Increasing refinement in contemporary biostratigraphic and geochronologic correlation allows critical testing of space-time relations of regional disconformities within and between large marine sedimentary basins. This is especially true in the Cretaceous Period, where global correlation is possible within 0.5 m.y. or less time/biostratigraphic units. The most critical questions posed by regional disconformities are: (1) their mode of origin, and especially whether or not they reflect regional tectonic/sedimentologic or global eustatic controls; and, (2) their temporal relations--are they regionally diachronous, with minimal correlation value, or synchronous, reflecting global factors?

Regional Cretaceous disconformities are numerous, well studied, and precisely dated in both Europe and North America, providing an opportunity to test various hypotheses concerning their origins. They are most commonly reflected by: (1) mature hardgrounds; (2) broadly erosional disconformities; (3) lag deposits and calcarenites, in some places overlying hardgrounds or erosion surfaces; (4) paraconformities and sediment bypass surfaces identifiable by biostratigraphic/geochronologic gaps; and (5) sharp, flat erosional surfaces truncating the tops of large progradational sequences in areas of highly active sedimentation. An intercontinental test shows precise correlation of many Cretaceous disconformities regardless of type (1 to 5 above) between the Western Interior and coastal plains f North America, and the carbonate platform/shelf facies of central and western Europe, proving a eustatic origin (stillstand events). Most such regional disconformities occur during punctuated eustatic rise (transgression).

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