Revealing the Mineralogical and Petrographic Signs of Fluid-Related Processes in the Kelebia Basement Area (Szeged Basin, S Hungary): A Case Study of Alpine Prograde Metamorphism in a Permo-Triassic Succession

Figure 8

Thin-section photomicrographs of the Permian ignimbrites: deformation textures ((a–c, e) well Kel–7 core #8; (d) well Kel–7 core #7; (f) well Kel–23 core #3). (a) Domino-type fragmented quartz porphyroclast (red arrow). (b, c) Mosaic fragmented quartz porphyroclast. Note: fragmentation is postdated by dolomite crystallization in the matrix. (d) White mica strain shadows around fragmented quartz porphyroclasts in a finer grained matrix (the section is normal to the foliation). (e) Elongated quartz strain shadow around a dolomite replacing an earlier feldspar phenocryst. Note: mechanical twinning in dolomite (red arrow). (f) Disjunctive foliation in a deformed ignimbrite sample (the trend of the cleavage domains is indicated by the yellow line; the section is normal to the foliation). Note: strain shadows are associated with strain caps. Abbreviations: XPL: cross-polarized light; Bt: biotite; Dol: dolomite; Ms: muscovite; Qz: quartz; Zrn: zircon.

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