Stratigraphic and Geochronologic Constraints on Tectonic, Biologic and Geochemical Events, Vendian to Cambrian Nama Group, Namibia

文德周期及其代表的时间间隔 向寒武纪的过渡是 地球的进化。 主要构造、生物和地球化学 在全球范围内发生的事件，包括增长和 超大陆重组，海平面大幅波动 水平和气候，出现了软体和小壳 后生动物，海水的同位素和微量元素组成， 以及大气层的组成。 这些事件大多是 在横跨文迪亚河的沉积物记录中 寒武纪过渡期，并在所有大陆上保存。 这项研究将是一个详细的调查， 那玛盆地地层学、沉积学和年代学 （纳米比亚）在文迪安和寒武纪早期发展。 这 工作将测试具体的假设，例如， 盆地沉降机制、地层成因 层序和界线，以及关键化石的绝对年龄 和遗迹化石组合（如埃迪卡拉动物群，Cloudina， Phycodes pedum，前寒武纪-寒武纪界线和碳 同位素和锶同位素曲线。 这项工作将 辅以高分辨率锆石U-Pb测年， 火山灰层穿插在整个序列中， 提供世界上最好的校准部分之一， 这个关键的时间间隔。

The time interval represented by the Vendian period and its transition into the Cambrian is one of the most significant in the evolution of the earth. Major tectonic, biologic and geochemical events occurred on a global scale and include the growth and reorganization of supercontinent, significant fluctuations in sea level and climate, the advent of soft-bodied and small shelly metazoans, the isotopic and trace element composition of seawater, and the composition of the atmosphere. Most of these events are represented in the record of sediments that spans the Vendian- Cambrian transition, and which is preserved on all continents. The research will be a detailed investigation of the stratigraphy, sedimentology, and geochronology of the Nama basin (Namibia) developed during Vendian and early Cambrian time. This work will test specific hypotheses concerning, for example, the mechanisms(s) of basin subsidence, origin of stratigraphic sequences and boundaries, and the absolute ages of critical fossil and trace fossil assemblages (e.g. Ediacaran fauna, Cloudina, Phycodes pedum, the Precambrian-Cambrian boundary, and carbon isotopic and strontium isotopic curves. The work will be supplemented by high resolution U-Pb zircon dating of numerous volcanic ash beds intercalated throughout the sequence, thereby providing one of the best calibrated sections in the world through this critical time interval.