sentences:  The ultimate source of the mineralizing fluid(s) in MVT deposits is unknown.The ore fluids of MVT deposits are typically low temperature (100 °C-150 °C) and have the composition of basinal brines (10-30 wt.% NaCl equivalent) with pH's of 4.5-5 (buffered by host carbonates).This hydrothermal fluid may or may not carry the required sulfur to form sulfide minerals.