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https://www.ias.ac.in/article/fulltext/jess/123/05/0923-0934

Cretaceous; condensate; Jaisalmer basin; biomarkers; conifer source.

The present study reports the biomarker distribution of condensate belonging to the early Cretaceous time frame using gas chromatography-mass spectrometry (GC–MS). The early Cretaceous palaeoenvironment was inscribed into these molecular fossils which reflected the source and conditions of deposition of the condensate. The saturate fraction of the condensate is characterized by normal alkanes ranging from 𝑛-C_{9} to 𝑛-C_{29} (CPI-1.13), cycloalkanes and C_{14} and C_{15} sesquiterpanes. The aromatic fraction comprises of naphthalene, phenanthrene, their methylated derivatives and cyclohexylbenzenes. Isohexylalkylnaphthalenes, a product of rearrangement process of terpenoids, is detected in the condensate. Several aromatic sesquiterpenoids and diterpenoids have been recorded. Dihydro-ar-curcumene, cadalene and ionene form the assemblage of sesquiterpenoids which are indicative of higher plant input. Aromatic diterpenoid fraction comprises of simonellite and retene. These compounds are also indicative of higher plants, particularly conifer source which had been a predominant flora during the Cretaceous time.

Sharmila Bhattacharya¹ Suryendu Dutta¹ Ratul Dutta²

1. Department of Earth Sciences, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, India.
2. Geoscience Department, Oil India Limited, Jodhpur 342 005, Rajasthan, India.

Published

July 2014

Manuscript received

29 August 2013

Manuscript revised

26 February 2014

Accepted

28 February 2014