Sakhalin Amber (Naibuchi Fm., Middle Eocene [~47.8-38 Ma])
“Sakhalin Amber”
Sakhalin Island, Russia
Starodubskoye, Nayba River Estuary
Naibuchi Fm. (Autochthonous)
Middle Eocene (~47.8-38 Ma)
Specimen D: 0.3g / 14x8x5mm
Lighting:
140lm LED
Entry eight of ten, detailing various rare ambers from European, Asian, and North American localities.
The island Sakhalin is located in the Far East region of Russia, just north of the island of Hokkaido, Japan. Amber is usually found washed onto the shoreline, near the village of Starodubskoye; it is eroded from coal exposures of the Naibuchi Fm. and carried by the Nayba River, emptying in the Okhotsk Sea. The amber is considered autochthonous (found in original place of formation) or in the case of amber on the shoreline, parautochthonous (carried a relatively short distance from original deposit).
Sakhalin amber is a variety of Rumanite which, as has been shown through recent analyses (E.C. Stout, et.al. 2000), is an amber identical or nearly identical to succinite (Baltic amber) that has undergone a high degree of polymerization; significant geological forces (heat, pressure) exerted on the resin during its burial, altered the resin itself and degraded/deformed any biological inclusions contained in the resin. As is often the case with Rumanite, particularly Sakhalin amber, the cavities inside trapped insects are found filled with resin, due to the intense forces the resin was subjected to. Rumanite also has a slightly higher melting point than Baltic amber, at 300-350˚C (as opposed to 250-300˚C).
As of 2019, nearly 1,250 insect and arachnid inclusions have been discovered in Sakhalin amber, with aphids and chironomids (non-biting midges) comprising the majority of inclusions; strangely, beetle larvae are more common than their adult forms in this amber. Simetite, as a fresh resin, was believed to have low-viscosity as compared to other ambers; this property made it less likely for animals to become trapped. Interestingly, from a previously-studied collection of Rovno amber, it was found that 23% of all hemipteran inclusions were of the suborder Auchenorrhyncha, namely planthoppers (Infraorder: Fulgoromorpha, Superfamily: Fulgoroidea) and leafhoppers (Infraorder: Cicadomorpha, Superfamily: Membracoidea), with a 10% finding in Baltic amber, and less than 0.3% in Sakhalin amber: the low rates of occurrence in Sakhalin amber are possibly due to the small size of specimens in general, the low-viscosity nature of the resin, and/or a limited presence of planthoppers and leafhoppers in the ancient forest. Only a single leafhopper specimen has been described from Sakhalin amber.
Sources:
“First record of Cicadellidae (Insecta, Hemiptera, Auchenorrhyncha) from Eocene Sakhalinian amber”; ZooKeys, Issue 886; Christopher H. Dietrich, Evgeny E. Perkovsky 2019
“Amber Deposits in Romania, with Particular Emphasis on Those Located on the Eastern Side of the Carpathians (Bibliogeographical Considerations and a few Field Investigations)”; Annales d’Université Valahia Targoviste, Section d’Archéologie et d’Histoire, Tome XIX, pp. 33-56; Cârciumaru, et. al. 2017
Copyright
© Kaegen Lau
From the album:
Fossil Amber and Copal: Worldwide Localities
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Photo Information
- Taken with SAMSUNG SAMSUNG WB35F/WB36F/WB37F
- Focal Length 4.3 mm
- Exposure Time 1/49
- f Aperture f/3.1
- ISO Speed 80
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