Testing an arc volcanism - climate link in a high-latitude Plio-Pleistocene marine tephra archive at ODP Site 882 (northwest Pacific)

测试 ODP 站点 882（西北太平洋）高纬度上里欧-更新世海洋火山灰档案中的弧火山活动与气候之间的联系

• 批准号: 1950006
• 负责人: Susanne Straub
• 金额: $ 29万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-03-15 至 2024-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1950006&HistoricalAwards=false
• 关键词: Testing; arc; volcanism; climate; link

This project explores high latitude volcanic activity. It is hypothesized that the volcanic activity is linked to cyclic variations in Earth’s climate, especially the growth and shrinking of terrestrial ice sheets during the glacial / interglacial cycles of the last ~2.6 million years. Sediment cores will be studied that were recovered by ocean drilling as part of the multi-national Ocean Drilling Program (ODP). In those cores the number and composition of ash layers produced by the volcanoes of Kamchatka Peninsula and the Aleutian Islands will be measured. Current data show a strong increase of volcanic activity at the beginning of the Earth’s most recent glacial period, 2.6 million years ago. That increase was followed by periodic changes in how often volcanoes erupt. This study will show whether those volcanic cycles are timed with orbitally-driven climate cycles through that 2.6 million year period, which would be expected if Earth’s volcanism was linked to global climate cycles. The project will be carried out by international team of researchers from the United States, Australia and Mexico that includes igneous geochemists and climate scientists. The team is led by a women scientist with a disability. The project provides opportunities for graduate and undergraduate student training, for connecting with colleagues in Russia and Germany who work on complementary projects, and for outreach to K-12 teachers and students and to the general public. The proposed project will test the glacio-volcano hypothesis whether the increase in marine fallout ash bed frequency at ~2.6 Ma and its subsequent fluctuation in the North Pacific is causally related to the Pleistocene ice cycles. This will be done by means of the Plio-Pleistocene ash bed record drilled in two holes at ODP Site 882 (Leg 145), which are 100% recovered by advanced piston coring (APC)-techniques and that contain a rich and time-precise, late Pliocene to Recent ash bed record from high-latitude volcanic arcs where the effects of global glaciation cycles are strongest. The team will obtain a revised, detailed lithostratigraphic description of the Site 882 ash beds, and augment the existing compositional data by additional major and trace element analyses, including Cl, and Pb and Nd isotope ratios in order to test whether (i) Milankovitch periods are present in the ash bed series; (ii) there is a tell-tale change in ash bed cyclicity across the Mid-Pleistocene Transition (~0.7-1.1 Ma); (iii) ash bed cyclicity is affected by provenance from different arcs; and (iv) there is a magmatic control on ash bed cyclicity. The study could provide an answer to whether tempos of explosive arc volcanism as recorded in the marine ash bed series are paced by glaciation, or whether such signals are largely lost in the maze of other processes that influence the timing of explosive arc volcanism.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

该项目探索高纬度火山活动。据推测，火山活动与地球气候的周期性变化有关，特别是在过去约260万年的冰期/间冰期周期中陆地冰盖的生长和收缩。作为多国海洋钻探计划（ODP）的一部分，将对海洋钻探回收的沉积物岩心进行研究。在这些岩心中，将测量堪察加半岛和阿留申群岛火山产生的火山灰层的数量和成分。目前的数据显示，在260万年前地球最近的冰川期开始时，火山活动强烈增加。火山喷发频率的周期性变化紧随火山喷发频率的增加之后。这项研究将显示这些火山周期是否与260万年期间轨道驱动的气候周期同步，如果地球的火山活动与全球气候周期有关，这将是预期的。该项目将由来自美国，澳大利亚和墨西哥的国际研究人员团队进行，其中包括火成岩地球化学家和气候科学家。该小组由一名残疾女科学家领导。该项目为研究生和本科生提供培训机会，与俄罗斯和德国从事补充项目的同事建立联系，并与K-12教师和学生以及公众进行外联。 拟议的项目将检验冰川火山假说，海洋沉降灰床频率在~2.6 Ma时的增加及其随后在北太平洋的波动是否与更新世冰周期有因果关系。这将通过在ODP 882号站点（第145航段）的两个钻孔中钻取的上新世-更新世灰床记录来完成，这些记录是通过先进的活塞取芯（APC）技术100%回收的，其中包含来自高纬度火山弧的丰富和时间精确的上新世晚期至近代灰床记录，全球冰川循环的影响最强。该小组将获得882号地点灰层的订正详细岩石地层学描述，并通过额外的主要和微量元素分析，包括Cl、Pb和Nd同位素比率，扩大现有的成分数据，以测试（i）灰层系列中是否存在米兰科维奇期;（ii）在中更新世过渡期，灰层的旋回性发生了明显的变化火山灰层旋回性受不同弧源的影响，火山灰层旋回性受岩浆活动的控制。这项研究可以提供一个答案，是否在海洋灰床系列记录的爆发性弧火山活动的节奏是由冰川作用，或者是否这样的信号很大程度上失去了迷宫的其他过程，影响爆发性弧volcanism的时间。这个奖项反映了NSF的法定使命，并已被认为是值得通过评估使用基金会的智力价值和更广泛的影响审查标准的支持。