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The occurrence of extended tricyclic terpanes in the Proterozoic and Paleozoic

Created 16/10/2025

Updated 16/10/2025

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The C19-C26 tricyclic terpanes are ubiquitous in oils and bitumens from a range of depositional environments and throughout the geological record. The percursor molecule and biological source of this series of biomarkers is unknown but, they constitute a large proportion of organic matter, highlighting the biological sources’ ecological significance. Ratios of particular homologs are utilized to distinguish source rocks, assess post-depositional microbial degradation and to reconstruct paleo-environmental conditions [1], [2]. The C19-C26 tricyclic terpanes are frequently described in the literature, however there is little known about the occurrence of the extended tricyclic terpane series (C27-C54) through geological history. Previous reports of the extended tricyclic terpanes are restricted to the Phanerzoic Eon and there is ongoing debate about their paleoenvironmental and biological interpretations [3],[4]. Here we present the first report ofindigenous tricyclic terpanes ranging from the Paleoproterozoic to the early Paleozoic Era. Extended tricyclic terpanes (>C27) were detected in almost every sample analysed, highlighting their potential as paleoenvironmental parameters. Furthermore, our data infers a possible link between the extended tricyclic terpanes and salinity and we will propose a novel parameter to describe this relationship. We will also offer speculation about the biological source of these enigmatic orphan biomarkers.
[1] J. E. Zumberge, “Terpenoid biomarker distributions in low maturity crude oils,” Org. Geochem., vol. 11, no. 6, pp. 479–496, 1987. [2] S. Tao, C. Wang, J. Du, L. Liu, and Z. Chen, “Geochemical application of tricyclic and tetracyclic terpanes biomarkers in crude oils of NW China,” Mar. Pet. Geol., 2015. [3] S. M. B. De Grande, F. R. Aquino Neto, and M. R. Mello, “Extended tricyclic terpanes in sediments and petroleums,” Org. Geochem., vol. 20, no. 7, pp. 1039–1047, 1993. [4] S. Dutta, P. F. Greenwood, R. Brocke, R. G. Schaefer, and U. Mann, “New insights into the relationship between Tasmanites and tricyclic terpenoids,” Org. Geochem., vol. 37, no. 1, pp. 117–127, Jan. 2006.

Presented at the 2019 Goldschmidt Conference

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Field Value
Title The occurrence of extended tricyclic terpanes in the Proterozoic and Paleozoic
Language eng
Licence Not Specified
Landing Page https://data.gov.au/data/dataset/407430f2-49be-462e-85da-6da5c0895bd5
Contact Point
Geoscience Australia Data
clientservices@ga.gov.au
Reference Period 01/07/2018 - 10/07/2022
Geospatial Coverage
Map data © OpenStreetMap contributors
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Data Portal Geoscience Australia

Data Source

This dataset was originally found on Geoscience Australia "The occurrence of extended tricyclic terpanes in the Proterozoic and Paleozoic". Please visit the source to access the original metadata of the dataset:
https://ecat.ga.gov.au/geonetwork/srv/eng/csw/dataset/the-occurrence-of-extended-tricyclic-terpanes-in-the-proterozoic-and-paleozoic