A CO2 decrease-driven cooling and increased latitudinal temperature gradient during the mid-Cretaceous Oceanic Anoxic Event 2
A CO2 decrease-driven cooling and increased latitudinal temperature gradient during the mid-Cretaceous Oceanic Anoxic Event 2
复制标题
DOI：
10.1016/j.epsl.2010.02.027
复制
发表时间：
2010-04-15
影响因子：
5.3
通讯作者：
Schouten, Stefan
中科院分区：
文献类型：
--
作者：
Damste, Jaap S. Sinninghe;van Bentum, Elisabeth C.;Schouten, Stefan
白垩纪中期被认为是一个温室世界，与现在相比，大气pCO（2）和海洋表面温度显着较高，以及纬度温度梯度更平坦。这段时间间隔被塞诺曼/图伦的海洋缺氧事件（OAE-2，类似于9350万年前）打断，这是一个全球性的大规模有机碳埋藏事件，可能导致pCO 2大幅突然下降。然而，这种pCO（2）下降的气候后果还没有得到很好的限制。我们确定了第一个，高分辨率的海面温度（SST）记录OAE-2从深海沉积序列在大洋钻探计划（ODP）网站1276中纬度纽芬兰盆地，西北大西洋。通过使用有机古温度计TEX 86，我们发现跨越OAE-2间隔的SST非常高，但被显著大的冷却（5-11 ℃）打断，这与赤道大西洋站点的SST记录中的2.5-5.5 ℃冷却和“Plenus冷事件”同步。由于这一全球变冷事件与有机碳埋藏增加同时发生，因此它可能是对相关pCO（2）下降的反应。我们的研究结果表明，在全球变冷和大气pCO（2）减少的这一时期，原北大西洋纬向SST梯度大幅增加，表明温室气候条件下pCO（2）和纬向热梯度之间存在强耦合。(C)2010 Elsevier B. V.保留所有权利。
The mid-Cretaceous is thought to be a greenhouse world with significantly higher atmospheric pCO(2) and sea-surface temperatures as well as a much flatter latitudinal thermal gradient compared to the present. This time interval was punctuated by the Cenomanian/Turonian Oceanic Anoxic Event (OAE-2, similar to 93.5 Myr ago), an episode of global, massive organic carbon burial that likely resulted in a large and abrupt pCO2 decline. However, the climatic consequences of this pCO(2) drop are yet poorly constrained. We determined the first, high-resolution sea-surface temperature (SST) record across OAE-2 from a deep-marine sedimentary sequence at Ocean Drilling Program (ODP) Site 1276 in the mid-latitudinal Newfoundland Basin, NW Atlantic. By employing the organic palaeothermometer TEX86, we found that SSTs across the OAE-2 interval were extremely high, but were punctuated by a remarkably large cooling (5-11 degrees C), which is synchronous with the 2.5-5.5 degrees C cooling in SST records from equatorial Atlantic sites, and the "Plenus Cold Event". Because this global cooling event is concurrent with increased organic carbon burial, it likely acted in response to the associated pCO(2) drop. Our findings imply a substantial increase in the latitudinal SST gradient in the proto-North Atlantic during this period of global cooling and reduced atmospheric pCO(2), suggesting a strong coupling between pCO(2) and latitudinal thermal gradients under greenhouse climate conditions. (C) 2010 Elsevier B.V. All rights reserved.