GeoLines 16 (2003) 123 Introduction This filed trip focuses on fabrics and structures of phonolite and trachyte volcanic bodies of the České Středohoří Mts. Mesoscopic fabric patterns of three volcanic bodies are ac- companied by analysis of anisotropy of magnetic susceptibility (AMS) and electron back scattered diffraction study (EBSD) to discuss complex flow properties of magmas with contrast- ing viscosities. The fabrics of selected volcanic domes will be discussed in terms of their emplacement mechanisms, micro- structure development and geometrical boundary conditions controlling the magma flow. Since the pioneering work of Cloos and Cloos (1927) the mesoscopic fabrics of phonolitic domes have been studied in several European volcanic provinces (Cloos, 1935; Vabet, 1971; Jan čušková et al., 1992). However, the understanding of flow patterns was limited by applied methods as field mapping of macroscopically measurable fluidality and universal stage measurements. These studies allowed only to determine the flat- tening plane (XY) of the fabric ellipsoid but the flow axis (X) as well as the main kinematic flow plane (XZ) could have not been established. The universal stage measurements of crystal- DAY 1 Contrasting Flow Fabrics of Phonolite and Trachyte Domes and Implication to their Emplecement Mode: Example from České Středohoří Mts. – North Bohemia Jakub ŠMÍD, Karel SCHULMANN and František HROUDA Institute of Petrology and Structural Geology, Charles University, Albertov 6, 128 43, Czech Republic Fig. 1. Map of the Cenozoic volcanism in the České středohoří Mts. and distribution of sampling sites (see table 1).