Reactive transport modeling of coupled feldspar dissolution and secondary mineral precipitation and its implication for diagenetic interaction in sandstones

Comparisons between modeling results and observations of natural sandstone diagenesis suggest that an MA-1 assemblage is likely to occur in buried sandstones at high temperatures (>70-80 °C) and low flow rates. An MA-2 assemblage may occur in moderately buried sandstones at moderate temperatures (40-70 °C), in deeply buried sandstones with faults and fractures serving as conduits of meteoric freshwater, or in shallow sandstones where meteoric water is not abundant. An MA-3 assemblage tends to occur in shallow sandstones at low temperatures (<40-50 °C) and high flow rates, or in buried sandstones where faults and fractures develop widely and serve as freshwater conduits. These proposals are valid in natural arkosic sandstones and of great significance in deciphering the diagenetic environments where the feldspar dissolution and secondary mineral precipitation have occurred.