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

该奖项支持一个项目，该项目使用光学粉尘记录仪对Dome C井眼中的灰尘和灰烬进行高分辨率记录。以20-50 cm/秒的速度测井，仅需数小时，即可获得整个3270 m井眼至~800 ka的尘埃浓度和火山灰层的毫米级深度分辨率。与~0.02 m2的岩心相比，该记录仪探测的面积为m²，极大地抑制了沉积噪声，使该技术不受岩心损坏或丢失的影响。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，可以探测到岩芯中不可见或缺失的爆炸沉降物颗粒层，并经常揭示标准岩芯分析无法揭示的微妙趋势变化。利用高分辨率的尘埃记录，有望在东南极洲、西南极洲和格陵兰岛之间找到新的同步年龄标志。这些数据可能有助于统一全球气候记录，或解决诸如从41 kyr冰期旋回到100 kyr明显旋回的转变等谜团。该项目将扩展先前的发现，该发现为火山爆发事件与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有说服力的案例。还将寻找证据，证明一些已确定的世界范围内的爆炸性沉降物事件可能是由彗星或小行星的撞击造成的。研究人员将评估陆地撞击坑记录的可靠性，以及地球撞击比一般认为的要频繁得多的可能性。更好地了解导致气候突变的因素、大型火山爆发的复发率和触发机制，以及Gt至tt能量的火流星撞击的频率，对人类文明至关重要。2008-11年度的工作计划包括在第一年对现有硬件进行改装和测试；伐木现场工作，最有可能在第二年；第三年的数据分析和结果公布。由于EPICA合作伙伴将在现场提供合适的测井绞车，因此该项目的后勤需求不大，可以由McMurdo的Twin Otter公司提供。该建议本着国际极地年（IPY）的精神，通过建立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.