Porosity sandstone compaction/diagenesis

One of the most challenging aspects of diagenesis is to quantify the time and duration of cementation. In the San Joaquin basin we used several methods to estimate when carbonate cements formed. One method, which has also been applied by many previous workers in other basins (e.g. Galloway, 1979), is to infer the porosity at the time of cementation from the volume of pore-filling cement. If the compaction history for uncemented sands is known, the cement volume in fully cemented sandstones implies the burial depth at which cementation occurred. In the case of the San Joaquin basin, most areas underwent simple subsidence to their present depth, and the relation between depth of burial and porosity for uncemented sandstones is known from abundant porosity-depth data (e.g. Ziegler Spotts, 1976). Thus the depth of cementation can be inferred and, combined with a time-depth burial curve, so can the timing of cementation. 

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