Quaternary explosive volcanism of the Cape Verde Archipelago: On- and offshore tephrostratigraphy

佛得角群岛第四纪爆发性火山活动：陆上和近海地层学

• 批准号: 207266739
• 负责人: Privatdozent Dr. Armin Freundt
• 金额: --
• 依托单位: Forschungseinheit Magmatische und Hydrothermale Systeme
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2011
• 资助国家: 德国
• 起止时间: 2010-12-31 至 2015-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/207266739?language=en
• 关键词: Quaternary; explosive; volcanism; Cape; Verde

28 gravity cores up to 9 m long, collected during cruise M80/3 around and across the Cape Verde Archipelago, contain a total of 205 ash layers that document highly explosive eruptions from several of the islands since the late Pleistocene. This project aims to correlate ash layers between cores and with tephras on land in order to establish a tephrostratigraphic framework supported by absolute age dating. Geochemical, petrological and volcanological characterization of these mafic, felsic, and occasionally compositionally zoned, highly alkalic tephras will then be used to constrain temporal and spatial changes in eruption processes, magnitudes and frequencies as well as conditions of magmatic evolution. A special focus will be on the generation of the apparently abundant mafic Plinian eruptions. Comparison of our results on late Quarternary volcanism with data from a parallel project on seamounts and island flanks representing earlier growth stages will improve understanding of ocean island evolution. The stratigraphic framework of marker beds will also constrain ages and rates of other geological events (turbidity currents from island-flank instability, input of Saharan dust, diagenesis) as well as marine plankton evolution.

28个长达9米的重力岩心是在M80/3号巡航期间在佛得角群岛周围和整个群岛上收集的，总共包含205个火山灰层，记录了自更新世晚期以来几个岛屿的高度爆炸性喷发。该项目旨在将岩心之间的火山灰层与陆地上的火山灰层联系起来，以建立一个由绝对年龄定年支持的地层格架。地球化学、岩石学和火山学特征的这些基性、长英质，偶尔组成分区，高碱性的tephras将被用来约束喷发过程、震级和频率以及岩浆演化条件的时空变化。一个特别的重点将是产生明显丰富的地中海普林尼火山喷发。将我们关于晚第四纪火山作用的结果与代表早期生长阶段的海山和岛屿侧翼的平行项目的数据进行比较，将提高对海洋岛屿演化的理解。标志层的地层格架也将限制其他地质事件的年龄和速率（来自岛屿侧面不稳定的浊度流、撒哈拉沙尘的输入、成岩作用）以及海洋浮游生物的演化。