Tectonic Ocean Spreading at the Charlie-Gibbs Fracture Zone (TOSCA)

查理-吉布斯断裂带的构造洋扩张 (TOSCA)

• 批准号: 406419728
• 负责人: Professor Dr. Sebastian Krastel
• 金额: --
• 依托单位: Arbeitsgruppe Marine Geophysik und Hydroakustik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/406419728?language=en
• 关键词: Tectonic; Ocean; Spreading; Charlie; Gibbs

In recent years, there has been a growing realisation that seafloor spreading at many slow and ultra-slow spreading mid-ocean ridges is accommodated not by volcanism, but by tectonic stretching resulting in the dissection of the oceanic crust and exhumation of the underlying mantle. The resulting structures are known as oceanic core complexes; they expose lower crustal and upper mantle rocks in the footwalls of long-lived, low-angle detachment faults.Conditions at the central rift of the Charlie-Gibbs Fracture Zone have the optimum attributes for the development of oceanic core complexes. The Charlie-Gibbs Fracture Zone is a major fracture zone that offsets the Mid-Atlantic Ridge approximately 350 km left-laterally, between Iceland and the Azores (52° to 53° N). It comprises two seismically active E-W transform-fault valleys separated by a short ridge. The scheduled RV Celtic Explorer Expedition TOSCA (Tectonic Ocean Spreading at the Charlie-Gibbs Fracture Zone) will take place from May 13th to June 7th 2018. The main objective of this cruise is to study the effects of a long-lived asymmetric spreading and associated hydrothermal venting at the Charlie-Gibbs Fracture Zone in an interdisciplinary approach. An integral part of the work is the collection of high-resolution reflection seismic data in order to image the sedimentary sequence infilling the Charlie-Gibbs Fracture Zone troughs. These data should be collected by means of the high-resolution seismic system of Kiel University. Main objectives addressed by seismic surveying include i) the investigation of the mechanism by which mid-ocean ridges get destroyed and buried away from the spreading centres, ii) to map deep-seafloor mass wasting deposits in the troughs as a record of past seismic activity, and iii) to image the basement topography. The Charlie-Gibbs Fracture Zone is so poorly known that we can look at the recovery of any data and material as a true exploration that will increase our knowledge and understanding of this critical region.

近年来，人们越来越认识到，许多缓慢和超缓慢扩张的洋中脊的海底扩张不是由火山作用调节的，而是由导致洋壳解剖和底层地幔折返的构造伸展调节的。由此产生的结构被称为大洋核复合体;它们在长期存在的低角度拆离断层的下盘暴露下地壳和上地幔岩石。查理-吉布斯断裂带中央裂谷的条件具有大洋核复合体发育的最佳属性。查理-吉布斯断裂带（英语：Charlie-Gibbs Fracture Zone）是一个主要的断裂带，在冰岛和亚速尔群岛之间（北纬52°至53°），向左偏移大西洋中脊约350公里。它包括两个地震活跃的东西转换断层谷由一个短脊分开。预定的RV Celtic Explorer Expedition TOSCA（查理-吉布斯断裂带的构造海洋扩展）将于2018年5月13日至6月7日举行。这次航行的主要目的是以跨学科方法研究查理-吉布斯断裂带长期不对称扩张和相关热液喷发的影响。这项工作的一个组成部分是收集高分辨率反射地震数据，以便对填充查理-吉布斯断裂带槽的沉积序列进行成像。这些数据应通过基尔大学的高分辨率地震系统收集。地震勘测的主要目标包括：㈠调查洋中脊被破坏和掩埋在远离扩张中心的地方的机制; ㈡绘制海槽中深海海底物质耗损沉积物的地图，作为过去地震活动的记录; ㈢绘制基底地形图。查理-吉布斯断裂带是如此鲜为人知，我们可以把任何数据和材料的恢复看作是一个真正的探索，这将增加我们对这个关键区域的知识和理解。