Geological Research at the IGS
Chemostratigraphy of the Borden Group utilizing pXRF technology
||Dec 7, 2015
||Jun 30, 2016
Indiana University - Indiana Geological & Water Survey
||The Mississippian Borden Group is characterized by thick sequences of deltaic shale, siltstones, and sandstones that are difficult to differentiate and correlate. The biostratigraphy of this interval is little studied and thus chronostratigraphic correlation is lacking. Further, this interval contains phosphate horizons and other chemical sedimentary rocks whose composition is little known, but demonstrate the potential to pose a significant danger to ground water quality. To resolve this major gap in our ability to accurately predict the distribution, and utilizing major and minor element analysis via portable X-Ray Fluorescence (pXRF), define stratigraphic changes in elemental composition and differentiate element signatures that reflect local depositional environments from those reflecting more widespread changes in ocean chemistry (i.e., those that cross-cut local environments).
||Hypothesis: Correlation at the member-level can be enhanced by incorporating chemostratigraphy with the traditional applications of lithostratigraphy and geophysical logs. Analyses can be utilized to facilitate correlations or to prioritize more intensive analyses utilizing destructive techniques such as XRD or thin sectioning.
||This approach will quickly, accurately, and precisely quantify elemental variation in stratigraphy of cores, cutting, and outcrops.
||IGS Report of Progress; contribution to the STATEMAP mapping efforts in Morgan County.
||Determination of the utility of incorporating chemostratigraphy (via pXRF) can serve as a complement to other tools in stratigraphic correlation.