峡东地区早奥陶世C同位素异常及其成因

摘要

以宜昌黄花场奥陶系剖面为研究对象,开展峡东地区早奥陶世C同位素研究,建立了峡东地区早奥陶世C同位素曲线,并识别出可全球对比的2次正漂移(C1,C3)和2次负漂移(C2,C4).通过分析峡东地区沉积相序列及海平面变化特征,发现峡东地区C同位素变化曲线与海平面波动曲线一致,表明峡东地区C同位素的变化主要受控于海平面的波动.%The carbon stable isotope curve was constructed in this paper from the Huanghuachang sections of Lower Ordovician in the eastern Yangtze Gorges area. δ13C data demonstrate that there existed two δ13C positive excursions(C1,C3)and two negative excursions(C2,C4), all of which are comparable in the global scale. Based on the sedimentary sequence characteristics of Lower Or?dovician in the eastern Yangtze Gorges area, the authors observed that the curve of δ13C is coincident with the curve of the regional sea-level fluctuations. This study indicates that the geochemistry as well as the sequences was well controlled by the sea level changes.