Passive Roof Thrust

Banks and warburton 1986 joined with the underlying body rides over the foreland.

Passive roof thrust.

2 a passive roof duplex requires two regionally active detachments that are kinematically linked in the foreland fig. Formation of the passive roof duplex and the symmetrical detachment folds in its roof may have been facilitated by relatively low shortening and the effectiveness of the kayak shale as a detachment horizon. A trust where the trustee is held accountable for additional responsibilities. On the contrary backthrusting occurs when the roof sequence decoupled from the underlying body is passively transported over the hinterland.

Experiments simulate many of the principal characteristics of fold and thrust belts developed above a basal evaporite décollement as well as the development of passive roof duplexes at mountain fronts. Develop at the front of fold and thrust belts. In this type of structure termed passive roof duplex by banks and g arburton 1986 the roof sequence the rocks lying above the passive roof thrust glides passively over. 57 43 ma man iobra formation in the eastern orocopia mountains fig.

A thrust emplaced roof is preserved locally above these folds indicating that they constitute a duplex of fault truncated folds. However active roof duplexes couzens and wiltschko 1996 do not strictly follow the geometric characteristics of triangle zones which have a hinterland verging passive roof thrust. I suggest that the fault was a northeast directed passive roof thrust that linked with a southwest directed basal décollement the vincent thrust during early tertiary flat subduction of the farallon plate beneath north america. Passive roof duplex underlying floor sequence is commonly referred to as passive roof thrusting.

With an active trust those additional responsibilities can be in respect to the control or management. Continuous thrusting results in shortening between the lower and the upper detachment and consequent formation of a duplex bound by two thrusts of opposite vergence. Lower to middle eocene ca. The central appalachian fold thrust belt is characterized by a passive roof duplex and as such the total shortening accom modated by the sequence above the roof thrust must equal the shortening.

Above the roof thrust the shortening is accommodated in different ways. Extruded thrust sheet is bounded at top by orocopia chocolatefault ocf acting as a passive roof thrust. This model may also explain a similar structural relationship between the main central thrust and the south tibet. An overstep passive roof thrust sakhwal fault is interpreted west of dhurnal which developed due to southward progression of the deformation front beneath the earlier passive roof thrust.

The passive roof thrust crops out just north of dhurnal on the steep northern limb of the soan syncline.