Journal of Analytical and Applied Pyrolysis 105 (2014) 100–107 Contents lists available at ScienceDirect Journal of Analytical and Applied Pyrolysis journa l h om epage: ww w.elsevier.com/locate/jaap Terpenoid composition and chemotaxonomic aspects of Miocene amber from the Koroglu Mountains, Turkey Oluwadayo O. Sonibare a,b,c,∗ , Ru-Jin Huang a,1 , Dorrit E. Jacob b,c,2 , Yunyun Nie d , Eike Kleine-Benne d , Thorsten Hoffmann a,c , Stephen F. Foley b,c,2 a Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg-University of Mainz, Duesbergweg 10-14, D-55128 Mainz, Germany b Department of Geosciences and Earth System Research Centre, University of Mainz, Becherweg 21, 55099 Mainz, Germany c Geocycle Research Centre, Institute of Geosciences, University of Mainz, Becherweg 21, 55099 Mainz, Germany d Gerstel GmbH & Co. KG, Eberhard-Gerstel-Platz 1, 45473 Mülheim an der Ruhr, Germany a r t i c l e i n f o Article history: Received 29 August 2013 Accepted 15 October 2013 Available online 24 October 2013 Keywords: Cretaceous amber Turkey Chemotaxonomy Terpenoids Pinaceae a b s t r a c t A recently discovered fossil resin from Koroglu Mountain in Turkey has been analyzed by gas chromatography–mass spectrometry and pyrolysis gas chromatography–mass spectrometry to deter- mine its structural class and botanical origin. The sesqui- and diterpenoids contained in the amber extract were used as chemosystematic markers when compared with terpenoids in extant conifers. The pyrolysis products were dominated by labdanoid derived bicyclic products together with succinic acid indicating Class Ia type amber. The biomarker compositions of the resin comprise mainly sesqui- and diterpenoids, and lack triterpenoids. This distribution suggests a gymnosperm, and more specifically a conifer source. The exclusive presence of abietane- and labdane-type diterpenoids together with the absence of phe- nolic diterpenoids strongly suggest that the resin was derived from Pinaceae. However, the presence of methyl-16,17-dinor callitrisate in the pyrolysate also suggests that Cupressaceae cannot be excluded as a possible source for the amber. © 2013 Elsevier B.V. All rights reserved. 1. Introduction Amber is fossilized tree resin that occurs naturally as lumps or layers in sediments and coals. Plant resins consist of a complex mixture of mono-, sesqui-, di- and triterpenoids and/or phenolic compounds [1–4]. Mono- and sesquiterpenoids are volatile com- ponents of plant resins and are gradually lost when exposed to the atmosphere. During fossilization, the original bioterpenoids undergo some minor diagenetic transformation to form geoter- penoids which are found in amber [5]. Despite various chemical alterations processes that occur during diagenesis, the geoter- penoids still retain the basic skeletal structures of their biological precursors and can be used as chemosystematic markers [6–9]. Therefore, knowledge about the chemical composition of ambers ∗ Corresponding author. Permanent address: Petroleum and Environmental Geo- chemistry Research Group, Chemistry Department, University of Ibadan, Nigeria. Tel.: +234 8080 627 459. E-mail addresses: sonibaredayo@yahoo.com, oo.sonibare@mail.ui.edu.ng (O.O. Sonibare). 1 Present address: Laboratory of Atmospheric Chemistry, Paul Scherrer Institute (PSI), 5232 Villigen, Switzerland. 2 Present address: RC Center for Excellence for Core to Crust Fluid Systems, Department of Earth and Planetary Sciences, Macquarie University, North Ryde, NSW 2109, Australia. can provide evidence about their botanical origin, ancient terrige- nous ecosystem and climatic change [10–14]. Diterpenoids are the major products of conifer (gymnosperm) – derived resins whereas triterpenoids (e.g. oleanane, ursane and lupane) are products of angiosperm resins [9,15,16]. The determination of the geographic origin of amber collected from archeological objects is also of great importance in drawing the map of cultural and trade networks among primitive human settlements [17–22]. Gas chromatography–mass spectrometry (GC–MS) and pyrolysis-gas chromatography–mass spectrometry (Py-GC–MS) are useful methods for elucidating the molecular composition of ambers [11,23–30]. While the GC–MS allows only (semi-) volatile organic soluble components, which rarely account for more than 20% of the whole resin, to be identified, Py-GC–MS has the advantage of breaking polymeric constituents, insoluble and non-volatile macromolecules present in amber into smaller and highly volatile molecules that can be analyzed by GC–MS. Amber has been recently discovered in northern Turkey, near Bolu in the Koroglu Mountains. This is a zone of young tectonic folding, with an area of young volcanic activity to the east [31]. The rock in which the resin was found has been identified as fine- grained but poorly sorted wacke sandstone (greywacke). The resin is found in rock in the form of pebbles, but also in dripstone and classic form [31]. Most of the volcanism in the region appears to be Miocene or earlier, therefore it is possible that the amber is Miocene 0165-2370/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.jaap.2013.10.008