Collaborative Research: The Pulse of Holocene Glaciations in New Zealand's Southern Alps

人类文明是在大约11,500年前开始的全新世时期发展起来的。全新世被传统地认为是气候稳定的时期。然而，最近的古气候记录表明，突然的气候变化确实发生在全新世，其中一些与人类历史的曲折相吻合。全新世气候的时空格局、自然变率和驱动机制虽然直接影响到人类的生存环境，但人们对全新世气候的时空格局、自然变率和驱动机制还不甚了解，阻碍了对当前气候变化的可靠评估。全新世气候波动大到足以影响人类，但小到足以迷失在？噪音？在大多数地质气候记录中的自然变化。然而，地球上许多地区的冰川对全新世气候变化的反应敏感而迅速，并产生了独特的地貌或冰碛。这些地貌的年龄直接表明了这些大陆全新世气候变化发生的时间，但到目前为止，还缺乏一个强大的，统一的和可靠的冰碛物定年工具。最近在宇宙成因测年领域的进展表明，冰碛物可以在整个全新世时期以前所未有的准确度测年，从而为全新世气候变化的特征提供了新的视角。这项拨款是一个跨学科的，多组的努力，以确定在新西兰全新世冰碛序列？的南阿尔卑斯山的应用高精度10 Be表面暴露测年（SED）结合当地校准的10 Be生产率，以评估潜在的气候变化，并分析结果在一个跨半球的角度来看。新西兰似乎是进行这种研究的理想地点：㈠受热带和极地信号影响的南部中纬度地区的陆地古气候数据很少，迫切需要用来评估气候变化的区域足迹;（ii）在个别冰川前保存了多达五个或更多不同的全新世冰碛，使人们能够深入了解南部中纬度地区全新世气候变化的细节，包括？小冰河时期？(iii)在南部中纬度地区的冰川响应大气/海洋的变化（没有大陆气候的影响）;（四）一般的地形设置和岩石类型是非常适合我们的SED方法;（五）一套详细的冰川地貌（地貌）新西兰地图？我们的合作者正在进行冰川学建模研究，使其成为地球上最好的冰川记录之一。为了实现一个区域，详细的年表的冰川在南中纬度地区的主要网站，我们将结合联合收割机大山谷冰川系统与较小的山谷冰川，半干旱的东侧以及非常潮湿的西侧南阿尔卑斯山，评估不同的降水制度的重要性冰川。我们将把我们的冰川年表与新西兰和其他地方的少数记录进行比较，测试全新世冰川脉冲的区域性和半球间特征。这里的焦点之一将是被称为？小冰河时期，欧洲冰川有详细的历史记录。智力价值和更广泛的影响：我们希望通过解决关键问题，如：全新世冰川半球间的驱动程序，大大提高我们的理解在南部中纬度地区的全新世冰川波动？是大气环流变化参与了这些事件的驱动，还是全球和区域力量都参与了？该项目是一个独特的机会，创建一个参考数据集的全新世冰川波动在南部中纬度地区。这些数据对于校准气候模型以及广大的气候科学家和冰川地质学家来说应该具有很高的价值。我们进一步发展了宇宙成因10 Be定年方法，我们的地球化学/地质年代学工具包将适用于未来的全新世冰碛定年项目。新的南阿尔卑斯山脉中部地貌地图集将在本项目期间根据我们的冰川年表进行更新。除了扩大LDEO/CU课程，一名女硕士生将接受教育，几个早期职业科学家将参与，高中学生和教师（？拉蒙特-多尔蒂中学实地项目？）我们将积极参与这个项目。除了标准的数据传播，我们还将在公共活动中介绍该项目，如每年的L-DEO开放日（通常有4,000名游客），并将利用我们与纽约公共媒体的密切联系，寻求报纸（纽约时报）和电视（历史频道）对该项目的报道。该项目将促进拉蒙特-多尔蒂地球天文台、缅因州大学、加州大学伯克利分校和新西兰GNS科学之间富有成效的合作。

Human civilizations have developed during the Holocene epoch that began approximately 11,500 years ago. The Holocene is classically considered a period of outstanding climate stability. However, recent paleoclimate records suggest that abrupt climatic shifts did occur within the Holocene and that some of those coincided with twists and turns in human history. Although directly influencing human habitat, temporal and spatial patterns, natural variability and driving mechanisms of Holocene climate are not well understood, hampering reliable evaluation of current climate change. Holocene climate swings were large enough to impact humans but small enough to get lost in the ?noise? of natural variability in most geological climate records. Glaciers in many areas on Earth, however, have responded sensitively and quickly to the Holocene climate changes and have produced distinctive landforms, or moraines. The age of these landforms directly indicates when these continental Holocene climate changes occurred, but so far a robust, uniform and reliable dating tool for moraines was lacking. Recent progress in the field of cosmogenic dating demonstrates that moraines can be dated with unprecedented accuracy throughout the Holocene period, allowing novel perspectives on the characteristics of Holocene climate changes. This grant is an interdisciplinary, multi-group effort to date the Holocene moraine sequences in New Zealand?s Southern Alps by applying high-precision 10Be surface exposure dating (SED) combined with local calibration of the 10Be production rate, to evaluate the underlying climate changes, and to analyze the results within an interhemispheric perspective. New Zealand appears to be an ideal location for such a study: (i) terrestrial paleoclimate data from southern mid-latitudes, influenced by tropical and polar signals, are sparse and urgently needed to evaluate the regional footprint of climate changes; (ii) up to five or more different Holocene moraines are preserved in front of individual glaciers, allowing insight into the details of the Holocene climate changes in southern mid-latitudes, including the ?Little Ice Age?; (iii) glaciers in southern mid-latitudes respond to atmospheric/oceanic changes (no continental climate effects); (iv) the general landform setting and rock type is well suited for our SED approach; (v) a suite of detailed glacier landform (geomorphologic) maps of New Zealand?s Southern Alps have been developed, paleo-snowlines have been reconstructed in detail, and glaciological modeling studies are ongoing by our collaborators, making this one of the better investigated glacier records on Earth. To achieve a regional, detailed chronology of glaciations on a prime site in southern mid-latitudes, we will combine large valley glacier systems with smaller valley glaciers on both, the semi-arid east flank as well as on the very humid west flank of the Southern Alps, evaluating the importance of different precipitation regimes for glaciations. We will compare our glacial chronologies to the few records available from New Zealand and elsewhere, testing the regional to inter-hemispheric character of the Holocene glacial pulse-beat. One of the foci herein will be the time period known as the ?Little Ice Age, where detailed historical records are available for European glaciers. Intellectual Merit and Broader Impacts: We expect to greatly improve our understanding of drivers of Holocene glacier fluctuations in southern mid-latitudes by tackling key questions such as: Were Holocene glaciations inter-hemispheric? Were atmospheric circulation changes involved in driving these events or were both, global and regional forces involved? This project represents a unique opportunity to create a reference data set of Holocene glacial fluctuations in southern mid-latitudes. These data should be of high value to calibrate climate models and to the broad community of climate scientists and glacial geologists. We further develop the method of cosmogenic 10Be dating and our geochemical/geochronological tool-kit will be applicable to future Holocene moraine-dating projects. The new atlas of geomorphic maps of the central Southern Alps will be updated with our glacial chronologies during this project. In addition to extending the LDEO/CU curriculum, a female master student will be educated, several early-career scientists will be involved, and high school students and teachers (?Lamont-Doherty Secondary School Field Program?) will actively participate in this project. Beyond standard data dissemination, we will present the project at public events, such as the annual L-DEO Open House (typically 4,000 visitors) and will use our close contacts to New York public media to seek coverage of this project in newspapers (New York Times) and television (History Channel). The project will foster the fruitful collaboration between the Lamont-Doherty Earth Observatory, the University of Maine, the UC Berkeley, and the GNS Science, NZ.