Investigation an a fossil Sequoia bark from Turkey

Abstract

A fossil bark from a complete Sequoia trunk recovered near Istanbul (Turkey) was investigated to assess the degree of degradation of some of its components with respect to a modern Sequoia. Polyoses were studied by cation exchange technique while terpenes with GC/MS analyses of the dichloromethane extracts. Exchange measurements have shown the loss of nearly all carboxyl ester groups of the fossil bark like in most fossil woods. The moist environment is considered the major cause of the hydrolysis of original carboxyl esters to free carboxyl groups. Trifluoroacetic lignins have shown the occurrence of carboxyl groups attributable to the non-polyose fraction of bark in amounts nearly equivalent to those of polyoses. This acidity occurs in forms of free carboxyls and carboxyl esters, analogously to the acidity supplied by polyoses. Terpene content, both as amount and component number, is lower in the fossil bark than in the reference one. Identified components of fossil bark were some monoterpenes and sesquiterpenes in traces, the diterpenes abietatriene, simonellite and dehydroferruginol as well as vanillin and beta-sitosterol. Reference bark revealed the presence of abietatriene, simonellite, the phenol-diterpenes sugiol, dehydroferruginol and perhaps methylferruginol in addition to beta-sitosterol. While the structure of mass spectra of unidentified components has pointed to the presence of other phenol-diterpenes, no evidence of fats or long-chain alcohols was found.