Cements, Waters, and Scales: An Integrated Study of the Szeged Geothermal Systems (SE Hungary) to Characterize Natural Environmental Conditions of the Thermal Aquifer

Figure 12

Inner structure of the thick carbonate scale (inner part of the sample G-03). The growth direction is marked by yellow arrows. (a) The scale precipitation begins with a thin (<500 μm) compact lamina composed of limpid, tightly packed fibrous or bladed crystals (F zone), following a relatively compact dendritic–botryoidal zone (B1 zone). (b) Dendritic and feather-like calcite generation in the B1 zone. (c, d) Spherical growth zones made up of dendritic and bladed crystals and subdivided by a thin, bright luminescent film. Note: B1/B2 boundary (an intermittent brownish stained layer) separates annual operational rhythms. Red arrow indicates a very thin brownish stained layer without luminescence. (e) Feather-like dendrites in the porous B2 zone. (f) Contact of a limpid, tightly packed zone, made up of fibrous crystals and a fine, tightly packed zone with turbid crystals in the compact B3 zone. Abbreviations: PPL = plane polarized light; CL = cathodoluminescence.

(a)

(b)

(c)

(d)

(e)

(f)