A 99-Million-Year-Old Crime Scene
In the Hukawng Valley of Kachin State lies a vast deposit of amber known as Burmite. This fossilized tree resin dates to the earliest Cenomanian age of the mid-Cretaceous period, approximately 99 million years ago. U-Pb dating of zircon crystals found within the amber-bearing layers has established a precise maximum age of 98.79 million years. The amber shows a subtropical forest ecosystem that existed when dinosaurs roamed the Earth. The study of how organisms and materials become preserved in this amber is a field called taphonomy, and it shows a dynamic and sometimes violent story.
The resin itself was produced by coniferous trees, likely belonging to the Araucariaceae or Cupressaceae families. But the trees did not release these massive quantities of resin for no reason. Modern forestry shows that a major trigger for large-scale resin production is physical damage, especially from boring insects. The amber contains the evidence. Some pieces show flow structures that clearly originated from inside insect tunnels in the wood. This suggests that much of the Burmite deposit is the result of ancient trees producing enormous amounts of sticky resin to defend themselves—flushing out and trapping the insects that were attacking them.