Summary statement
This paper investigates the formation process of iron minerals in red oolitic grainstones of the Lower Jurassic Nieniexiongla Formation, demonstrates organomineralization of sulfate-reducing bacteria mediated pyrites in carbonate ooids. We propose that sulfate-reducing bacteria would utilize organic matter within ooids after sedimentation, resulting changes in the mineral composition of ooids.
Keywords : Ooidal limestone; Pyrite; Hematitization; Organomineralization; Lower Jurassic Nieniexiongla Formation; Southern Tibet