Detailed Fluid Inclusion and Stable Isotope Analysis on Deep Carbonates from the North Alpine Foreland Basin to Constrain Paleofluid Evolution

Table 4

Hydrochemical data from the deep wells showing a dilution of the Jurassic seawater from the St. Gallen well [61], Geretsried, Unterhaching, and the most diluted formation water at the Traunreut well.

Parameter	Jurassic seawater		St. Gallen		Geretsried		Unterhaching		Traunreut
	(g/L)	(%)	(g/L)	(%)	(g/L)	(%)	(g/L)	(%)	(g/L)	(%)
Sodium	10.7	30.5	6	30.9	0.8	26.5	0.12	17.5	0.13	23.5
Potassium	0.4	1.1	2.2	11.3	0.08	2.6	0.02	2.9	0.02	3.6
Magnesium	1.3	3.7	0.03	0.2	0.02	0.7	0.005	0.7	0.004	0.7
Calcium	0.4	1.1	0.12	0.6	0.1	3.3	0.03	4.4	0.03	5.4
Chloride	19.3	55.0	9.6	49.5	1.4	46.4	0.11	16.1	0.08	14.4
Sulphate	2.7	7.7	0.15	0.8	0.08	2.6	0.02	2.9	0.01	1.8
HCO3-	0.2	0.6	1.2	6.2	0.44	14.6	0.28	40.9	0.28	50.5
Residual	0.1	0.3	0.1	0.5	0.1	3.3	0.1	14.6	<0.1	<18.1
Sum	35.1	100	19.4	100	3.02	100	0.685	100	0.554	100

The determined, calculated, and measured temperatures of the Upper Jurassic aquifer are shown in Table 5. The , trapping, and maximum trapping temperatures measured in the vein calcites using microthermometry were higher than the recent reservoir temperature in nearly every measured well. However, the reservoir temperature was not corrected for the borehole temperature BHT and could have an error of around 20 K.