概括
甲时期的极地澳大利亚在一个凉爽的季节性气候中拥有多样化的生命,包括特有恐龙. 这表明寒冷和黑暗并不是恐龙灭绝的唯一驱动因素.
科学领域:
- 古生物学的古生物学
- 古气候学 古气候学
- 生物地理学是生物地理学.
背景情况:
- 在白纪 (大约1.05亿至1.30亿年前) 期间,全球各地出现了多样化的陆地生态系统.
- 极地通常被认为是恶劣的环境,可能会限制复杂的生命.
研究的目的:
- 研究澳大利亚东南部的白纪极地生态系统的组成和气候.
- 分析这个高度生物群对恐龙生存和灭绝理论的影响.
主要方法:
- 对化石脊椎动物,无脊椎动物和植物 (>150个种类) 的分析.
- 氧同位素分析用于古气温度重建的diagenetic石.
- 化石树林的树年代学,以推断季节性.
主要成果:
- 发现了一种多样化的生物群,包括特有的海普西洛福登蒂德和热足动物 (例如,Allosaurus).
- 古气候重建表明凉爽 (年平均温度<5°C) 和季节性气候.
- 对于像迷宫形两动物这样的种类来说,延长生存的证据.
结论:
- 澳大利亚东南部的白纪极地带支持了丰富的非热带生态系统.
- 恐龙对高度条件的适应能力挑战了寒冷和黑暗在它们灭绝中的主要作用.
- 地理隔离可能在某些种类的延长生存中发挥了作用.
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