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Zeolites and zeolite rocks are commonly used in different industrial applications. Natural zeolites present an attractive material for environmental applications because of their high abundance, availability and low costs. Depending on geological settings and conditions during mineral formation, natural zeolite deposits usually represent a heterogeneous mixture of zeolite minerals together with varying amounts of gangue minerals (e. g. quartz, feldspars and phyllosilicates). Hence, profound mineralogical knowledge and a detailed characterization of natural zeolites are essential for tapping their full potential in any practical application. However, this is rarely done as detailed mineralogical characterizations are elaborate and often neglected in favour of bulk chemical analyses (e. g. XRF). In this paper we describe typical technical applications for natural zeolites as well as the requirements demanded for their use. An analytical protocol has been developed for the detailed characterization of natural zeolites for ammonium exchange consisting of a combination of mineralogical and chemical methods and is exemplarily demonstrated. The methodology comprises mineralogical investigations with X-ray diffraction (XRD) and electron microprobe analyses (EPMA) to provide qualitative data on mineral compositions and in-situ analysis of mineral chemistry (Si/Al-ratio, cation contents). The examinations are accompanied by bulk chemical analysis (XRF) as well as thermoanalytical investigations (TG/DSC) to distinguish between certain zeolite minerals. Finally, ion exchange experiments for ammonium have been carried out to determine the cation exchange capacity (CEC) of zeolite samples for a defined range of concentrations.The aim of the study is to develop an analytical routine in order to enable the detailed characterization of natural zeolite samples with standardized means of mineralogi-

This is especially true for some of the Irish (e.g., Navan) and Alpine (e.g., Bleiberg; Schroll, 1997) examples. One neglected aspect in the study of carbonate-hosted Pb-Zn deposits is the role of microbial processes in their formation, a topic that started to attract the general interest of economic geologists only recently (e.g., Southam and Saunders, 2005). Most evidence for the involvement of microorganisms in the formation of carbonate-hosted Pb-Zn deposits is based on sulfur isotopes. Strongly negative sulfur isotope compositions of sulfides are commonly regarded as evidence for BSR (e.g., Fallick et al., 2001; Bawden et al., 2003). Microtextural evidence for the involvement of bacteria in the mineralization process is rare. Sulfide microglobules interpreted as biogenic peloids have, however, been reported from carbonate-hosted Pb-Zn deposits in Ireland (Kucha, 1988; Kucha et al., 1990) and the Upper Silesian MVT deposits in Poland and Belgium (Kucha and Viaene, 1993). In this study we present nano-to macrotextural and sulfur isotope evidence supporting the hypothesis that microorganisms

In the Huckitta region of the eastern Arunta Inlier, central Australia, two terrains with distinct metamorphic histories are separated by a zone of sinistral strike-slip mylonitic deformation and reworking, the Entire Point Shear Zone (EPSZ). To the south of the EPSZ, in the Harts Range Group, Ordovician (c. 470 Ma) intraplate granulite facies metamorphism (c. 800°C, 8-10 kbar) was followed by decompression to c. 7 kbar. In contrast, the Kanandra Granulite, to the north of the EPSZ, is characterized by Palaeoproterozoic high-grade metamorphism at 770-850°C and 5-7 kbar, followed by inferred near-isobaric cooling. Juxtaposition of these terrains along the EPSZ occurred at upper amphibolite facies conditions (700°C, 7 kbar), and resulted in extensive reworking of the Kanandra Granulite. Monazite growth within EPSZ mylonites is dated at 445-4-5