Dust Logging at Dome C for Abrupt Climate Changes, Large Volcanic Eruptions and Bolide Impacts

BAY 0739743该奖项支持使用光学尘埃记录仪对穹顶C钻孔中的尘埃和火山灰进行高分辨率记录的项目。以20-50厘米/秒的速度测井，在几个小时内，可以提供整个3270米钻孔的尘埃浓度和火山灰层的毫米级深度分辨率，回到~800ka。与约0.02平方米的岩心相比，该测井仪探测的层位面积为m2数量级，极大地抑制了沉积噪声，使该技术不受岩心损坏或损失的影响。该方法在匹配或比较冰芯记录方面实现了前所未有的气候变化分辨率，可以从岩心中看不见或找不到的爆炸性尘埃中检测颗粒层，并且经常揭示微妙的趋势变化，而这可能无法进行标准的岩心分析。随着高度分辨的尘埃记录，预计将在东南极洲、西南极洲和格陵兰岛之间发现新的同步年龄标志。这些数据可能有助于统一全球气候记录，或解开从41 KYR冰川周期到表观100 KYR冰川周期的转换等谜团。该项目将扩展之前的发现，这些发现为火山爆发事件和千年时间尺度上的突然气候变化之间的因果关系提供了迄今为止最令人信服的证据。还将寻找证据，证明已查明的一些世界范围内的爆炸性尘埃事件可能是由彗星或小行星撞击造成的。研究人员将评估地球撞击坑记录的可靠性，以及地球撞击比人们通常认为的要频繁得多的可能性。更好地了解迫使气候突然变化的因素、大规模火山喷发的复发率和触发机制，以及GT到TT-能量流星撞击的频率，对文明至关重要。2008-11年的工作计划包括在第一年修改和测试现有硬件；很可能在第二年进行实地采伐工作；在第三年进行数据分析和公布结果。由于EPICA的合作者将在现场提供合适的伐木绞车，因此该项目的后勤需求不大，可以由麦克默多的Twin Otter提供。该提议本着国际极地年(IPY)的精神，建立了具有潜在社会效益的国际合作。该项目将为来自美国和其他国家的学生和博士后研究员提供跨学科培训。

Bay 0739743This award supports a project to make high-resolution logs of dust and ash in the Dome C borehole using an optical dust logger. Logging at 20-50 cm/sec, in a matter of hours, mm-scale depth resolution of dust concentration and volcanic ash layers over the entire 3270 m borehole back to ~800 ka can be provided. The logger probes an area of order m2 of the horizon compared to the ~0.02 m2 core, greatly suppressing depositional noise and making the technique immune to core damage or loss. The method achieves unprecedented resolution of climate variations for matching or comparing ice core records, can detect particulate layers from explosive fallout which are invisible or missing in the core, and often reveals subtle trend changes which can elude standard core analyses. With the highly resolved dust record, it is expected to find new synchronous age markers between East Antarctica, West Antarctica and Greenland. The data could be instrumental in unifying global climate records, or resolving mysteries such as the transition from 41-kyr glacial cycles to apparent 100-kyr cycles. The project will extend previous finding, which make the most convincing case to date for a causal relationship between explosive volcanic events and abrupt climate change on millennial timescales. A search will also be made for evidence that some of the worldwide explosive fallout events that have been identified may have resulted from impacts by comets or asteroids. The investigators will evaluate the reliability of terrestrial impact crater records and the possibility that Earth impacts are considerably more frequent than is generally appreciated. Better understanding of the factors which force abrupt climate changes, the recurrence rate and triggering mechanisms of large volcanic eruptions, and the frequency of Gt to Tt-energy bolide impacts are of vital interest for civilization. The work plan for 2008-11 comprises modifying and testing of existing hardware in year one; logging field work, most likely in year two; data analysis and publication of results in year three. Because the EPICA collaborators will provide a suitable logging winch onsite, the logistical needs of this project are modest and can be accommodated by Twin Otter from McMurdo. The proposal is in the spirit of the International Polar Year (IPY) by forging an international collaboration with potential societal benefit. The project will provide interdisciplinary training to students and postdoctoral fellows from the U.S. and other countries.