Exploring the potential of a new North American Plio-Pleistocene paleoclimate record from a drillcore from Paleo-Lake Idaho

这是先前获得批准的跨学科项目的后续提案，该项目专注于探索icdp衍生的MHAFB11岩心的古气候潜力，该岩心是来自古爱达荷湖的高质量沉积物岩心，可能发展成为北美中纬度地区晚上新世至早更新世气候和生态系统变化的关键档案。对于第一个项目阶段，提交了由三个提案组成的一个提案，我们在此将继续请求作为两个独立的，但仍在主题上相关的提案提交。本建议的pi在第一个项目阶段负责的子项目已经产生了一个重要的古地磁年龄标志（即高斯/松山反转的位置）和上新世/更新世过渡区间的第一个低分辨率花粉记录。本项目最后12个月的后续项目旨在(i)建立一个在MHAFB11核心440-730 m研究区间内平均分辨率为1.5 m的孢粉学数据集，据我们所知，这将是北美第一个此类数据集；（ii）生成基于花粉的植被和气候动态重建。在此基础上，该项目将建立北美西部中纬度地区上新世/更新世过渡时期的古环境和古气候概念模型。它将批判性地评估上新世-新世/更新世过渡期间气候过程的现有情景。特别是，它在北美西部的地理位置将使我们有可能检验一个假设，即来自太平洋的湿度增加可能为北美北部提供了水蒸气，从而允许北半球冰川作用的开始。

This is a follow-up proposal of a previously granted interdisciplinary project that focused on exploring the paleoclimate potential of the ICDP-derived MHAFB11 core, a high-quality sediment core from Paleolake Idaho that may develop into a key archive for late Pliocene to early Pleistocene climate and ecosystem change in the mid-latitudes of North America. Whereas for the first project phase one proposal consisting of three proposal components had been submitted, we here submit the continuation requests as two stand-alone, but still thematically related proposals. The sub-projects that the PIs of the present proposal have been responsible for during the first project phase have yielded a crucial paleomagnetic age marker (i.e., the position of the Gauss/Matuyama reversal) and a first, low-resolution pollen record across the Pliocene/Pleistocene transition interval. The here proposed follow-up project for the final twelve project months aims (i) to establish a palynological dataset with a mean resolution of 1.5 m across the 440–730 m study interval of the MHAFB11 core, which to our knowledge will be the first of its kind for North America, and (ii) to generate pollen-based reconstructions of vegetation and climate dynamics. Based on the resulting datasets, the project will develop conceptual paleoenvironmental and paleoclimatic models for the Plio¬cene/Pleistocene transition in the mid-latitudes of western North America. It will critically assess existing scenarios for the climatic processes across the Plio¬ce-ne/Pleistocene transition. In particular, its geographical position within western North America will make it possible to test the hypothesis that enhanced humidity from the Pacific may have provided water vapour to northern North America, thereby allowing the initiation of Nor¬thern Hemisphere glaciation.