Illinois Basin ultradeep drillhole



Throughout the Phanerozoic, the depocenter of the Illinois Basin has remained at or above the intersection of the Reelfoot Rift, the Rough Creek Graben, the Cottage Grove Fault System, and the Wabash Valley Fault System. A proposed Illinois Basin Ultradeep Drillhole (IBUD) (Figure 1) will explore the crustal processes that resulted in the deposition of 400,000 km3 of sediment in this mid-continent region of the North American plate.

At a workshop held April 1–4, 1986, in Champaign, Ill., more than 120 geologists, geochemists, geophysicists, and drilling engineers addressed the scientific and economic significance of IBUD and prepared a draft science plan to be incorporated in a later formal proposal. The science plan includes the experiments, expected results, and scientific justifications for investigations of basement age, composition, and evolution; tectonics and structure; rock mechanics; basin analysis, hydrogeology, and brine geochemistry; geophysics and seismology; and hydrocarbon and ore deposit studies in IBUD.