Inferring origin of mercury inclusions in quartz by multifractal analysis
Inferring origin of mercury inclusions in quartz by multifractal analysis
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DOI：
10.5194/npg-22-47-2015
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发表时间：
2015-01
影响因子：
2.2
通讯作者：
T. Shibata;T. Maruoka;T. Echigo
中科院分区：
文献类型：
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作者：
T. Shibata;T. Maruoka;T. Echigo
为了进一步了解流体包裹体是如何被捕获在寄主矿物中的，我们利用X射线计算机断层扫描（CT）技术对石英样品中的汞包裹体（液态Hg0）进行了非破坏性观察。X射线CT装置可以观察样品的内部结构，并从X射线穿过样品的透射中给出横截面图像。从剖面图像中获得了汞包裹体的三维空间分布，并利用分形和多重分形方法对其进行了定量分析。虽然样品来自不同的地质环境，但San Benito和Itomuka样品的所得分形维数分别为1.70和1.71。分形维数也接近那些由扩散限制聚集模型和渗流理论，这是由不可逆动力学控制预测。根据分维值及其机制，我们认为含汞流体不是原生流体包裹体，而是通过扩散作用进入石英晶体的原生裂隙中。
In order to refine our understanding of how fluid inclusions were trapped in the host minerals, we non- destructively observed mercury inclusions (liquid Hg 0 ) in quartz samples using X-ray computed tomography (CT) technique. The X-ray CT apparatus can observe internal structures of the samples and give cross-sectional images from the transmission of the X-rays through the sam- ples. From the cross-sectional images, we obtained three- dimensional spatial distributions of mercury inclusions, and quantitatively analyzed them using fractal and multifractal methods. Although the samples were from different geolog- ical settings, the resultant fractal dimensions were 1.70 and 1.71 for the San Benito and Itomuka samples, respectively. The fractal dimensions were also close to those predicted by diffusion-limited aggregation models and percolation theory, which are controlled by the irreversible kinetics. Given the fractal dimension and its implied mechanism, we conclude that the mercury-bearing fluids were not primary fluid in- clusions, but migrated into the pre-existing cracks of quartz crystals by diffusion processes.