在海洋无氧事件期间二氧化碳的变化与入冈德瓦纳煤炭有关
Jennifer C McElwain1, Jessica Wade-Murphy, Stephen P Hesselbo
1Department of Geology, The Field Museum, 1400 S. Lake Shore Drive, Chicago, Illinois 60605-2496, USA.
Nature
|May 27, 2005
概括
海洋无氧事件 (OAE) 与碳循环变化有关. 这项研究使用叶子口腔数据表明,可能是岩入侵,而不是甲水合物,导致了Toarcian OAE.
科学领域:
- 古气候学 古气候学
- 地质化学 地质化学
- 古生物学的古生物学
背景情况:
- 海洋无氧事件 (OAEs) 标志着有机碳埋葬的增加,碳同位素游览和海洋灭绝.
- 托尔西安OAE (18300万年前) 与负碳同位素外流有关,可能是由甲释放引起的.
- 托尔西安OAE的两种假设包括从海洋气体水合物或入的有机丰富岩石中释放甲.
研究的目的:
- 为了调查Tuarcian OAE负碳同位素外流的因果机制.
- 为了重建高分辨率的大气二氧化碳水平在托尔西安OAE期间.
- 为了测试气体水合物与岩入侵假设的托尔西安OAE启动.
主要方法:
- 对化石叶子口腔频率的分析,以确定过去大气中的二氧化碳度.
- 海洋和陆地碳同位素记录的高分辨率地质化学分析.
- 古气候建模以推断全球温度变化.
主要成果:
- 大气中的二氧化碳水平初步下降350±100 p.p.m.v.,随后急剧上升1200±400 p.p.m.v. 在负碳同位素外流过程中.
- 推导全球冷却2.5 ± 0.1°C,随后温室变暖6.5 ± 1°C.
- 观察到的二氧化碳波动与气体水合物从气体中释放的灾难性甲不一致.
结论:
- 在Tuarcian OAE启动期间大气中二氧化碳变化的模式支持了岩入侵假设.
- 这些发现表明,卡罗 - 费拉尔多莱里特入贡德瓦纳煤的入侵导致热源性甲释放,导致负碳同位素外流.
- 这项研究为海洋无氧事件的触发因素和环境后果提供了关键的见解.
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