Biotic and sedimentologic evolution of the Cambrian

寒武纪的生物和沉积演化

• 批准号: 46403-2013
• 负责人: Pratt, Brian
• 金额: $ 3.07万
• 依托单位: University of Saskatchewan
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2013
• 资助国家: 加拿大
• 起止时间: 2013-01-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=521767
• 关键词: Biotic; sedimentologic; evolution; Cambrian

The 'Cambrian Explosion' half a billion years ago was a turning point for life on Earth: the appearance of animals, which gave rise to fossils of shells, spicules, skeletons, even sometimes soft tissues, plus new kinds of microbes, all of which caused profound ecological revolution in the marine realm. Sediment changed fundamentally due to processes of burrowing, pelletization, organic binding and bacterial decay. The first metazoan reefs appeared. We address these phenomena in an interdisciplinary way by combining sedimentology with paleontology in order to explore more fully this tremendous yet still mysterious evolutionary episode. The natural laboratory for us is mainly the splendidly exposed strata of the Cordillera and high Arctic, although we plan to recreate artificially some of the peculiar sedimentary features that are so distinct for this time. Our work on the bedrock geology is necessary documentation of an important component of Canada's natural history as well as critical background for natural resource exploitation. We do taxonomic work describing the trilobites, brachiopods, soft-bodied animals, corals and archaeocyathan and siliceous sponges, finding many new species, and we aim to elucidate in detail biological interactions such as predation. Our biostratigraphic data permit close temporal correlation and reveal patterns of diversification, extinction and phylogeny. Sedimentary features and paleoecology are used to compare the origin and evolution of facies and organo-sedimentary processes from the preceding Proterozoic through early Paleozoic time, and sporadically thereafter. Earthquake deformation structures are providing novel insight, and developing criteria to differentiate tsunami- versus storm-generated beds is ground-breaking. We are forging new ground with the Burgess Shale and various tropical carbonate reef, sand shoal, tidal flat and lagoonal deposits. We are employing geochemical data to reveal the source and processes of lithification of sediments and the tectonic history of the basins into which they were deposited.

5亿年前的“寒武纪大爆发”是地球上生命的转折点：动物的出现，产生了贝壳、针状体、骨骼，有时甚至是软组织的化石，以及新的微生物种类，所有这些都在海洋领域引发了深刻的生态革命。沉积物由于挖洞、成球、有机结合和细菌腐烂等过程而发生了根本性的变化。第一批后生动物礁出现了。我们将沉积学与古生物学结合起来，以跨学科的方式处理这些现象，以便更全面地探索这一巨大但仍然神秘的进化事件。对我们来说，自然实验室主要是科迪勒拉山脉和北极高纬度地区壮丽的暴露地层，尽管我们计划人工重建一些在这个时代如此独特的奇特沉积特征。我们在基岩地质方面的工作是加拿大自然历史重要组成部分的必要文献，也是自然资源开发的关键背景。我们对三叶虫、腕足动物、软体动物、珊瑚、古藻和硅质海绵进行了分类，发现了许多新物种，我们的目标是详细阐明捕食等生物相互作用。我们的生物地层资料允许密切的时间相关性和揭示多样化，灭绝和系统发育模式。沉积特征和古生态学用于比较前元古代至早古生代的相和有机沉积过程的起源和演化，并在此之后进行零星的比较。地震变形结构提供了新的见解，制定区分海啸和风暴形成的地层的标准是突破性的。我们正在与伯吉斯页岩和各种热带碳酸盐岩礁，沙浅滩，潮滩和泻湖矿床开拓新的领域。我们正在利用地球化学数据来揭示沉积物的石化来源和过程，以及它们沉积的盆地的构造历史。