Two clinoptilolites from genetically different volcanoclastic formations have been studied. Both deposits are located in the Logudoro region (North-Western Sardinia, Italy) within epiclastic and pyroclastic formations related to calcalkaline volcanic activity. Chemical characterization performed by electron microprobe analysis on both samples showed a quite similar composition ([Si/(Si+Al)] = 0.81/0.82), with the exception of some extra-framework cations. In particular the epiclastic clinoptilolites turned out to be much higher in Mg content (0.72 vs. 0.26 a.f.u.) and considerably lower in K (1.10 vs. 2.37 a.f.u.) than the pyroclastic clinoptilolites. Previous investigations evidenced a different behaviour of the two clinoptilolite samples towards cation exchange processes and a substantial difference between the theoretical and experimental CEC. In this frame, Rietveld refinements based on synchrotron data allowed to define a different cationic population within the four exchangeable cation sites.

This content is PDF only. Please click on the PDF icon to access.

First Page Preview

First page PDF preview
You do not have access to this content, please speak to your institutional administrator if you feel you should have access.