INSTITUTO ARGENTINO DE NIVOLOGIA, GLACIOLOGIA Y CIENCIAS AMBIENTALES
Unidad Ejecutora - UE
Compression-cuticle relationship of seed ferns: Insights from liquid-solid states FTIR (Late Palaeozoic-Early Mesozoic, Canada-Spain-Argentina)
ZODROW E L; D`ANGELO J A; MASTALERZ M; KEEFE D
INTERNATIONAL JOURNAL OF COAL GEOLOGY
Año: 2009 vol. 79 p. 61 - 61
Cuticles have been macerated from suitably preserved compressed fossil foliage by Schulze's process for the past 150 years, whereas the physical-biochemical relationship between the coalified layer with preserved cuticle as a unit has hardly been investigated, although they provide complementary information. This relationship is conceptualized by an analogue model of the anatomy of an extant leaf: vitrinite (mesophyll) + cuticle (biomacropolymer) = compression. Alkaline solutions from Schulze's process as a proxy for the vitrinite, are studied by means of liquid-solid states Fourier transform infrared spectroscopy (FTIR). In addition, cuticle-free coalified layers and fossilized cuticles of seed ferns mainly from Canada, Spain and Argentina of Late Pennsylvanian-Late Triassic age are included in the study sample.Infrared data of cuticle and alkaline solutions differ which is primarily contingent on the mesophyll + biomacropolymer characteristics. The compression records two path- ways of organic matter transformation. One is the vitrinized component that reflects the diagenetic-post-diagenetic coalification history parallel with the evolution of the associated coal seam. The other is the cuticle that reflects the sum-total of evolutionary pathway of the biomacropolymer, its monomeric, or polymeric fragmentation, though factors promoting preservation include entombing clay minerals and lower pH conditions. Caution is advised when interpreting liquid-state-based FTIR data, as some IR signals may have resulted from the interaction of Schulze's process with the cuticular biochemistry. A biochemical-study course for taphonomy is suggested, as fossilized cuticles, cuticle-free coalified layers, and compressions are responses to shared physicogeochemical factors.