The Amber of Lebanon: an Ecological Museum of FossilsProfessor Aftim Acra
Chairman, Department of Evironmental Health
Faculty of Health Sciences
American University of Beirut
1.1 Amber: General Considerations
Amber, a generic term derived from the Arabic name anber, represents over 100 varieties of fossil resins or gums of plant origin. In the Middle East, it is now frequently referred to as kahruba, kahraman, or kareb from the Greek electrum due to the negative electrical charge acquired by friction, signifying its power to attract straw. This unspecific property is known to be exhibited by a number of such other materials as plastics.
The confusion in the Arab World of anbar with ambergris (a greyish, odoriferous fatty substance used as a fixative in perfumery, and produced as an intestinal secretion in the sperm whale (Phyceter catodon) probably stems from the fact that both materials have been found floating in tropical seas for many centuries.
Amber fossil resins differ in chemical composition, and in physical properties, depending upon the variety. Amber occurs in irregular lumps of various shapes and sizes ranging from a few grams to the largest one ever found in the Baltic region weighing 15.5 kilograms. The color, hardness, clarity and biological inclusions also differ with the variety of amber.
Amber occurs in geological sedimentary deposits in various parts of the world, specimens having been collected from the Baltic region, UK, USA, Canada, Mexico, Argentina, Brazil, Rumania, Australia, New Zealand, Philippines, Colombia, Chile, Ecuador, Sicily, Japan, China, USSR, Spain, France, and few other countries. But the most important source of amber has been for centuries along the southern shore of the Baltic sea, where the material is generally buried at the bottom of the sea in areas which were covered with extensive forests of conifer trees millions of years ago. During stormy weather, the individual pieces of amber are detached, tossed upwards to float on the surface, eventually to become stranded on the shore or entangled in seaweeds from where they can be recovered by amber collectors.
However, most of the European amber is at present mined in large quantities from the ground deposits for commercial uses in such places as Kaliningrad, USSR (the world's largest reserves) where it is found embedded in the amber - bearing strata known as blue earth.
The commercial products made of polished natural amber, or of pressed amber (ambroid made from small fragments of amber) include beads, rings, bracelets, pendants, necklaces, brooches and worry beads- all of which are amber ornaments that have been produced since ancient times, and found in tombs in Europe and in the Orient. Worry beads made of polished natural amber or ambroid are still very popular in the Arab world.
Although amber deposits are widely distributed in age, ranging from Pleistocene (1 - 3.5 million years B.P) to Cretaceous (65 - 135 million years BP), no amber is known from the Permain (225 - 280 million years BP) and the Jurassic (195 - 225 million years BP), and relatively little from the early Cretaceous (100 - 136 million years BP). Canadian amber belongs to the Upper Cretaceous period (65 - 100 million years BP). In contrast, Baltic amber (which constitutes not less than 99% of the bulk of amber already collected throughout the world) is much more recent, mostly dating back to the Miocene (7 - 26 million years BP) and Oligocene (26 - 38 million years BP).
Biological materials such as insects, worms, seeds, leaves, twigs, and pollen grains are not infrequently trapped in the freshly exuded, sticky resin which is then transformed with time (million of years) into hardened fossil resin by gradually losing the volatile substances. These resins (or amber) may often remain burried under the deposited layer of greyish sand. The fossilized biological inclusions are consequently well preserved indefinitely, and could serve as specimens for study by paleobotanists and paleozoologists. These inclusions are considered to be much more superior to those fossils embedded in rocks by virtue of their intactness and detail. Besides, biological fossils contained in transparent or translucent amber can usually be observed from various angles.
Very little is known about the inclusions in the Early Cretaceous amber other than those found in the limited number of amber pieces found in Maryland, USA, which have been studied and documented. Most of the studies in the past have been centered on Baltic amber which was found to contain fossil insects and plant material. Recently, interest has developed in the study of North American amber, both in terms of the identification and classification of the biological inclusions, as well as in the chemical nature and composition of the fossil resin itself.
Knowledge of the chemistry of the fossil resin of Baltic amber, and the nature of its biological inclusions, has led to the conclusion that the parent, amber-producing trees are coniferous ones which represent a number of genera such as Pinus (pines), Picea (spruces), and Abies (firs). Amber from other sources have been associated with a variety of prehistoric trees that produced resins. The botanical affinities of these trees include Araucariaceae, Taxodiaceae, Burseraceae, Leguminosae, Dipterocarpaceae and Anacardiaceae.
With the exception of Hamamelidaceae, the resin-producing trees of most of the amber appears to have been coniferous until the Cretaceous period. Recently, these findings have generally been confirmed by infra-red spectra and X-ray diffraction studies of fossil resins from various sources, and these have also been compared with the patterns obtained by modern gums and resins, including what is generally known as kauri (1 to 2 million years of age).
The mechanism involved in fossil-resin production by the parent trees are not completely understood, although several hypotheses have been proposed.
1.2 The Amber of Lebanon
For many centuries people in the Middle East have been using polished natural amber as a semi-precious gem for making worry beads, amulets and various ornamental objects. Their dependence on imported amber from Europe and elsewhere probably arises from the lack of knowledge of the possible occurrence of amber deposits in some parts of the region (Lebanon, Jordan, and Israel).
It was not until 1875 that the German Geologist, Dr D. Fras, reported briefly on the presence of some kind of amber in a certain location in South Lebanon. This variety of very brittle, wine-red amber has been termed Schraufite by mineralogists. It is usually devoid of insect and plant fossils and is, therefore, of little interest for paleontological studies. Schraufite has also been found in the Carpathean sandstone. However, the Lebanese material was not collected since Fras' announcement, and so it remained unstudied for about a century.
In 1953, J. Pactl reported that J. Petrbok of the National Museum in Prague had found a relatively small piece of amber in Kurkar rocks near Jaffa, Palestine, between 1926 and 1929. Pactl suggested the name Jaffaite (a variety of Liptobiolite fossil resin), and dated it back to the Pleistocene period (about one million years BP) but did not report any biological inclusions.
In 1962, I accidentally discovered a single piece of amber in a locality near Dahr-El-Baidar while leading a group of AUB professors of geology and their students to a place in the Bekaa valley (central Lebanon) in search of fish fossils reported by a friend of mine to have been found there during the French Mandate of Lebanon. My companion, Professor Young (a geologist) Identified that piece of amber by burning its tip with his cigarettte lighter and smelling the typical odour of amber. He then asked the students, who were searching for mollusc petrified fossils, to search for other pieces like the one I had just found. My friend Mr. Raif Milki accompanied the group on that occasion. I felt so lucky when the students failed to find on that site any other amber piece besides the petrified fossils they were interested in. This stimulated me to continue searching for amber, and I thought that the same locality in the Bekaa Valley would be a logical place to start a more thorough search. I then recruited the company and help of my friend Mr. Raif Milki and my son Fadi who was then nine years old. A fortnight later I drove with my two companions to the same locality where I had previously found the solitary piece of amber. When I parked my car on the right-hand side of the road, Raif stepped out of the car and yelled "Eureka, I found one piece". We then started searching the plot of land on the right-hand side of the road, not the one where I had found the solitary piece of amber.
By 1972, when I and my two companions discovered four locations with fairly rich amber deposits in various parts of the country, about 30kg of amber had been collected by me and my son Fadi. The amber collected by Raif was kept separately by him to take home. Several other sites were later identified, but the outbreak of the civil disturbances in Lebanon (1975 - 1991), and the lack of security obliged us to discontinue our activities during that period.
By 1975, the Acra collection of amber amounted to about 100 kg . It consisted of various kinds of amber ranging in weight from about 0.5 gm up to the largest one weighing 1653 gm. The usual colours are light yellow, orange, brown, cream and red. A few of the specimens are bone-white, resembling candle wax in texture and appearance. Some specimens are transparent, while others are translucent or opaque. Wheras a few varieties are relatively hard, the majority are rather fragile. This is in contrast to the Baltic amber which is much harder and can, therefore, be worked into ornamental objects. However, the Lebanese material can be melted and pressed to produce ambroid which, though inferior to amber and much less popular, is hard enough to make it possible to work into ornamental objects like amulets and worry beads. But, we decided not to encourage such a practice at all. This attitude was based on the much greater importance in view of the much greater importance of the scientific value of the fossil inclusions, particulary because the Amber of Lebanon is extremely rich in its content of very well preserved fossils and its great geologic age which goes back to the era when the flowering flowers began to evolve. Our findings thus far indicated that the amber deposits in Lebanon, generally lying at elevations of about 1000 meters, can potentially yield fairly large quantities of material if properly mined by technologies developed in Poland, Lithuania, and other countries bordering the eastern shores of the Baltic region.
The Lebanese amber generally occurs in greyish sand strata, and is often found to be partially embedded in chunks of fossil wood possibly associated with the trees believed to have exuded the amber resins. On the basis of the available geological evidence, both the amber and the fossil wood are attributed to the Lower Cretacious (Aptian / Neocomian) geological period, thus placing the age of the fossils at 100 - 130 million years B.P.
I and Fadi have incessantly continued to work on the numerous small pieces of raw amber collected from the various sites by properly coding, carefully washing to detach the soil, drying, weighing, and packing each individual specimen in separate plastic boxes with a label attached showing the date collected, the site, later the prominent kind of fossil inclusion (plant or insect). The numerous pieces of amber produced by accidentally shattering a large lump of amber while excavating it from the ground were wrapped together with aluminum foil and placed in a larger plastic box appropriately labeled. The reason for such an action was based on the assumption that all of the fossil inclusions contained in each single component belonged to the same age, in contrast to the small pieces found scattered here and there which might differ appreciably in age. Subsequently, as time permitted, each piece of amber was carefully inspected under a stereo-microscope, and those containing inclusions were manually polished down to the level of the desired inclusions with graded emery paper in preparation for photographing under the microscope. The polishing operation had to be carried out with continuous observation under the microscope for fear of obliterating some of the fossil inclusions which are, with only a few exceptions, extremely tiny, and the large majority being about one millimeter or less in size. As there was no one around for us to consult about the proper manner to process the amber specimens and to photograph the fossil inclusions, we had to resort to patience, determination, repeated trial and error, and innovation to ultimately achieve success. The first encouraging photographic trials were accomplished, with a limited input by a friend, in black and white. Eventually, we succeeded in preparing colour slides by using techniques we had developed independantly. Ultimately with time we were able to produce about 3,000 colour slides. It should be noted that the microscopic study had revealed the presence of thousands of various kinds of fossil insects and plant material in a remarkably well preserved state. Among the multitude of inclusions are flies, beetles, spiders, moths, mites, larvae, worms, pollen , spores, ova, uni-cellular organisms, twigs, leaves, rootlets, mushrooms, a single tiny snail, tiny specks of metal, and liquid bubbles, in addition to various other objects that are not readily identifiable.
It would be useful and interesting to record the actual materials and techniques used throughout the entire process from polishing each piece of amber to photographing each outstanding fossil inclusion. Such a venture is beyond the scope of this report because of the bulk of information.
An extremely interesting finding refers to the variety of unicellular microorganisms present in a number of amber specimens. These cells vary in shape and size, and many of them are distinctly nucleated. Their colour generally varies from light brown to orange or pink.
Some amber specimens are extremely rich in insects and/or plant materials, while others are completely devoid of biological inclusions. The presence of insect attractants or repellents in the various kinds of amber may offer one possible explanation for the presence in abundance or complete absence of insect fossils. The fossil pollen grains can yield information of great value with reference to the kinds of flowering plants that started to evolve during that period of time.
1.3 Our work: an overview
The work I and Fadi had accomplished from the start of the project in 1962 with respect to the specimens of amber collected from the various amber sites in Lebanon is briefly described hereunder for the purpose of recognizing the procedures that need to be applied in future projects.
It must be realized at the outset that the work involving collection, preliminary preparation of the specimens, inspection and microscopical scanning of each one, manual polishing of individual specimens, and micro-photographic operations are time consuming and extremely tedious tasks, particularly in view of the tens of thousands of amber pieces involved. The same can also be said about the study and description of the individual fossil inclusions by highly experienced specialists and taxonomists. It should be appreciated that the experts with some experience in the study and identification of amber fossils are rather scarce throughout the world. We were indeed lucky to be able to establish contact with Dr. Paul Whalley of the Department of Entomology at the British Museum (Natural History) in London who showed interest in studying part of our collection of amber, and I was only too happy to make arrangements to send him about 1000 pieces of amber during 1975-1976. Some of the members of the British team of news reporters, who came to Beirut to cover the disturbances that flared up in Lebanon in April 1975, volunteered to hand-carry the amber I had carefully packed in small wooden boxes.
1.3 1 The progress of our work
For a little more than a decade (1962 - 1975) our search for sites of amber deposits continued with some success and a lot of failures. Some ten different locations have been identified so far, but the quantity and kind of amber available in each place vary considerably, for some locations have an abundance of amber burried in the strata of sediments, and occasionally embedded in rock formations. Occasionally we would find some pieces of amber associated with chunks of fossil wood. During the dry season it becomes quite difficult to extract the amber specimens from the hardened, dry soil. Experience has shown that it is much more feasible to collect the amber during the rainy season when the soil is wet and soft, a practice we and Raif adopted as a general rule.
Mrs. Kirkwood, wife of Dr. Samuel Kirkwood, President of the American University of Beirut, would occasionally ask to join our group on a given amber trip which invariably started very early in the morning. The President would walk her to the door of Marquand House where they lived within the AUB Campus and tell her as she walked towards us : " Sunny, I think you are crazy !! " That would not help to change her mind. At the site, she normally had some difficulty getting down to the ravine where the amber is found. She would sometimes call Fadi to help her get on her feet whenever she stumbles while looking for exposed pieces of amber. At the end of the very enjoyable and rewarding expedition Fadi would, out of courtesy, give her some nice pieces of the amber he had collected.
It is certain that there are many more potential amber sites that need to be discovered throughout the country through extensive search and field surveys. Pertinent geological information to be provided by geologists familiar with the local conditions would greatly facilitate the identification of these potential sites. Such surveys may become necessary if it is desired to collect samples of amber from as many localities as possible in order to determine the environmental conditions prevailing during the early Cretaceous period, to form an idea about the geographic distribution of the fauna and the flora existing at the time in various parts of the country.
The number of pieces of our amber that have been treated in preparation for microphotography is in the order of several thousands. Each of these contain at least one important fossil inclusion. In some specimens the interesting fossil inclusions are numerous. Not uncommonly, a piece of amber the size of a wheat grain may contain several inclusions, but such specimens are extremely difficult to polish manually under the microscope.
At the beginning of the 1970's, the first attempts at photographing the microscopic inclusions were promising, but not successful. This was on account of the lack of appropriate equipment - a suitable microscope with a camera attachment.
By 1974, once a limited fund was made available, unsophisticated equipment were purchased, and the results were spectacular. In 1976, at the time when the disturbances reached their climax, about 350 colored slides were prepared. The films had to be sent to the British Museum (Natural History) for development through the courtesy of Dr. Paul Whalley as it was not possible to do so in Beirut at the time.
While the work on the amber never actually ceased, except for short spells of time, photographing the microfossils was resumed in January 1980 in a systematic manner, and on a more intensive basis. This was possible for three prime reasons:
1.3 2 The Work by Dr. Paul Whalley
Negotiations with the British Museum (Natural History) led to an agreement to have a group of experts headed by Dr. P. Whalley to carry out a study of some of the insect fossils contained in the Amber of Lebanon. The preliminary inspection of a few trial specimens convinced Dr. Whalley to undertake the task of selecting as many pieces of amber that he and his collaborators are capable of studying the kinds of insects of interest to each one of them. Accordingly, in 1973 a substantial batch of amber pieces were hand-carried to London as previously mentioned, and soon thereafter the scientific study of the Acra collection of the Amber of Lebanon commenced at the British Museum (Natural History) in London
Actually, several batches of amber were hand-carried and delivered to Dr. Whalley in London. This was partly prompted by the need to safeguard as much of the best part of our amber collection as possible from the ravages of the on-going civil war. In this way, more that 1000 amber specimens were transferred to the British Museum (Natural History), where the study continued until February 1980. They were then brought back to Beirut by my colleague, Miss Zeina Raffoul, for the purpose of photographing the inclusions by me at AUB. It is important to note that all of the specimens sent to Dr. Whalley were collected from only one location in southern Lebanon. Therefore, they are not necessarily representative of the specimens in the other amber sites known to us at the time. The preliminary studies undertaken by Dr. Whalley indicate that among the amber specimens available at the British Museum there are 561 complete fossil insects, apart from the many more fragments of insects (e.g. heads, wings, and appendages) that are often recognizable. For further details reference should be made to the preliminary report by Dr. Whalley (see Appendix).
Certain fossil insects present in our amber collection were selected and studied by Dr. Whalley and others with the aim of identifying and classifying them. Dr Whalley, for instance, selected and described the characteristic features of certain fossil moths that led to their classification and nomenclature. He then published his findings in three papers. In recognition of the important contribution of the Acra's, Dr. Whalley named three of the six moths studied by him as indicated below:
1.3 3 The work by certain German Scientists
Guided by the observations recorded by Russegger (1836) and by Fras (1875) regarding the presence of a certain kind of amber in the southern Lebanon, an expedition was organized by some German scientists under the leadership of Dr. Schlee for the purpose of collecting amber from the location mentioned by Russeger And Fras. This expedition took place in the winter of 1968-69, and was limited to one locality near Jezzin. The site from where this group of scientists collected amber is only one of the many where our team managed to find since 1962.
Several papers and monographs have been published to-date as a result of the studies carried out at the Stuttgard Museum by Dr. Schlee and his associates. In fact a chapter was devoted to the Amber of Lebanon in a book recently published by Von Dieter Schlee.
1.3 4 Amber in Israel
A. Nissenbaum reported in 1975 that some amber specimens were recently collected from four localities in Israel, two of these localities being very close to the southern border of Lebanon. The specimens are believed to date back to the Lower Cretacious period, and are therefore of the same age as those found in the southern parts of Lebanon.
Nissenbaum believes that the deposits of amber, existing in Israel form part of a continuous belt of amber deposits of the Lower Cretacious period that extends over a distance of several hundred kilometers from Lebanon to Israel. This belt is supposed to be almost as extensive as that of the Baltic amber.
Well preserved fossil fungi have been reported in amber specimens collected from southern Israel but the study of other inclusions was underway.
1.3 5 Amber in Jordan
Abbas Haddadin Abdallah, a school teacher from Jordan, wrote to me in 1974 indicating that he was stimulated by my recent reports in the media on the existence, collection, and study of the Amber of Lebanon. He, therefore, wished to have more information about this amber and its characteristics to guide him in his search for amber in Jordan during his spare-time job of surveying plots of land.
In response to this request, I sent him a letter in which I provided him with the needed information, particularly about the method of collection, washing, coding, polishing, microscopic scanning, and photography of the inclusions. The samples of transparent light brown amber subsequently collected by him in the vicinity of ancient town of Jarash, and which he mailed to me for inspection and comments, were found to be devoid of any identifiable biological inclusions. However, I replied that the specimens were indeed amber, though devoid of biological inclusions, and that I adamantly encourage him to continue his search in various localities.
Communications between me and Abbas were interrupted because of the disturbances in Lebanon, and resumed again in 1980 by me after having recieved a paper published (May 1979) jointly by K. Bandel ,a German paleontologist serving as a professor at the University of Jordan in Amman, and A. Haddadin Abdallah entitled "The Depositional Environment of Amber-Bearing Rocks in Jordan". I wrote to Abbas to congratulate him heartily for his achievement.
In this report, the authors announced the discovery of amber of the Lower Cretaceous period in 1977, thus placing it at the same age as that of the Amber of Lebanon. Several amber-bearing sites were identified and studied in this Zarqa River basin between the King Talal Dam and Jarash.
The colour of the Amber of Jordan is usually red-brown, with shades ranging from brown-honey colors to almost colorless yellow. Some of the specimens are clear and transparent as glass, and others are opaque. Most of the amber specimens found are quite brittle, except for a few that are of semi-gem quality.
Fossil plant remains were also found in the amber-bearing sediments and rocks. These include fern leaves (Weichselia reticulata), as well as fossil wood, roots and leaves believed to be those of a gymnosperm conifer tree of the Araucariacea family related to the large pine trees of the genus Agathis still existing in the Southern Hemisphere. The kauri copal or kauri gum is obtained from the kauri pine Agathis australis, which is New Zeland's largest and most important kind of tree. Copal is a subfossil gum found in the ground in areas forested with Agathis pine trees in prehistoric times, and resembles fossil amber in many respects.
Based on their findings and those of others, K. Bandel and A. Haddadin Abdallah have postulated a picture depicting the environmental conditions existing in the area where the Amber of Jordan was produced by the large forest trees during the Lower Cretaceous period (120-135 million years B.P.).
During the Lower Cretaceous period Jordan belonged to the realm of the Southern Hemisphere as part of the Arabian-African continent. It was separated from the Northern Hemisphere by the barrier of the Tethys Sea. This explains the great differences in climate, as well as in the fossil flora and fauna found in Jordan compared to those of similar age found in Europe and North-America.
At the beginning of the Lower Cretaceous period, Jordan was bordering the ancient sea which lay to the west. A river system originating from the Arabian-African Continent flowed through Jordan from the south and east towards the sea. The Jarash area, where amber was recently found, formed part of the coastal region.
The coastal region was penetrated by streams that brought what is now termed as the Kurnub Group of sediments that were deposited on the banks of the streams flowing towards the coast. The coastal region consisted of deltas and estuaries, and must have been studded with muddy swamps and shallow lagoons of fresh or somewhat saline water separated from the sea by sandy shoals.
A vegetation composed of ferns, cycadophytes and conifers covered the riverbanks, the coastal lowlands, and the swamp areas. The ancient conifer tree (family Araucariacea) with some affinity to the modern Agathis conifer represented the principal tree that grew in the coastal swamps and forests. These conifer trees produced resins that were transformed into fossil amber through loss of volatile matter and oxidation of the resin itself.
The coastal lowlands were periodically flooded by transgressions of the sea, afterwards to fall dry again when the sea regressed. During the periods when the sea transgressed these forested coastal lowlands, the conifer trees and other vegetation died, and were substituted by marine flora and fauna. Hence, the coexistence of the fossil remains of both terrestrial and marine plants and animals in the form of fossils in the Jarash area. Such changes in the environmental conditions are believed to have occurred five times during the Lower Cretaceous period.
Fossil Insects in the Lebanese Amber (Lower Cretaceous Period). A report by Paul Whalley, British Museum (Natural History), London (1974 - 1977).
Of a total number of Lebanese amber fragments submitted to the British Museum (Natural History) by Professor Aftim Acra and his son (well over 1000 pieces) there were 561 complete and exceedingly well preserved insects, apart from the many more insect fractions included in the specimens (heads, appendages, wings, etc.). Excluding such insects that are recognizable as mites, spiders and pseudo-scorpions, the ones studied in a more or less preliminary fashion are listed below .
Diptera include the earliest acalyptrate and many Nematocera. Amongst these are Phlebotomus (all males at present!) but which Dr. D.J. lewis says are important in relation to the disease transmission/continental drifts problem.
Homoptera include Cicadellidae and Fulgoridae, one of which Dr. Fennah has determined almost to genus (Oliarus), pointing out that the characters have remained virtually unchanged for over 100 million years. Neuroptera are particularly interesting with Coniopterygids and Beorthids. The latter is a rather rare tropical family. Species of recent Berothidae have raptorial forelegs which show clearly in the amber fossils
Age: Lower Cretaceous. 100-130 million BP. Aptian or Neocomian age not agreed currently but there are several deposits which may be of either age (still over 100 million BP)
Quantity: We have over 1000 pieces which have yielded 561 complete insects and many more (often recognisable) fragments. Prof. A.Acra and F. Acra have a larger quantity available and know of many sites.
Quality: Insects, plants, arachnids. Gaseous, mineral and liquid inclusions common* (Acra, personal comm.). Certainly our "sample" is a very rich specimen. Many of the insects are perfectly preserved and can be:
While I have seen many small inclusions, they have not been studied. It is possible that protozoa, bacteria, diatoms (and perhaps viruses?) are trapped in the amber and will be visible under the electron microscope. Similarly, the botanical and the mineral/gas inclusions need studying. The possibility of deriving more direct information about the Lower Cretaceous environment is perhaps feasible with this amber. I have made a preliminary infra-red spectroscopic examination of the amber (after instruction by the Department of Mineralogy). Further botanical and mineralogical advice on these results are needed.
Insect Orders: 1000+fragments 562 (whole) insects
The Lepidoptera are very important, both from the evolutionary and comparative morphology aspects but also their co-evolutionary relationship with flowering plants.
* I have also seen inclusions.
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