Transport of Pb and Zn by carboxylate complexes in basinal ore fluids and related petroleum-field brines at 100 °C: the influence of pH and oxygen fugacity

Table 5 Lead speciation, as a function of pH and log along the 0.01 ppm Pb isopleth of the model composite ore-brine at 100°C^ab

pH	log	Iron phase^csaturation	Cation	Chloride complexes	Sulfide complexes	Hydroxide complexes	Acetate complexes	Malonate complexes	Data set
8.00	-52.20	Hm	5.6 × 10^-2	23.6	2.3 × 10^-6	73.47	0.80	2.6 × 10^-3	8
7.00	-51.95	Hm	0.17	72.64	7.6 × 10^-5	22.37	2.58	8.3 × 10^-3	7
5.00	-51.90	Py	0.23	96.68	0.59	0.30	2.18	0.01	6
4.00	-51.90	Py	0.17	71.75	27.67	0.02	0.37	6.4 × 10^-3	5
4.20	-52.00	Py	0.17	68.42	30.85	0.03	0.52	6.3 × 10^-3	4
4.75	-52.90	Py	4.1 × 10^-3	1.70	98.26	3.0 × 10^-3	0.03	1.7 × 10^-4	3
5.80	-54.00	Py	3.5 × 10^-5	0.02	99.98	2.9 × 10^-4	4.6 × 10^-6	1.6 × 10⁶	2
6.30	-55.00	Py	3.2 × 10^-6	1.4 × 10^-3	99.99	8.4 × 10^-5	4.6 × 10^-5	1.5 × 10^-7	1

^aSpeciation for the indicated complexes is given as mol% of total Pb. ^bThe 0.01 ppm isopleth is illustrated in Fig. 2. ^cSaturated with respect to hematite (Hm), pyrite (Py), or magnetite (Mt).

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