古生代後期の気候に地殻変動と天文学的要因が影響（PKU Breakthrough: Tectonics and Astronomy Shape Late Paleozoic Climate）

2025-10-27 北京大学（PKU）

北京大学エネルギー研究所の金之俊院士らの研究チームは、古生代後期（約3億6,000万〜2億5,000万年前）の気候変動が、地球内部のテクトニクス活動と天文学的周期の相互作用によって形成されたことを明らかにした。プレート運動・火山活動・山脈形成などの地殻活動が活発な時期にはCO₂放出が増え、気候が不安定化。一方、活動が穏やかな時期にはCO₂放出が抑えられ、軌道変動による温度・降水の周期変化が明瞭化し、有機炭素の大量埋没が進んだ。これは地球内部と外部（太陽系運動）の結合が長期的炭素循環を制御してきたことを示す。研究はNature Communications誌に掲載され、現代の気候変動理解にも新たな視座を与える成果となった。

Fig. 1. Late Paleozoic climate variability in temperature and precipitation (360–250 Ma).

＜関連情報＞

後期古生代気候と有機炭素埋没の形成における地殻変動と天文学的相互作用 Tectonic–astronomical interactions in shaping late Paleozoic climate and organic carbon burial

Ren Wei,Zhijun Jin,Mingsong Li,Shuai Yuan,Yongyun Hu,Lin Dong,Rui Zhang & Juye Shi
Nature Communications Published:27 August 2025
DOI:https://doi.org/10.1038/s41467-025-63896-z

Abstract

Tectonic processes and astronomical cycles are key drivers of Earth’s climate and carbon systems. However, their interplay in shaping late Paleozoic climate variability remains poorly constrained. Here, we divide the late Paleozoic (~360–250 Ma) into three distinct tectonic phases based on full-plate tectonic reconstructions, geochemical datasets, and carbon cycle modeling, thereby elucidating how global sea levels and organic carbon burial responded to astronomically forced climate fluctuations under different tectonic phases. Our results show that intervals spanning ~360–330 Ma and ~280–250 Ma were characterized by elevated atmospheric CO₂ levels and intensified tectonic activity, which coincided with heightened climate variability and reduced regularity in orbitally paced sea-level changes. In contrast, during ~330–280 Ma, multiple proxies indicate reduced tectonic forcing and lower CO₂ concentrations, which were accompanied by more stable climate conditions and clearer expression of astronomical cycles. These conditions facilitated rhythmic deposition and widespread organic carbon burial.