22 August, 2015
Paper: Dolomite formation in non-marine bentonite deposits
On August 6th the first of three publications that are a part of my doctoral research was finally published online in the Clay Minerals Journals at GSW (alternatively via ingentaconnect - abstract also available on RG). The study explores the role of authigenic carbonate formation during bentonitization. We used a combination of X-ray diffraction, micromorphology (based on thin-sections and SEM) and stable isotope analysis to investigate bentonite-associated dolomite and calcite formation.
Bentonites in the Upper Freshwater Molasse formed from practically Ca- and Mg-free, calc-alkaline, rhyolitic air-fall tuffites. The presence of abundant authigenic dolomite (one deposit is capped by 1 m thick dolomite horizon) was a major surprise, and we extensively used XRD to confirm the mineralogical composition. The combination of methods enabled us to distinguish both dolomite-rich and calcite-rich pedogenic, palustrine and groundwater facies within bentonite deposits. The figures taken from the paper illustrates some of the carbonate microfabrics.
M. H. Köster and H. A. Gilg (2015) Pedogenic, palustrine and groundwater dolomite formation in non-marine bentonites (Bavaria, Germany) Clay Minerals, June 2015, v. 50, p. 163-183, published online August 6, 2015, doi:10.1180/claymin.2015.050.2.0