Chamaecydin is a chemical compound with the molecular formula C30H40O3. It is made up of three six-membered rings and two five-membered rings and has one polar
hydroxyl functional group. It is well preserved in the rock record and is only found in a specific family of
conifers, the
swamp cypress subfamily. The presence and abundance of chamaecydin in the rock record can reveal environmental changes in ancient
biomes.
Chamaecydin is a
biomarker for certain species of
Conifer trees. Once living organism die, the organic molecules they biosynthesized often undergo various chemical transformations in the soil and thus usually retain only basic structures of the molecules that were synthesized. These modified molecules are biomarkers but can often only be used as chemical tracers for a wide group of organisms. Chamaecydin is rare because it is a polar molecule that is found perfectly preserved millions of years later, and can therefore be used to trace specific species.[5] Despite being a polar compound, chamaecydin is likely preserved because it is found trapped in
resinous plant material, where it is prevented from bonding to
kerogen. In the paleorecord, it is found in clayey sediments, which prevents further oxidation.[5] Chamaecydin is found in concentrations ranging 3–8.7 mg/g of organic carbon.[6]
Conifers, deduced by the presence of chamaecydin in the paleorecord, managed to flourish across a wide range of latitudes over Earth's history. Below are some well studied occurrences of
conifers.
The paleoflora of the Maritza-East basin was a marine environment that developed
limnic conditions due to a
marine regression. The area then experienced alternating dry and wet periods from intense precipitation during the
Oligocene to
Pliocene epochs (33.9-2.58 Ma). We can infer that the forested flood plains were dominated by Taxodioideae because of the presence of chamaecydin. The biomarker is captured in 3 thick
lignite beds that formed in the dry periods, with one bed reaching 30 m in thickness.[6]
Chamaecydin also confirms that large
deciduousconifer forests were present north of the Arctic Circle (78 N) during the mid
Eocene (45 Ma) at
Axel Heiberg island. This is a unique habitat, which required them to be dormant during 3 months of winter darkness. The Arctic Circle at this time was very different from today: it was ice free and warm (12-17 degrees warmer than today) with lots of precipitation. These deposits occur in
fluvial and
lacustrine settings.[8]
The mid
Eocene (45 Ma)
resinites from brown coal pits in northern
Germany contain chamaecydin and reveal a
cypress semitropical
swamp environment.[9]
^Simoneit, Bernd R.T.; Otto, Angelika; Kusumoto, Norihisa; Basinger, James F. (December 2016). "Biomarker compositions of Glyptostrobus and Metasequoia (Cupressaceae) fossils from the Eocene Buchanan Lake Formation, Axel Heiberg Island, Nunavut, Canada reflect diagenesis from terpenoids of their related extant species". Review of Palaeobotany and Palynology. 235: 81–93.
Bibcode:
2016RPaPa.235...81S.
doi:
10.1016/j.revpalbo.2016.07.012.
ISSN0034-6667.
^Simoneit, Bernd R.T.; Otto, Angelika; Menor-Sálvan, Cesar; Oros, Daniel R.; Wilde, Volker; Riegel, Walter (February 2021). "Composition of resinites from the Eocene Geiseltal brown coal basin, Saxony-Anhalt, Germany and comparison to their possible botanical analogues". Organic Geochemistry. 152: 104138.
Bibcode:
2021OrGeo.15204138S.
doi:
10.1016/j.orggeochem.2020.104138.
ISSN0146-6380.
S2CID228967077.