RUI: P2C2--Reconstruction of Recent and Late Holocene Tropical Cyclone Landfalls in Northwestern Australia using Flood Deposits in Aragonite Stalagmites

该奖项帮助创造了热带气旋活动的记录，这些洞穴是从西澳大利亚热带的金伯利地区发现的，可以追溯到全新世晚期(约4000年B.P.)。研究人员之前的研究表明，文石石笋在金伯利洞穴中丰富，从全新世晚期到现在，具有极高的生长速度，并且只有在热带气旋引发的洪水期间，洞穴才能捕获沉积在石笋表面的粘土。由于这些石笋含有较高的铀丰度，较高的234铀值，并且基本上没有碎屑(洪水沉积除外)，因此可以用铀-钍质谱仪进行极高精度的测年(上个世纪内±1年)。为了限制淹没洞穴所需的气旋距离/强度阈值，研究人员将结合石笋沉积学洪水记录和过去100年增长的稳定同位素分析；这是一个可以获得热带气旋强度和风暴轨迹历史记录的时间间隔。这项分析将有助于建立一个基线，用于估计过去作为粘土层记录在各个洞穴中的风暴的强度-距离比。更广泛的影响涉及到更好地了解气旋活动历史的可能性和新的气候指标的发展。这项研究还包括大量本科生参与该项目。

This award helps develop a record of tropical cyclone activity from speleothems recovered from the Kimberley region of tropical Western Australia and dated to the late Holocene (~4,000 yr B.P.).Previous research by the researcher demonstrated that aragonite stalagmites are abundant in caves in the Kimberley through the late Holocene and up to the present time, are characterized by extremely high growth rates, and the caves trap clays deposited on stalagmite surfaces only during tropical cyclone-induced flooding. Because these stalagmites contain elevated Uranium abundances, high delta 234-Uranium values, and are largely devoid of detritus (other than in flood deposits), they can be dated with extremely high precision using Uranium-Thorium mass spectrometry (±1 year within the last century). In order to constrain the cyclone distance/intensity threshold required to flood the caves, the researcher will combine the stalagmite sedimentological flood records with stable isotopic analyses over the last 100 years of growth; an interval for which historical records of tropical cyclone intensity and storm track are available. This analysis will help establish a baseline for estimating the intensity-distance ratio of past storms recorded as clay layers in individual caves.The broader impacts involve the potential for greater understanding of the history of cyclonic activity and the developement of a new climate proxy. The research also involves substantive undergraduate student participation in the project.