Middle miocene zeolite-bearing turbidites, abràmut basin (Pannonian basin), NW Romania

Abstract

Detailed litho strati graphic data from a borehole in the Abràmut Basin, located in the northwestern part of Romania, has revealed the presence of turbiditic deposits containing several layers with tuff/tuffaceous materials in the lower Badenian. The age of these deposits is determined by the presence of the foraminifera Praeorbulina glomerosa and Orbulina suturalis. Detailed quantitative and qualitative X-ray diffraction data (XRD) on 10 different tuff layers situated at depths between 2450 and 2640 m show a mineralogical association comprising analcime, quartz, volcanic glass, smectite, mica, calcite, K-feldspar, glass and minor quantity of chlorite and albite. The presence of analcime suggests that the albite isograd for the interval studied has been never reached and the maximum temperatures have been lower than c. 125°C since the early Badenian.