| 词条 | En echelon veins |
| 释义 |
In structural geology, en échelon veins or "en échelon gash fractures" are structures within rock caused by noncoaxial shear.[1] They appear as sets of short, parallel, planar, mineral-filled lenses within a body of a rock. They originate as tension fractures that are parallel to the major stress orientation, σ1, in a shear zone. They are subsequently filled by precipitation of a mineral, typically quartz or calcite. As soon as they form, they begin to rotate in the shear zone. Subsequent growth of the fracture therefore causes the vein to take on a sigmoidal shape. They can be used to determine the incremental kinematics of the deformation history of the rock. References1. ^{{cite book | first1 = G. H. | last1 = Davis | first2 = S. J.| last2 = Reynolds| title = Structural Geology of Rocks and Regions.| edition = 2nd | year = 1996 | isbn = 0-471-52621-5}} {{geology-stub}} 1 : Structural geology |
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