Systematic variations in the eruptive history of the Christiana-Santorini-Kolumbo volcanic field (Greece) - The IODP Expedition 398 tephra time series and its implications

克里斯蒂安娜-圣托里尼-科伦博火山场（希腊）喷发历史的系统变化 - IODP Expedition 398 tephra 时间序列及其含义

• 批准号: 527924707
• 负责人: Privatdozent Dr. Steffen Kutterolf
• 金额: --
• 依托单位: Forschungseinheit Magmatische und Hydrothermale Systeme
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/527924707?language=en
• 关键词: Systematic; variations; eruptive; history; Christiana

During IODP Expeditions 398 the objectives were to study the volcanic record of the central Hellenic island arc to document the links and feedbacks between volcanism/magmatism, crustal tectonics and sea level, and to investigate the processes and products of shallow submarine eruptions of silicic magma. Reconstructing the subsidence history of the southern Aegean Sea, and searching for deep life inside and outside of Santorini caldera, were additional objectives. The expedition drilled ten sites originally proposed, plus two extra sites that were requested during the expedition. Outside of Santorini caldera, drilling penetrated the thick basin fills of the crustal rift system hosting the Christiana-Santorini-Kolumbo volcanic field, identifying numerous pumice and ash layers, some known from onland and others hitherto unknown, pushing back the onset of volcanism in the area into the early Pleistocene or even Pliocene. Huge events of mass wasting into the basins, accompanied by very high sedimentation rates, were also documented. These basin sites served to groundtruth the seismic stratigraphy of the basins and to open the way to unravelling relationships between volcanic activity and crustal rift pulses. Two sites of condensed sequences on the basin margins served to sample many volcanic layers within the detailed age-depth constraints provided mainly by biostratigraphy. Drilling inside Santorini caldera penetrated to ~120 mbsf and yielded a detailed tephra record of the history of the Kameni islands. Tephra deposits from Exp. 398 complemented by tephras found on land provide the unique opportunity to investigate and compare the history of highly explosive volcanic activity of the Christiana-Santorini-Kolumbo volcanic field in the heart of Southern Europe, including one of the most famous and most active volcanoes in our neighborhood. This project focuses therefore on the ~1200 volcanic horizons derived from highly explosive eruptions during the Pliocene and Quaternary and found in the cores. Geochemical, petrological and volcanological approaches for tephra and sediment characterization will be used to quantitatively and qualitatively decrypt their provenance and the eruption succession. Additionally, absolute age dating will improve and confirm the existing age models since robust age models are needed to study the temporal and spatial changes in eruption processes, magnitudes and frequencies of large volcanic eruptions. The herewith-established compositional data and eruptive time series will serve as base to address questions regarding recurrence rates and cyclicities, and compare them with external controlling mechanism like tectonics and sea level changes. Recovered sediments will also facilitate to investigate the temporal and quantitative characterization of the sediment composition in the basins of the Aegean Sea in relation to the volcaniclastic input and answer the question how this may be connected to the basin evolution.

在IODP 398考察期间，目标是研究希腊中部岛弧的火山记录，以记录火山活动/岩浆活动、地壳构造和海平面之间的联系和反馈，并调查海底浅层岩浆喷发的过程和产物。重建爱琴海南部的沉降历史，并在圣托里尼火山口内外寻找深层生命，是额外的目标。探险队钻探了最初提议的10个地点，加上探险期间要求的两个额外地点。在圣托里尼破火山口之外，钻探穿透了克里斯蒂娜-圣托里尼-科伦博火山场所在的地壳裂谷系统的厚盆地填充物，确定了许多浮石和火山灰层，其中一些是在陆地上已知的，另一些是迄今为止未知的，将该地区火山活动的开始推回到了更新世早期甚至上新世。还记录了大量物质浪费到盆地中的巨大事件，伴随着非常高的沉积速率。这些盆地遗址为盆地的地震地层学奠定了基础，并为解开火山活动和地壳裂谷脉冲之间的关系开辟了道路。盆地边缘的两个地点的浓缩序列提供了详细的年龄-深度的限制，主要是由生物地层学的许多火山层的样品。圣托里尼火山口内的钻探深度约为120 mbsf，并获得了卡梅尼群岛历史的详细火山灰记录。火山碎屑沉积物在陆地上发现的火山岩的补充下，398提供了独特的机会来调查和比较位于南欧中心的克里斯蒂安-圣托里尼-科隆博火山区的高爆炸性火山活动的历史，包括我们附近最着名和最活跃的火山之一。因此，本项目的重点是在岩芯中发现的上新世和第四纪期间高度爆炸性喷发产生的约1200个火山层位。火山灰和沉积物特征的地球化学，岩石学和火山学方法将用于定量和定性解密其来源和喷发序列。此外，绝对年龄测定将改进和确认现有的年龄模型，因为需要可靠的年龄模型来研究大规模火山爆发的喷发过程、规模和频率的时空变化。本文建立的成分数据和喷发时间序列将作为基础，解决有关复发率和周期性的问题，并将其与外部控制机制，如构造和海平面变化进行比较。覆盖的沉积物也将有助于调查的时间和定量表征的沉积物组成在爱琴海盆地的火山喷发输入和回答的问题，这可能是连接到盆地的演变。