Abstract
Amber has been used as jewelry, currency and incense for centuries and continues to attract people's attention today. Amber research has been developing in recent years and provides us with valuable information, for example about the composition of the atmosphere, but above all also about the life of animals and plants that were embedded in the resin.
The formation of amber is a long process that takes place in geological time in the order of millions of years. It begins with the production of resin by specialised glands and ducts of plants.
Its chemical composition is a mixture of volatile and non-volatile fat-soluble compounds. The reason for resin production is to protect plant wounds from infections, insects and herbivores.
The key process in the formation of amber is polymerisation, which is possible thanks to free radicals on non-volatile terpenes, most often diterpenes. Amber inclusions can be pyritised, silicified, or calcified when there are cracks in the amber that are due to pressure exerted by overlying sediments or local tectonics.
The oldest amber comes from the early Pennsylvanian (Carboniferous). Most Mesozoic amber comes from the Cretaceous, when terrestrial ecosystems were undergoing major changes.
The boundary for fossil resin to be considered amber begins with the Neogene period, the younger fossil resins are considered to be copal. Extraction of DNA from amber is impossible due to the rapid degradation of nucleic acids.
The species composition of amber inclusions is similar to those captured on sticky traps placed on the bark of trees, so they most often preserve insects living near or on the bark of trees, or in the soil. Sometimes small vertebrates such as amphibians, snakes and lizards are preserved in amber, and even rarer marine animals such as ostracods and ammonite shells if the resin was near coastal areas.
We know several areas in the Czech Republic where amber can be found, for example near Študlov or Valchov in Moravia.