Dike Growth and the Transition to Diapirism in Cracking, Flowing Rock

众所周知，当流体物质（岩浆、水、盐等）通过时，深部岩石会以一种（或两种）韧性或脆性的方式发生变形。从经验上看，寄主岩石与流动流体的粘度对比越大，在狭窄的裂缝和岩脉中发现流体的可能性越大，在底辟岩和井中发现流体的可能性越小。虽然这一观察结果直观地吸引人，但迄今为止，在确定可能或可能发生岩脉侵入的地质制度时，很少有人努力量化宿主/流体粘度对比的作用。PI将研究岩脉/底辟过渡，将岩脉作为粘弹性寄主岩石中扩展的充满流体的裂缝。其结果除了具有一般的地质学意义外，还应特别适用于若干重要的问题和过程。这些问题包括花岗岩和蛇纹岩体沿断层的浮力上升，岩体/地壳粘度对比是否使得花岗岩可以通过断裂和流动的组合上升，其速度比斯托克流溶液更快（因此在冻结前穿过更多的地壳），在分裂（裂谷）岩石圈块体之间浮力软流层上涌。

It is well established that rock at depth can deform in either (or both) a ductile or brittle fashion in response to the passage of a more fluid material (magma, water, salt, etc.). Empirically, the greater the viscosity contrast between the host rock and the fluid moving around, the more likely one is to find the fluid in narrow cracks and dikes, and the less likely one is to find it in diapirs and plutions. Although this observation is intuitively appealing, as yet there has been little effort to quantify the role of host/fluid viscosity contrast in determining the geologic regimes under which dike intrusion is likely or possible. The PI will study the dike/diapir transition be treading dikes as propagating, fluid-filled cracks in viscoelastic host rock. The results, in addition to being of general geologic interest, should find particular application to a number of important questions and processes. These include the buoyant rise of granitic and serpentinite bodies along faults, the question of whether pluton/crustal viscosity contrasts are such that granities can ascend via a combination of fracture and flow, at rates greater than that of the Stoke's flow solution ( and hence traverse more of the crust before freezing), and the upwelling of buoyant asthenosphere between diverging (rifting) lithospheric blocks.