57Fe Mössbauer spectroscopy study of sediments collected from test wells drilled in the Bikaner–Nagaur basin

For the first time, 57Fe Mössbauer spectroscopic investigation of deep subsurface sediments of Bikaner–Nagaur petroliferous basin (containing heavy viscous oil) is reported. In present investigation Mössbauer study was carried out on the samples of wells Lunkha-1 and Pinodha-1 collected from different depth interval. Our results show that Paleocene sedimentary sequence of this basin have appreciable presence of iron in clay, Jurassic sediments are rich in siderite. Majority of the samples from other formation do not show any Mössbauer signal, indicating very meager presence of iron, beyond the detection limit of Mössbauer Spectroscopy. But few of them indicated presence of iron, out of which many samples exhibit presence of hematite, signature of oxidizing condition in sediments.

► The chemical state of iron and depositional environment of sediments are correlated.
► Oxidizing condition is present in various formations.
► Iron is adequately present in Paleocene terrigenous components.
► Iron is poorly present in Cambrian sediments containing biogenous components.