Chemistry of Tertiary Resins from India

Mallick, Monalisa ¹; Dutta, Suryendu ¹; Greenwood, Paul ²; Bertram, Norbert ³; Saxena, Rakesh ^4
1 Department of Earth Sciences, Indian Institute of Technology Bombay, Mumbai, India.
² WA Biogeochemistry and John de Laeter Mass Spectroemtry Centres, University of Western Australia, Perth, WA, Australia.
³ LTA-Labor für Toxikologie und Analytik, Königswinter, Germany.
⁴ Birbal Sahni Institute of Palaeobotany, Lucknow, India.

Resins, a sticky secretion of higher plants that hardened on atmospheric exposure, often recorded as lumps in coal or sedimentary layer and identifiable for hundreds of millions of years for their non-biodegraded nature. Despite a high structural stability, fossil resin structure may break down during late stage diagenesis or early stage catagenesis releasing a wide range of aliphatic and aromatic hydrocarbons which have been detected in coal extracts and crude oils.

Fossil resins are ubiquitous in Indian lignites, but molecular character of these fossil resins have not yet been studied in detail nor correlated to resins from different geographical or geological locations. Here is a first attempt to characterize Tertiary resins from Vastan lignite mine, Cambay Basin, and Panandhro lignite mine, Kutch Basin, Western India and Neyveli lignite mine, Cauvery Basin, Southern India.

The molecular structure of these Tertiary resins has been investigated using Fourier Transform Infrared Spectroscopy and Pyrolysis-Gas Chromatography-Mass Spectroscopy techniques. The FTIR spectra show strong aliphatic CHx (3000-2800 and 1460-1450 cm-1) and CH3 (1377 cm-1) absorptions and less intense aromatic C=C (1560-1610 cm-1) absorptions. The major products from analytical pyrolysis are cadalene based bicyclic sesquiterpenoids including some C30 and C31 bicadinenes and bicadinanes. These are diagnostic biomarkers of the dammar resins of Angiosperm species, and probably reflect terrestrial inputs of tropical forest supported by palaeoclimatic conditions of the region.

AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009