Sub-fossils in copal: An under-valued resource

Dr David Penney and Dr David I Green (UK) Copal (derived from the Spanish copalli meaning incense), the precursor of amber, is subfossilised tree resin not old or polymerised enough to be classed as amber. Given that the transformation of resin into copal and then into amber is dependent on factors such as temperature and pressure, there is no set age at which one turns into the other and the nomenclature (with respect to age) of these different transitional stages is still being debated. Some authors have proposed an arbitrary age of 2Ma to demarcate the transition from copal to amber, whereas others have suggested classifying anything that can be carbon dated as copal and anything too old for radiocarbon dating as amber. The debate continues and it seems that the age at which copal becomes amber will remain controversial for the foreseeable future. Furthermore, reaching a consensus terminology has been hampered by both amber researchers and dealers complicating the issue with terms such as sub-fossil resin, young amber, copal amber and so on. Fig. 1. Orb-web spider (Araneae: Araneidae) in Colombian copal. (From the collection of S Shawcross.) Nonetheless, copal preserves insects and other arthropods in the same way as amber and, given the younger age, the inclusions are often preserved with stunning, life-like fidelity. Remarkably, and in contrast to amber, very little research has focused on inclusions in copal because of its young age relative to amber. Such specimens are not deemed old enough to be of any … Read More

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