Correlation between crystallochemical parameters of phyllosilicates and mineral facies in very low-grade metasediments of the Betic Cordilleras, Spain: a synthesis
Authors: Ruiz Cruz M.D.; Rodríguez Jiménez P.
Source: Clay Minerals, Volume 37, Number 1, 1 March 2002 , pp. 169-185(17)
Publisher: Mineralogical Society
Abstract:Clay mineral evolution in diagenetic and very low-grade metamorphic sedimentary rocks from the Maláguide Complex was studied using the following parameters: illite and chlorite crystallinity, b cell dimension of illite, chemistry of chlorite, and the occurrence and distribution of the following phyllosilicates: I-S mixed-layer minerals, kaolin polytypes, chlorite-bearing mixed-layer minerals (tosudite and mica-chlorite interstratifications), vermiculite-like minerals, paragonite and biotite. The distribution of IC values permits the subdivision of the study area into three zones: diagenetic, anchizone and epizone. On the contrary, the distribution of CC values cannot be used in the study of the metamorphic zonation. The mineralogy and b dimension of illite indicate that the Maláguide samples display a low to low-medium pressure metamorphism, also characterized by steep temperature gradients. The correlation between IC data and distribution of other significant minerals has permitted the establishment of a zonation within the chlorite zone, which is confirmed by the appearance of some index minerals, such as paragonite, biotite, chloritoid and andalusite.
Document Type: Research article
Publication date: 2002-03-01