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 9

Thin-section photomicrographs of Lower Triassic sandstones showing a mature composition of quartz arenite (well Móra–1 core #17). (a–d) Rounded framework grains and accessory minerals. Notice the line of inclusions marked by yellow arrows showing the original grain boundary. Quartz grains and overgrowths are frequently replaced by microcrystalline silica. Sets of parallel microcracks marked by fluid inclusion plains also occur. (e, f) Overgrowth cement is postdated by silica and carbonate replacement. The original grain boundaries are visible as lines of tiny inclusions (yellow arrows). Note: deformation lamellae in quartz (red arrow). Abbreviations: PPL: plane-polarized light; XPL: cross-polarized light; FIP: fluid inclusion plain; Cb: carbonate; Lv: volcanic lithic fragment; Mc: microcline; Tur: tourmaline; Qm: monocrystalline quartz; Qp: polycrystalline quartz; Zrn: zircon.

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