Chronological framework for Lake Baikal and Lake Elgygytgyn drill cores and orbital forcing of continental climate in the Northern Hemisphere during the past 3.6 Ma

我们建议开发一个新的理解（a）轨道强迫和（B）演变的北方半球大陆性气候在上新世更新世使用两个世界上最长的连续古气候记录在ICDP资助的钻探项目：最近获得的3.6 Ma记录Elgygytgyn湖，西伯利亚东北部，和最高的3.6 Ma部分的记录贝加尔湖，西伯利亚东南部。我们将为这两个记录开发一个共同的轨道调整时间尺度，建立两个记录中个别冰川间冰期的准确相关性，并详细说明它们与海洋氧同位素阶段的关系。然后，我们将使用由此产生的新的共同时标来解决的轨道签名在大陆代理记录上新世“41-kyr世界”，（ii）的开始北方半球冰川在2.7马，（iii）过渡到“100-kyr世界”。我们将进一步解决（iv）在41-kyr世界的海洋δ 18 O记录中岁差频率缺失方差的“谜团”，以及（v）测试高纬度轨道强迫大陆信号是否与上新世冰期起源的“纬度热梯度假说”一致。在过去的3.6 Ma系统的贝加尔Elgygytgyn比较也将揭示（六）放大的机制相比，在北极的气候变化在轨道时间尺度上的北方半球中高纬度地区。

We propose to develop a new understanding of (a) orbital forcing and (b) evolution of the Northern Hemisphere continental climate during the Plio-Pleistocene using two world’s longest continuous paleoclimate records obtained in ICDP-funded drilling projects: the recently obtained 3.6-Ma record from Lake Elgygytgyn, NE Siberia, and the uppermost 3.6-Ma portion of the record from Lake Baikal, SE Siberia. We will develop a common orbitally-tuned timescale for both records, establish accurate correlations of individual glacial-interglacial intervals in both records, and detail their relationship to marine oxygen isotope stages. We will then use the resultant new common timescale to address the orbital signatures in the continental proxy records of (i) the Pliocene ’41-kyr world’, (ii) the inception of the Northern Hemisphere glaciations at 2.7 Ma, and (iii) the transition to the ‘100-kyr world’. We will further address (iv) the ‘mystery’ of missing variance at precession frequencies in the marine δ18O records of the 41-kyr world, and (v) test if the high-latitude orbitally-forced continental signal is consistent with the ‘latitudinal heat gradient hypothesis’ on the origin of the Pliocene ice-ages. A systematic Baikal-Elgygytgyn comparison over the past 3.6 Ma will also shed light on (vi) the mechanisms of amplification of climate changes in the Arctic as compared to those in the upper mid-latitudes of the Northern Hemisphere on orbital time scales.