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Full-Text Articles in Physical Sciences and Mathematics
Constraints On Unroofing Rates In The High Himalaya, Eastern Nepal, Mary S. Hubbard, L. H. Royden, K. V. Hodges
Constraints On Unroofing Rates In The High Himalaya, Eastern Nepal, Mary S. Hubbard, L. H. Royden, K. V. Hodges
Geosciences Faculty Publications
Thermobarometric data for samples across the Main Central thrust zone in eastern Nepal show an inversion in temperature but not in pressure. These data have been interpreted to represent a portion of the paleogeotherm at the time of Main Central thrust deformation. A 40Ar/39Ar age on hornblende (closure temperature (Tc)=500±50°C) constrains the timing of this deformation to be ∼21±0.2 Ma. The 40Ar/39Ar ages of other minerals (muscovite, Tc=350°C, age (t)=12.0±0.2 Ma; K-feldspar, Tc=220°C, t=8.0±0.2 Ma) from the same location further constrain the cooling history of this region. Together the geochronologic and thermobarometric data yield an average unroofing rate of 1.2±0.6 …
Hydrogeology Of Thrust Faults And Crystalline Thrust Sheets: Results Of Combined Field And Modeling Studies, Craig B. Forster, James P. Evans
Hydrogeology Of Thrust Faults And Crystalline Thrust Sheets: Results Of Combined Field And Modeling Studies, Craig B. Forster, James P. Evans
Geosciences Faculty Publications
Field, laboratory, and modeling studies of faulted rock yield insight into the hydraulic character of thrust faults. Late‐stage faults comprise foliated and subparallel faults, with clay‐rich gouge and fracture zones, that yield interpenetrating layers of low‐permeability gouge and higher‐permeability damage zones. Laboratory testing suggests a permeability contrast of two orders of magnitude between gouge and damage zones. Layers of differing permeability lead to overall permeability anisotropy with maximum permeability within the plane of the fault and minimum permeability perpendicular to the fault plane. Numerical modeling of regional‐scale fluid flow and heat transport illustrates the impact of fault zone hydrogeology on …