Clays and Clay Minerals, Vol. 59, No. 1, 21–33, 2011.
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Authors
Jaisi, Deb P.
Eberl, Dennis D.
Dong, Hailiang
Kim, Jinwook
Issue Date
2011
Type
Article
Language
Keywords
Periodicals , Geology , Illite-smectite Reaction , Microbial Fe(III) Reduction , NAu-2 , Shewanella putrefaciens CN32 , Thermus scotoductus SA-01
Alternative Title
The Formation Of Illite From Nontronite By Mesophilic And thermophilic Bacterial Reaction
Abstract
The formation of illite through the smectite-to-illite (S-I) reaction is considered to be one of the most important mineral reactions occurring during diagenesis. In biologically catalyzed systems, however, this transformation has been suggested to be rapid and to bypass the high temperature and long time requirements. To understand the factors that promote the S-I reaction, the present study focused on the effects of pH, temperature, solution chemistry, and aging on the S-I reaction in microbially mediated systems. Fe(III)-reduction experiments were performed in both growth and non-growth media with two types of bacteria: mesophilic (Shewanella putrefaciens CN32) and thermophilic (Thermus scotoductus SA-01). Reductive dissolution of NAu-2 was observed and the formation of illite in treatment with thermophilic SA-01 was indicated by X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). A basic pH (8.4) and high temperature (65ºC) were the most favorable conditions forthe formation of illite. A long incubation time was also found to enhance the formation of illite. K-nontronite (non-permanent fixation of K) was also detected and differentiated from the discrete illite in the XRD profiles. These results collectively suggested that the formation of illite associated with the biologically catalyzed smectite-to-illite reaction pathway may bypass the prolonged time and high temperature required for the S-I reaction in the absence of microbial activity.
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Citation
Clays and Clay Minerals, Vol. 59, No. 1, 21–33, 2011.
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