Ở một vài nơi khi mà đá gốc bị phủ bởi các tích tụ chưa cố kết có ý nghĩa quan trọng như các tầng sét tảng lăn, tích tụ thềm, hoàng thổ, hoặc chúng mang các đặc điễm quan trọng khác thì chúng cũng được thể hiện. | Mapping Geomorphological Environments Davis karstic evolution cycle. the movement of surface waters so that they flow into the deeper layers even quicker. The hydrographical network rivers and watergullies is periodically drained dry karstic valleys introducing a seasonal flow. Small karstic formations such as clints grikes and dolines begin to appear on the bare karstic relief. Groundwater is moving towards greater depths and karstic springs appear around the dissolvable carbonate rocks. PhaseIV At this phase cracks have been expanded and deepened considerably. The hydrographical networks lead to sinkhole systems and exhibit low and seasonal surface runoff. Instead of surface fluvial gullies the subterranean karstic network is intensely developed whereas some parts of hydrographical networks go out of use and are fossilised . Phase V In this phase along the gully beds in altitudes lower than those of sinkholes dolines appear. Former river mouths now emerge as hanging valleys. Blind valleys are formed. The subterranean karstic tubes of the subterranean rivers have already been considerably expanded and big subterranean caves have been formed. Phase VI This is the last evolutionary phase in karstic areas. This phase begins when in the blind valleys sinkholes appear and suppress the hydrographic networks underground flow thereby even the subterranean rivers becomes dry and fossilised . The adjacent dolines of the previous phase are now linked together and have become uvalas. The permanently humid and water saturated wet zone is now located deeper and in the nonsaturated dry zone continuous and dominant karstification takes place. Some caves roofs fall and so they open exposing the subterranean networks and karstic tubes to atmospheric processes. Phase VII In this phase karstification is interrupted. The surface karstic forms are transformed or are covered by newer sediments while the subterranean karstic forms passages and tubes are associated in more complex ones .
