PROVENANCE OF MODERN SOILS OF MIDDLE TENNESSEE ASSESSED USING ACCESSORY MINERAL U-PB GEOCHRONOLOGY
Here, we estimate the proportions of these endmembers in soils from Middle Tennessee, which is mostly underlain by limestone bedrock, using zircon and monazite U-Pb age spectra and concentration ratios of immobile elements (e.g. Zr, Ti, Nb, and Ta) from analyses of soil-bedrock pairs and the potential endmember parent materials. No previous studies have attempted to recover accessory minerals from limestone for geochronology. The results give us a better understanding of the roles of loess and alluvium deposition and chemical weathering of limestone in soil development. In addition, age spectra of zircon or monazite within the limestone could potentially reveal sources of sediments deposited during limestone formation in the early to middle Paleozoic. We believe the new methods in this study could open up whole new areas of research, specifically application of accessory mineral geochronology for determining provenance of soils and the clastic portions of limestones.