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

文迪亚时期及其向寒武纪的过渡所代表的时间间隔是地球演化中最重要的时间段之一。在全球范围内发生了重大的构造、生物和地球化学事件，包括超大陆的生长和重组、海平面和气候的显著波动、软体和小型壳状后生动物的出现、海水的同位素和微量元素组成以及大气的组成。这些事件中的大多数都体现在文迪亚-寒武纪过渡时期的沉积物记录中，这些记录在所有大陆上都得到了保存。这项研究将是对文迪亚和早寒武世时期纳马盆地(纳米比亚)的地层学、沉积学和年代学的详细调查。这项工作将检验关于盆地沉降机制(S)、地层层序和边界的起源、关键化石和遗迹化石组合的绝对年龄(例如，埃迪卡拉纪动物群、Cloudina、Phycodes peumm、前寒武纪-寒武纪边界)以及碳同位素和锶同位素曲线的具体假设。除了这项工作外，还将对贯穿整个层序的众多火山灰层进行高分辨率的锆石U-Pb测年，从而在这一关键时间间隔内提供世界上最好的校准剖面之一。

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.