Evolution of the Terminal Ediacaran–earliest Cambrian ecosystems in the southern Nama Basin (GRIND-ECT drilling project): When, why, and how? – A multidisciplinary approach

纳玛盆地演替为研究地球上第一批多细胞生命形式的生存条件、迅速灭绝和被形态不同的动物取代提供了独特的可能性。该项目提案涉及重建这些后生动物在Adamastor海洋关闭和沉积条件变化的情况下兴衰变化的环境。了解地球上生命进化中这些关键事件的机制和时间对于确定生命本身发展的驱动因素至关重要。据我们所知，本项目是第一个详细描述纳马盆地新元古代晚期至寒武纪早期动力学的综合方法，它将利用一种结合盆地分析中成熟方法的新方法，提供有关盆地演化的全面图景。本文试图回答以下工作假设：(1)那马盆地序列包含了大量的小尺度和大尺度沉积事件。(2)奎必斯亚群沉积具有被动边缘沉积特征。(3) Schwarzrand亚群沉积物受Adamastor洋闭合和构造格局变化的影响，受到高度火山弧的影响。(4)埃迪卡拉系后生动物对纳马盆地的殖民历史是由盆地构造背景决定的。(5)第一后生动物宿主生态系统的演化受海平面变化的影响。(6)前寒武纪—寒武纪过渡期动物交换的驱动因素可能是构造环境。回答这些假设将导致一个全面的，前寒武纪纳玛盆地的高时间风化方案，并可能提供一个独特的机会来理解海水中的大地构造影响，并破译埃迪卡拉纪晚期第一批多细胞生命出现的驱动力。我们将借助现代和创新的方法（碳酸盐的U-Pb测年，灰烬的U-Pb高精度锆石测年，碎屑锆石的最大沉积年龄，基于岩斑的生物地层学）来进行更完善的年龄控制。这决定了影响这些生态系统的因素和事件发生的时间，它们被触发的原因，以及它们是如何导致生物群更替的。

The Nama Basin successions offer a unique possibility for studying the living conditions, rapid extinction and replacement by morphologically distinct animals of the first multi-cellular lifeforms on earth. This project proposal deals with reconstructing changing environments during the rise and fall of these metazoans which was accompanied by the closure of the Adamastor Ocean and changing sedimentary conditions. Understanding the mechanism and timing of these key events in evolution of life on earth is crucial for determining drivers of development of life itself. To the best of our knowledge the present project represents the first integrated approach describing the Nama Basin dynamics in such a detail during the Late Neoproterozoic to the earliest Cambrian that it will provide a comprehensive picture concerning the basin evolution using a novel approach of a combination of well-established methods in basin analysis. We try to answer the following work hypotheses: (1) The Nama Basin successions incorporate a great number of small and big scale sedimentary events. (2) The Kuibis Subgroup sediments are characterized by passive margin sedimentation. (3) The Schwarzrand Subgroup sediments show high volcanic arc influence induced by the closure of the Adamastor Ocean and a changing tectonic regime. (4) The colonisation history of the Nama Basin by the Ediacaran metazoans was determined by the basinal tectonic setting. (5) The evolution of first metazoan hosting ecosystems is influenced by sea level changes. (6) Possible driving factors of faunal exchange during the Precambrian-Cambrian transition are induced by tectonic environments.Answering these hypotheses will result in a comprehensive, high temporal weathering scheme of the Precambrian Nama Basin and may offer a unique opportunity understanding the geotectonic impact in seawater and to decipher driving forces for the late Ediacaran of-a-kind appearances of the first multicellular life. We will do so with the help of a much more improved age control by modern and innovative methods (U-Pb dating of carbonates, U-Pb high precision zircon dating of ashes, maximum deposition ages derived from detrital zircon, biostratigraphy based on acritarchs). This determines WHEN factors and events influencing these ecosystems happened, WHY they were trigged, and HOW they led to a biota replacement.