Impact of Conjugated Shear Joint of“X”Type on Macroscopic Karstification on the Basis of the Analysis of Google Earth Images

摘要

As viewed from space remote-sensing images(e.g.Google Earth images) of South Guizhou and North Guangxi,the authors found that macroscopic karst landscape on the Earth's surface is strongly controlled by the Conjugated shear joint of "X" type.Joints of this kind constitute a huge infiltration network and act as channel-ways for the permeation of meteoric waters from the surface,thus,leading to the dissolution of carbonate rocks nearby.As a result,the karst landscape is formed,which is dominated by linear karst valleys.An "X" karst valley network structure appears in the area where horizontal strata are distributed,and a feather-like network structure appears in the area where vertical strata are distributed,respectively.When the water permeates downwards to the underground-water level,it will flow horizontally along the strike of "X" joints toward the local base level of erosion to form an "X" network system of underground conduits in the area where horizontal strata are distributed,but it is relatively complex,because of the joining of other joints.This is the first time we have made use of Google Earth images to study the karst environment.Therefore,it has been successful in research on the Earth's geomorphology,which could only rely on aerial photos and satellite photos in the past.Google Earth images provide low-cost and applicable imaging materials for the study of Earth's geomorphology and karst rocky desertification and its control.