The biotic and sedimentologic evolution of the Cambrian

寒武纪的生物和沉积演化

• 批准号: RGPIN-2016-03914
• 负责人: Pratt, Brian
• 金额: $ 2.11万
• 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: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=683269
• 关键词: biotic; sedimentologic; evolution; Cambrian

The `Cambrian Explosion' half a billion years ago was a turning point for life on Earth: the evolutionary appearance of animals in the sea, which gave rise to fossils of shells, spicules, skeletons, even sometimes soft tissues, plus new kinds of microbes and algae. This new and complex biota caused profound ecological revolution in the marine realm. Sediment changed fundamentally due to processes of burrowing, digestion, excretion, organic binding and bacterial decay. The first metazoan reefs appeared. My group will continue to investigate these phenomena in an interdisciplinary way, by combining sedimentological and paleontological approaches in order to explore more fully this exciting yet still mysterious episode of Earth History. The natural laboratory for us will be the spectacular southern Rocky Mountains. The indoor laboratory includes a wide range of analytical techniques from optical microscopy to elemental mapping using synchrotron X-ray fluorescence. The origin and evolution of ancient sediments and organo-sedimentary processes in various tropical carbonate reef, sand shoal, tidal flat, shelf and lagoonal environments will be studied from the preceding latest Precambrian through early Paleozoic time via sedimentary features, paleoecological attributes and geochemical data. In a short span of time-just some 50 million years-these successive carbonate platforms show dramatic contrasts yet also remarkable similarities. We will reconsider long-held facies interpretations and assumptions, and develop criteria to differentiate tsunami- versus storm-generated beds, and earthquake cracking from desiccation. The stratigraphic occurrence of fossils will permit high-resolution temporal correlation of lithological units and will help reveal patterns of diversification, extinction, phylogeny and times of regional and global change captured in these rocks. This wide-ranging and interdisciplinary dataset will allow us to interpret Cambrian paleoclimate, paleoceanography, sea level and sedimentation, as well as elucidate the tectonic history of the vast continental shelves and inland seas in which these rocks accumulated.

5亿年前的寒武纪大爆发是地球上生命的一个转折点：海洋中动物的进化外观，产生了贝壳、针状体、骨骼，有时甚至是软组织的化石，以及新种类的微生物和藻类。这种新的、复杂的生物群在海洋领域引发了深刻的生态革命。由于挖洞、消化、排泄、有机结合和细菌腐烂等过程，沉积物发生了根本性的变化。第一批后生生物礁出现了。我的团队将继续以跨学科的方式研究这些现象，结合沉积学和古生物学的方法，以便更全面地探索地球历史上这段令人兴奋但仍然神秘的插曲。我们的天然实验室将是壮观的南部落基山脉。室内实验室包括广泛的分析技术，从光学显微镜到使用同步加速器X射线荧光的元素测绘。通过沉积特征、古生态属性和地球化学资料，研究前寒武纪至早古生代各种热带碳酸盐礁、砂滩、滩涂、陆棚和泻湖环境中的古沉积物和有机沉积作用的起源和演化。在短短5000万年的时间里，这些连续的碳酸盐岩台地显示出巨大的对比，但也有显著的相似之处。我们将重新考虑长期存在的相解释和假设，并制定区分海啸和风暴生成的岩层、地震裂缝和干燥的标准。化石的地层产状将使岩性单位的高分辨率时间对比成为可能，并将有助于揭示这些岩石中捕捉到的多样化、灭绝、系统发育和区域和全球变化的时间模式。这一范围广泛的跨学科数据集将使我们能够解释寒武纪的古气候、古海洋学、海平面和沉积作用，以及阐明这些岩石聚集的巨大大陆架和内海的构造史。