Arterial faults and their role in mineralizing systems
| Autor: | Richard H. Sibson |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
010504 meteorology & atmospheric sciences
Continental crust Hydrostatic head lcsh:QE1-996.5 Crust Active fault 010502 geochemistry & geophysics 01 natural sciences law.invention lcsh:Geology law Fluid dynamics Shear stress General Earth and Planetary Sciences Hydrostatic equilibrium Shear zone Petrology human activities Geology 0105 earth and related environmental sciences |
| Zdroj: | Geoscience Frontiers, Vol 10, Iss 6, Pp 2093-2100 (2019) |
| ISSN: | 1674-9871 |
| DOI: | 10.1016/j.gsf.2019.01.007 |
| Popis: | In quartzo-feldspathic continental crust with moderate-to-high heat flow, seismic activity extends to depths of 10–20 km, bounded by isotherms in the 350–450 °C range. Fluid overpressuring above hydrostatic in seismogenic crust, is heterogeneous but tends to develop in the lower seismogenic zone (basal seismogenic zone reservoir = b.s.z. reservoir) where the transition between hydrostatically pressured and overpressured crust is likely an irregular, time-dependent, 3-D interface with overpressuring concentrated around active faults and their ductile shear zone roots.The term Arterial Fault is applied to fault structures that root in portions of the crust where pore fluids are overpressured (i.e. at > hydrostatic pressure) and serve as feeders for such fluids and their contained solutes into overlying parts of the crust. While arterial flow may occur on any type of fault, it is most likely to be associated with reverse faults in areas of horizontal compression where fluid overpressuring is most easily sustained. Frictional stability and flow permeability of faults are both affected by the state of stress on the fault (shear stress, τ; normal stress, σn), the level of pore-fluid pressure, Pf, and episodes of fault slip, allowing for a complex interplay between fault movement and fluid flow. For seismically active faults the time dependence of permeability is critical, leading to fault-valve behaviour whereby overpressures accumulate at depth during interseismic intervals with fluid discharged along enhanced fault-fracture permeability following each rupture event. Patterns of mineralization also suggest that flow along faults is non-uniform, concentrating along tortuous pathways within the fault surface.Equivalent hydrostatic head above ground level for near-lithostatic overpressures at depth ( |
| Databáze: | OpenAIRE |
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