BALTIC AMBER

Of all the amber deposits in the world, probably the most famous and certainly the largest is that of the Baltic region. It represents some 80% of the worlds known amber resource. Going back into prehistory this amber has been used and fashioned by humankind in countless ways and in measureless quantities.

Amber from this source can be found on the East Coast of Britain all the way to the far shores of Estonia. The Baltic amber deposits range between 35 to 40 million years old and is without the largest source of amber yet discovered.

Botanical Origins

The source of most of this amber has for many years presumed to be the extinct species of tree Pinites Succinifer. This conclusion was originally made by Aycke in 1853. However, as recently as 1985 Poinar and Haverkamp completed research involving infrared spectroscopy and drawing on earlier thin-layer chromatographic studies by Kucharska and Kwiatkowski cast some doubt on this long held view. Poinar et al speculate that probably more than one tree was responsible for the Baltic amber deposits.

Grimaldi in his latest book ‘Amber - Window to the Past’ refers to current research (not specified) which may at last resolve this mystery. Most Baltic amber possesses Succinic acid. This is a problem when attributing Baltic fossil resin to a species of pine, as up until recently no extant pine tree resin was known to contain succinic acid. But, two recent pine tree genera’s have been found which do possess succinic acid in their resin, they are Keteleeria and Pseudolarix. The latter has been discovered in the Eastern mountain ranges of China. An important and relevant observation is that the ecological systems which are supported by the Pseudolarix trees in China appear to reflect those presumed and extrapolated from the inclusions discovered in Baltic amber.

What is equally interesting is the presence of Pseudolarix pine cones in a fossil resin discovered on the Axel Heiburg island in Canada which also has succinic acid present. From this it can safely be presumed that this tree was capable of producing the resin which would transform over millions of years into amber. Pseudolarix is therefore beginning to look more likely as the true source of the Baltic Amber deposits.

It should of course be recognised that the term Baltic Amber is a generic one, and under this umbrella term are many subdivisions of this fossil resin. (Click here to read about some of these sub divisions). Bitterfield amber, from the now abandoned German coal mines, for instance, comes under the general heading of Baltic amber. Bitterfield amber is the youngest from this source being 20 million years old. This wide range of Baltic amber varieties may in some part account for Poinar and Haverkamp’s findings.

Of the total amber obtained from this region approximately 90% possesses the Baltic amber signature chemical; succinic acid, which constitutes some 8% of the amber by weight, hence the official name of Succinite for amber originating from this region.

The Amber Forest

The size of the Baltic amber forest has been speculated upon by various scientific bodies and researches, amongst them being:

Barabara Kosmowska-Ceranowicz, Ph.D. of the Polish Academy of Sciences - Museum of the Earth.
Patty C. Rice, Ph.D. Author, ‘Amber - the Golden Gem of the Ages’.
Åke Dahlstrom & Leif Brost of the Swedish Amber Museum.

Reviewing the content of this work the following map is offered as an amalgamation of their combined efforts and an averaging of their results.

the Baltic Sea and Scandanavian Penninsula.As you can see it occupied the greater part of

It can clearly be seen from this that the forest must have ranged over a huge area over a long period of time. It is unlikely though possible that during some periods it occupied the entire region simultaneously.

Despite this original position of the amber forest, fossil resin from this area has been discovered in: Poland, Germany, Lithuania, Latvia, Estonia, Denmark, Sweden, Holland, the United Kingdom and Belorussia, some areas are more prolific in their amber bearing strata than others. Significantly around the southern coast of the Baltic sea and predominantly the Samland Peninsula, particularly the Northwestern part of Kalingrad, an area of some 1280 square kilometres. This area actually accounts for 90% Baltic Amber production. There are a number of reasons for this concentration, some are commercial and others natural.

When amber was first found to proliferate in this district individual private collectors soon turned into professional collectors/dealers. This ‘amber boom’ in the late medieval period lead to amber collecting laws, (Click here to read about the human history of amber) and from these early beginnings an industrial centre developed to which most amber was sent for processing and re sale. The Samland deposits were commercially exploited at a truly industrial level from the mid 19th century onwards.

The geological reason for the concentration of amber in this region has been described by a number of authorities. N.O. Holst, the Swedish State Geologist referred to an ancient river called the ‘Alnarps’ which he wanted to call the ‘Amber River’. The river followed a fault in the geological strata taking a roughly Southeast route starting near the city of Ystad and it has been tracked as far as Northern Själland. Barabara Kosmowska-Ceranowicz has identified an ancient river course which she has named the ‘Eridanus’ and also an ancient delta at the mouth of the ‘Eridanus’, which has been called the ‘Chlapowo-Sambian’ delta. None of these geological entities exist today. The Delta spilled out into an ancient sea basin called the ‘Tethys’. It was here that the newly transported resin, in some cases still plastic and soft began its long metamorphosis into amber.

Both researches state that these ancient river courses are pre glacial and probably eroded the primary deposit sites of the amber, carrying the fossil resin down stream, eventually feeding out into an area, part of which we now know today as the Samland Peninsula.

The route of these ancient rivers is detailed in the following map. Holst’s ‘Alnarps’ and, Kosmowska-Ceranowicz’s ‘Eridanus’, both in Red, the ‘Chlapowo-Sambian’ delta is shown in yellow.

Properties

Baltic amber generally has the following characteristics;
Hardness: 2.0 - 2.5 Moh’s Scale.
Specific Gravity - 1.050 - 1.096
Refraction Index - 1.54
Melting point - 480/720^Of (250/380⁰c)

Geological Occurence

The Samland Peninsula is famous for its ‘Blau Erde’ or ‘Blue Earth’ deposits within which the amber occurs. The ‘Blue Earth’ strata is located approximately 25-30 metres below the surface. On some areas of the coast, the ‘Blue Earth’ is much closer to the surface, on notable area being Palmnicken. The amber bearing layer must also outcrop on the sea bed in certain areas. After a strong storm out at sea or sever gales amber can be gathered from the beach. No doubt as a result of the currents tearing pieces out from the sea floor.

Confusingly the blue earth is in fact a green colour, a result of a mineral called Glauconite present in the soil, and nothing directly to do with the amber.

Here is a stratagraph showing the ‘Blue Earth’ in situ at the Samland Peninsula.

Adapted from Poinar - Life in Amber

As a result of trace fossils (Nannoplankton) present with the amber its age has been determined. (The dating of amber on its own is an imprecise science to date). The result of this research (Poinar - Life in Amber) is that Baltic amber ranges throughout the Eocene and Early Oligocene, a range of some 35 - 40 million years.