State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, 163 Xianlin Avenue, Nanjing, 210023, China.
Electron Microscopy Laboratory, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China.
Sci Rep. 2020 Nov 17;10(1):19993. doi: 10.1038/s41598-020-76813-9.
Volume expansion reactions involved in mineral-fluid interactions are linked to a number of geological processes, including silicate weathering, retrograde metamorphism, and mineralization. However, the effect of volume expansion on replacement reactions remains unclear. Here, we demonstrate that reactions associated with volume expansion during the replacement of pyrite by chalcopyrite involve two competing processes. The reaction is initially augmented because of the development of reaction-induced fractures in the pyrite. However, these fractures are subsequently filled by compacted products, which ultimately disrupts the contact and interaction between bulk fluids and the pristine pyrite surface. These competing processes indicate that replacement reactions are both augmented and inhibited by volume expansion reactions during pyrite replacement.
体积膨胀反应与许多地质过程有关，包括硅酸盐风化、逆向变质和矿化。然而，体积膨胀对取代反应的影响尚不清楚。在这里，我们证明了在黄铁矿被黄铜矿取代过程中，与体积膨胀相关的反应涉及两个竞争过程。由于黄铁矿中反应诱导裂缝的发展，反应最初得到增强。然而，这些裂缝随后被压实产物填满，最终破坏了主体流体与原始黄铁矿表面之间的接触和相互作用。这些竞争过程表明，在黄铁矿被取代的过程中，体积膨胀反应既增强又抑制了取代反应。
