A map that shows the restored thicknesses of rocks is called a palinspastic map 

 (fig. 24-45). 



Figure 24-42 shows an isopach map of a series of limestones and dolomites. 

 Uplifts on which none of the sediments are present occur in the northwest and 

 northeast quadrants. From the constant rate of thickening into the basinal 

 regions, it can be inferred that the uplift in the northwest predates the sediments 

 represented by the isopach contours, or that erosion has been uniform over the 

 entire region. The axis of this uplift extends far to the southeast from the 

 granite area. The contours tell a different story about the uplift in the northeast 

 quadrant. The extremely high rate of thinning along the flanks and the abrupt 

 termination of the axis show that the sediments were truncated and probably 



Figure 24-42. Isopach map showing reconstruction of thickness contours 

 over a young, truncated uplift. 



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