Consortium for continental reflection profiling Michigan surveys: Reprocessing and results

Abstract

Reprocessing of Consortium for Continental Reflection Profiling data from central Michigan, with emphasis on deconvolution and velocity filtering before stack and more detailed velocity analysis, has resulted in greatly improved imaging of a previously reported Keweenawan rift buried beneath the Paleozoic of the Michigan Basin. The seismic stratigraphy of the sub‐Paleozoic units can now be related to the basin‐filling Middle Keweenawan volcanic sequence and the Upper Keweenawan clastic assemblage in greater detail. Important structural and stratigraphic features can be seen for the first time. For example, reprocessing has imaged an unconformity within the Upper Keweenawan. It is possible some of these newly imaged features are associated with a late Keweenawan compressive episode. Furthermore, reprocessing also reveals previously unrecognized sub‐Keweenawan structures, including a deeply penetrating reflection which may represent a major crustal fault, and possible weak reflections from midcrustal (25 km) and Moho (43 km) depths.