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Hydrothermal alteration of graywacke and basalt by 4 molal NaCl.

January 1, 1983

Rock-water interaction experiments were carried out at 350oC and 500 bar at a 1/10 rock/fluid ratio using 4 molal NaCl brine. Reaction of brine and greywacke lead to the conversion of illite, dolomite and quartz to albite and smectite. In the process, the rock gained Na and released Ca, K, heavy metals and CO2 to solution. Metal mobilization was found to primarily depend on acidity which was produced by Na metasomatism and by dedolomitization. Reaction of brine and basalt produced only minor alteration in which some smectite and little albite formed. No significant acidity was produced nor did metals become mobilized. Production of acidity during albitization depends entirely on the phase being altered. Albitization of greywacke produces H+ whereas the albitization of basalt apparently consumes this ion. -J.E.S.

Citation Information

Publication Year 1983
Title Hydrothermal alteration of graywacke and basalt by 4 molal NaCl.
Authors R.J. Rosenbauer, J.L. Bischoff, A. S. Radtke
Publication Type Article
Publication Subtype Journal Article
Series Title Economic Geology
Index ID 70011221
Record Source USGS Publications Warehouse