Collaborative Research: Coordinated TIMS U-Series Dating and Paleoenvironmental Interpretation of Pedogenic Carbonate

合作研究：成土碳酸盐的协调 TIMS U 系列测年和古环境解释

• 批准号: 0207490
• 负责人: Ronald Amundson
• 金额: $ 3.88万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-08-15 至 2005-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0207490&HistoricalAwards=false
• 关键词: Collaborative; Research; Coordinated; TIMS; Series

PROJECT SUMMARY With prior support from NSF, we have shown that TIMS (Thermal Ionization Mass Spectrometry) U-series dating of pedogenic carbonate can provide a precise chronology of pedogenesis and reliable ages for appropriate Quaternary alluvial deposits (Sharp et al., accepted). Though the U/Th ratios of pedogenic carbonate of carbonate-clast dominated alluvium at Kyle Canyon (Nevada) are too low for U-series dating, pedogenic carbonate in granitic-clast dominated gravels of the Wind River Basin (Wyoming) is highly suitable. Precise U-series ages (1-2 percent, 2) may be measured on a few cubic millimeters of pedogenic carbonate and require only very small corrections for detrital 230Th. Suites of ages may be screened for reliability using criteria inherent in the U-series results. The time lag between clast deposition and accumulation of datable carbonate.a critical parameter if U-series dates of innermost clast-rinds are to be used to date host Quaternary deposits.is estimated to be 5+ 5 kyr in the Wind River basin. O- and C-isotope analyses of a trial suite of pedogenic carbonate samples shows that a temporally resolved stable isotope paleoclimatic record can be constructed using pedogenic carbonate dated by U-series. Funds are requested to further develop U-series dating of pedogenic carbonate and its application to the refinement of a Rocky Mountain glacial chronology. Emphasis will be placed on resolving the timing of Bull Lake glacial advances (at their type locality) with respect to other regional and global climate records. Moreover, we propose to characterize the spatial and temporal accumulation of pedogenic carbonate in relict soils of Late-Middle to Late Pleistocene deposits, and measure the O- and C-isotopic compositions of carbonate samples dated by U-series. We will interpret these data to provide a comprehensive history of paleoenvironmental change in the Wind River Basin throughout much of the late Illinoian and Wisconsin glacial cycles. Ultimately, our goal is to correlate the soils-based paleoenvironmental record with the geomorphic expressions of paleoclimatic change.the well-preserved glacial moraines and glacio-fluvial terraces of the Basin.by establishing a common chronological framework based on precise U-series ages. This is a collaborative proposal. Warren Sharp and Ken Ludwig (Berkeley Geochronology Center) will be responsible for U-series analyses and age interpretations; Ron Amundson (U.C. Berkeley) will provide field and laboratory expertise in pedology and stable isotope analysis and interpretation; Oliver Chadwick (U.C. Santa Barbara) will provide expertise in Quaternary geology, geomorphology and soil stratigraphy as well as familiarity with the Wind River area.

在NSF的事先支持的情况下，我们已经表明，TIMS（热电离质谱法）U系列的u系列碳酸盐的年代日期可以提供精确的成语年代学和可靠年龄的适当年龄，以适合适当的季型冲积沉积物（Sharp等人接受）。尽管在凯尔峡谷（NEVADA）中占主导地积的碳酸盐层的碳酸盐含量太低，但对于U系列约会而言，但在风河盆地（Wyoming）的花岗岩塑料中占主导地位的碳酸盐（Wyoming）非常适合。 精确的U系列年龄（1-2％，2）可以在几立方毫米的Pedoenic碳酸盐中测量，并且仅需要很小的校正才能进行第230颗。 使用U系列结果固有的标准，可以筛选年龄的套件。碎屑沉积与数据堆积之间的时间滞后。关键参数，如果将最内在的碎屑覆盖的U系列日期用于宿主第四纪沉积物的日期。估计在风河盆地中为5+ 5 kyr。 对碳酸盐样品的试验套件的O-和C-同位素分析表明，可以使用由U系列的Pedogentic碳酸盐来构建时间分辨的稳定同位素古气候记录。要求资金进一步开发成种植碳酸盐的U系列日期及其在岩石山冰川年表的改进中的应用。 将重点放在解决其他区域和全球气候记录方面的公牛湖冰川前进的时机（在其类型地区）。此外，我们建议表征成源性碳酸盐在中期的遗物土壤中的空间和时间积累到更新世后期沉积物，并测量由U系列使用的碳酸盐样品的O-和C-同位素组成。我们将解释这些数据，以提供整个伊利诺伊州和威斯康星州冰川周期的大部分冰河盆地古环境变化的全面历史。最终，我们的目标是将基于土壤的古环境记录与古气候变化的地貌表达相关联。通过建立基于精确的U系列年龄的普通年代框架，保存完好的冰川山地和冰川露台。 这是一个协作提案。沃伦·夏普（Warren Sharp）和肯·路德维希（Ken Ludwig）（伯克利地天地学中心）将负责U系列分析和年龄解释；罗恩·阿蒙森（Ron Amundson）（伯克利（U.C. Berkeley））将提供教学和稳定同位素分析和解释方面的领域和实验室专业知识； Oliver Chadwick（U.C. Santa Barbara）将提供第四纪地质，地貌学和土壤地层的专业知识，以及对风河地区的熟悉。