Searching for direct evidence of the consequences of land plant evolution on silicate weathering and continental sediment retention

寻找陆地植物进化对硅酸盐风化和大陆沉积物滞留影响的直接证据

• 批准号: NE/T00696X/1
• 负责人: Neil Davies
• 金额: $ 70.62万
• 依托单位: University of Cambridge
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FT00696X%2F1
• 关键词: Searching; direct; evidence; consequences; land

Mud matters! The production of mud (chemical weathering) and deposition of mudrock is fundamental to how Earth works as a planet. Chemical weathering links the continents and oceans via the transformation of solid rock into solutes. In doing so it regulates the elemental mass budget of the oceans and provides the nutrients that sustain life both on the continents and oceans. Chemical weathering also acts as a planetary thermostat that regulates climate over geological time; with silicate weathering providing the long-term sink for atmospheric CO2 that is degassed by the solid Earth. As well as being an integral part of the functioning Earth system, mudrock also acts as a historical record. The importance of mudrocks as a repository of geological information arises from the fact that they are primarily formed of recycled silicate weathering materials: the sediment that is produced as chemical weathering breaks down exposed land surfaces. The characteristics of these materials, in particular clay minerals, are highly attuned to factors that influenced the chemical weathering process, such as climate, tectonics, and biological evolution. Mudrock is thus one of the most important and evolutionarily revealing rock types at the Earth's surface, and has acted as both as an archive and a regulator throughout the planet's history. Our proposal hinges on our new observation regarding Earth's mudrock record: that there is a massive upsurge in the amount of mudrock preserved in river-deposited sediments at around 400 million years ago. Before this shift, the amount of mudrock in alluvium was typically less than 2% of total sedimentary rock volume, but afterwards mud could account for up to 95% of any given river-deposited succession.This major shift in the nature of the rock record happened only once in Earth history, and occurs at the same time that newly-evolved land plants were beginning their greening of the continents. Our proposal aims to shed further light on this critical evolutionary chapter in Earth history. There was little mud preserved in river systems before plants, so did mud end up washed out into the marine realm, or lakes, or was there just less mud being produced in the first place? Did land plants help to promote chemical weathering and the production of mud? Or was it the physical effect of land plants, trapping and binding mud on land with their roots and stems, which was most important? By combining sedimentary geology, petrography, and geochemistry techniques to track the preserved record of mud through different environments from 3500- to 300-Ma ago, we will answer all the above questions and change the understanding of the evolution of the Earth system. Our four complimentary strands of geological research are: 1) Geological fieldwork: we will visit seven different case localities, chosen because together they encompass the deposits of deep and shallow marine, alluvial and lake sedimentary environments ranging from 1450-360 Ma. Our fieldwork will enable us to build conceptual models about the distribution of mud in ancient environments before and after plant evolution. 2) Petrology: by assessing the mineralogy of samples from our field sites we will track changes to the composition of mud through the key interval. 3) Geochemistry: by looking at the isotopic record of our samples, we can address questions regarding the intensity of chemical weathering before and after plant evolution. 4) Database analysis: by combining information from every single known sedimentary rock unit worldwide, from the oldest known sediment to those deposited when plants were in full flourish on the continents, we will have a strong global picture of the evolution of mudrock on the Earth surface during the first 3 billion years of its history.

泥很重要！泥浆的产生（化学风化）和泥岩的沉积是地球作为行星运行的基础。化学风化通过将固体岩石转化为溶质将大陆和海洋联系起来。在此过程中，它调节海洋的元素质量预算，并提供维持大陆和海洋生命的营养物质。化学风化作用还可以充当行星恒温器，在地质时期调节气候。硅酸盐风化为固体地球脱气的大气二氧化碳提供了长期的汇。泥岩不仅是地球系统的一个组成部分，而且还是历史记录。泥岩作为地质信息库的重要性在于，它们主要由回收的硅酸盐风化材料形成：化学风化分解暴露的土地表面时产生的沉积物。这些材料（特别是粘土矿物）的特性与影响化学风化过程的因素高度一致，例如气候、构造和生物进化。因此，泥岩是地球表面最重要、最具进化意义的岩石类型之一，并且在整个地球的历史中既充当档案又充当调节器。我们的提议取决于我们对地球泥岩记录的新观察：大约 4 亿年前，河流沉积物中保存的泥岩数量大幅增加。在这一转变之前，冲积层中的泥岩量通常不到沉积岩总体积的 2%，但之后泥岩可能占任何给定河流沉积序列的 95%。岩石记录性质的重大转变这种情况在地球历史上只发生过一次，而且发生在新进化的陆地植物开始绿化大陆的同时。我们的提议旨在进一步阐明地球历史上这一关键的进化篇章。在植物出现之前，河流系统中几乎没有保留泥浆，因此泥浆最终会被冲刷到海洋领域或湖泊中，还是一开始产生的泥浆就少了？陆地植物是否有助于促进化学风化和泥浆的产生？还是陆地植物的物理作用，用根和茎将泥土捕获并粘合在陆地上，这才是最重要的？通过结合沉积地质学、岩石学和地球化学技术，追踪3500至300Ma前不同环境中保存下来的泥浆记录，我们将回答上述所有问题，并改变对地球系统演化的认识。我们的四个互补的地质研究领域是： 1) 地质实地考察：我们将访问七个不同的案例地点，之所以选择这些地点是因为它们共同涵盖了 1450-360 Ma 范围内的深浅海洋、冲积和湖泊沉积环境的沉积物。我们的实地工作将使我们能够建立有关植物进化前后古代环境中泥土分布的概念模型。 2) 岩石学：通过评估现场样品的矿物学，我们将跟踪关键区间内泥浆成分的变化。 3）地球化学：通过查看样本的同位素记录，我们可以解决有关植物进化前后化学风化强度的问题。 4) 数据库分析：通过结合全球每个已知沉积岩单元的信息，从已知最古老的沉积物到大陆上植物繁盛时沉积的沉积物，我们将获得地球上泥岩演化的清晰全球图景在其历史的前 30 亿年中出现。

项目成果

The composition and weathering of the continents over geologic time

• DOI: 10.7185/geochemlet.2109
• 发表时间: 2021-03-02
• 期刊: GEOCHEMICAL PERSPECTIVES LETTERS
• 影响因子: 4.9
• 作者: Lipp, A. G.;Shorttle, O.;Yang, J.
• 通讯作者: Yang, J.

Ichnology of a Middle Devonian regression: Environment, terrestrialization and true substrate controls on trace fossils of the Hangman Sandstone Formation, SW England

中泥盆世回归的技术：英格兰西南部 Hangman 砂岩地层痕迹化石的环境、陆地化和真实基质控制

• DOI: 10.1016/j.palaeo.2023.111671
• 发表时间: 2023
• 期刊: Palaeogeography, Palaeoclimatology, Palaeoecology
• 作者: Davies N

The Invasion of the Land in Deep Time: Integrating Paleozoic Records of Paleobiology, Ichnology, Sedimentology, and Geomorphology

• DOI: 10.1093/icb/icac059
• 发表时间: 2022-05-31
• 期刊: INTEGRATIVE AND COMPARATIVE BIOLOGY
• 影响因子: 2.6
• 作者: Buatois, Luis A.;Davies, Neil S.;Shillito, Anthony P.
• 通讯作者: Shillito, Anthony P.

The Invasion of the Land in Deep Time: Integrating Paleozoic Records of Paleobiology, Ichnology, Sedimentology, and Geomorphology.

远古时期陆地的入侵：整合古生物学、技术学、沉积学和地貌学的古生代记录。

• DOI: 10.17863/cam.84853
• 发表时间: 2022
• 作者: Buatois L

Earth's earliest forest: fossilized trees and vegetation-induced sedimentary structures from the Middle Devonian (Eifelian) Hangman Sandstone Formation, Somerset and Devon, SW England

• DOI: 10.1144/jgs2023-204
• 发表时间: 2024-07-01
• 期刊: JOURNAL OF THE GEOLOGICAL SOCIETY
• 影响因子: 2.7
• 作者: Davies，Neil S.;McMahon，William J.;Berry，Christopher M.
• 通讯作者: Berry，Christopher M.