Research progress of fibrous layered veins

Fibrous layered veins often appear in shale and carbonate formations. The for-mation mechanism and the formation of cone-shaped structures in them are of great significance to the diagenetic sedimentary environment of surrounding rocks and the geological history of surrounding rocks. In the past, scholars gen-erally used the fracture closure mechanism to explain the formation process of fibrous veins. However, with the discovery of anti-axial tensile veins, the frac-ture mechanism cannot fully explain its causes. Therefore, it is necessary to fur-ther explore the formation mechanism of fibrous veins. Based on previous stud-ies, this paper collected and analyzed the literature related to fibrous veins, and comprehensively described and analyzed the research status, crystal structure classification, material migration mechanism and different genetic interpreta-tion types. It provides a comprehensive understanding of the formation mecha-nism of different types of fibrous veins. It also provides an important reference value for understanding the origin and evolution process of fibrous veins and cone-in-cone structures in the formation. At the same time, this paper summa-rizes and analyzes that the crystal morphology of many fibrous veins cannot be explained by the classical crystal growth theory. Some recent studies have also shown that veins can be formed without rupture. Under the mechanism of diffu-sion and mass transfer, crystal growth forces the separation of surrounding rock and may form unruptured veins.