New insights into the relationship between Tasmanites and tricyclic terpenoids Suryendu Dutta a, * , Paul F. Greenwood b , Rainer Brocke c , Rainer G. Schaefer a , Ulrich Mann a a Forschungszentrum Ju ¨ lich, Institut fu ¨ r Chemie und Dynamik der Geospha ¨ re, Sedimenta ¨ re Systeme, D-52425 Ju ¨ lich, Germany b Department of Applied Chemistry, Curtin University of Technology, Perth, GPO Box 1987, WA 6845, Australia c Forschungsinstitut Senckenberg, Pala ¨ obotanik, Senckenberganlage 25, D-60325 Frankfurt/Main, Germany Received 11 April 2005; accepted 2 August 2005 (returned to author for revision 23 May 2005) Available online 24 October 2005 Abstract Extraordinarily well-preserved Tasmanites and Leiosphaeridia prasinophytes from a new Silurian-Devonian sedimen- tary sequence in South-East Turkey were hand picked from different stratigraphic levels, cleaned and analysed using Curie point pyrolysis-gas chromatography/mass spectrometry (GC/MS). Tricyclic terpenoids in the pyrolysates (e.g., mono- and diunsaturated terpenes and monoaromatics) were detected for the genus Leiosphaeridia, but not for the genus Tasmanites. These results suggest that an inherent source/biomarker relationship between taxa of Tasmanites and tricyclic terpenoids may not always exist. Moreover, the detection of tricyclic terpenoid compounds from pyrolysis of Leiosphaeridia indicates that these pyrolysis products are not exclusive to the genus Tasmanites. Ó 2005 Elsevier Ltd. All rights reserved. 1. Introduction Organic-walled, acid-resistant Tasmanites micro- fossils, known to occur from the Precambrian throughout the Phanerozoic, have been a long time interest of palynologists. Specimens of Tasmanites were first described by Hooker in 1852 as possible lycopod seed cases (see Mendelson, 1993), but in a significant report published in 1875, Newton pro- posed the genus Tasmanites, named after the Perm- ian oil shales of Tasmania in which they occur in high abundance. They were initially thought to be some sort of spore, but Schopf et al. (1944) and Eise- nack (1958) later suggested they might be of algal origin. Today, they are generally regarded as phyco- mata of prasinophyte algae (e.g., Tappan, 1980). Morphological characteristics identified with trans- mitted light, and scanning electron and transmission electron microscope studies, suggest similarities be- tween the Tasmanites and the living green alga Pachysphaera (Wall, 1962; Tappan, 1980; Guy-Ohl- son and Boalch, 1992; Guy-Ohlson, 1996). Molecular characterisation of Tasmanite oil shales have frequently shown a high abundance of tricyclic terpenoids which were soon believed to be 0146-6380/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.orggeochem.2005.08.010 * Corresponding author. Tel.: +49 2461 612468; fax: +49 2461 612484. E-mail address: s.dutta@fz-juelich.de (S. Dutta). Organic Geochemistry 37 (2006) 117–127 www.elsevier.com/locate/orggeochem Organic Geochemistry