Establishing causes of sea-level change and oceanic anoxia in the Late Cretaceous: regional versus global patterns

确定白垩纪晚期海平面变化和海洋缺氧的原因：区域与全球模式

• 批准号: NE/H020756/1
• 负责人: Ian Jarvis
• 金额: $ 19.28万
• 依托单位: Kingston University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2011
• 资助国家: 英国
• 起止时间: 2011 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FH020756%2F1
• 关键词: Establishing; causes; sea; level; change

The Cretaceous, 146-66 million years ago, experienced high levels of atmospheric CO2, and the warmest climates and highest global sea-levels in the last 300 Ma. On several occasions, the oceans became abruptly depleted in oxygen, so-called oceanic anoxic events (OAEs), when organic matter accumulated in the oceans, producing widespread black shales that now act as oil source rocks. However, the mechanisms that caused these events remain hotly debated. This proposal aims to use a new multi-dynamic approach to better understand the mechanisms that caused the onset, duration and cessation of global carbon burial events during the Late Cretaceous. Burial of organic matter leads to the preferential removal of isotopically light carbon from the oceans, increasing the 13C/12C ratio of seawater and, via the atmospheric CO2 reservoir, the entire Earth surface system. Weathering releases 12C back to the surface carbon cycle. Carbonates and organic matter in rocks preserve changes in C-isotope ratios through time, providing a basis for C-isotope stratigraphy. Major changes are synchronous and global in extent, and we have proposed that C-isotope variation in the Late Cretaceous may be used as a proxy for global sea-level change; this remains to be tested. Osmium, a platinum group element with a short ocean residence time of <40 kyr, also shows isotopic variation in seawater through time, being controlled predominantly by two end-member components: weathering of crust and input from volcanic activity (mantle). These have drastically different ratios, so Os isotopes potentially may provide high-resolution stratigraphic control during times of palaeoenvironmental change, such as episodes of increased weathering or volcanic input. The modern oceans display a uniform Os-isotope ratio, but our new data for Os isotopes through an OAE at ~94 Ma indicate that the Atlantic displayed diachronous shifts in Os isotopes. This offers an exciting potential new tool for studying palaeocean-mixing. However, this OAE may be a unique event with regard to oceanic Os; further regions and OAEs need to be tested. This project will use C-isotope stratigraphy from organic matter to correlate global successions from diverse environments, palaeolatitudes and oceanic settings. The time interval to be investigated, 101-83 Ma, was characterized by two OAEs and other significant changes in the carbon cycle. We aim to answer the following: (1) Are secular C- and Os-isotope curves related to sea-level change? (2) Can Os-isotope stratigraphy be used for chemostratigraphy: is it synchronous or diachronous? (3) Do OAEs coincide with Os-isotope excursions, and what was the steady state of the oceans? (4) What are the relationships between sea-level change, climate and ocean anoxia; can we finally identify the key forcing mechanism for widespread ocean stagnation? Sites in Canada, France, Czech Republic, Far East Russia, Ecuador, South Atlantic, and offshore Australia will be studied. The relative sea-level histories for each basin, correlated using C-isotopes, will be used to test relationships between C-isotope stratigraphy and sea-level change. Key stratigraphic time intervals will be characterised for Os isotopes and trace-metals to: establish the evolution of Os isotopes in the Late Cretaceous oceans; evaluate possible regional variation in the Os-isotope composition of seawater; establish levels of seawater oxygenation in the associated water masses; and identify the causes of widespread ocean stagnation. Results from our Cretaceous extreme-greenhouse study will provide unique constraints for modelling interactions between, and the impacts of, sea-level and climate change, and perturbations of the global carbon cycle for an icecap-free Earth; the increasingly likely near-future for our planet. The proposed research will aid in understanding whether periods of ocean stagnation are a likely future consequence of present-day global warming.

白垩纪，1.46 -66亿年前，经历了高水平的大气二氧化碳，最温暖的气候和最高的全球海平面在过去的300 Ma。有几次，海洋突然变得缺氧，即所谓的海洋缺氧事件（OAE），当时有机物质在海洋中积累，产生了广泛的黑色页岩，现在充当石油源岩。然而，导致这些事件的机制仍然存在激烈的争论。该建议旨在使用一种新的多动力学方法，以更好地了解导致晚白垩世全球碳埋藏事件发生，持续时间和停止的机制。有机物的埋藏导致同位素轻碳从海洋中优先去除，增加了海水的13 C/12 C比率，并通过大气CO2库增加了整个地球表面系统。风化释放12 C回到地表碳循环。岩石中的碳酸盐和有机质保存了碳同位素比值随时间的变化，为碳同位素地层学提供了基础。主要变化是同步的和全球性的，我们提出晚白垩世的碳同位素变化可以用作全球海平面变化的代表;这仍有待检验。锇是一种铂族元素，在海洋中的停留时间短，小于40 kyr，在海水中的同位素随时间变化，主要受两种端元成分的控制：地壳风化和火山活动（地幔）的输入。这些具有截然不同的比率，因此Os同位素可能在古环境变化期间提供高分辨率的地层控制，例如增加风化或火山输入的事件。现代海洋显示一个统一的Os同位素比，但我们的新数据，通过OAE在~94 Ma的Os同位素表明，大西洋显示穿时变化的Os同位素。这为研究古海洋混合提供了一个令人兴奋的潜在新工具。然而，这OAE可能是一个独特的事件，就海洋Os，进一步的地区和OAE需要进行测试。该项目将利用有机物的碳同位素地层学，将不同环境、古纬度和海洋环境的全球演替联系起来。被调查的时间间隔，101-83 Ma，其特征是两个OAE和其他显着的变化，在碳循环。我们的目标是回答以下问题：（1）长期的C-和Os-同位素曲线与海平面变化有关？(2)锇同位素地层学能否用于化学地层学：是同期的还是穿时的？(3)OAE是否与Os同位素的漂移相吻合？海洋的稳定状态是什么？(4)海平面变化，气候和海洋缺氧之间的关系是什么？我们最终能否确定大范围海洋停滞的关键动力机制？将研究加拿大、法国、捷克共和国、俄罗斯远东、厄瓜多尔、南大西洋和澳大利亚近海的地点。每个盆地的相对海平面历史，使用碳同位素相关，将被用来测试碳同位素地层学和海平面变化之间的关系。关键的地层时间间隔将被表征为Os同位素和痕量金属：建立晚白垩世海洋中Os同位素的演变;评估海水中Os同位素组成的可能区域变化;建立相关水体中海水氧合水平;并确定广泛海洋停滞的原因。我们对白垩纪极端温室效应的研究结果将为模拟海平面和气候变化之间的相互作用及其影响以及全球碳循环的扰动提供独特的限制，以实现一个无冰盖的地球;我们的星球越来越有可能在不久的将来。这项拟议中的研究将有助于了解海洋停滞期是否是当今全球变暖的一个可能的未来后果。

项目成果

Upper Pliensbachian and Lower Toarcian paleogeography and sedimentary environments of northern England

英格兰北部上普林斯巴阶和下托阿尔阶古地理和沉积环境

• 发表时间: 2014
• 期刊: GSA Abstracts
• 作者: Atar E

Mountain glaciation drives rapid oxidation of rock-bound organic carbon.

• DOI: 10.1126/sciadv.1701107
• 发表时间: 2017-10
• 期刊: Science advances
• 影响因子: 13.6
• 作者: Horan K;Hilton RG;Selby D;Ottley CJ;Gröcke DR;Hicks M;Burton KW
• 通讯作者: Burton KW

Response of foraminiferal assemblages to precession-paced environmental variation in a mid-latitude seaway: Late Turonian greenhouse of Central Europe

• DOI: 10.1016/j.marmicro.2021.102025
• 发表时间: 2021-08
• 期刊: Marine Micropaleontology
• 影响因子: 1.9
• 作者: M. Chroustová;K. Holcová;J. Laurin;D. Uličný;L. Hradecká;M. Hrnková;S. Čech;F. Hrouda;I. Jarvis

An open ocean record of the Toarcian oceanic anoxic event

• DOI: 10.5194/se-2-245-2011
• 发表时间: 2011-01-01
• 期刊: SOLID EARTH
• 影响因子: 3.4
• 作者: Groecke, D. R.;Hori, R. S.;Schwark, L.
• 通讯作者: Schwark, L.

Intercontinental correlation of organic carbon and carbonate stable isotope records: evidence of climate and sea-level change during the Turonian (Cretaceous)

• DOI: 10.1002/dep2.6
• 发表时间: 2015-12-01
• 期刊: DEPOSITIONAL RECORD
• 影响因子: 2.4
• 作者: Jarvis, Ian;Trabucho-Alexandre, Joao;Laurin, Jiri
• 通讯作者: Laurin, Jiri