APPLICATION OF PLANT FOSSILS IN THE RECONSTRUCTION OF THE LATE TRIASSIC PALEOENVIRONMENT AND ECOSYSTEM IN NORTHERN CHINA
The Triassic marked a pivotal transition for modern ecosystems, with early and late mass
extinctions and vertebrate groups emerging. Floras diversified after the end-Permian
crisis; early Triassic vegetation was low in diversity, but the Late Triassic hosted more
complex assemblages, shaped by Pangaea’s vast landmass and broad distributions. This thesis
investigates three Late Triassic plant-fossil topics from western Liaoning and the Karamay
Formation, Xinjiang. In western Liaoning, the Upper Triassic Yangcaogou Flora comprises 77
species in 34 genera studied for decades. A refined profile enables correlations with middle
to-high-latitude ecosystems across North China, Japan, Korea, and Russia’s Far East before
Pangaea’s breakup. Detrital zircon dating provides the flora’s first isotopic age, about 226 Ma,
anchoring it to the North China Craton and enabling reconstruction of the paleoenvironment
in the northern western Paleo-Pacific zone under Pangaea’s climate.
In Shendigou, Junggar Basin, Late Triassic phytostratigraphy clarifies biostratigraphy and vegetation
trends. Abundant seed ferns preserved in cuticles illuminate past CO2 and paleoclimate. Macro-and
mesofossil charcoal indicate conifer participation and wildfires, implying a more diverse conifer
flora and a seasonally wet climate in mid-latitude northeastern Pangaea.
Studying plant fossils from the Triassic Karamay Formation in the Junggar Basin, and their
implications will improve our understanding of the terrestrial recovery after the most severe mass
extinction events in the Earth’s history. Also, it will provide significant information on the
environmental circumstances that may have impacted the Triassic ecosystems.
Additional information: Miss Yangyang XIA, u3008601@connect.hku.hk