Interlayer Cations Distribution Models for Hydrothermal K-NH4 Dioctahedral Mica Series : Verification and Application

K-NH_4双八面体云母系的层间阳离子分布模式及由此产生的I-T（伊利石-吐贝利石）间层体系是Drits等（1997）所关注的一个课题。为了更好地区分这类间层体系，本文分别对随机（无序）、规则（有序）和偏聚等不同的I-T间层模型进行了XRD计算剖面模拟。结果表明，这些层间结构是005反射波展宽的主要特征，并由005（2 Ω）和002（5 Ω）反射波的反射峰宽比与层间NH_4比（或I/T比）的比值决定。随层间NH_4比的增加，峰宽比逐渐增大，在NH_4=0.5时，无规层间和偏聚层间的峰宽比均出现极大值，但偏聚层间的峰宽比增大幅度较大，且增大了一倍。对于有序夹层， 关于我们 在中间I/T比（NH_4=0.2-0.3和NH_4=0.7-0.8）附近出现双峰极大值。与叶蜡石存款（霍罗矿）和锡脉存款（圣何塞矿）有关的天然样品具有介于随机和有序I-T间层之间的中间特征。而合成云母系列则更接近于有序的I-T间层结构。I-T-S间层体系也可以用预处理过程中蒙皂石组分层转化为类云母组分层（伊利石或吐白石）的I-T间层体系来分析。用1 NKCl或NH_4Cl溶液在150℃下浸泡6小时，然后在空气中控制相对湿度为0%的条件下进行X射线照射，结果令人满意。少

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, … More 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