Discriminating Deep Water Deposits for IODP Expedition 401: "Mediterranean-Atlantic Gateway Exchange" (Acronym: DISCRIMINATE)

IODP 401 号远征的深水沉积物识别：“地中海-大西洋门户交换”（缩写：DISCRIMINATE）

• 批准号: NE/Y005511/1
• 负责人: F Javier Hernandez-Molina
• 金额: $ 3.26万
• 依托单位: Royal Holloway University of London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FY005511%2F1
• 关键词: Discriminating; Deep; Water; Deposits; IODP

Ocean basins are connected by gateways (e.g., Drake Passage), sometimes referred to as seaways, passages, straits, and corridors. Marine gateways play a critical role in the exchange of water, heat, salt and nutrients between oceans and seas. The advection of dense waters helps drive global thermohaline circulation and, since the ocean is the largest of the rapidly exchanging CO2 reservoirs, this advection also affects atmospheric carbon concentration. Changes in gateway geometry can therefore significantly alter both the pattern of global ocean circulation and associated heat transport and climate, as well as having a profound local impact.Today, the volume of dense water supplied by Atlantic-Mediterranean exchange through the Gibraltar Strait is amongst the largest in the global ocean. For the past five million years this overflow has generated a saline plume at intermediate depths in the Atlantic, generates bottom currents distinctive deposits (called "contourites") in the Gulf of Cadiz and contributes to the formation of North Atlantic Deep Water. This single gateway configuration only developed in the early Pliocene, however. During the Miocene, a wide, open seaway linking the Mediterranean and Atlantic evolved into two narrow corridors: one in northern Morocco; the other in southern Spain. Formation of these corridors permitted Mediterranean salinity to rise and a new, distinct, dense water mass to form and overspill into the Atlantic for the first time. Further restriction and closure of these connections resulted in extreme salinity fluctuations in the Mediterranean, leading to the formation of the Messinian Salinity Crisis salt giant. The International Ocean Discovery Program (IODP) Expedition 401: "Mediterranean-Atlantic Gateway Exchange" is planned to recover a complete record of Atlantic-Mediterranean exchange from its Late Miocene inception to its current configuration. This IODP expedition is the offshore component of the Land2Sea Proposal IMMAGE "Investigating Miocene Mediterranean-Atlantic Gateway Exchange", which aims to constrain quantitatively the consequences for ocean circulation and global climate of the inception of Atlantic-Mediterranean exchange; to explore the mechanisms for high amplitude environmental change in marginal marine systems and to test physical oceanographic hypotheses for extreme high-density overflow dynamics that do not exist in the world today on this scale.The JOIDES Resolution Science Operator (JRSO) was pleased to invite my participation as a Sedimentologist on IODP Expedition 401. This proposal "Discriminating Deep Water Deposits for IODP Expedition 401: "Mediterranean-Atlantic Gateway Exchange" (DISCRIMINATE) would support my participation in the IODP Exp 401 covering my participant's cost; staff, travel and subsistence, and moratorium period research. This research project aims the discrimination d of deep marine deposits, with special emphasis on possible deposits generated by bottom currents (contourites) or sediment reworked by currents (as reworked turbidites), on the Atlantic sites from IODP Expedition 401. The specific research objectives of the proposed research based on than general aim are: a) recognise and discriminate bottom current deposits, for estimate the bottom current variability and circulation before, during and after the Messinian Salinity Crisis; b) Understand the long- and short-term dynamics and exchange of water masses during key intervals during the Late Miocene (as the early and Late Messinian), and c) determine the key events and their significance for basin analysis and palaeocirculation. The growing interest in, and implications of, contourite and sediment reworked by currents deposits demonstrates that these sediments represent significant deep-marine sedimentary environments.

海洋盆地通过网关连接（例如，德雷克海峡（Drake Passage），有时也被称为航道、通道、海峡和走廊。海洋通道在海洋与海洋之间的水、热、盐和营养物质交换方面发挥着关键作用。稠密沃茨的平流有助于推动全球温盐环流，而且由于海洋是最大的快速交换的二氧化碳储存库，这种平流也影响大气中的碳浓度。因此，门户几何形状的变化可以大大改变全球海洋环流的格局和相关的热量输送和气候，并对当地产生深远的影响，今天，南极-地中海交换通过直布罗陀海峡提供的密集水的数量是全球海洋中最大的。在过去的五百万年里，这种溢出在大西洋的中间深度产生了盐水羽流，在加迪斯湾产生了底流独特的沉积物（称为“等深流”），并有助于北大西洋深水的形成。然而，这种单一的网关配置只在上新世早期发展起来。在中新世，一条连接地中海和大西洋的宽阔开阔的海道演变成两条狭窄的走廊：一条在北方摩洛哥，另一条在西班牙南部。这些走廊的形成使得地中海的盐度上升，一个新的、独特的、密集的水团形成，并第一次溢出到大西洋。这些连接的进一步限制和关闭导致了地中海极端的盐度波动，导致了墨西拿盐度危机盐巨人的形成。国际海洋发现计划（IODP）远征401：“地中海-大西洋门户交换”计划恢复从晚中新世开始到目前配置的南极-地中海交换的完整记录。这次国际大洋钻探计划考察是IMMAGE“调查中新世地中海-大西洋通道交换”陆地转海洋提案的近海组成部分，其目的是从数量上限制地中海-地中海交换开始对海洋环流和全球气候的影响;探索边缘海洋系统高幅度环境变化的机制，并检验极端高-密度溢出动力学，在当今世界上不存在这种规模。JOIDES分辨率科学操作员（JRSO）很高兴邀请我作为IODP远征401的沉积学家参与。本提案“为IODP Expedition 401区分深水矿床：“地中海-大西洋门户交换”（DISCRIMINATE）将支持我参加IODP Exp 401，包括我的参与者的费用;工作人员，旅行和生活费，以及暂停期研究。该研究项目旨在辨别深海沉积物，特别强调在国际海洋学钻探项目第401次考察的大西洋地点可能由底流（等深流）或由海流改造的沉积物（改造浊积岩）产生的沉积物。本研究的具体目标是：（1）识别和判别底流沉积，估计梅西尼亚盐度危机前后底流的变化和环流; B）了解晚中新世关键时段水团的长期和短期动态和交换（如早、晚中生代）;（3）确定关键事件及其对盆地分析和古环流的意义。等深岩和沉积物被海流沉积物改造的兴趣和影响日益增加，表明这些沉积物代表了重要的深海沉积环境。