ABSTRACT

Samples were collected across the stratigraphic section at Lametaghat, the type area for the Lameta beds. Calcite, secondary silica and ferruginous matter constitute the cements of the sandstones. Calcite was precipitated contemporaneously with the clastic particles. Secondary silica, derived from the overlying Deccan Trap, replaced the calcite, at some post-depositional stage and with the decline of the concentration of silica in the percolating water calcite was probably again precipitated. Ferruginous matter appeared last among the cements. Silica, occurring as overgrowths on detrital quartz was inherited from the earlier Jabalpur cycle.

Diagenetic replacement of clastic particles is common. "Concertina" boundaries appear to be a result of partial replacement of staurolite by calcite. There are four microforms of quartz and the development of each type appears to be a function of the availability of space. Diagenesis of the limestones involves recrystallisation of the microcrystalline calcite.