Interior Cratonic Basins

Interior Cratonic Basins, a product for the World Petroleum Basins series of the American Association of Petroleum Geologists (AAPG), was approved in 1984 and initiated in early 1985.¹ Contributors undertook to provide useful geologic information on the regional setting, stratigraphy, structure, tectonics and basin evolution, and oil and gas systems of seven cratonic basins.

A detailed overview of the Illinois basin, selected by the AAPG ad hoc committee as a representative type (see Foreword), is followed by less detailed reviews of six other selected interior cratonic basins: the Williston, Michigan, Baltic, Paris, Parana, and Carpentaria basins. The goal is to develop a better understanding of the basin-forming, basin-filling, and basin-modifying processes that control hydrocarbon plays and resultant oil and gas fields in this class of basins. The idea is to describe and document the variations, opportunities, and exploration problems that can be expected.

We selected seven basins, productive and nonproductive, from four continents (Figure 1): five basins formed on Precambrian crust (Illinois, Michigan, Williston, Baltic, and Parana basins); one formed on accreted Paleozoic crust (Paris basin); and one formed on Paleozoic and Proterozoic volcanics and sediments and Proterozoic metamorphic rocks (Carpentaria basin). Some are rift related; some are not.

Information from other interior cratonic basins balances the coverage. At the conclusion of the introduction, a selection of paleogeographic maps is presented for later reference throughout the volume on the time, place, and setting of the seven basins. We conclude the volume with a section on interiorcratonic basins and their place in the scheme of global tectonics, and an epilogue highlights what we know and what we still do not know about these basins.

Craton and cratonic (Sloss and Speed, 1974) have been difficult to define. The word craton was originally used by Stille (1936, 1941) in the sense of a strong unyielding buckler or shield (Sloss, 1998a). Presumably, the immobile shield was circumscribed by peripheral miogeosynclines. Kay (1947, 1951) recognized bounding flexures, the "Wasatch line" and "Adirondack line," which marked the western and eastern inboard limits of the North American miogeosynclines and defined the broad stable region between the flexures as the craton. Miogeosynclines faded out of vogue when it was recognized that the wedges or prisms of sediments associated with them are a consequence of deposition on subsident continental margins (Sloss, 1988a). This recognitoin left in limbo the definition of cratons and what IS or is not cratonic or extracratonic.