PEDOGENIC CONCEPTS AS A TOOL FOR INVESTIGATING GLAUCONITE

The relative maturity of glauconite is commonly utilized to infer sedimentation rates as well as placing sediments within the context of transgressive-regressive sequences. Historically, studies of glauconite have fallen under the auspices of mineralogy, sedimentology, and oceanography. The application of pedogenic concepts can enhance the study of glauconite and place it within a framework of associated processes and subaqueous “landscape” stability. Morphology, as well as potassium content, determines glauconite maturity. It is understood that increased glauconite maturity records longer periods of sediment starvation on the continental shelf. The type of sediment, owing to its porosity and surface area to volume ratio, has also been shown to affect glauconite maturity. Like soils, glauconite tends to occur at unconformities under regimes of non-aggradation and non-degradation and may indicate relative subaqueous “landscape” stability. There is precedent for the use of pedogenic concepts to classify permanently submersed sediments. (Demas & Rabenhorst, 1999), whose work has spurred an amendment to the USDA Soil Survey definition of soil to be “characterized by… horizons, or layers, that are distinguishable from the initial material as a result of additions, losses, transfers, and transformations of energy and matter”. The Soil Survey Staff goes on to define the upper limit of soil “is the boundary between soil and air [or] shallow water”. Additions of sediment and organic matter, losses due to leaching and organic matter decomposition, translocations due to bioturbation, and transformations of ions and sediments into authigenic minerals all occur in submersed environments (Demas & Rabenhorst, 1999). The use of pedogenesis as a conceptual framework for the study of glauconite could lead to new insights pertaining to past oceanic conditions. Horizons of authigenic minerals, understood as representing the footprint of a particular association of multiple processes, could be used to marry more detailed paleoenvironmental reconstructions of oceans with terrestrial stratigraphy and paleoenvironmental proxies. References Demas, G. P., and Rabenhorst, M. C., 1999, Subaqueous Soils: Pedogenesis in a submersed environment: Soil Science Society of America Journal, v. 63, p. 1250-1257