DIAGENETIC HISTORY OF SEDIMENTARY CARBONATES - CONSTRAINTS FROM COMBINED CATHODOLUMINESCENCE AND TRACE-ELEMENT ANALYSES BY MICRO-PIXE

Trace element data for a succession of cements can contribute to the r econstruction of the diagenetic history of sediments. In the case of c arbonate cements, cathodoluminescence (CL) microscopy has been success fully utilized for qualitative description of different cementation en vironments. In order to interpret correctly CL colour, trace element d ata other than Mn and Fe are often required. Due to frequent microscal e zonation of trace elements in natural calcites and due to their low threshold concentration for CL activation, microsampling techniques wi th high spatial resolution and low detection limits are required. In t his case study, trace element concentrations have been correlated with the CL behaviour of carbonate cements using the Bochum proton micropr obe (PIXE) and a hot cathode luminescence device. The CL patterns, inc luding the fine zonation, correlate well with the trace element distri bution.