Geology and gemology of the Bayburt amber occurrences

Amber, which is the fossilized version of trees' natural defense mechanism of resin, is found in Baltic countries, Italy, Mexico, Canada, Myanmar and Dominican Republic. The majority of economically valuable ambers are being extracted from Baltic countries and these ambers are of Eocene age. Ambers of Eocene age are investigated for the first time in our country with this study. Additionally, physical, mineralogical and gemological properties of Baltic and Bayburt ambers of the same age have been investigated hereby to present their similarities and differences. Regionally being located within the old Eocene flysch type submarine delta environment, Bayburt amber lies within a sedimentary rock series of mudstone, sandstone and small quantities of marn folded due to high amounts of tectonism. These ambers are generally nodular shaped, 3-10 cm in size and have colors of honey yellow, orange and dark red. The amber formations are found in Sırataşlar Formation that consists of Eocene limestone, sandstone, gravel, occasional marn and sandy limestone. Channel formations filled with sand and gravel are observed near the upper segment of the amber-bearing layers. This points out that the deposits are generally formed near the shore and the delta environment. In electron microscope examinations it is observed that Bayburt amber has a very homogeneous texture. Due to high levels of tectonism marcasite, pyrite, opal and calcite minerals have been formed secondarily in the macroscopic and microscopic cracks present in the ambers. At some levels, amber formations are accompanied by jet stones. Occasional pyrite formations have been observed in between the cracks of organic, branch-like and ligneous textured jet stones. The identification of ambers using FTIR is established with characteristic peaks located at 2923 and 2847 cm-1. When peak intervals at 500-1500 cm-1 were investigated, some differences between Baltic-Dominican ambers have been found. Nevertheless, the most obvious peak differences have been observed between peaks at 1050-1350 cm-1. The differences and similarities in the peak values showed that the compared amber presented similar values even though they were formed in different places, times and environments. As a result of the analyzes made, it was determined that Bayburt amber is real amber.