Layer Silicates from Serpentinite-Pegmatite Contact (Wiry, Lower Silesia, Poland)

Abstract

Abstract--Highly tectonized contact between serpentinite and younger pegmatite in the magnesite mine of Wiry contains various layer silicates. Vermiculite, chlorite, smectite, and interstratified mica-vermiculite were recognized by means of routine XRD examination. Two three component interstratifications of mica-vermiculite-chlorite and chlorite-swelling cblorite-smectite were identified by a combined procedure of deconvolution of the XRD patterns and simulation of XRD tracings. A mineral with large diffraction maxima, displaying "chlorite intergrade" characteristics, appeared to be a mixture of chlorite, mixed layer chlorite-smectite, and vermiculite. Polytypes of phyllosilicates were determined by the X-ray transmission method. Due to the heritage of parent mineral polytype structure by transitional products of alteration, two distinct sequences of layer silicates were observed: one formed from trioctahedral mica (vermiculite, mixed layer mica-vermiculite); and one evolved from chlorite (e.g., mixed layer chlorite-swelling chloritesmectite). A tentative scheme of the primary contact zone structure, not obscured by subsequent brittle tectonics either by transformation of layer silicates, is proposed.

Unusual X-Ray Characteristics of Vermiculite from Wiry, Lower Silesia, Poland

“…The vermiculite from Wiry is a transitional mineral in the sequence phlogopite --~ interstratified vermiculite-phlogopite --~ vermiculite --+ saponite, where honeycomb saponite aggregates unequivocally form owing to dissolution-precipitation (Jelitto et aL, 1993;Dubifiska et al, 1995). The 28 ,~ domains may be where initial dissolution of the vermiculite occurs.…”

“…The vermiculite from Wiry is a product of phlogopite alteration, found in the contact zone between serpentinite and granite-type apophysis. Details of the vermiculite occurrence are given in Sachanbifiski (1993), Jelitto et al (1993, Dubifiska et al (1995), and Janeczek and Sachanbifiski (1995).…”

Vermiculitization of Phlogopite in Metagabbro, Central Turkey

“…The major elemental composition of vermiculites is closely related to that of the parent mica, although there is partial disruption of the mica structure (Jelitto et aL, 1993). Vermiculites resulting from the alteration of micas commonly involve the replacement of the interlayer K by a hydrated cation, generally Mg (Moore and Reynolds, 1989;Nemecz, 1981).…”

Corrensite from Nasławice (Lower Silesia, Poland): Some Problems of Mineral Identification and Origin

“…Deconvolution of XRD patterns of a stage-heated, rehydrated and glycolated sample suggested an admixture of ambiguous phase diffraction maxima (newly formed phase-nfp, Figures 5 and 6). These maxima can be tentatively ascribed to an interstratified swelling chlorite-smectite-chlorite using M6ring (1949) diagrams modified by Drits and Sakharov (1976) and the procedure of Dubifiska (1984) and Jelitto et al (1993). Figure 12).…”