Mid-Cretaceous High Arctic stratigraphy, climate, and Oceanic Anoxic Events
Mid-Cretaceous High Arctic stratigraphy, climate, and Oceanic Anoxic Events
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DOI：
10.1130/g36439.1
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发表时间：
2015-05-01
期刊：
影响因子：
5.8
通讯作者：
Fath, Jared
中科院分区：
文献类型：
--
作者：
Herrle, Jens O.;Schroeder-Adams, Claudia J.;Fath, Jared
在过去的几十年里，许多研究都集中在白垩纪中期的温室气候，广泛的富含有机物的黑色页岩的形成，以及从低纬度到中纬度地区的冷却间隔。然而，来自北极高纬度地区的数据有限。在本文中，我们提出了一个类似的高分辨率地球化学记录1.8公里厚的沉积序列暴露在阿克塞尔海伯格岛在加拿大北极群岛在一个类似于71度N的古纬度。这是第一次，我们有数据限制的时间和幅度最主要的海洋浮游生物事件（OAEs）在咸水（OAE1a）和货架（OAE1b和OAE2）设置在白垩纪中期高北极。这与低纬度深水记录报告的碳气候扰动是一致的。在阿普第阶上部到阿尔必阶下部观察到钙铝榴石层，覆盖时间约为6百万年。在118到112 Ma之间。虽然对斜长石的形成仍在讨论中，但这些年代确定的产状可能支持高北极斯维尔德鲁普盆地此时存在冷大陆架沃茨，这与最近来自亚热带大西洋的地球化学数据显示海面温度下降近4摄氏度是同时期的。
Over the past decades, much research has focused on the mid-Cretaceous greenhouse climate, the formation of widespread organic-rich black shales, and cooling intervals from low-to mid-latitude sections. Data from the High Arctic, however, are limited. In this paper, we present high-resolution geochemical records for an similar to 1.8-km-thick sedimentary succession exposed on Axel Heiberg Island in the Canadian Arctic Archipelago at a paleolatitude of similar to 71 degrees N. For the first time, we have data constraints for the timing and magnitude of most major Oceanic Anoxic Events (OAEs) in brackish-water (OAE1a) and shelf (OAE1b and OAE2) settings in the mid-Cretaceous High Arctic. These are consistent with carbon-climate perturbations reported from deep-water records of lower latitudes. Glendonite beds are observed in the upper Aptian to lower Albian, covering an interval of similar to 6 m.y. between 118 and 112 Ma. Although the formation of glendonites is still under discussion, these well-dated occurrences may support the existence of cool shelf waters in the High Arctic Sverdrup Basin at this time, coeval with recent geochemical data from the subtropical Atlantic indicating a drop in sea-surface temperature of nearly 4 degrees C.