Devonian Stragtigraphy and Conondont Biostratigraphy from Portions of Two Cores in Central Iowa, Dcember 1982

(1982) Devonian Stragtigraphy and Conondont Biostratigraphy from Portions of Two Cores in Central Iowa, Dcember 1982. University of Iowa

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Abstract

During a temporary employment period (May 16 - September 15, 1980) with the Iowa Geological Survey, two cores were examined in order to better establish the stratigraphic relationships between geologic units in the central part of Iowa and those in other parts of the state. The examined intervals of the Peterson #1 core from northeastern Webster County, and the Hummell #4 core from southwestern Dallas County, Iowa (Fig. 1) are shown to be primarily of late Middle to early Late Devonian age. The lowest part of the Peterson #1 core that was examined, however, was found to be Ordovldan. Nine lithologic units were recognized in the Peterson core. The Hummell #4 core is divided into 3 such units. In addition to lithologies each of these units was examined in terms of faunal content, deposltlonal environment, and biostratigraphy. Each of these criteria will be discussed separately for each unit of the two cores.