The Kentland Dome is an enigmatic, thought-provoking, structurally complex anomaly, subsequently covered by glacial drift, in an area surrounded by normal, undisturbed, flay-lying Paleozoic strata. Rocks in thecore of the Kentland structure havebeen uplifted more than 2,000 ft (610 m), folded into a structural dome, and intricately disrupted by faulting. A significant portion of the Ordovician central core is revealed in the spectacular Kentland Quarry. One must see the quarry and its superb rock exposures that challenge the imagination to grasp the magnitude of the anomaly and complexities of its structural pattern.
The oldest quarries at Kentland (McKee and Means) date from more than 100 years ago. Since that time, generations of geologists, applying the scientific method to the exposures in the continually expanding quarry, have built a case history on the evolution of thought to the origin of this unusual structure. The problem has been, and remains, to explain this geometic jigsaw puzzle with respect to its spatial pattern, chronology of disruption, and genesis of deformational mechanics. For example, shatter cones and their orientations in the Kentland Quarry inspired Dietz (1947, 1972) to suggest a meteorite-impact origin simply because the cone apices point upward upon reconstruction of the strata to their normal, flat-lying position. Are Dietz, and other devotees of extraterrestrial origin, correct? Or are there plausible alternative endogenetic explanations?
References to significant developments of the quarries at Kentland and in thought on the origin of the structure can be found in various annual reports
Figures & Tables
North-Central Section of the Geological Society of America
One hundred field guides, with area maps, to locations in Illinois, Indiana, Iowa, Michigan, Minnesota, Missouri, Nebraska, Ohio, and Wisconsin.