by hydrothermal flow in rocks and indicative of ore forming processes. The Nanling Range in southern China is a world-class tungsten province. However, it is poorly understood why alteration halos normal to veins in many tungsten deposits in the area decrease with increasing depth, and the time it takes to form the halos. Finite element based numerical experiments were conducted to investigate hydrothermal flow and species diffusion processes from fractures to adjacent wallrock in the tungsten deposits. The vertical distribution of alteration halos is influenced by wallrock porosity, fracture permeability, and the duration of hydrothermal flow in fractures. When hydrothermal fluids flow upwards, wider alteration halos are formed at deeper levels, when the wallrock has a constant porosity for a depth of around one kilometre. This is inconsistent with the characteristics of alteration halos in the tungsten deposits in southern China. Alteration halos in the tungsten deposits could be formed when the wallrock porosity decreases with increasing depth. The silicification and greisenization of the tungsten deposits could form over a period from tens of years to a few thousand years. Such a period is much shorter than the uncertainties of existing isochronal ages and may represent the duration of mineralizing pulses rather than all the geological events associated with tungsten mineralization. Tungsten diffusion from fractures to adjacent wallrock cannot produce large-scale disseminated tungsten mineralization during such a short period of time.
登录
查看更多内容
DOI：
10.2113/gsecongeo.92.7-8.766
发表时间：
1997-11-01
期刊：
ECONOMIC GEOLOGY AND THE BULLETIN OF THE SOCIETY OF ECONOMIC GEOLOGISTS
影响因子：
--
作者：
Cathles, LM;Erendi, AHJ;Barrie, T
通讯作者：
Barrie, T
影响因子：
4.8
作者：
Wen-Feng Wei;R. Hu;X. Bi;Jian‐tang Peng;W. Su;Shengqiong Song;Shaohua Shi
通讯作者：
Wen-Feng Wei;R. Hu;X. Bi;Jian‐tang Peng;W. Su;Shengqiong Song;Shaohua Shi
影响因子：
5.8
作者：
A. Campbell;D. Rye;U. Petersen
通讯作者：
A. Campbell;D. Rye;U. Petersen
影响因子：
3.3
作者：
Wenlei Wang;Jie Zhao;Q. Cheng;E. Carranza
通讯作者：
Wenlei Wang;Jie Zhao;Q. Cheng;E. Carranza
影响因子：
3.9
作者：
H. Xing
通讯作者：
H. Xing