Collaborative Research/RUI: Assessing Multi-scale Holocene Climate Variability in Western North America Using Sediments from Lake Elsinore (Southern CA)

北美西部淡水的供应和质量与自然气候变化直接相关。 由于观测记录和仪器记录持续时间短，确定相关时间尺度上气候变化的能力受到限制。在南加州，对长时间、高分辨率的古气候记录的需求尤为迫切，那里有2000多万人易受气候变化的影响。 这项赠款将开发第一个完整的陆地全新世气候记录南加州使用沉积物从埃尔西诺湖和比较这一记录与其他良好的日期从该地区的陆地和海洋档案。历史数据的分析表明，埃尔西诺湖是一个很好的网站记录气候变率为南加州。对湖泊最深盆地的2个钻孔岩芯的初步研究表明，相对较厚（约10米/9，000年-基于21个AMS 14 C日期），连续的全新世沉积物序列，沉积物不连续的证据很少。几个沉积学参数的分析显示厘米级的变化，这是一致的2个核心。该资助支持使用已建立的气候敏感性替代方法对岩心沉积物进行进一步分析。到目前为止，质量磁化率，总有机质和总碳酸盐已分析在1厘米的连续间隔为深盆地的核心。该研究资助侧重于两个额外的分析：粒度（湖盆和流域沉积物动力学的代理）和d18 O（方解石）和d13 C（方解石）（湖泊水文预算和湖泊/流域生产力的代理，分别）。结合北美西部和太平洋的其他古气候记录，埃尔西诺湖记录将被用来更好地描述北美西部全新世气候变化的演变以及时空模式。此外，这一记录将提供全新世自然气候变化的基线，南加州水管理组织-他们资助了最初的研究-可以据此评估目前的水管理政策。这一记录还将有助于评估水文系统对一系列气候条件的敏感性，这项研究的知识价值将为描述和了解当地和区域尺度上的全新世气候变化提供关键信息。这项研究还将有助于回答有关全新世气候演变及其与大尺度海洋-大气动力学关系的几个重要问题。这项工作的更广泛的影响，包括研究经验和论文准备2个本科生和1个硕士生。这项研究的结果将传播给市民和管理人员的埃尔西诺湖，滨江县，加州通过一个互动的网站，以及在加州州立富勒顿实验室类使用的现场开发。作为RUI和少数民族服务研究所，这项研究还将为CSUF科学领域代表性不足的个人提供研究机会。最后，这项研究将提供社会相关的洞察未来水的变化在北美西部，水资源管理是未来社会经济稳定的关键区域。

The availability and quality of freshwater in western North America is directly linked to natural climate variability. The ability to determine climate variations on relevant time scales is limited by the short duration of observational and instrumental records. The need for long, high-resolution paleoclimatological records is particularly acute in Southern California, where over 20 million people are vulnerable to climate variability. This grant will develop the first complete terrestrial Holocene climate record for southern California using sediment from Lake Elsinore and compare this record to other well-dated terrestrial and marine archives from the region. Analysis of historical data indicates that Lake Elsinore is an excellent site for recording climate variability for southern California. Preliminary research on 2 drill cores from the lake's deepest basin indicates a relatively thick (~10m/9,000 yrs - based on 21 AMS 14C dates), continuous Holocene sediment sequence with minimal evidence for sediment discontinuities. Analyses of several sedimentological parameters reveal centimeter-scale variability that is consistent between the 2 cores. This grant supports further analysis of the cored sediment using established climate-sensitive proxy methods. To date, mass magnetic susceptibility, total organic matter, and total carbonate have been analyzed at 1cm contiguous intervals for both deep basin cores. This research grant focuses on two additional analyses: grain size (a proxy for lake basin and drainage basin sediment dynamics) and d18O(calcite) and d13C(calcite) (proxies for lake hydrologic budget and lake/drainage basin productivity, respectively). In conjunction with other paleoclimate records from western North America and the Pacific Ocean, the Lake Elsinore record will be used to better describe the evolution as well as the spatial and temporal patterns of Holocene climate variability over western North America. Furthermore, this record will provide a baseline of Holocene natural climate variability from which Southern California water management organizations - whom funded the initial research - can assess present water management policies. This record will also help to assess the sensitivity of the hydrologic system to a range of climate conditions.The intellectual merit of this study will provide critical information for characterizing and understanding Holocene climate variability on a local and regional scale. This research will also help to answer several important questions regarding Holocene climate evolution and its relationship to larger-scale ocean-atmosphere dynamics. The broader impacts of this work include research experience and thesis preparation for 2 undergraduate students and 1 M.Sc. student. The results of this study will be disseminated to the citizens and managers of Lake Elsinore, Riverside County, California through an interactive web site as well as the development of a field site for use in lab classes at Cal-State Fullerton. As a RUI and Minority Serving Institute, this research will also provide research opportunities for underrepresented individuals in the sciences at CSUF. Lastly, this research will provide socially relevant insight into future water variability in western North America, a region where water resource management is critical to future socio-economic stability.