Paleontologists in China found 241 tiny pieces of amber in the Hujiersite Formation in Xinjiang, and the Middle Devonian amber fossil China find is about 385 million years old. That pushes the earliest known amber record back by about 65 million years.
Cihang Luo, with the Nanjing Institute of Geology and Palaeontology at the Chinese Academy of Sciences and the Senckenberg Research Institute and Natural History Museum, said, "Amber, specifically fossilized resin, is thought to be one of the ancient exudates of seed plants" and added, "Secreted resin hardens and transforms into amber during diagenetic and catagenetic processes, under elevated temperatures and pressures."
Hujiersite Formation in Xinjiang
Researchers analyzed about 10 kg of coal from a coal seam near Hoxtolgay in China’s Xinjiang region. Under ultraviolet light, they found small clusters of amber embedded in the coal, then extracted 241 pieces by hand under a microscope. Most pieces measured just 0.1 to 0.5 mm across, and some contained bubbles.
The fossils fluoresce bright blue under ultraviolet light. Most of the amber is translucent to opaque and ranges from pale yellow to dark brown. The amber-bearing layer in the Hujiersite Formation is Middle Devonian and approximately 385 million years old.
Carboniferous amber records
Until this find, the oldest definitively verified amber came from the Late Carboniferous and was about 320 million years old. Another definite record from the latest Carboniferous of Canada was about 300 million years old. Before the Permian period, there are only two definite records of amber from the Carboniferous period.
Luo said, "The viscous resin sometimes traps organisms, which are subsequently preserved as fossil inclusions within amber, providing critical information on the evolution of terrestrial ecosystems." He also said, "Although amber is a unique repository of environmental, diagenetic, and biological data, its occurrence is not continuous through Earth history."
Resin before seed plants
Fourier transform infrared spectroscopy and gas chromatography coupled with mass spectrometry showed that the Hujiersite amber’s chemistry closely resembles resin from modern and fossil conifers rather than resin from flowering plants. Seed plants had not yet evolved when it formed, so the authors suggest the resin likely came from progymnosperms or tree-like lycopsids.
For researchers studying early terrestrial ecosystems, the practical result is a much older amber record with preserved material old enough to test how resin production began before seed plants existed. Which exact ancient plant lineage produced the Hujiersite amber is not settled by the findings, so the discovery now gives scientists a dated target, not a final answer.
