Unconformities are gaps in the geologic record within a stratigraphic unit. They are particularly significant as stratigraphic markers in petroleum geology. Modern excavation techniques are based on stratigraphic principles. Formal definitions of stratigraphic boundaries allow scientists in different locations to correlate their findings. Isopach maps detail the variations in thickness of stratigraphic units. Plays consist of stratigraphic traps mostly concentrated in the Central Basin Platform. Traps can be of two types&colon; stratigraphic or structural. Kanesh is the result of several superimposed stratigraphic periods. This variation in temperature makes the lake seasonally stratigraphic. This age largely corresponds with stratigraphic evidence using 4 different dating methods. In most sites there was an overlap of styles with no stratigraphic separation discernible. Instead thrust faults generally cause a thickening of the stratigraphic section. This is the stratigraphic method focusing on the minima representing a stratigraphic horizon. These first mines worked copper-filled fissure veins that cut across stratigraphic layers. The rocks formed during a period belong to a stratigraphic unit called a system.