深水浊积岩层序地层学研究中碳氧同位素的应用——以湖南大庸田坪剖面为例

The application of carbon and oxygen isotopes to the sequence stratigraphy of deep-water turbidites: An example from the Tianping section in Dayong, Hunan

笔者通过海平面变化曲线与碳氧同位素曲线比较,发现两者曲线基本吻合。碳同位素曲线显示的海平面变化更接近露头层序地层的海平面变化;氧同位素曲线与露头层序海平面变化大体一致,局部出现相反结论。碳同位素曲线对沉积环境变化较氧同位素曲线更敏感。通过两者曲线研究,说明运用稳定同位素曲线变化可作为浊积岩层序地层学研究的一个研究手段。

The variations in carbon and oxygen isotopic values may be used to deduce the sealevel changes of depositional environments and to study the sequence stratigraphy of deepwater turbidites. The correlation of the sealevel curve based on the outcrop sequence stratigraphy and carbon and oxygen isotopic curves for the Tianping section in Dayong, Hunan shows that: (1) the sealevel curve based on the outcrop sequence stratigraphy is in general agreement with the carbon and oxygen isotopic curves; (2) sealevel changes indicated by the carbon isotopic curve approximate to those based on the outcrop sequence stratigraphy, while the oxygen isotopic curve is in general agreement with those based on the outcrop sequence stratigraphy. Occasionally the opposite situations are present; (3) the carbon isotopic curve is more sensitative to sediment changes. The higher δ13C values may represent the finegrained turbidites and deepwater sediments in the same cycles.