Developing a tephra database to document the evolution of explosive volcanism along the Gulf of Alaska margin for the past six million years

开发火山灰数据库来记录过去六百万年阿拉斯加湾边缘爆发性火山活动的演变

• 批准号: 1434656
• 负责人: Jeff Benowitz
• 金额: $ 21.45万
• 依托单位: University of Alaska Fairbanks Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-07-15 至 2017-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1434656&HistoricalAwards=false
• 关键词: Developing; tephra; database; document; evolution

Explosive volcanism can be influenced by a range of geologic and climatic processes. In areas like the Gulf of Alaska, both the rate and angle of convergence of tectonic plates are understood to influence the rate of explosive volcanism. Less well understood is the influence of glaciers and whether climate fluctuations resulting in the ebb and flow of glaciers indirectly impact eruption frequency through increased erosion rates. Gaining a better understanding of how these factors contribute to explosive volcanic frequency can inform us on the nature of particular tectonic subduction zones like the Gulf of Alaska, helping mitigate the impact of potential volcanic hazards on vulnerable populations. The Gulf of Alaska margin is one of the most volcanically active regions in the world, making it a good area for study. However, continuous records of past volcanism in this region are rare due to extensive glaciation and erosion during over the past 2.5 million years. The high-quality deep-sea cores collected during the Integrated Ocean Drilling Program (IODP) Expedition 341 to the southern Alaskan margin provide new and rare material to examine volcanism in this region during key tectonic and climatic events. The proposed work seeks to develop a database of volcanic material from these cores to quantify the development and evolution of Gulf of Alaska volcanism during key tectonic and climate events over the past six million years.Technical Description: The proposed work will identify and develop a geochemical and geochronological database for tephras from IODP sites U1417 & U1418. A combination of data will be collected to (i) determine tephra sources from the region?s three major volcanic provinces; (ii) reconstruct the late Miocene-to-present evolution of eruptive volcanism along the Gulf of Alaska Margin; (iii) design a marine tephra database for use in terrestrial paleoclimatic studies. Methods will include microscope and magnetic susceptibility identification of tephra, grain-specific major and trace element geochemical fingerprinting, and 40Ar/39Ar radiometric dating of glass, hornblende, biotite, and/or sanidine. Results will be integrated with paleomagnetic, oxygen-18 isotope and microfossil chronostratigraphies of Sites U1417 & U1418, as well as with existing terrestrial Alaskan and Canadian Yukon tephra data. The overall results of this research will provide new constraints on (i) the effect of different tectonic-climate boundary forces on eruptive volcanic frequency, (ii) the genetic relationships between variations in eruption rate and the initiation of the Northern Hemisphere glaciations, and (iii) create a public database of well-dated geochemically fingerprinted marine tephras to provide an improved framework for reconstructing the paleoclimatic history of Alaska and the Yukon.

爆发性火山活动可能受到一系列地质和气候过程的影响。在阿拉斯加湾等地区，构造板块的收敛速度和角度被认为会影响火山爆发的速度。人们不太了解冰川的影响，以及导致冰川涨落的气候波动是否会通过增加侵蚀率来间接影响喷发频率。更好地了解这些因素如何影响火山爆发频率，可以让我们了解阿拉斯加湾等特定构造俯冲带的性质，有助于减轻潜在火山危害对弱势群体的影响。阿拉斯加湾边缘是世界上火山最活跃的地区之一，使其成为一个很好的研究区域。然而，由于过去250万年的广泛冰川作用和侵蚀，该地区过去火山活动的连续记录很少见。在综合海洋钻探计划 (IODP) 第 341 次阿拉斯加南部边缘探险期间收集的高质量深海岩心为研究该地区关键构造和气候事件期间的火山活动提供了新的稀有材料。拟议的工作旨在开发这些岩心火山物质的数据库，以量化过去六百万年的关键构造和气候事件期间阿拉斯加湾火山活动的发展和演化。 技术描述：拟议的工作将识别和开发地球化学数据库以及来自 IODP 站点 U1417 和 U1418 的火山灰年代学数据库。将收集一系列数据来 (i) 确定该地区三个主要火山省份的火山灰来源； (ii) 重建阿拉斯加湾边缘沿线中新世晚期至今喷发火山活动的演化； (iii) 设计一个海洋火山灰数据库，用于陆地古气候研究。方法包括对火山灰进行显微镜和磁化率鉴定、谷物特定的主要和微量元素地球化学指纹识别，以及玻璃、角闪石、黑云母和/或闪石的 40Ar/39Ar 放射性测年。结果将与 U1417 和 U1418 地点的古地磁、氧 18 同位素和微化石年代地层以及现有的陆地阿拉斯加和加拿大育空火山灰数据相结合。这项研究的总体结果将为（i）不同构造气候边界力对火山喷发频率的影响，（ii）喷发率变化与北半球冰川作用之间的遗传关系提供新的约束，以及（ iii) 创建一个包含日期明确的地球化学指纹海洋碎石的公共数据库，为重建阿拉斯加和育空地区的古气候历史提供改进的框架。

项目成果

A stable isotope record of late Cenozoic surface uplift of southern Alaska

阿拉斯加南部晚新生代地表隆起的稳定同位素记录

• DOI: 10.1016/j.epsl.2017.11.029
• 发表时间: 2018-01
• 期刊: Earth and Planetary Science Letters
• 影响因子: 5.3
• 作者: Bill, Nicholas S.;Mix, Hari T.;Clark, Peter U.;Reilly, Sean P.;Jensen, Britta J.L.;Benowitz, Jeffrey A.
• 通讯作者: Benowitz, Jeffrey A.

Deep Sulfate-Methane-Transition and sediment diagenesis in the Gulf of Alaska (IODP Site U1417)

阿拉斯加湾深层硫酸盐-甲烷转变和沉积物成岩作用（IODP 站点 U1417）

• DOI: 10.1016/j.margeo.2019.105986
• 发表时间: 2019-11-01
• 期刊: Marine Geology
• 影响因子: 2.9
• 作者: M. Zindorf;C. März;T. Wagner;S. Gulick;H. Strauss;J. Benowitz;J. Jaeger;B. Schnetger;L. Childress;L. Levay;C. L;Michelle La Rosa
• 通讯作者: Michelle La Rosa

Neogene sedimentary record of the evolution of a translated strike-slip basin along the Denali fault system: Implications for timing of displacement, composite basin development, and regional tectonics of southern Alaska

沿德纳利断层系平移走滑盆地演化的新近纪沉积记录：对位移时间、复合盆地发育和阿拉斯加南部区域构造的影响

• DOI: 10.1130/ges02435.1
• 发表时间: 2022-02
• 期刊: Geosphere
• 影响因子: 2.5
• 作者: Allen, Wai K.;Ridgway, Kenneth D.;Benowitz, J.A.;Waldien, T.S.;Roeske, S.M.;Fitzgerald, P.G.;Gillis, R.J.
• 通讯作者: Gillis, R.J.

Late Miocene to Quaternary evolution of the McCallum Creek thrust system, Alaska: Insights for range-boundary thrusts in transpressional orogens

阿拉斯加麦卡勒姆溪逆冲系统的晚中新世至第四纪演化：对压折造山带范围边界逆冲的见解

• DOI: 10.1130/ges01676.1
• 发表时间: 2018-10
• 期刊: Geosphere
• 影响因子: 2.5
• 作者: Waldien, Trevor S.;Roeske, Sarah M.;Benowitz, Jeffrey A.;Allen, Wai K.;Ridgway, Kenneth D.;O’Sullivan, Paul B.
• 通讯作者: O’Sullivan, Paul B.