Interlayer Cations Distribution Models for Hydrothermal K-NH4 Dioctahedral Mica Series : Verification and Application
| Project/Area Number |
17540456
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Petrology/Mineralogy/Science of ore deposit
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| Research Institution | Kochi University |
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Principal Investigator |
HIGASHI Shoji Kochi University, Faculty of Science, Professor, 理学部, 教授 (90036583)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2006: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2005: ¥2,800,000 (Direct Cost: ¥2,800,000)
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| Keywords | Clay Minerals / Interstratified Structures / Geochemistry / Illite / Tobelite / イライイト |
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| Research Abstract |
Interlayer cations distribution modes of K-NH_4 dioctahedral mica series and resulting I-T (illite-tobelite) interstratified system are an interesting topic as noted by Drits et al. (1997). In order to discriminate such interstratified system more closely, XRD calculated profile simulation has been made on the basis of different I-T interstratified models such as random (disordered), regular (ordered) and segregated in the present study. The results indicate that these interstratified structures are individually most characteristic of broadening of the 005 reflection and are determinative by the reflection peak width ratio of the both 005 (2Å) and 002 (5Å) reflections against the interlayer NH_4 ratio (or I/T ratio). The peak width ratio is enlarged gradually with the interlayer NH_4 ratio and show a maxima at NH_4=0.5 for the both random and segregated interstratifications although the broadening effect is steep and doubly magnified in the latter. For the ordered interstratification,
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however, the broadening effect is less pronounced and shows bimodal maxima around intermediate I/T ratio (NH_4=0.2-0.3 and NH_4=0.7-0.8).
Natural and synthetic K-NH_4 mica series samples have been investigated to test and verify the XRD analytical criteria for I-T interstratified system. Natural samples associated with pyrophyllite deposit (Horo mine) and tin-vein deposit (San Jose mine) are of intermediate character between random and ordered I-T interstratifications. In contrast, synthetic mica series are rather closer to ordered I-T interstratification. The I-T-S interstratified system can also be analyzed as I-T interstratified system when the smectite component layer is converted to mica-like component layer (illite or tobelite) through pretreatment procedure. When these I-T-S interstratified ones are to be soaked with 1N KC1 or NH_4Cl solution at 150℃ for 6 hours; then x-rayed in atmosphere under controlled condition of relative humidity of 0%, the results are excellently satisfied. Less
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Report
(3 results)
Research Products
(8 results)
