There has been some confusion and contention about what defines "fossilized" amber from copal, especially copal from Colombia, South America, and amber and copal fro around the world. Amber and copal are both polymerized tree "sap" resins.
by Terrence M. Allen, May 3, 2010
Revised November 30, 2010 for clarification, and updates
There has been some confusion and contention about what defines "fossilized" amber from copal, especially copal from Colombia, South America, and amber and copal fro around the world. Amber and copal are both polymerized tree "sap" resins."AMBER" is defined as a hard, yellowish to brownish translucent fossil resin (tree sap from extinct flora/trees) that takes a fine polish and is used cheifly in making ornamental objects including beads or jewelry such as earrings, necklaces, pins and brooches, and more. It can sometimes be blue/green (from outside deposits), to near black (from coal mines), to cranberry red (Tibetan), to opaque white (bone). Although the color can be variable depending upon age, chemical and physical components, and the locality or contient where found, amber is recently in the last 15 or so years (since the release of the movie "Jurassic Park" directed by Steven Spielberg in 1993, based on the book "Jurassic Park" by author Michael Crichton in 1990) it has been sought out and valued for having fossil insects and spiders, mosquitoes being the most asked for (see notes at end), leaf or flower parts, and other small organisms, entombed inside these naturally hardened jewels. Termed "inclusions", these organisms permanently encased and preserved in three-dimensions, many of which may now be extinct yet some which can be extant species of animals and plants, have brought amber to a higher level if intrinsic, scientific, and of course, monetary value.
"COPAL is the term used for resins obtained from various tropical trees. It can be collected from living trees or from accumulations in the soild beneath the trees, or mined it is is buried. Copals fro different sources can have similar physical properties but different chemical properties. They are of the ame approximate hardness as amber, but differ from amber in that they are still wholly or partially soluble in organic solvents. Buried copal is the nearest to amber in durability, and is in many cases virtually indistinguishable from it. Fossial copal from the London blue clay has been called copalite or Highgate resin. The name copal itself probably comes from (Spanish): nehuatl copalli, meaning "resin". The island of Zanzibar (a part of Tanzania) is a major source of buried copal. Copal also comes from China, Borneo, Madagascar, North Island, New Zealand, Brazil, Colombia, and other South American countries. It is used in making varnishes, lacquers, inks, and linoleum." (Source: DK/Smithsonian, Rock and Gem, The Definitive Guide to Rocks, Minerals, Gems, & Fossils, by Ronald Louis Bonewitz, c-2005/2008, page 319. Editions by TMA.)
Generally speaking, the age of different amber(s) and similar copal(s) cannot be determined by any direct analysis, but may be estimated by comparative analysis.
"Resins are produced by many trees and other plants. Unfortunately, no one can presently date these resins by any definitive tests. Because they have been continuously produced, there are no drastic changes from one geological period to another. We can infer age, if we know the age of a sedimentary deposit in which they are found (this would be a minimum, because older material could have been redeposited)." (Source: Colombian Amber, by Dr. Robert E Woodruff, Emeritus Taxonomist, Florida State Collection of Arthropods, 2007.)
It is plausible, but not exact, that buried amber or copal may be approximately dated based on other known indicator or index fossils in the associated sediment where found, but again there is no way of knowing exactly how long the resin in question took to become deposited in a defined layer of sediment. If the resin was geologically re-worked, that is, if it eroded from one deposit and re-deposited elswhere, the resin could be either younger or much older than what the identified indicator or index fossils in the associated sediment reveal.
It may also be possible to estimate the date of particular amber or copal pieces by comparing specific inclusions (arthropods and plants) in the resin with the same specific inclusions in other known more accurately dated resins. Some species of insects or spiders or plants may have become extinct over time and not appear in younger amber or copal; inversely, newer evolved or advanced or extant species may not appear in older ambers. This type of comparison or deductive reasoning can be difficult as many species of arthropods (and other animals) and plants exhibit "perpetual longetivity", that is, they have continually lived and reproduced for hundreds of millions of years with little or significant change; examples include: cockroaches (Blattodea), snakeflies (Raphidiodea), dung beetles (Scarabaeoidea), scorpions, mites, harveatmen or Opiliones (aka: daddy-long-legs), horsetail plants (Equisetum ap.), and ferns.
Conversely, it may be possible to infer or even conclude that a piece of amber is of a particular age if it includes an indicator species, scientifically ascertained from the rock and amber fossil record, that disappeared at a known geological time period. For example, it is generally accepted that Trilobites and Eurypterida (aka: sea-scorpians), both prehistoric marine or sea-living arthropods, along with 90 percent of other life on Earth, disappeared approximately 250 million years ago during a mass extinction period called the Permian Extinction. Dinosaurs, Ammonites, Belemnites, and Orthoceride and most Nautiloids, and others died out during another mass extinction event, labeled the Cretaceous-Tertiary or K-T Boundary, around 65 million years ago.
In regards to amber and copal, stellate oak tree/plant hair, (aka:SOH), is often found in Baltic Amber, sometimes in Dominican Amber, and rarely in Chiapas (Mexico) Amber, but is lost in the subsequent fossil record approximately 20-million years ago. (SOH identified in Chiapas amber by T.M. Allen (Nov 2010); Alex Brown (Berkely) concurrently id'd SOH in Chiapas amber from The Bone Room, owner Ron Cauble (Berkely, CA).) If this plant inclusion is found in a piece of Colombian "copal", it seems reasonable that the sample of "copal" can be approximated to be at least 20 million years old, and thus be defined as or termed "amber".
"The consensus age estimate (of Colombian Amber) seems to be Pleistocene (up to 2 million years old), but estimates range to the Lower Miocene (about 20 million years old)." (Source: http://www.fossilmall.com, Fossil Mall Science Section.)
"Copal" (aka: copalite) is defined by Webster's New Collegiate Dictionary as a recent or fossil resin from various tropical trees. In comparison with the two major sources of amber (Dominican and Baltic Ambers) most readily available to the public, Dominican Amber, fossilized resin or tree sap from ancient legume trees (Hymenaea protera (Dr G.O. Poinar)), comes from the Dominican Republic on the island of Hispaniola in the Greater Antiles (Caribbean, West Indies). Current evidence indicates that most of the insect-bearing Dominican Amber was deposited during the Lower to Middle Miocene Epoch, of the Tertiary/Paleogene Period, and is dated to be approximately 20 million to 23 million years old. Baltic Amber, fossilized tree sap from ancient pine trees (Agathia sp., i.e. kauri pine) or conifers, is from western Europe. It is recovered from countries surrounding the Baltic and North Seas, including Poland, Russia, Germany, Denmark, Latvia, Estonia, and Lithuania. It sometimes washes ashore far away in Denmark, Norway, and England. Dated to be from the Tertiary/Paleogene Period, from the Upper Eocene to the Lower Oligocene Epochs, Baltic Amber is approximately 40 million years old (i.e. amber from Borneo, some of which is referred to as copal) to 140 million years old (i.e. amber from the Isle of Wight, UK).
Colombian copal/amber is produced by several trees given the common names: Kauri Gum tree, Jotaba tree, and Algarroba tree. Some of the Colombian copal/amber is produced by the Hymenaea courbaril tree which grows in Colombia and other countries in South America. Dr. George Poinar describes three species of Hymenaea trees (related to the Hymenaea tree of Dominican amber sources) that occur in Colombia including H. courbaril and H. oblongifolia. The insect and other arthropod inclusions found in Colombian copal/amber by this author (T.M. Allen) are similar (and sometimes the same species), strange, exotic, rare and prehistoric species identified in Baltic, Dominican, and Chiapas amber pieces.
Amber provides us with rare glimpses of life from ancient tropical rain forests from continents and islands around the world during different time periods. Sometimes insects and their droppings (frass/copralites), spiders, and their web (silk), other arachnids, plant parts (leaves, flowers, petals, stamens, pollens, stems, bark, and plant-hairs), and rarely very small vertebrate animals, including reptiles and amphibians, hairs of mammals, feathers of birds, bacteria, fungi, nematodes, mollusks, and air, gases, and liquids, became entrapped and preserved in the sticky tree sap. These specimens of the prehistoric past, some extinct and others extant, are termed "inclusions". The saem, similar, or different species found entombed in amber, separated by hundreds of miles or millions of years, are part of the Earthe's fossil record.
"I believe, based on the fact that stellate oak (floral) hair (Family: Faqaceae, Genua: Quercus sp.) was discovered in Colombian copal/amber by this author (T.M. Allen, April 2010), and that stellate oak hair is used as an indicator fossil species foudn in Dominican Amber, Chiapas (Mexico) Amber, and Baltic Amber scientifically aged to be 20 million, 25 million, and 40 million years old respectively, that some Colombian copal/amber can be dated to be approximately 20 million years of age and can be termed to be true fosillized "Colombian Amber". (Or too, maybe stellate oak hair is a more recent product of the flora kingdom than originally thought.) All debates aside, about whether "fossilized" tree or plant resins from different or designated localities around the world should be termed "amber" or "copal", as long as it is qualified and recorded as to where the samples of prehistoric resins originate, the arthropod (and other faunal) and plant inclusions are all valuable scientific specimens and are direct evidence and indicators as the the history and evolution of life on Earth". (T.M. Allen)
Terrance M Allen
Retired Entomologist, California State Dept. Food & Agriculture
Certified Technician in Mosquito Control, Los Angeles County, State of California, Department of Health
Arachnologist, Practicing Paleontologist, and Factotum Naturalist
May 3, 2010. Revised November 30, 2010.
New definitions and concepts presented here include:
- Perpetual Longevity of Species: Species of animals and plants that have continually lived and reproduced for hundreds of millions of years with little or no significant change.
- Dating amber/copal using comparative analysis by using indicator or index species.
- Stellate Oak/Plant Hair (aka: SOH) (Family: Fagaceae, Genus:Quercus sp.) found in Colombian copal/amber, a new, upreported find, and using it as a dating tool (T.M. Allen, April, 2010).