Spectrochemical characterization of naturally macerated remains of Dicroidium odontopteroides (Corystospermaceae, Triassic, Ischigualasto, Argentina)

D`ANGELO J A; COLOMBI, C; ZODROW, E L; CAMÍ, G

La Plata

Simposio; XVI Simposio Argentino de Paleobotánica y Palinología; 2015

Facultad de Ciencias Naturales y Museo (Universidad Nacional de La Plata) y del Museo Argentino de Ciencias Naturales

Functional groups (chemical structure) of fossilized-cuticle remains of Dicroidium odontopteroides (Morris) Gothan (Corystospermaceae) from the Triassic of Ischigualasto, western Argentina are reported for the first time.Compact masses of fossilized-cuticle leaves, revealing a corystosperm-dominated flora are spectrochemically characterized by means of Fourier transform infrared (FTIR) spectroscopy. Semi-quantitative chemical parameters, calculated by peak-area integration of infrared spectra indicate that D. odontopteroides specimens have undergone a natural maceration process. Functional groups include relatively low values of both aromatic carbon and aliphatic structures. High contributions of oxygen-containing compounds and methylene/methyl groups indicate relatively long and unbranched polymethylenic chains likely bridged by ester bonds. This is indicative of the presence of a cutin-like structure making up the cuticle of D. odontopteroides leaves. Noted are functional-group similarities amongst D. odontopteroides FTIR data and those of Type II Kerogen and coal macerals (e.g., cutinite and resinite). The chemical study of this unusual deposit of fossilized-cuticle remains is important in elucidating the complex pathways of organic matter transformation involved in plant-fossilization processes.