Geochemical/hydrochemical evaluation of the geothermal potential of the Lamongan volcanic field (Eastern Java, Indonesia)

Geothermal Energy

Science – Society – Technology

Table 2 Chemical composition (mg/L) and stable-isotope and ⁸⁷Sr/⁸⁶Sr-composition of ground and thermal waters sampled during the field campaigns

Sample		Ca	Mg	K	Na	Fe	Li	Rb	Si	B	Cl⁻	HCO₃ ⁻	SO₄ ²⁻	Ionic balance	¹⁸O	²H	⁸⁷Sr/⁸⁶Sr
WP17 Oct 2012	Spring NE	33.5	37.4	44.1	249	0.0	0.0	0.2	26.1	4.9	330	632	0.0	−19^a	−5.85	−31.4	n.d.
Tiris 1 June 2012	Spring E	63.9	159	49.0	273	n.d.	0.29	0.17	68	14	355	1280	23.8	−3	−5.8	−36.9	0.70464 (±3)
Tiris 2 June 2012	Spring E	93.5	227	76.5	406	n.d.	0.39	0.28	83	21	521	2100	23.1	6	−5.1	−35.5	0.70464 (±2)
Tiris 3 June 2012	Spring E	86.1	201	69.1	370	n.d.	0.35	0.26	77.6	20	465	1650	23.2	−2	−5.06	−36.9	n.d.
Tiris December 2011	Spring E	80.3	168	67.1	353	1.30	0.47	0.28	65.0	13.2	441	1340	n.d.	1	n.d.	n.d.	n.d.
Tiris 5 June 2012	Spring E	61.9	222	45.7	268	n.d.	0.22	0.16	70.4	14	130	1680	4.63	4	−5.28	−33.9	n.d.
Tiris 6 December 2012	Spring E	54.3	192	43.9	254	n.d.	0.3	0.2	57.8	10.3	348	1400	n.d.	−3	−5.49	−36.5	n.d.
WP7 Lad June 2012	Lake	39.7	34.0	8.0	33.3	n.d.	0.0	0.0	20.4	2.0	8.1	427	15.0	−8	n.d.	n.d.	n.d.
WP18 June 2012	River	29.1	17.1	4.7	17.4	n.d.	0.0	0.0	32.5	0.0	11.9	323	11.0	−12	n.d.	n.d.	n.d.
WP 5 June 2012	Diluted and contaminated seawater	257	963	282	773	n.d.	0.0	0.2	4.2	2.0	12,800	610	2450	1	n.d.	n.d.	n.d.

^aSampling of WP17 was additionally conducted by the Indonesian project partners. Their sampling yielded similarly poor ionic balances, with the value scattering between −19 and −22. The poor quality of the ionic balance is due to anthropogenic activities of a nearby village (approximately 1 km)