COLLABORATIVE RESEARCH: A Detailed Test of Cosmogenic Radionuclide Dating of Moraines: Pinedale and Bull Lake Moraines, Fremont Lake, Wyoming

合作研究：对冰碛宇宙成因放射性核素测年的详细测试：怀俄明州弗里蒙特湖的派恩代尔和布尔湖冰碛

• 批准号: 9208944
• 负责人: Roy Middleton
• 金额: --
• 依托单位: University of Pennsylvania
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-07-01 至 1994-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9208944&HistoricalAwards=false
• 关键词: COLLABORATIVE; RESEARCH; Detailed; Test; Cosmogenic

This research is a detailed test of cosmogenic radionuclide exposure dating based principally on measurements of 1OBe, 26Al, and 14C in quartz from boulders which lie on moraine crest of known or accepted ages at the Pinedale Glaciation type locality, Fremont Lake, Wyoming. The purpose is to determine the limits, accuracy, precision, and resolution of the cosmogenic dating technique. We will adher to a stringent sampling strategy which minimizes errors due to high erosion rate (i.e. fire-induced surface spallation), pre-exposure, cosmic radiation shielding, unsuitable boulder surface geometries, and disturbed exposure, cosmic radiation shielding, unsuitable boulder surface geometries, and disturbed exposure histories due to redeposition or burial of the boulder. In the first year we will determine the reliability and precision of the technique to date a moraine by sampling multiple boulders on single moraine ridges, and multiple samples from selected boulders. Based on direct dating, regional correlations to dated stratigraphic equivalents, and correlation to the high resolution oxygen isotope chronostratigraphy they Pinedale (Stage 2) and Bull Lake (Stage 6) deposits can be aged bracketed at 14-30 ka and 130-160ka. We will date 30 samples from each of the Pinedale and Bull Lake terminal moraines at Fremont Lake. In the second year, armed with a measure of the method's precision, we will date samples from each of 6 nested Pinedale recessional moraines in order to determine its resolution. If the ages of the outermost to innermost moraines yield progressively younger ages this will imply that the technique will be able to directly measure rates to alpine or continental glacial retreat. We will also date 10 boulders from a suspect Stage 4 moraine which lies between the Pinedale and Bull Lake deposits in order to establish whether or not Stage 4 (Early Pinedale) deposits are preserved at the Pinedale type locality. Finally, we will make a useful cross check of dates produced from our method with dates using F. Phillips' 36C1 technique on duplicate samples from 10 boulders which yield the best dates from Year 1.

本研究是对宇宙成因放射性核素的详细测试 主要基于1 OBe，26 Al， 和14 C在石英从巨石躺在冰碛峰已知的 或弗里蒙特派恩代尔冰川类型地区的公认年龄 湖，怀俄明州。 目的是确定极限、准确度、 宇宙起源测年技术的精确度和分辨率。 我们 我会坚持严格的抽样策略，尽量减少错误 由于高腐蚀率（即火灾引起的表面剥落）， 预暴露，宇宙辐射屏蔽，不合适的巨石 表面几何形状，受干扰的暴露，宇宙辐射 屏蔽，不合适的巨石表面几何形状， 暴露的历史，由于再沉积或埋藏的巨石。 在第一年，我们将确定可靠性， 通过多重取样测定冰碛物年代的技术精度 单冰碛脊上的巨石， 精选的巨石 根据直接测年， 与年代久远的地层等价物， 派恩代尔阶（Stage）的分辨率氧同位素年代地层学 2)和布尔湖（第6阶段）沉积物的年龄可在14-30 ka和130- 160 ka。 我们将从每一个样本中提取30个样本， 弗里蒙特湖的派恩代尔和布尔湖终端冰碛。 在第二年，配备了该方法的措施， 精密度，我们将对6个嵌套派恩代尔中的每一个样本进行日期测定 以确定其分辨率。 如果 从最外层到最内层的冰碛年龄逐渐增大 年轻的年龄，这将意味着技术将能够 直接测量高山或大陆冰川退缩的速度。 我们还将从一个可疑的第四阶段冰碛石， 位于派恩代尔和布尔湖矿床之间， 确定第4阶段（早期派恩代尔）矿床是否 保存在派恩代尔型产地。 最后，我们将做一个 有用的交叉检查从我们的方法产生的日期与日期 利用F. 菲利普斯的36 C1技术，用于10份重复样品 从第一年开始产生最好的日期的巨石。