Hot summers in the Bighorn Basin during the early Paleogene
Hot summers in the Bighorn Basin during the early Paleogene
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DOI：
10.1130/g33567.1
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发表时间：
2013
期刊：
影响因子：
5.8
通讯作者：
K. Snell;B. Thrasher;J. Eiler;P. Koch;L. Sloan;N. Tabor
中科院分区：
文献类型：
--
作者：
K. Snell;B. Thrasher;J. Eiler;P. Koch;L. Sloan;N. Tabor
在古近纪早期，大陆内部的气候被认为比今天更温暖、更均匀，但对这一时期季节性温度变化的估计是有限的。古近纪的全球和区域气候模型预测大陆内部的温度比代理数据所暗示的要低，并且预测的季节温度范围与今天相似。本文通过对美国怀俄明州比格霍恩盆地古近系沉积物中古土壤碳酸盐的块状同位素测温，记录了夏季气温。我们的夏季温度估计值比化石叶片分析估计的年平均温度高~ 18°C。当这两个记录结合在一起时，产生的季节温度范围与今天该地区相似，冬季温度接近冰点。这些数据与bighhorn盆地早始新世的高分辨率气候模型结果一致。我们认为，在古近纪早期温室时期，大陆内部的温度在所有季节都更温暖，但并不比现在更均匀。如果总体上是正确的，这就消除了我们对温室条件下陆地气候动力学的理解中一个长期存在的矛盾。
During the early Paleogene, climate in continental interiors is thought to have been warmer and more equable than today, but estimates of seasonal temperature variations during this period are limited. Global and regional climate models of the Paleogene predict cooler temperatures for continental interiors than are implied by proxy data and predict a seasonal range of temperature that is similar to today. Here, we present a record of summer temperatures derived from carbonate clumped isotope thermometry of paleosol carbonates from Paleogene deposits in the Bighorn Basin, Wyoming (United States). Our summer temperature estimates are ∼18 °C greater than mean annual temperature estimated from analysis of fossil leaves. When coupled, these two records yield a seasonal range of temperature similar to that in the region today, with winter temperatures that are near freezing. These data are consistent with our high-resolution climate model output for the Early Eocene in the Bighorn Basin. We suggest that temperatures in continental interiors during the early Paleogene greenhouse were warmer in all seasons, but not more equable than today. If generally true, this removes one of the long-standing paradoxes in our understanding of terrestrial climate dynamics under greenhouse conditions.