Neoproterozoic to Earliest Cambrian Sequence Stratigraphy and Evolution of the Adelaide "Geosyncline", South Australia

我们建议在南澳大利亚州阿德莱德地槽测试和扩展现有的层序地层学和沉积学对新元古代至最早寒武纪岩石的解释。层序地层学为显著改善稀疏化石岩石的盆地内对比提供了一种独立的方法，并提供了分析生物地层学、化学地层学、磁性地层学和地质年代学数据的物理背景。新元古代冰盖的消长一定影响了海平面，我们推断，至少一些最持久的层序界面是全球范围的。这种可能性需要与关键区段新出现的地层记录进行对比测试。阿德莱德地槽厚度大(15公里)，露头质量好，变形和变质作用有限，可获得相同时代相邻盆地的地震和岩心资料，生物群(包括尖晶石、遗迹化石、埃迪卡拉组合后生动物和叠层石)，以及稳定同位素地球化学的适应性，因此被选为层序地层学研究的参考剖面。火山灰层的U-Pb年代学也有一定的潜力，我们建议系统地寻找这样的层。拟议的研究将在国际地质对比方案(新元古代事件和资源)项目320的框架下与其他机构的工作相协调，其长期目标是记录和评价在较新的新元古代岩石中记录的各种生物、环境和构造现象之间的联系。

We propose to test and extend existing sequence stratigraphic and sedimentological interpretations of rocks of Neoproterozoic to earliest Cambrian age in the Adelaide geosyncline, South Australia. Sequence stratigraphy provides an independent method for significantly improving intro-basinal correlation in sparsely fossiliferous rocks, and a physical context in which to analyze biostratigraphic, chemostratigraphic, magnetostratigraphic and geochronological data. To the extent that the waxing and waning of Neoproterozoic ice sheets must have influenced sea level, we infer that at least some of the most persistent sequence boundaries are of global extent. This possibility needs to tested against the emerging stratigraphic record in key sections. The Adelaide geosyncline was selected as a reference section for sequence stratigraphic research on the basis of its great thickness (15 km), quality of outcrop, limited deformation and metamorphism, availability of seismic and core data in adjacent basins of the same age, varied biota (including acritarchs, trace fossils, Ediacara assemblage metazoa, and stromatolites), and amenability to stable isotope geochemistry. There is some potential also for U-Pb geochronology of ash beds, and we propose to search systematically for such layers. The proposed research will be co-ordinated with the work of others under the umbrella of Project 320 of the International Geological Correlation Programme (Neoproterozoic Events and Resources), with the long-term objective of documenting and evaluating the connections between a variety of biological, environmental and tectonic phenomena recorded in younger Neoproterozoic rocks.