Creation of Secondary Porosity in Dolostones by Upwelling Basement Water in the Foreland of the Alpine Orogen

Figure 15

(a, c) Calculated δ¹⁸O signatures of calcite and saddle dolomite parent-waters and (b, d) fluid inclusion salinities plotted against corresponding strontium isotope ratios of the secondary calcite and saddle dolomite (SD) in the Muschelkalk. The ranges in fluid inclusion salinity reflect different generations of primary fluid inclusions, whereas the strontium isotope ratio reflects a bulk value. Accordingly, the values at the high salinity end of the horizontal bars are likely to show lower strontium isotope ratios than the values at the low salinity end of the bars (black arrows). The grey areas represent mixing trends calculated for two infiltration scenarios outlined in Section 2.3 and 5.: (a, b) recharge of meteoric runoff in the Black Forest Highlands (BFH) and lateral infiltration of the Muschelkalk in the Swiss Molasse Basin and (c, d) infiltration of deep groundwater from the Buntsandstein (Bsst) and/or the crystalline basement (CB) via fluid ascent along faults or fractures (Figure 5).

(a)

(b)

(c)

(d)