Source of Potassium for the Illitization Process in Buried Argillaceous Rocks: A Case for Evidence from the Woodford Shale, North-Central Oklahoma M. W. Totten 1 , D. Ramirez-Caro 1 , S. Chaudhuri1, N. Clauer 2 , R. Boutin 2 , G. Riepl 4 , J. Miesse 3 , and K. Semhi 2 1 Department of Geology, Kansas State University, Manhattan, Kansas 66506 2 Ecole et Observatoire des Scinces de la Terre, Universite Strasbourg, Strasbourg, France 3 Pablo Energy II LLC, 2209 W. 7th, Ste. 403, Amarillo, Texas 79109 4 Independent, 119 N. Robinson Ave., Oklahoma City, Oklahoma 73102 ABSTRACT We present a unifying concept about the supply of chemical elements in the conver- sion of smectite to illite in deep burial argillaceous sediments. Transformation of organ- ic materials deposited with the sediments provides at least part, if not the entire amount, of K needed for the diagenetic mineral conversion. According to this concept, Al does not have to be considered as conservative in the conversion process as some have sug- gested. Some Al could have also come from the organic matter. Furthermore, we main- tain that illitization of smectite and organic matter transformation are coeval, in which case oil genesis and illitization in the same source bed could very easily be contemporary events. INTRODUCTION The conversion of expandable, smectite-rich, clay minerals to non-expandable, illite, clay minerals during burial has been widely discussed in the literature. Studies on deeply buried Tertiary sediments in the Gulf Coast region made a major contribution to our understanding of this very important specific clay mineral diagenetic transformation under deep burial conditions. A major drive toward having a thorough understanding of this clay mineral transformation process began soon after the publications of the works of Weaver (1959, 1960). A num- ber of subsequent studies went on to provide some conceptual models that could explain the mechanics of the conversion process. A new era began following the work of Perry and Hower (1970), and then came the most widely circulated work of Hower et al. (1976) which well documented the increase in illite with depth for buried Tertiary sediments in the Gulf Coast. To provide additional documents in support of the mineralogical change, Hower and his colleague presented radiogenic argon dates on the Gulf Coast sediments (Aronson and Hower, 1976). Many subsequent studies on sediments in the Gulf Coast region and also on sediments of different geo- logic ages and depositional settings confirmed the presence of the trend of increasing illite content with increas- ing burial depth. Many of these different illustrations of illite increase with burial depths have been reported in Weaver (1989). The Gulf Coast model for the diagenetic illitization became the guidelines for an explanation of nearly each case of an illitization event in diagenetic sediments. A major crux of the illitization process has been undoubtedly the source of K for the conversion of smectite to illite. The suggestion of Hower et al. (1976) that it could have come from dissolution of K-feldspar or mica minerals has been widely applied to answering questions in nearly all issues of diagenetic conversion of smectite to illite. The balancing of other chemical elements that will be necessary, such as Si, Al, and possibly Fe, has received relatively less attention. Si release from the con- version process has been linked to growth of some silt-sized quartz (Totten et al., 1996). Fe release from the conversion process has been viewed in terms of secondary Fe oxide growth, which led some (McCabe et al., Totten, M. W., D. Ramirez-Caro, S. Chaudhuri, N. Clauer, R. Boutin, G. Riepl, J. Miesse, and K. Semhi, 2013, Source of potassium for the illitization process in buried argillaceous rocks: A case for evidence from the Woodford Shale, north- central Oklahoma: Gulf Coast Association of Geological Societies Transactions, v. 63, p. 449–454. 449