Analysis of continent-scale geological maps

Geological maps are important products of geological work that display results of generations of field geologists’ work. Most original geological maps are generated and utilized at local scales. At regional scales, geological maps have gained in practical significance ever since William Smith’s 1815 geological map of England exemplified the powerful nature of mapping and correlating strata beyond local scales. However, by comparison, geological maps compiled at continental-scales appear to be of limited use outside of geological circles. Often, they are oversized which inhibits their practical use, so they decorate our geoscience hallways and lecture halls for their beautiful colors and their general esthetic appearance. Few outsiders can even read these maps. Their special color-coding, the multiple non-diverging color schemes and their complex legends further inhibit non-geologists from being able to recognize the enormous knowledge stored in these maps. I present an analysis of continent-scale geological maps by visualizing time not represented by the rock record (hiatus) and by examining the dimensions of hiatal surfaces at interregional scales. The maps yield great variability in dimensions and space-time patterns of hiatal surfaces, a behavior which is to be expected in light of interregional-scale processes induced by both, the plate and the plume mode of mantle convection. However, to test models of mantle convection rigorously, the temporal resolution of continent-scale maps must be increased to stages level, i.e., the scale at which tectonic processes take place.