Collaborative Research: A high-resolution middle Pleistocene paleoclimate record from the Valles Caldera, New Mexico

合作研究：来自新墨西哥州火山口火山口的高分辨率中更新世古气候记录

• 批准号: 0902888
• 负责人: Josef Werne
• 金额: $ 23.37万
• 依托单位: University of Minnesota Duluth
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2012-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0902888&HistoricalAwards=false
• 关键词: Collaborative; Research; resolution; middle; Pleistocene

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).This grant supports a collaborative project between the University of New Mexico, Northern Arizona University and the University of Minnesota, Duluth which will conduct detailed analyses of a unique 82-m long lacustrine sediment core (VC-3) from the Valles Caldera, in northern New Mexico. This core represents a critical time interval in the past that is similar to the modern. As such, an understanding of climatic changes observed in the core will lead to the most detailed assessment of expected future climate variability in the southwest ever recorded.Intellectual Merit: In May 2004, the GLAD5 drilling project recovered an 82-m deep lacustrine sediment core from the Valles Caldera, New Mexico. Ar-Ar age estimates from a tephra near the base of the core (552±3 ka), two distinct glacial terminations (VI and V) in multiple proxies, and the identification of a two geomagnetic polarity "events", correlated to globally recognized events (14a; and 11a) constrain these lake sediments to the middle Pleistocene (MIS 14 to MIS 10). Initial work by this group shows an intriguing relationship between temperature and hydroclimate during the two long interglacials present in the core (MIS 11 and MIS 13). Peak interglacial temperatures (MBT proxy, pollen) correlate well with extended dry periods in the core (mudcrack intervals). This is consistent with recent predictions of extended drought in SW North America in response to global warming by a marked reduction in winter precipitation.To better understand this critical relationship, the team will conduct more detailed sampling of the VC-3 core at intervals of ~10 cm or less to analyze for temperature (MBT proxy, pollen), lake productivity (organic carbon, Si/Ti ratios, biogenic silica), hydroclimate (del-18O of diatom silica, core sedimentologic characteristics, and pollen and charcoal). Specifically, they will test the hypothesis that during long interglacials, warming leads to extended dry climates with reduced winter frontal precipitation. Additional analyses to be conducted include remanence and rock magnetic properties, major and minor element geochemistry, XRD, XRF scanner analyses, carbon and nitrogen stable isotopes and C/N ratios, and plant macrofossils, all of which will aid in refining paleoclimate proxies. In conjunction with this work, LANL collaborators will conduct compound specific del-D analyses and obtain U‐series dates to improve the chronology at no cost to NSF. Results from this work will shed light on two important paleoclimate questions: the relationship between peak interglacial temperatures and extended dry conditions, and the nature of orbital- to millennial-scale climate change during the middle Pleistocene.Broader Impacts: This study will further our understanding about the nature of climate change in southwestern North America and its impact on montane ecosystems. This project involves collaborations between four research institutions, UNM, NAU, UMD, and Los Alamos National Lab. Both graduate students and faculty will benefit from interactions with the other institutions and the different expertise that collaborators at each institution bring to bear on the project. The results of this study will be available to the general public using displays and outreach programs through the newly created Valles Caldera National Preserve. This information will include not only the timing of lakes forming in the Valles Caldera and the paleoclimatic records derived from them, but also information about the materials preserved at depth in the Valles Caldera and the nature of the interactions between volcanic processes in the caldera and surficial processes. The project will involve education and training of several graduate students at UNM, NAU and UMD. UNM graduate students include a female Hispanic pursuing a PhD and another female graduate student. The results of this study will be integrated into several courses offered at the participating institutions.

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。该赠款支持新墨西哥州大学，北方亚利桑那大学和明尼苏达大学杜卢斯分校之间的合作项目，该项目将对新墨西哥州北方Valles Caldera的独特的82米长的湖泊沉积物岩心（VC-3）进行详细分析。这个核心代表了过去的一个关键时间间隔，与现代相似。因此，了解气候变化观察到的核心将导致最详细的评估，预计未来的气候变率在西南部有史以来recorded.Intellectual优点：在2004年5月，GLAD 5钻井项目恢复了82米深的湖泊沉积物岩心从山谷火山口，新墨西哥州。根据岩芯底部附近的火山灰（552±3 ka）、多个代用指标中两个不同的冰川终止（VI和V）以及与全球公认的事件（14 a和11 a）相关的两个地磁极性“事件”的鉴定，对这些湖泊沉积物进行了Ar-Ar年龄估计，将其限制在中更新世（MIS 14至MIS 10）。该小组的初步工作表明，在核心（MIS 11和MIS 13）中存在的两个漫长的间冰期期间，温度和水文气候之间存在着有趣的关系。峰值间冰期温度（MBT代理，花粉）与延长干燥期的核心（泥裂间隔）。这与最近预测的北美西南部长期干旱是一致的，因为全球变暖导致冬季降水量显著减少。为了更好地了解这种关键关系，研究小组将对VC-3核心进行更详细的采样，间隔约10厘米或更少，以分析温度（MBT代用指标、花粉）、湖泊生产力（有机碳、硅/钛比、生物硅）、水文气候（硅藻硅的del-18 O、岩芯沉积学特征、花粉和木炭）。具体来说，他们将检验一个假设，即在漫长的间冰期，变暖导致延长干燥气候减少冬季锋面降水。将进行的其他分析包括剩磁和岩石磁性、主要和次要元素地球化学、XRD、XRF扫描仪分析、碳和氮稳定同位素和C/N比以及植物宏体化石，所有这些都将有助于完善古气候代用指标。在这项工作的同时，LANL的合作者将进行化合物特定的del-D分析，并获得U #8208;系列日期，以改进年表，而不需要NSF承担任何费用。从这项工作的结果将揭示两个重要的古气候问题：间冰期的峰值温度和延长干燥条件之间的关系，和轨道的性质，以千年尺度的气候变化在中更新世。更广泛的影响：这项研究将进一步了解气候变化的性质在北美西南部及其对山地生态系统的影响。该项目涉及四个研究机构之间的合作，UNM，NAU，UMD和洛斯阿拉莫斯国家实验室。研究生和教师都将受益于与其他机构的互动，以及每个机构的合作者为项目带来的不同专业知识。这项研究的结果将通过新创建的Valles Caldera国家保护区的展示和推广计划向公众提供。这些信息不仅包括在Valles Caldera形成湖泊的时间和从中得出的古气候记录，而且还包括在Valles Caldera深处保存的物质的信息以及Caldera火山过程和surgical过程之间相互作用的性质。该项目将涉及在UNM、NAU和UMD教育和培训几名研究生。UNM的研究生包括一名攻读博士学位的西班牙裔女性和另一名女性研究生。这项研究的结果将纳入参与机构提供的若干课程。