Journal of Petroleum Geology, Vol.16, No.2, pp. 223-236, 1993

©Copyright 2000 Scientific Press, Ltd.

HYDROCARBON POTENTIAL OF SANDSTONE RESERVOIRS
IN THE EAST SLOVAKIAN BASIN,
PART 2: ZEOLITES AND CLAY MINERALS

J. K. Reed*, M. Gipson, Jr.** and D. Vass***

* Earth Sciences and Resources Institute, University of South Carolina.

** Department of Geological Sciences, University of South Carolina, Columbia. South Carolina 29208, USA.

*** Dionyz Stur Geological Institute, Mlyska dolina 1, 817 04 Bratislava, Slovakia.

Abstract

Zeolites and authigenic/diagenetic clay minerals in Neogene sandstones of the East Slovakian Basin are closely related to the presence of locally-abundant tuffs and tuffaceous sediments. In tuffs, plagioclase crystals, glass shards, and volcanic rock fragments alter to zeolites and clay minerals. In sandstones, zeolites are formed both from the direct alteration of volcanic rock fragments, and as authigenic pore-filling minerals; clay minerals occur as diagenetic products of both volcanics and feldspars. Zeolites present include erionite, clinoptilolite, mordenite, analcime, and minor offretite, phillipsite, and laumontite. Authigenic/diagenetic clay minerals include smectite, illite, chlorite, and kaolinite. Vertical and lateral distributions of authigenic/diagenetic mineral assemblages tend to follow published models. A complete paragenetic model of the occurrences of these minerals within the basin is not currently possible with the present, limited database.