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GEOREF RECORD

Macroscopic palygorskite from Lisbom volcanic complex

Mercedes Suarez and Emilia Garcia Romero
Macroscopic palygorskite from Lisbom volcanic complex
European Journal of Mineralogy (February 2006) 18 (1): 119-126

Abstract

The palygorskite occurring as veins in the Lisbom volcanic complex, Portugal, is notable both for its purity and the size of its fibres. The crystals are large with exfoliation traces of several hundred microns to a few millimetres in length. In thin section, it is colourless, negative biaxial with positive elongation and parallel extinction. The optically homogeneous fibres and laths are shown to be composed of aggregates of much thinner fibres rotated differently around the c axis which represents their common direction of elongation. The mean of 14 X-ray EDS analyses gave the formula Si (sub 8.02) O (sub 20) (Al (sub 1.91) Fe (sub 0.04) Mg (sub 2.01) )(OH) (sub 2) (OH (sub 2) ) (sub 4) Ca (sub 0.01) Na (sub 0.07) . 4H (sub 2) O very close to the ideal formula of a pure Mg-Al palygorskite, with almost no octahedral Fe and no Al in tetrahedral sites. The cell parameters are a or asinbeta = 12.64, b = 17.84, c = 5.3 Aa.


ISSN: 0935-1221
EISSN: 1617-4011
Serial Title: European Journal of Mineralogy
Serial Volume: 18
Serial Issue: 1
Title: Macroscopic palygorskite from Lisbom volcanic complex
Affiliation: Universidad de Salamanca, Departamento de Geologia, Salamanca, Spain
Pages: 119-126
Published: 200602
Text Language: English
Publisher: Schweizerbart'sche Verlagsbuchhandlung (Naegele u. Obermiller), Stuttgart, Federal Republic of Germany
References: 36
Accession Number: 2006-036667
Categories: Mineralogy of silicates
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 1 table
N38°43'60" - N38°43'60", W09°07'60" - W09°07'60"
Secondary Affiliation: Universidad Complutense, ESP, Spain
Country of Publication: Germany
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United KingdomTwickenhamUKUnited Kingdom
Update Code: 200620
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