An attempt to correlate the physical properties of fossil and subfossil resins with their age and geographic location

Abstract

<jats:title>Abstract</jats:title> <jats:p>Testing of the correlation between physical properties of natural resins such as microhardness, density and UV-excited fluorescence emission with their age, geological conditions, botanical and geographical origin and chemical structure was performed. These physical parameters, especially microhardness, are the result of resins fossilization processes like cross-linking and polymerizations of compounds present in the fossils. In addition, hardening of the resins may be also an effect of miscellaneous chemical processes induced by various environmental, biological and geological conditions. The principal component analysis found that the correlation of microhardness, density and fluorescence intensity with the resin age is quite low. The results suggest that variability of physical properties is caused by geographic location and locally occurring geological conditions. The physical properties of natural resins are most strongly correlated with chemical structure and geographic location. The resins with higher microhardness values come from marine environment depositions. The same trend was observed for resins affected by volcanic activity. Moreover, high fluorescence intensity was also observed for resins affected by above mentioned geological conditions. However, the density values of tested resins revealed the lowest correlation with their age, botanical source and geological history.</jats:p>

The Characteristics and Origin of Amber Deposits in the Dominican Republic

“…The resins have strong uorescence from green-blue to blue in UVL (365 nm). Their uorescence intensity is higher than those observed for fossil resins from La Cumbre deposit 10,57 .…”

Unravelling the mystery of “Madagascar copal”: Age, origin and preservation of a Recent resin

“…Poinar [12] considered that the existence of copal in Madagascar dated from between 3 and 4 Ma ago, while Le Gall et al [81] assigned an age of between 1 and 2.6 Ma, in both cases without evidence. Other authors [13,29,[82][83][84], suggested that "Madagascar copal" from the north coast (Antsiranana) had a presumed age of between 10,000 and 50,000 years; in no case was the exact provenance of the analysed pieces indicated.…”

A revised definition for copal and its significance for palaeontological and Anthropocene biodiversity-loss studies

“…resin can harden within days due to the position of the carboxylic group in iso-ozic acid at the C4 position and the enantio configuration 73 giving the impression of being older than it actually is 8 , 15 . Recently, Stach et al 74 attempted to correlate microhardness of copal and amber with age; unluckily, these authors used uncorroborated and wrongly cited ages for the copals tested, apart from the fact that the provenance of Malagasy and Tanzanian copals is frequently uncertain 8 . With this information, they argued an older age for Malagasy copal than that for the Colombian and Tanzanian copals.…”