The Archean to Paleoproterozoic transition as recovered in the FAR DEEP cores: LA-ICP-MS U-Pb geochronology of detrital zircons and accompanying provenance analysis of siliciclastic sedimentary rocks

远深岩心中发现的太古代到古元古代的过渡：碎屑锆石的 LA-ICP-MS U-Pb 地质年代学和硅质碎屑沉积岩的相关物源分析

• 批准号: 75363574
• 负责人: Professor Dr. Hans Heinrich Bahlburg
• 金额: --
• 依托单位: Institut für Geologie und Paläontologie
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2008
• 资助国家: 德国
• 起止时间: 2007-12-31 至 2012-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/75363574?language=en
• 关键词: Archean; Paleoproterozoic; transition; recovered; FAR

During the Archaean-Palaeoproterozoic transition many global environmental changes occurred in the Earth’s system at the same time as tectonic reorganisations led to the break-up of the supercontinent Kenorland. Stratigraphic successions registering these events were successfully drilled in northern Russia (Fennoscandia) in the FAR-DEEP/ICDP project. - The first part of our study aimed at improving age constraints by Laser Ablation ICP-MS U-Pb geochronology on detrital zircons for three of these events recorded in the FAR DEEP cores. The events are the Huronian glaciation, the Lomagundi-Jatuli positive excursion of δ13C, and the Shunga event of enhanced deposition of Corg-rich sediments. Our data resulted in tighter temporal constraints for these events. In rocks marking the transition from the Lomagundi-Jatuli to the Shunga event we also found U-Pb ages, now confirmed by ID-TIMS, which are too young regarding their stratigraphic position, and which are difficult to explain in view of the allegedly undisturbed stratigraphic succession. These need to be verified by additional analyses.- Also, the provenance of the analysed zircons and the nature of the recycled, partly Palaeoarchaean crust will be established by LA ICP-MS Hf isotope analysis on dated zircons and by ion microprobe analysis of heavy minerals like tourmaline and rutile.

在古细胞 - 帕拉莫氏元过渡期间，地球系统发生了许多全球环境变化，同时在构造重组导致超大陆肯纳兰（Kenorland）破裂。在深入/ICDP项目中，在俄罗斯北部（Fennoscandia）成功钻取了记录这些事件的地层继承。 - 我们研究的第一部分旨在改善激光消融ICP-MS U-PB地质学对碎屑中的三个事件的碎屑锆石的限制。这些事件是人类冰川，Δ13C的Lomagundi-Jatuli阳性游览和shunga事件增强了富含CORG的沉积物的沉积。我们的数据对这些事件产生了更严格的临时约束。在标志着从Lomagundi-Jatuli到Shunga事件的过渡时，我们也发现了U-PB年龄，现在由ID-TIMS确认，它们在其地层位置还太年轻，并且鉴于所谓的不受干扰的地层成功，这很难解释。这些需要通过其他分析来验证。-此外，将通过LA ICP-MS HF同位素分析在已过时的锆石上以及由Tourmaline和Rutile等重型矿物质分析来建立分析的锆石的出处以及可回收的，部分的，部分的，部分的Palaeoarchaean地壳。