Complex polytypism: relationships between serpentine structural characteristics and deformation

J. F. Banfield, S. W. Bailey, W. W. Barker, R. C. Smith

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28 Citations (Scopus)


Serpentinite from Woods Chrome Mine, Lancaster County, Pennsylvania, consists of planar serpentine, randomly interstratified serpentine-chlorite, a series of phases based on regular interstratification of serpentine and chlorite, minor chlorite, polygonal serpentine, and antigorite. The assemblage contains planar serpentines with long-range order in octahedral cation sequences but with random b/3 (and possibly a/3) displacements between adjacent layers. The strong lineation in the foliation defined by the silicate sheets parallels either a or b, suggesting serpentine crystals were rotated, recrystallized, or both during shear deformation. The paper suggests that for crystals with b parallel to the lineation, deformation induced regular layer displacements. For crystals with a parallel to the lineation, periodic displacements of OH planes may have promoted development of regular octahedral cation sequences. -from Authors

Original languageEnglish
Pages (from-to)1116-1131
Number of pages16
JournalAmerican Mineralogist
Issue number11-12
Publication statusPublished - 1995
Externally publishedYes

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