Thermoluminescence Dating of Loess and Tephra from Fairbanks, Alaska

没有准确和连续的年代学存在于140ka的老乌鸦Tephra之上和阿拉斯加中部最古老的C-14年代(约35ka)之下的黄土和Tephra。相关的地层单位(金溪建造和等值黄土，以及下伏的上金山黄土)主要是带有互层不连续的苔藓和一些有机层的黄土。这些沉积物在大约30-140ka之间缺乏准确的沉积年龄，使得对当地和区域的古环境和古生物记录的解释含糊不清。因此，这项提议试图通过对费尔班克斯附近5个地点广泛分布的黄土和偶尔夹层的盖夫拉进行热释光(TL)测年，来建立这一时间范围内这些沉积物的第一个可靠的年代学。还需要额外的实验室设备，以便在该实验室有效地执行该项目和其他热释光测年项目。这项研究将证明热释光测年的可靠性，并获得阿拉斯加关键地质区全新世和威斯康星州黄土和特弗拉的热释光年龄。

An accurate and continuous chronology does not exist for the loess and tephra overlying the 140ka-old Old Crow tephra and underlying the oldest C-14 dated (ca 35ka) beds in central Alaska. The relevant stratigraphic units (Goldstream Formation and equivalent loess, and underlying upper Gold Hill Loess) are dominantly loess with interbedded discontinuous tephra and some organic layers. The lack of accurate deposition ages for these sediments in the time period ca. 30-140ka makes interpretation of the local and regional paleoenvironmental and paleontological records ambiguous. This proposal therefore seeks to develop the first firm chronology for these sediments in this time range by thermoluminescence (TL) dating of the widespread loess and occasional interbedded tephra from 5 sites near Fairbanks. Additional laboratory equipment is also requested to permit the efficient execution of this and other TL dating projects in this laboratory. This research will demonstrate the reliability of TL dating and obtain TL dates of Holocene and Wisconsin loess and tephra in a key geologic area of Alaska.