Литосфера (Oct 2016)
Block folding: experimental studies and practical significance
Abstract
Definition and description of a block folding model of rheological and tectonically stratified Earth crust deformation on the sections of horizontal uniaxial compression have been done. The main differences of block folding are listed, the major of which is a dividing of a crust by overlap oncoming falls to the blocks of the positive and negative curves, while retaining its quasi-plate state. In a negative block bending thickening occurs through the top of the crust, and in a positive block bending, on a contrary, due to the lower part of a crust. In a process of deformation stress transfer retains an ability to bark at a distance. Experimental researches of block folding with a use of sandy and clay-sand models have identified a number of characteristics of volumetric deformation of blocks. It’s turned out that both types of blocks in the long axis of ellipses on the lateral surface of the models form an opened up fan. This can be explained by material squeezing up out of folds’ cores, which creates a complex combination of deformation of pure and simple shifts, used in a gradient field of voltages. The brittle deformations in a zone of compression of a negative block bending prepare a wide space conjugated with the large faults. Subsequently, the faults are capable of playing the role of fluid channels and a free space is favorable for ore location. We can give an example of the Safjanovskoe ore deposit at the Middle Urals that is considered to be massive sulphide ore.
