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

海洋同位素阶段（MIS）M2发生在329万年前，被描述为气候系统达到完整冰川状态的早期失败尝试，代表了上新世的第一个严重寒冷时期。 然而，紧接着是一段异常和持续的温暖时期，由于其与模拟未来气候的相关性，引起了人们的强烈兴趣。 而M2在很大程度上被忽视了。 我们的研究重点是冷事件MIS M2，它的开始，（在）稳定性，恢复，并过渡到持续的温暖，我们是第一个已经发表了具体和详细的。我们的研究结果显示，北大西洋电流（NAC）突然向南移动，使格陵兰冰盖扩大。 然而，尽管这些原因对于未来和过去气候的建模至关重要，但新议程不稳定的原因仍然不确定。 拟议的研究通过以千年尺度分辨率分析北大西洋的新站点来扩大我们的空间覆盖范围。 我们使用一种新的组合代理（甲藻孢囊，地球化学，冰筏碎片）重建海面温度，盐度，冰融化的证据，和NAC的强度。

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.