Site Survey for IODP Proposal 646-Full:- Icelandic V-Shaped-Ridges

IODP 提案 646-Full 的现场调查：- 冰岛 V 形山脊

基本信息

批准号：
NE/G001251/1
负责人：
Bramley Murton
金额：
$ 2.42万
依托单位：
NATIONAL OCEANOGRAPHY CENTRE
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2008
资助国家：
英国
起止时间：
2008 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FG001251%2F1
关键词：
Site Survey IODP Proposal 646

项目摘要

This Urgency Grant Proposal aims to take advantage of a site survey opportunity in support of a UK-led IODP proposal to drill the North Atlantic basement. A bid made last October to the Science Foundation, Ireland and the Irish Marine Institute by Steve Jones (Trinity Colege, Dublin) and Bramley Murton (NOCS) resulted in 450,0000 euros of ship-time being awarded. The Celtic Explorer has been made available to Jones and Murton between mid-April and mid-May 2008. To support this expedition, funds are sought to mobalise and set-up a portable multibeam exchosounder (Reson 8160), and to hire several dredges from NMFD. The costs are modest, at about 2.5% of the ship-time. The scientific objectives are to map and sample along the strike of a V-shaped ridge that is exposed on the western flank of the Rejkanes Ridge, southwest of Iceland. This Urgency Grant Proposal is in support of a major, UK-led, IODP proposal (646-Full) that addresses fundamental questions about the causes of fluctuations in the activity of volcanic hotspots and their effects on the Earth's environment including climate. Does deep upwelling in the mantle, localized temperature and compositional anomalies, or shallow-mantle flow cause hotspot fluctuations? What are the time scales and rates involved? Where mantle flow is involved, what is its fate as it flows away from a hotspot? To address these issues, we propose to sample time-transgressive features that are common where hotspots interact with mid-ocean spreading ridges. These phenomena are exceptionally clearly developed for the Iceland-Reykjanes Ridge couplet where a series of diachronous V-shaped ridges (VSR's) preserve a record of changing hotspot activity, over the last 35Ma, on the floor of the North Atlantic. Linked to these fluctuations in the Iceland hotspot are variations in the flux of North Atlantic Component Water (NACW) that drives the 'global ocean conveyor' and whose return flow is manifest as the North-Atlantic Drift that moderates the climate of northwestern Europe. The significance of the Iceland VSR's as indicators of the processes of hotspot fluctuations has been recognised in the recent Large Igneous Province IODP Workshop (Colrain, 2007). Sampling the diachronous VSR's by drilling on the flanks of the Reykajnes Ridge in the North Atlantic is the only way to access this geological record. We propose to sample lavas from a transect along one of the youngest VSR's, exposed on the western flank of Reykjanes Ridge. The geochemistry of these lavas will yield insights into the genesis of the VSR's, and hence the causes and processes of hotspot fluctuation. The nature of the questions being addressed and our methodology have been informed from four separate, internationally sponsored workshops over the past 4 years. During the most recent, an UK-IODP workshop 'Rift2Ridge '07', Southampton, 2007, we identified an important link between this proposal and another IODP proposal by Wright et al, (in prep.) that aims to investigate the correlation between the initiation of VSR's on Iceland and fluctuations of NACW overflow strength.

这项紧迫的赠款提案旨在利用现场调查机会，以支持由英国领导的IODP提案，以钻探北大西洋地下室。史蒂夫·琼斯（Steve Jones）（都柏林三一科尔格（Trinity Colege））和布拉姆利·默顿（Bramley Murton）（NOCS）于去年10月向科学基金会，爱尔兰和爱尔兰海洋研究所提出了出价，从而授予了450,0000欧元的船舶时间。凯尔特探险家已向琼斯和2008年5月中旬之间的琼斯和默顿提供。为了支持这次探险，寻求资金来移动和建立一家便携式多型货币库（Reson 8160），并从NMFD雇用了几种疏通。费用谦虚，约占船舶时间的2.5％。科学的目标是沿着冰岛西南雷贾卡尼斯山脊的西侧的V形山脊的罢工绘制和采样。这项紧急赠款的提案是为了支持一个由英国领导的IODP提案（646-FULL），该提案解决了有关火山热点活动中波动及其对地球环境（包括气候）的影响的基本问题。地幔，局部温度和组成异常或浅层竖井流中的深度上升是否会导致热点波动？涉及的时间尺度和费率是什么？涉及地幔流的位置，当它从热点流出时，它的命运是什么？为了解决这些问题，我们建议在热点与中海中的山脊相互作用的情况下采样时间转换特征。这些现象是针对冰岛 - 雷克雅内斯山脊对联的特殊开发的，其中一系列的直觉V形山脊（VSR）保留了在北大西洋上的最后35mA中改变热点活动的记录。与冰岛热点中的这些波动有关的是北大西洋零件水（NACW）的变化，它驱动了“全球海洋传送带”，其回流流如北大西洋漂移而显现为减轻西北欧洲气候的北大西洋漂移。冰岛VSR作为热点波动过程的指标的重要性已在最近的大型火成岩省IODP研讨会中得到认可（Colrain，2007年）。通过在北大西洋的雷卡尼斯山脊的侧面进行钻探来取样时长的VSR。我们建议从沿雷克雅内斯山脊西部的最年轻的VSR中的一个沿横断面采样熔岩。这些熔岩的地球化学将对VSR的起源产生见解，因此，热点波动的原因和过程。在过去的四年中，已经从四个独立的国际赞助研讨会上获悉了所解决的问题和我们的方法论的性质。在最近的一次，UK-IODP研讨会“ Rift2ridge” 07'，Southampton，2007年，我们确定了该提案与Wright等人的另一项IODP提案之间的重要联系（（在准备中），旨在研究VSR On on Iceland的NACW溢出强度的启动之间的相关性。