COLLABORATIVE RESEARCH: Coordinated TIMS U-Series Dating and Paleoenvironmental Interpretations of Pedogenic Carbonate, Wind River Basin, Wyoming

合作研究：怀俄明州风河流域成土碳酸盐的协调 TIMS U 系列测年和古环境解释

• 批准号: 0207963
• 负责人: Warren Sharp
• 金额: $ 18.91万
• 依托单位: Berkeley Geochronology Center
• 依托单位国家: 美国
• 项目类别: Continuing 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=0207963&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.

项目摘要 在 NSF 的事先支持下，我们已经证明成土碳酸盐的 TIMS（热电离质谱）U 系列测年可以提供精确的成土年代学和适当的第四纪冲积矿床的可靠年龄（Sharp 等人，已接受）。虽然凯尔峡谷（内华达州）碳酸盐碎屑为主的冲积层的成土碳酸盐 U/Th 比对于 U 系列测年来说太低，但风河流域（怀俄明州）花岗岩碎屑为主的砾石中的成土碳酸盐非常适合。 精确的U系列年龄（1-2%，2）可以在几立方毫米的成土碳酸盐上测量，并且只需要对碎屑230Th进行非常小的修正。 可以使用 U 系列结果中固有的标准来筛选年龄组的可靠性。碎屑沉积和可测定碳酸盐积累之间的时滞是风河流域中碎屑外皮 U 系年代测定宿主第四纪沉积物的关键参数，估计为 5+ 5 kyr。 对成土碳酸盐样品试验套件的 O 和 C 同位素分析表明，可以使用 U 系列定年的成土碳酸盐构建时间分辨的稳定同位素古气候记录。需要资金进一步开发成土碳酸盐的U系列测年及其在落基山冰川年代学完善中的应用。 重点将放在解决布尔湖冰川推进（在其典型地点）相对于其他区域和全球气候记录的时间。此外，我们建议描述晚更新世沉积物残土中成土碳酸盐的时空积累特征，并测量U系列测年碳酸盐样品的O和C同位素组成。我们将对这些数据进行解释，以提供风河流域在伊利诺伊州晚期和威斯康星州冰川周期大部分时期的古环境变化的全面历史。最终，我们的目标是通过建立基于精确U系列年龄的共同年代框架，将基于土壤的古环境记录与古气候变化的地貌表现、盆地保存完好的冰川冰碛和冰川河流阶地联系起来。 这是一个合作提案。 Warren Sharp 和 Ken Ludwig（伯克利地质年代学中心）将负责 U 系列分析和年龄解释； Ron Amundson（加州大学伯克利分校）将提供土壤学以及稳定同位素分析和解释方面的现场和实验室专业知识； Oliver Chadwick（加州大学圣巴巴拉分校）将提供第四纪地质学、地貌学和土壤地层学方面的专业知识以及对风河地区的熟悉程度。