Plio-pleistocene dinoflagellate cysts and paleoceanography of the North Atlantic region

上更新世甲藻包囊和北大西洋地区的古海洋学

• 批准号: 327150-2011
• 负责人: Head, Martin
• 金额: $ 2.04万
• 依托单位: Brock University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=548992
• 关键词: Plio; pleistocene; dinoflagellate; cysts; paleoceanography

Described as an early failed attempt by the climate system to reach a full glacial state, marine isotope stage (MIS) M2 occurring 3.29 million years ago represents the first severely cold episode of the Pliocene. Yet it was followed immediately by an interval of exceptional and sustained warmth that has attracted intense interest owing to its relevance for modeling future climate. MIS M2 in contrast has been largely overlooked. Our research focuses on the cold event MIS M2, its inception, (in)stability, recovery, and transition to sustained warmth, and we are the first to have published specifically and in detail on it. Our results show an abrupt southward shift of the North Atlantic Current (NAC) that allowed the Greenland ice sheet to expand. Yet the causes of NAC instability remain uncertain, although they are critical to the modeling of future as well as past climates. The proposed research expands our spatial coverage by analyzing new sites in the North Atlantic at millennial-scale resolution. We use a novel combination of proxies (dinoflagellate cysts, geochemistry, ice-rafted debris) to reconstruct sea-surface temperature, salinity, evidence of ice melting, and NAC strength.

329万年前发生的海洋同位素阶段（MIS）M2被描述为气候系统达到完全冰川状态的早期失败尝试，代表了上新世的第一次严寒时期。 然而紧随其后的是一段异常且持续的温暖时期，由于其与未来气候建模的相关性而引起了人们的强烈兴趣。 相比之下，MIS M2 在很大程度上被忽视了。 我们的研究重点是寒冷事件 MIS M2、它的开始、稳定性、恢复以及向持续温暖的过渡，并且我们是第一个专门详细发表该事件的人。 我们的结果显示北大西洋洋流（NAC）突然向南移动，导致格陵兰冰盖扩张。 然而，NAC 不稳定的原因仍然不确定，尽管它们对于未来和过去气候的建模至关重要。 拟议的研究通过以千年尺度的分辨率分析北大西洋的新地点，扩大了我们的空间覆盖范围。 我们使用一种新颖的代理组合（甲藻包囊、地球化学、冰筏碎片）来重建海面温度、盐度、冰融化的证据和 NAC 强度。