Terrestrial carbon isotope excursions and biotic change during Palaeogene hyperthermals
Terrestrial carbon isotope excursions and biotic change during Palaeogene hyperthermals
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DOI：
10.1038/ngeo1427
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发表时间：
2012-05-01
影响因子：
18.3
通讯作者：
Lourens, Lucas J.
中科院分区：
文献类型：
--
作者：
Abels, Hemmo A.;Clyde, William C.;Lourens, Lucas J.
60 至 5000 万年前明显的短暂全球变暖事件与轻同位素碳快速注入海洋大气系统有关(1,2)。然而，目前尚不清楚最大的高温事件，即古新世-始新世最热事件（PETM；参考文献 3），是否与随后的温室气候事件 (1,6)（例如始新世最热事件 2 和 H2 事件）具有相似的起源 (4,5)。这些事件的时间和演变在海洋记录中有详细记录(7,8)，但在陆地上并没有很好的限制。在这里，我们报告了来自美国怀俄明州比格霍恩盆地的古土壤碳酸盐结核的碳同位素记录，这些记录记录了高温。我们的年龄模型源自旋回地层学，并显示了陆地和海洋记录中类似的事件结构。此外，陆地同位素偏移的幅度与海洋记录一致，这表明每次事件期间局部古环境变化的严重程度与全球碳同位素偏移的大小成正比。我们将这种一致性解释为在所有三种高温期间碳释放的类似机制的指示。然而，与 PETM 期间不同（参考文献 9,10），随后的高温期间的陆地环境变化与大角盆地哺乳动物动物群的大量更替无关。
Pronounced transient global warming events between 60 and 50 million years ago have been linked to rapid injection of isotopically-light carbon to the ocean-atmosphere system(1,2). It is, however, unclear whether the largest of the hyperthermals, the Palaeocene-Eocene Thermal Maximum (PETM; ref. 3), had a similar origin(4,5) as the subsequent greenhouse climate events(1,6), such as the Eocene Thermal Maximum 2 and H2 events. The timing and evolution of these events is well documented in marine records(7,8), but is not well constrained on land. Here we report carbon isotope records from palaeosol carbonate nodules from the Bighorn Basin, Wyoming, USA that record the hyperthermals. Our age model is derived from cyclostratigraphy, and shows a similar structure of events in the terrestrial and marine records. Moreover, the magnitude of the terrestrial isotope excursions is consistently scaled with the marine records, suggesting that the severity of local palaeoenvironmetal change during each event was proportional to the size of the global carbon isotope excursion. We interpret this consistency as an indication of similar mechanisms of carbon release during all three hyperthermals. However, unlike during the PETM (refs 9,10), terrestrial environmental change during the subsequent hyperthermals is not linked to substantial turnover of mammalian fauna in the Bighorn Basin.