Stable isotope analysis and temperature reconstruction data from DSDP Hole 94-609B and ODP Hole 162-984B

The Greenland ice sheet is accepted as a key factor controlling the Quaternary glacial scenario. However, the origin and mechanisms of major Arctic glaciation starting at 3.15 Ma and culminating at 2.74 Ma are still controversial. For this phase of intense cooling Ravelo et al. proposed a complex gradual forcing mechanism. In contrast, our new submillennial-scale paleoceanographic records from the Pliocene North Atlantic suggest a far more precise timing and forcing for the initiation of northern hemisphere glaciation (NHG), since it was linked to a 2-3 °C surface water warming during warm stages from 2.95 to 2.82 Ma. These records support previous models, claiming that the final closure of the Panama Isthmus (3.0- ~2.5 Ma induced an increased poleward salt and heat transport. […]

格陵兰冰盖被普遍认为是控制第四纪冰川情景的关键因素。然而，始于3.15百万年前、结束于2.74百万年前的重大北极冰川化的起源与机制仍存在争议。对于这一剧烈降温阶段，Ravelo等人提出了一种复杂的渐进式强迫机制。与此相对照，我们新近从上新世北大西洋获得的亚千年尺度古海洋学记录，对于北半球冰川化（NHG）起始的精确时间和强迫因素提供了更为精确的见解，因为它与2.95至2.82百万年前温暖阶段期间2至3摄氏度的表层水增温相关联。这些记录支持了先前模型的观点，即巴拿马地峡的最终封闭（约3.0至2.5百万年前）导致向极地方向的盐分和热量输送增加。