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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Amber: Frozen moments in time

Gary Platt (UK) Amber has a deep fascination for people, both as a gem and as a chance to look back into the past with a remarkable clarity. Its warm, lustrous touch beguiles us and the remarkable inclusions sometimes found within it capture our imagination. Fig. 1. Ant in Baltic amber – Hymenoptera sp. Amber is found all over the world including, nearer to home, the Isle of Wight. This article looks at some aspects of amber that might interest both the casual and the informed reader. Formation of amber Amber begins as resin exuded from trees millions of years ago. Most known deposits of amber come from various tree species that are now extinct. Baltic amber was produced by a tree called Pinites succinifer, a tree sharing many characteristics of the modern genus Pseudolarix. In appearance, it would have looked similar to a pine or spruce tree. Fig. 2. Fly in Baltic amber – Diptera sp. The resin may have originally been used as a defensive mechanism against insect infestation or fungal attack. Once released from the tree, the resin begins to go through a number of stages to become amber. The first stage involves the evaporation of volatile oils. The oils, called “turpenes”, slowly permeate out of the amber. This may take many thousands of years before the process turns the resin into something approaching the structure of amber. Turpenes give resin its distinctive and powerful odour. Fig. 3. Gnat in Baltic amber – Dipteria cecidomyiidae. Following the … Read More

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Fossils in amber (Part 1): Biodiversity

Dr David Penney and Dr David Green (UK) It is almost two decades since the original blockbuster movie, Jurassic Park, brought the existence of fossil insects in amber (fossilised tree resin) into the limelight. Since then, numerous books and research papers have been published. Fossiliferous amber deposits are still being discovered, including, in recent years, the first major deposits in Africa, India and Australia. The market for fossils in amber experienced a boom in the 1990s, but it has since declined for various reasons, including fakery, copal (sub-fossil resin) being sold as genuine amber and the current economic conditions. Nevertheless, there are many reputable sources for those wishing to develop their passion for amber – a substance that has fascinated people for millennia. It has been endowed with mystical, magical and medicinal properties, and used as an artistic medium and in jewellery. However, today, it is probably most famous for the fossil insect inclusions it preserves with life-like fidelity. It is these that are the focus of this article. This is the second part of a series of articles on fossils in amber. The first is: Fossils in amber (Part 1): Preparation and study. Important fossiliferous deposits There are almost 200 known amber deposits around the world, some dating from as early as the mid-Carboniferous. Relatively few have produced abundant biological inclusions and those that do occur only in strata of Tertiary or Cretaceous age. Many of these ambers were produced by different tree families under somewhat different environmental conditions. … Read More

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