Crack-jump mechanism of microvein formation and its implications for stress cyclicity during extension fracturing

摘要: Abstract It is well accepted and documented that faulting produced by the cyclic behaviour of a stress field. Some extension fractures, such as veins characterised crack-seal mechanism, have also been presumed to result from repeated cycles. In present note, some commonly observed field phenomena relationships hackle marks vein joint spacing, are employed argue can display during extensional fracturing. Indeed, requirement critical conditions for occurrence failure events does not accord with presence contemporaneously open nearby parallel fractures. Therefore, because after each fracture event there release within surrounding volume rock, high density sets fractures strongly support idea rocks undergo cyclicity jointing veining. A comparison seismological data earthquakes dipole mechanical solutions, confirms this process presently occurs at depth in Earth crust. Furthermore, order explain dense hair-like closely spaced microveins, crack-jump mechanism introduced here an alternative mechanism. We propose consequence medium-scale brittle deformation, re-fracturing rock mass either one or other these two possible ways depending on ratio between elastic parameters sealing material those host rock. The when former stronger.