Roof Thrust Geology

The floor thrust of the duplex lies at depth in a heterogeneous assemblage of rocks deformed in pre mississippian time.

Roof thrust geology.

Early thrusting was dominantly a downward foreland propagating sequence as the higher earlier thrust sheets are. Develop at the front of fold and thrust belts. 13b or towards the hinterland with the occurrence of backthrusts such as in the western sftb banks and warburton 1986 fig. Generally a thrust places older strata over younger strata so that the stratigraphic sequence is generally.

A thrust is a contractional fault that accommodates horizontal shortening of a datum surface normally bedding in upper crustal rocks or a regional foliation surface in more highly metamorphosed rocks. Sulfide minerals galena sphalerite and pyrite are concentrated and remobilized along a pressure solution cleavage that is well developed in zones of high strain. By varying thrust activity in three dimensions within an imbricate system local parts of roof thrusts can generate domains of overstep behaviour that have only local significance. Passive roof duplex underlying floor sequence is commonly referred to as passive roof thrusting.

In prd geometry the roof sequence remains relatively stationary being underthrust by a wedge shaped floor duplex while in ofp displacement along the floor thrusts is transferred horizontally along the décollement layer. The duplex is capped by a flat lying upper detachment roof thrust above which less shortening has been accommodated. The roof thrust lies near the base of the overlying mississippian and younger cover sequence in the mississippian kayak shale. In this fashion the duplex roof can cut up and down stratigraphic section mimicking an extensional fault.

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. 1 passive roof duplex prd geometry e g banks and warburton 1986 and 2 outward propagation of folding ofp along the décollement e g davis and engelder 1985. Horses were displaced to the north. In the northern oman mountains several major thrust sheets of tethyan oceanic rocks dibba zone and a 12km thick complete ophiolite sequence have been thrust westward onto the depressed arabian continental margin musandam zone during the turonian to campanian late cretaceous.

When a thrust that has propagated along the lower detachment known as the floor thrust cuts up to the upper detachment known as the roof thrust it forms a ramp within the stronger layer. Experimental results indicate that roof sequences exhibit two distinct styles of deformation. Shortening above the roof thrust was accommodated.