GLOBAL ‘DIGITAL' CORRELATION OF MAJOR PENNSYLVANIAN CYCLOTHEMS FROM MIDCONTINENT U.S. TO RUSSIA AND UKRAINE

The succession of major Midcontinent Pennsylvanian marine cyclothems has been correlated with those in the Illinois and Appalachian basins and the north Texas shelf by means of the succession of similar conodont faunas in their highstand ‘core' shales. The long-standing difficulty of correlating Pennsylvanian strata globally among different faunal regions, where most conodonts appear to be provincial, is being resolved by using the few major cyclothems that had highstands when certain species achieved more global distribution than usual as primary tie-lines. In the late Desmoinesian—early Virgilian [late Moscovian—early Gzhelian] succession in the Midcontinent, these cyclothems are correlated by conodont species in common with certain cyclothems in Russia (Moscow Basin) and Ukraine (Donets Basin), and the remaining cyclothems fit ‘digitally' into the framework by position and scale. For example, late Desmoinesian Swadelina occurs in the major Altamont and Lost Branch cyclothems, in major Donets cyclothems N3/1 and N3/3, and in the major Voskresensk cyclothem in Russia. Below the Voskresensk, the major mid-Suvorovo cyclothem contains Streptognathodus subexcelsus, which occurs also in N3/1, thus allowing correlation of this succession of two major cyclothems among the three regions. Early Missourian S. cancellosus appears in the major Swope cyclothem and in the major Mid-Neverovo cyclothem in Russia. Above the Swope, S. confragus appears in the major Dennis cyclothem and in major Donets cyclothem O2. Combining these correlations lines up these two major cyclothems among the 3 regions [Swope—Mid-Neverovo—O1, Dennis—Upper-Neverovo—O2], and results in positional correlation of a similar number of cyclothems of similar scales between them and the Swadelina-bearing cyclothems below. Higher, in the early Virgilian, first appearance of Idiognathodus simulator [s.s.] allows correlation of the Oread cyclothem with the Upper Rusavkino cyclothem in Russia and Donets cyclothem O6, which results in positional correlation of a similar number of major cyclothems between this cyclothem and the two major lower Missourian cyclothems below. This procedure should lead to more precise global correlation of the Pennsylvanian, and perhaps ultimately to better calibration of the Pennsylvanian time scale.