The Ritland impact crater - Appearance and mechanisms of formation 2013

The objectives of the project will be met by detailed studies in the field, laboratory analyses and numerical modelling. The field studies will cover the impact rocks, the fractured basement rocks and the post-impact crater infill sequence, including search for ejected material. We will utilise the 3-dimensional erosional cut and the excellent exposures of the Ritland crater to reconstruct the original crater shape and the history of crater infilling by applying petroleum industry software (Petrel). This reconstruction will be the base for modeling the mechanics of crater formation (Shuvalov). The basement fracturing will be documented in sections with continuous detailed photographic coverage. Using the crater model, the sections can then be analysed with reference to their original xyz location relative to the pre-erosional crater structure. Geochemical studies will be carried out on samples of the impact rocks with suevite-like textures, as well as on selected post-impact sediments from the lowermost part of the crater structure. If the new field-work succeeds in finding ejecta material, this will also be included. Analyses of the platinum group elements as well as Os and Cr isotopes will be carried out at the University of Vienna, to obtain information about the impactor. We will also look into the possibility of radiometric dating of glass samples. The excellent exposures of fractured basement and crater fill of the Ritland Crater are complementary to, and will be compared with the Gardnos Crater, which is larger, more complex and with more scattered exposures. Elin Kalleson will finish her PhD on Gardnos in 2008 and her experience will be important for a flying start of this project. It is an objective to document the Ritland Crater as a reference area for future scientific studies. The project also aims to use the Ritland rater to develop interest for geology and natural sciences in the local community and the region.

Data from the project are presented in several papers. See references below.

本项目的研究目标将通过野外详细考察、实验室分析与数值模拟得以实现。野外研究将覆盖冲击岩（impact rocks）、破碎基底岩以及撞击后陨石坑充填序列，其中包括寻找溅射物。研究团队将借助石油行业专用软件Petrel，利用里特兰陨石坑（Ritland crater）的三维侵蚀切割面与极佳出露条件，重建陨石坑原始形态及其充填演化历史。该重建结果将作为模拟陨石坑形成力学过程（Shuvalov）的基础。研究人员将对覆盖有连续高清摄影资料的剖面开展基底破裂情况的详细建档工作。借助该陨石坑模型，可结合侵蚀前陨石坑构造的原始三维坐标，对各剖面展开针对性分析。研究团队将对具有苏维岩（suevite）类结构的冲击岩样品，以及陨石坑构造最底部的精选撞击后沉积物样品开展地球化学研究。若本次野外考察成功发现溅射物样品，也将纳入本次研究范畴。铂族元素以及锇（Os）、铬（Cr）同位素的分析工作将在维也纳大学开展，以获取有关撞击体的相关信息。研究团队还将探索对玻璃样品进行放射性同位素定年的可行性。里特兰陨石坑的破碎基底与陨石坑充填物出露条件极佳，可作为更大、更复杂且出露更为分散的加德诺斯陨石坑（Gardnos Crater）的补充研究对象，并将与其开展对比研究。埃琳·卡尔森（Elin Kalleson）将于2008年完成其关于加德诺斯陨石坑的博士学位论文，其相关研究经验将为本项目的快速启动提供重要助力。本项目的目标之一是将里特兰陨石坑建档为未来科学研究的参考区域。本项目同时旨在通过里特兰陨石坑，提升当地社区与区域民众对地质学与自然科学的兴趣。本项目的相关研究数据已发表于多篇学术论文，详见下文参考文献。