Siderite cement late generation

SI, early siderite cement S2, middle generation siderite cement S3, late generation siderite cement BD, distal braid delta BM, medial braid delta BS, beach-barrier sandstone MBB, back-barrier marsh. 

Fig. 10. Ternary diagrams showing the compositional ranges of different generations of siderite cement in the Tirrawarra Sandstone. The early generation of the siderite cement (SI) is very rich in Fe, whereas the middle (S2) and late generations (S3) have much higher substitution of Mg and fall within the realm of sideroplesite and pistomsite. S2 and S3 have almost identical compositions except that S2 has a slightly higher Ca content.

Fig. 17. Generalized paragenetic sequence for the Tirrawarra Sandstone in the Fly Lake-Moorari area. Cooper basin. The interpretation is based on the integration of petrographic, isotope and fluid inclusions results. The estimated timing of oil generation and migration is indicated (shaded zone). S1, early generation of siderite cement S2, middle generation of siderite cement S3, late generation of siderite cement D1 and D2, first and second phases of siderite dissolution, respectively.

---