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During precipitation of diagenetic minerals, any change in pore water chemistry may have a significant effect on the structure and composition of cement. Compositional zoning and dissolution phases in siderite cements of the Early Permian Tirrawarra Sandstone, Cooper Basin, South Australia have recorded pore water chemistry changes induced by tectonically active and passive conditions. Back-scattered electron images of siderite cement reveal three stages of siderite cement as the early (S1), middle (S2), and late (S3) stages. S1 is a structureless iron-rich siderite and S3 is a relatively homogenous cement without extensive compositional zoning, whereas S2 exhibits a rapid compositional zoning associated with several minor dissolution phases.
Temperatures of formation of siderite cements indicate that the formation of S1 and S3 has been during passive conditions in the Cooper Basin, whereas S2 formed during active tectonism. The use of compositional zoning of siderite cements may help to identify tectonic conditions during precipitation of cement in other basins.