Post on 02-Jan-2016
transcript
IntroductionFault-bend foldingFault-propagation foldingDetachment foldingBucklesFold-thrust complexes in multilayersTrishear
IntroductionFault-bend foldingFault-propagation foldingDetachment foldingBucklesFold-thrust complexes in multilayersTrishear
IntroductionFault-bend foldingFault-propagation foldingDetachment foldingBucklesFold-thrust complexes in multilayersTrishear
Fault-bend foldingFault-propagation folding
Panels of constant-dip strata, folds grow by hinge migration
“growth fans” ratherthan “growth trianglesare the usual style….
So are the fault-bendmodels applicable?
IntroductionFault-bend foldingFault-propagation foldingDetachment foldingBucklesFold-thrust complexes in multilayersTrishear
Structural styles in the Zagros…..Geomorphologic evolution suggests buckle sheet“detached” on Hormuz salt+ minor internal detachments
Geomorphological studies of developing folds using Landsat imagesfrom the Zagros Mountains, Iran. (Henry Lickorish)
IntroductionFault-bend foldingFault-propagation foldingDetachment foldingBucklesFold-thrust complexes in multilayersTrishear
Fold train initiatesIf one fold amplifies slightly faster…it will weakenSo strain transferred onto that fold - other folds slow down/stop.System experiences stress drop.
Viscosity ratio 10:1
Viscosity ratio 40:1
Longer wavelength (and lower diff stress) for higherviscosity contrast
Modelling fracture potential
and evolution
Timing might be crucial….Diagenetic “events”Fluid migration “events”
IntroductionFault-bend foldingFault-propagation foldingDetachment foldingBucklesFold-thrust complexes in multilayersTrishear
Thrust cuts through Ramp area folds Thrust breaks back
? continuum - localised slipplus distributed deformation
IntroductionFault-bend foldingFault-propagation foldingDetachment foldingBucklesFold-thrust complexes in multilayersTrishear