Amber Deposits

Barbara Kosmowska-Ceranowicz

 Baltic amber deposits of industrial significance are found only in Russia, Poland, the Ukraine and in Germany. Therefore, names such as Baltic amber, Ukrainian amber and Saxon (or Bitterfeld) amber refer to the same variety of amber; they can be considered synonyms of the name succinite. The deposits of this amber belong to the secondary deposits of sedimentary origin, which means that before they were ultimately deposited they were transported over longer or shorter distances.

 Very much has been written about amber deposits, while 16th century maps also recorded a good deal of knowledge. The majority of the older, quite well-known literature on prospecting and deposit research is in the German language. This is related as a matter of course to the East Prussia’s long-lasting control over the biggest deposit. Amber was first mined from the cliffs and fished along a many-kilometre stretch of the Baltic coast, and then mined in the Sambian Peninsula. Polish naturalists of the modern era did not have as easy an access to as much research material. Therefore, the studies by Polish researchers of old remain less known. In his works from the 18th century, Gabriel RZACZYNSKI differentiates between amber from the Baltic (Succinum in Mari Balthica) and from the coasts (Succinum in littoribus). Citing older literature or his own observations, he listed some 40 towns of which about half stretched from Gdansk to Klaipeda, where amber had been known to occur. Also Stanisław Staszic – who is known as the father of Polish geology – recorded an important piece of information about amber finds in the vicinity of Radzyn and the River Tysmienica – this is an area near the now documented deposit of the Parczew Delta. Original and abundant records about amber outcrops can also be found in the first Polish monographs by Jan Freyer and Jozef Haczewski.

IN THE PALAEOGENE

On the northern coast of the Eocene Sea

 The western (Polish) part of the Gdansk Delta was discovered in 1983 thanks to three drill holes near the village of Chlapowo. Amber was found in each of the test boreholes. The amber-bearing sediments in the Chlapowo area occur at a depth of 67.0–132.5 m, with an average depth of 96.5 m. Research on the profiles from Chlapowo clearly indicates that this part of the Delta is a continuation of the eastern (Russian) part mined in Sambia. The depth of the deposition varies; in the area from Gdansk all the way to Karwia, the deposit lies at a depth of about 90-120 m, which for the time being precludes the possibility of its extraction. The more intense sedimentation in the western (Polish) part of the Delta and the greater depth of deposition than in the eastern part may indicate a lack of equilibrium (lability) of the sea floor. The region’s tectonics, also known from research on the rocks of its older substrate, made it possible for the Gulf of Gdansk to form much later. After the Baltic formed, the amber-bearing Palaeogene sediments from the central part of the Delta were ultimately eradicated completely during the Ice Age and taken south by glaciers.

 The identification of the amber-bearing “blue earth” of the Gdansk Delta is possible today by analysing heavy minerals, which determine a set of layers with epidote grains, typical for these sediments. Such sediments were found in the profiles of many drill holes in the Gdansk region. Furthermore, the sandy-clayey amber-bearing sediment can be identified because it contains glauconite, which is formed in a marine environment. Even though glauconite is a green mineral, together with the clayey sediment, especially dry clayey sediment, it produces a bluish tint.

 The dating of the amber-bearing sediments in the Gdansk Delta changed along with the progress in research: from the Early Oligocene to the Late Eocene (Bartonian), and even, according to research based on radiometric dating, to the Middle Eocene (Lutetian). In the Polish part of the deposit, in the profiles of the three Chlapowo I–III drill holes, the resources were estimated at 643 820 tonnes, although in individual layers amber was found in quantities from 132 to 5976.79 g/m3.

Baltic amber nuggets from the Paleogene deposit in Sambia typical for their natural forms and varieties:

[a] form developed between bark layers;	[b] two visible flat surfaces (from the top and from the bottom) and an outline of third which reflect the level of the initially liquid resin;	[c] form developed in a tree crevice with a natural cavity left by a branch.

On the southern coast of the Palaeogene Sea

 Succinite, equally suitable for working as that from the Baltic region, also accumulated in Palaeogene sediments along the southern coast of the Eocene Sea. We know of at least two amber-bearing deltas: the Parczew Delta in Poland, and the Klesiv Delta in the Polessye -Volyhn Region in the Ukraine. The amber deposit resources in the Parczew Delta are estimated at 6,911 tonnes.

 Diagram of the depositing of Ukrainian amber along the southern coast of the epicontinental Eocene sea basin

[1] Parczew Delta; [2]  Klesiv Delta

 Just as the Baltic region sediments with epidote indicate that the fossil resins come from Fennoscandia, the sediments with andalusite and turmaline minerals indicated that it was the Ukrainian Shield where the amber found in Gorka Lubartowska, and extracted in Klesiv, Ukraine originated. The Ukrainian amber (succinite) extracted in Klesiv stretches to Belarus territory in the area of Gatcha - Osova.

Ukrainian amber boulders from the Klesiv area	Ukrainian amber covered with a typical dark weathered layer

The amber deposit in Bitterfeld

The rehabilitated Goitsche Amber Mine site (from a paper by Tropp & Haferkorn, 2007)	Dripstone forms of Bitterfield amber

 Middle Germany is an area where succinite is found in deposits younger than those by the Baltic and in western Ukraine. The amber deposit in the Goitsche Mine in Bitterfeld was formed in a sea gulf in the area of the Thuringia Trough at the turn of the Oligocene and Miocene. The resins carried from the nearby lands in the south were deposited in clayey noncalcareous grey-black sands with a large amount of muskovite, dispersed plant matter and brown coal. The marine environment is documented by infrequent glauconite and the presence of sea plankton. The amber-bearing sediments lie above the brown coal deposit. News about the amber deposit, just as about other Palaeogenic resources, were kept a secret in communist East Germany, which hindered research into this area. However, we received permission to enter the mine in the 1980s and the results of the research conducted there were published. The discussions on the deposit’s origin went on for many years, today the papers from 2006 yield satisfactory results.

 In the Goitsche Brown Coal Mine near Bitterfeld, amber known as Saxon (or Bitterfeld) amber was discovered in 1974. In 1990, the strip mining was discontinued due to the enormous dust pollution of the surrounding areas and, following the flooding of the mine, was replaced by the underwater extraction method. The mine operated until 1993, after which extraction ended for economic reasons.

 The annual amber output reached 50 tonnes. The material from the Goitsche Mine supplied the amber product factory in

Damgarten (near Ribnitz), but in communist East Germany the products had no labels to certify the origin of the material. Bitterfeld amber has not come in such large nuggets as those found in the Baltic region or in the Ukraine. A typical feature of Bitterfeld amber is its relatively quick development of secondary varieties, where the colour changes from yellow to yellow-red.

Outcrops in pleistocene deposits

 The distribution of amber-bearing sediments, which have been consistently extracted since the Neolithic Age, concerns mostly finds in the youngest deposits from the Pleistocene and the Holocene, which we define as scattered deposits. These deposits (often called outcrops due to their limited resources) have got a direct link to the deposits described above, i.e. the transport (redeposition) of older amber deposits from the Palaeogene to the south from at least 40 million years ago.

 The greatest destruction to the Palaeogene deposit took place during the Ice Age in the Quaternary Period. Successive glaciations eroded older and older layers and transported them in reverse order. The greatest amber density seems to be in the sediments of the youngest Baltic glaciation.

 The maps of amber finds developed in several European countries16 produced a result that was perhaps dubious, but which indicated the astonishingly wide distribution of amber in the Quaternary Period. In Poland, amber was found at least 740 times. Given amber’s low density, softness and the nuggets’ varying size versus the transport conditions, climate changes and its occurrence alongside boulders and coarse-grained sand-gravel sediments, it is amazing how it is found so far away from its source area (alimentation area), which the Gdansk Delta was during the Pleistocene.

Amber was transported southward by glaciers, rivers/glaciers and rivers across large stretches of Europe. Amber was carried in two ways.

1. Entire packets of blue earth with intact structure were transported across long distances as so-called floes embedded in glaciers. In Poland, floes were discovered in Zielnowo near Grudziadz and in Mozdzanowo near Ustka. In Zielnowo near Grudziadz amber was found in significant amounts and it was a place where the material was extracted in a small strip mine. Individual pieces measuring from several to 15 cm were found.
 
 The mines in Mozdzanowo were already referred to in chronicles from the late 1700s. Amber mining was performed in shafts up to about 22 m deep. However, the mine in Mozdzanowo was unable to withstand the competition with the developing mining industry in Sambia. Interest in the Mozdzanowo deposit reappeared in 1957, and then in the 1970s. The deposit’s documentation made it possible to determine the richest layer’s average depth at 11 m (5.45-17.5 m) and an average thickness at 1.7 m (0.15-3.4m). The resources were estimated at 20 tonnes (20,270.65 kg).
 
 Not enough research has been done on the amber-bearing sediments in the village of Ugoszcz, Bytow County, where large-scale amber mining developed at the turn of the 18th and 19th centuries. The mines operated for some 20 years. Mining went on at a depth of 12–15 m, and even up to 27.5 m20.
 

2. The second way amber was transported was through dispersed transport, sometimes as very well turned amber boulders in glacial tills, in water-glacial gravel, or as amber grains in Pleistocene sands. Geologists call amber boulders erratics, just as larger or smaller turned Scandinavian rock boulders.

The Breadloaf, a boulder-type amber nugget (3.25 kg) from a gravel pit near Zarnowiec. Private collection. Photo: J. Kupryjanowicz;
The Head, a boulder-type amber nugget

 One of the places where amber accumulated were sandur fans developing in front of the head of the continental glacier, accumulated by waters flowing out of tunnels in the ice or underneath it. One of these fans is the Kurpie sandur (in the middle Narew river basin), which besides accumulating amber in its sediments, also influenced the area’s present-day topographic profile, especially the development of the river network, which in the period that followed, the Holocene, took over the role of the water-glacial bodies and by rinsing the sandur sediments, led to the further segregation of chip material and the rinsing out of amber nuggets as the lightest of cobbles.

 As early as in the 17th century poet Maciej Kazimierz Sarbiewski wrote:
"Let songs cover this happy River Narew.
 Our boys and girls, when they look for the glimmering stones
 And gather the fiery tears of amber..."

 Amber extraction in the territory of the Russian partition of Poland began in 1796 when Wolgram de Voza commenced prospecting in the forests on the Kurpie sandur near the village of Wolkowe.

 The Tuchola Forest and the Kashubian Lakeland were other areas rich in amber in sediments “brought in” by glaciers or by the rivers that flowed out of them. In the Brda and Wda river basins, amber could be found in very large amounts right under the water’s surface or deeper up to 6 m. In 1835-1865, up to 200 workers laboured every day in some mines.

In the Kashubian Lakeland amber was extracted as early as in the 10th century on Amber Hill [Bursztynowa Gora] (105 m a.s.l..; today a nature reserve with an area of 5.03 ha) in gravel, sands and moraine clays in primitive strip mines. Traces in the form of craters with diameters up to 40 m and up to 15 m deep remain to this days.

Amber on holocene beaches

 Another instance of amber transport, this time not only from the old Palaeogenic deposits, but also from post-glacial Pleistocene deposits, was related to the origin and development of the Baltic Sea and the coastal sedimentation processes which go on to the present day. It is certain that amber finds on beaches, especially after heavy storms, were the first to be known to humankind and remain the best-known form of the fossil resin’s occurrence. This is why people who do not know much about amber’s history erroneously associate its origin with the young Baltic Sea, which is less that 10,000 years old.

Amber-bearing deposits originate especially from the period when the range of the coast of the Littorina Sea, the predecessor of today’s Baltic, changed (first transgression, then regression). They are covered with dune deposits. The richest, 8-metre layer with thin layers of peat (deposited some 7,000-4,300 years ago) occurs at a depth of 14 m. These are sands full of plant matter, which during undulation helped to trap amber and prevented it from escaping. When the former beach began to be covered with dunes, the amber was exposed to very special conditions (jewellery makers try to recreate these conditions, using methods based on high temperature and pressure in order to produce stones which are more interesting than the primary varieties). By basking in the hot sand and soaking in the rain, the nuggets assumed more intense secondary colours up to and including red, while their surface became covered in a thick layer of weathered amber.

An amber nugget which had basked in a dune and is covered with a „crust” of weathered amber

 The most ancient method of amber fishing with the use of nets (meshes fixed on long poles) is still in use today. For example, some 5 tonnes of raw amber was obtained each year in 1990 and 1991 by amber fishing during the spring and autumn storms.

 On the southern Baltic coast amber embedded in Holocene deposits has been long extracted (often illegally) using the hydraulic-cavity method. The sand that is pushed out onto the surface together with amber, pieces of wood and other plant remains (organic detritus) creates an alluvial fan where traps are placed to catch the amber and detritus into a net. Rinsing in a table salt solution takes place usually immediately near the area of extraction and separates the amber from the residue. The extraction from the Holocene deposits covers no more than 15-17% (ca. 30 tonnes) of the overall demand for raw amber, which in Poland in 1995 totalled some 200 tonnes.

 The history of amber extraction in large amounts on the southern coasts of the Baltic that dates back to at least the days of the Rzucewo Culture (during the Neolithic Age: 1700- 2400 BCE) shows that the accumulations of this material are renewable. Unfortunately, we will never know what the true resources on the Baltic floor were, because no records were ever kept of the material obtained from it.

 The recording of the places where amber appeared on beaches, for instance, from the west in Wolin, Darlowek, Jaroslawiec, Ustka, Wladyslawowo, Sobieszewo and others, indicates that these are mostly abrasive, wave-cut sections of the present-day coast. The results of prospecting research conducted since 1970 in the coastal area indicates that some 236 tonnes of amber were documented, of which 75% (= 177 tonnes) came from the mouth of the River Vistula. Recently a deposit in Stegna and Sztutowo has been documented.

 Amber in Holocene deposits in the Baltic coast area is of industrial importance in Poland. Therefore, research has to meet not only the requirements demanded of basic research, but also be directed to meet the needs of the large community of the amber industry.