Investigation of polytypes in lepidolite using electron back-scattered diffraction

Kogure, Toshihiro; Bunno, Michiaki

doi:10.2138/am-2004-11-1213

Cited by 18 publications

(15 citation statements)

References 11 publications

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“…Actually they are neither uniform nor alternate, proving that the two types of the stacking sequences can be mixed at a monolayer level. This is consistent with our previous result for lepidolite (Kogure and Bunno, 2004).…”

Section: Hrtem Observation Of Gümbelitesupporting

confidence: 94%

“…Identification of polytype and determination of crystallographic orientation by EBSD As described by Kogure (2002b) and Kogure and Bunno (2004), Kikuchi bands for phyllosilicates are divided into three categories: (1) hkl with h = 3n and k = 3n; (2) hkl with h = 3n and k = 3n; and (3) others with k = 3n if the indices are expressed using the orthohexagonal C-centered cell (note that the h and k indices are exchanged for the 2M 2 polytype because the a and b axes are exchanged). Kikuchi bands in the first category are common to all polytypes.…”

Section: Xrd Analysis Of Gümbelitementioning

confidence: 99%

“…Those in the second category are common to polytypes in the same subfamily, and those in the third category are characteristic of each polytype. Kogure and Bunno (2004) discriminated the 1M, 2M 1 and 2M 2 polytype in lepidolite in the following way. At first, subfamilies A and B were distinguished by the pseudo-trigonal and pseudo-hexagonal symmetries, respectively, formed by the bands in the second category.…”

Section: Xrd Analysis Of Gümbelitementioning

confidence: 99%

“…Then each polytype was identified by the bands described by the third category. Kogure and Bunno (2004) reported that several characteristic Kikuchi bands, such as 1 12, 11 2 and 022 in 1M, and 114, 1 1 4 and 025 in 2M 1 , and 114, 11 4, 204 and 2 04 in 2M 2 , are sufficiently intense to be used for identification of these polytypes. The same procedure was applied to the present sample.…”

Section: Xrd Analysis Of Gümbelitementioning

confidence: 99%

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Polytype and morphological analyses of gümbelite, a fibrous Mg-rich illite

Kameda

Miyawaki

Drits

et al. 2007

Clays and clay miner.

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Polytypism in gü mbelite and its relationship to the fibrous or ribbon-like morphology exhibited by this Mg-rich illite were investigated by powder X-ray diffraction (XRD), electron back-scattered diffraction (EBSD) and transmission electron microscopy (TEM). Comparison between the XRD pattern from oriented fibers using a conventional powder diffractometer and a randomly oriented pattern using a Gandolfi camera suggested that 2M 2 is dominant but other polytypes belonging to subfamily A also exist, and that the fiber axis of gü mbelite is parallel to <110> in 2M 2 , <110> in 2M 1 , and <100> in 1M. The EBSD analyses confirmed these crystallographic directions directly from individual crystals. Electron diffraction and high-resolution TEM showed that twinning and intergrowths of various polytypes including both subfamilies are common in a single crystal and that the two types of rotations [2n60º and (2n+1)60º] between adjacent layers are often randomly mixed at the monolayer level. The data suggest that high densities of twinning and intergrowths account for the origin of the fibrous morphology along <110> for 2M 1 and 2M 2 polytypes. Volume restriction in a confined vein space may also play a role.

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Section: Hrtem Observation Of Gümbelitesupporting

confidence: 94%

Section: Xrd Analysis Of Gümbelitementioning

confidence: 99%

Section: Xrd Analysis Of Gümbelitementioning

confidence: 99%

Section: Xrd Analysis Of Gümbelitementioning

confidence: 99%

See 2 more Smart Citations

Polytype and morphological analyses of gümbelite, a fibrous Mg-rich illite

Kameda

Miyawaki

Drits

et al. 2007

Clays and clay miner.

Self Cite

View full text Add to dashboard Cite

show abstract

“…In all cases, Raman analysis gave a perfect fit with reference spectra for lepidolite, but also a good fit with polylithionite. As lepidolite, once considered a distinct mineral, has been redefined as a lithium-bearing mica in the polylithionite-trilithionite series (Kogure and Bunno, 2004;Brigatti et al, 2005), lepidolite seems an appropriate general name for these inclusions.…”

Section: Magnified 40×) In Some Of the Fissures Isolated Two-phase mentioning

confidence: 99%