van Ruitenbeek Frank J A, Goseling Jasper, Bakker Wim H, Hein Kim A A
Department of Earth Systems Analysis, Faculty of Geo-Information Science and Earth Observation (ITC), University of Twente, Hengelosestraat 99, 7500 AA Enschede, The Netherlands.
Faculty of Electrical Engineering, Mathematics and Computer Science (EEMCS), University of Twente, Drienerlolaan 5, 7522 NB Enschede, The Netherlands.
Entropy (Basel). 2020 Jun 13;22(6):656. doi: 10.3390/e22060656.
Hydrothermal processes modify the chemical and mineralogical composition of rock. We studied and quantified the effects of hydrothermal processes on the composition of volcanic rocks by a novel application of the Shannon entropy, which is a measure of uncertainty and commonly applied in information theory. We show here that the Shannon entropies calculated on major elemental chemical composition data and short-wave infrared (SWIR) reflectance spectra of hydrothermally altered rocks are lower than unaltered rocks with a comparable primary composition. The lowering of the Shannon entropy indicates chemical and spectral sorting during hydrothermal alteration of rocks. The hydrothermal processes described in this study present a natural mechanism for transforming energy from heat to increased order in rock. The increased order is manifest as the increased sorting of chemical elements and SWIR absorption features of the rock, and can be measured and quantified by the Shannon entropy. The results are useful for the study of hydrothermal mineral deposits, early life environments and the effects of hydrothermal processes on rocks.
热液作用会改变岩石的化学和矿物学组成。我们通过一种新颖的香农熵应用方法，研究并量化了热液作用对火山岩组成的影响，香农熵是一种不确定性度量，常用于信息论。我们在此表明，根据热液蚀变岩石的主要元素化学成分数据和短波红外（SWIR）反射光谱计算出的香农熵低于具有可比原生组成的未蚀变岩石。香农熵的降低表明岩石在热液蚀变过程中发生了化学和光谱分选。本研究中描述的热液作用呈现了一种将热能转化为岩石中更高有序度的自然机制。更高的有序度表现为岩石化学元素和SWIR吸收特征的分选增加，并且可以通过香农熵进行测量和量化。这些结果对于热液矿床、早期生命环境以及热液作用对岩石影响的研究具有重要意义。
