Mat growth features

Because sandy siliciclastic subaqueous environmen ts are not typically characterized by mineral precipitation, their microbially mediated sedimentary structures have more subtle vertical relief when compared with microbial structures produced in mineral-precipitating carbonate environments. For a long time sedimentologists and palaeobiologists only worked on the more obvious stromatolites and associated carbonate structures, and microbial mat features from siliciclastic rocks were overlooked. But, in the past decade close examination of siliciclastic sedimentary rocks, particularly those from Precambrian and early Phanerozoic marine strata, has revealed a plethora of structures, largely formed due to growth of microbial mats at the sediment-water interface or the interaction of physical processes with biofilm- or mat-bound sediment surfaces.