Using Mossbauer spectroscopy to identify Indiana oil shales : an honors thesis ([HONRS] 499)
Oil shales are recognized as being a potential source of petroleum for the immediate future. Indiana may have a source of valuable oil in its NewAlbany Shale which is distributed throughout the southern and western regions of Indiana. Shales are sedimentary rocks formed in shallow seas which are mixtures of inorganic minerals and organic materials. The organic matter contained in the oil shales is mainly kerogen, an insoluble solid material which can be extracted from the rock and refined to produce petroleum products. Kerogen is formed from the decomposition of plants buried in sediments. -The process by which plant materials decompose and reform into kerogen as the sediments are compressed into shale is not well understood. In particular, the minerals in the shales which surround the organic material may or may not play a catalytic role in kerogen-formation.Investigations by the Indiana Geological Survey have shown that the New Albany Shale has a number of characteristic rock formations which reflect the organic content of the shale. There is a black shale rich in organic material with a high potential for petroleum development, a greenish-gray shale which is poor in organic material, and brown shales with an organic content which ranges between that of the black and the greenish-gray shales. Despite the obvious color differences in the shales, there are few mineralogical differences. For this reason standard mineralogical techniques cannot be used in trying to determine the relationship of the minerals present in the shales to the formation of kerogen.It has been hypothesized that the organically rich oil shales were formed in an anoxic environment. The kerogen poor shales were formed in an environment high in oxygen which supported the presence of burrowing animals who consumed the plants before the kerogen could be formed. On this basis, it is expected that minerals in the organically rich shaleswill be in a reduced oxidation state relative to those in the organically poor shales. (Maynard, 1982) This study reports an attempt to determine whether Iron-57 Mossbauer spectroscopy can be used to study the differences in the mineralogy of Indiana's New Albany Shales.