The Xigeda formation is a set of interbreds comprised of halfconsolidated silt,fine sand and clay with clear lamination and total thickness of 300 m.It is dated to be the early Pleistocene and widespread distributed...The Xigeda formation is a set of interbreds comprised of halfconsolidated silt,fine sand and clay with clear lamination and total thickness of 300 m.It is dated to be the early Pleistocene and widespread distributed on the Quaternary planes of denudation and leveling.This formation has particular tectonic deformation as expressed by deformed belts confined to certain locations,which extend linearly over long distances.It also manifests itself as graben and horst sequences where fault planes are very straight.Various deformation styles,such as horizontal,vertical and oblique dislocations,normal,reverse and thrust faulting resulted in tilts of small blocks in different directions.The clay beds are intruded by underlying sand layers.Parallel ridges and depressions characterize the landscape.These phenomena of deformation are probably the result of intensive vibration of soil bodies during major earthquakes which caused instantaneous shear,compression and extension.The analysis of generation factors for such tectonic deformation provides a new approach for determination of areas with seismic risks,assessment of earthquake intensity and research of earthquake mechanisms.展开更多
In the analysis of some in-seam slip fold structures in the area of Xuzhou and Huaibei Districta it is noted that there exist some in-seam roof and footwall rock layers extremely incompatible to the existence of coal ...In the analysis of some in-seam slip fold structures in the area of Xuzhou and Huaibei Districta it is noted that there exist some in-seam roof and footwall rock layers extremely incompatible to the existence of coal seams. Some of them are tbe slip fold structures that are wedged into coal seam by folding, but all of them are passively generated by in-seam shearing forces. In this paper, a discussion is put forward of the damage to coal seams by slip folds and the coal mining significance resulted from the study of slip fold structures.展开更多
文摘The Xigeda formation is a set of interbreds comprised of halfconsolidated silt,fine sand and clay with clear lamination and total thickness of 300 m.It is dated to be the early Pleistocene and widespread distributed on the Quaternary planes of denudation and leveling.This formation has particular tectonic deformation as expressed by deformed belts confined to certain locations,which extend linearly over long distances.It also manifests itself as graben and horst sequences where fault planes are very straight.Various deformation styles,such as horizontal,vertical and oblique dislocations,normal,reverse and thrust faulting resulted in tilts of small blocks in different directions.The clay beds are intruded by underlying sand layers.Parallel ridges and depressions characterize the landscape.These phenomena of deformation are probably the result of intensive vibration of soil bodies during major earthquakes which caused instantaneous shear,compression and extension.The analysis of generation factors for such tectonic deformation provides a new approach for determination of areas with seismic risks,assessment of earthquake intensity and research of earthquake mechanisms.
文摘In the analysis of some in-seam slip fold structures in the area of Xuzhou and Huaibei Districta it is noted that there exist some in-seam roof and footwall rock layers extremely incompatible to the existence of coal seams. Some of them are tbe slip fold structures that are wedged into coal seam by folding, but all of them are passively generated by in-seam shearing forces. In this paper, a discussion is put forward of the damage to coal seams by slip folds and the coal mining significance resulted from the study of slip fold structures.
