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Full-Text Articles in Earth Sciences
K-Ar Age Values Of Bulk Soil Samples And Clay Fractions: Effects Of Acid Extraction And Implications For The Origin Of Micaceous Clay In Savannah River Site Soils, South Carolina, Usa, Thomas E. Naumann
Geosciences Theses
Understanding how natural Cs, Rb, and K have been redistributed in Savannah River Site (SRS) soils during pedogenesis is important to understanding how radiocesium released to the soils will behave over the long term. In this effort, it is important to distinguish K that has participated in mineral-water reactions from that still residing in primary silicate structures, particularly in the clay fraction. The impact of different degrees of acid extraction on K and radiogenic Ar in bulk soil and in clay from five SRS soil samples has been determined. Strong treatment (50% HNO3, three hours, 100°C) releases K from primary …
The Timing And Causes Of Illite Formation In The Cretaceous Marias River Shale, Disturbed Belt, Montana, Stephen Gerard Osborn
The Timing And Causes Of Illite Formation In The Cretaceous Marias River Shale, Disturbed Belt, Montana, Stephen Gerard Osborn
Geosciences Theses
The clay mineralogy data and K-Ar ages of I/S measured in this study agree with previous work conducted within the Disturbed Belt (Hoffman, 1976) and show that diagenetic I/S formed quickly at several different places in response to thrust sheet burial during the Laramide orogeny. The averages of concordant age values for clay sub-fractions separated from three bentonites of Cretaceous and Jurassic depositional age increase from southeast (53.6 Ma) to northwest (56.7 Ma) along the trend of the Disturbed Belt. This northwestward increase of mean ages of I/S is consistent with a thrust sheet emplacement model for the Disturbed Belt …