Early Cretaceous lignites from inner-continental Asia as paleoclimate archive

来自亚洲内陆的早白垩世褐煤作为古气候档案

• 批准号: 493067120
• 负责人: Professor Dr. Ulrich Heimhofer
• 金额: --
• 依托单位: Institut für Geologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/493067120?language=en
• 关键词: Early; Cretaceous; lignites; inner; continental

Records documenting the climatic and environmental conditions prevailing in inner-continental paleo-Asia during the Early Cretaceous greenhouse phase are sparse, fragmentary and often contradictory. For the Aptian-Albian interval, a small set of proxy-derived continental paleotemperature estimates shows comparatively cool mean air temperatures, which contrast with exceptionally warm sea-surface temperatures obtained from the marine realm. The continental Choir-Nyalga Basin of central Mongolia contains thick, lignite-rich successions, which host an exceptionally well-preserved conifer-dominated flora representing a mid-latitude wetland ecosystem. This research proposal aims at studying these lignite-bearing deposits by combining brGDGT-based paleothermometry and coal petrology with palynological analyses. Investigations will focus on material from three open-cast lignite mines and a drill core studied and sampled during a previous field expedition. Preliminary organic geochemical and palynological results demonstrate that the low-mature coals and clastic interbeds are well suited for the chosen approach. The existing temporal framework will be improved by combining terrestrial carbon-isotope stratigraphy and palynostratigraphy with radiometric U/Pb chronology from tuffaceous horizons. The project will deliver new and important paleotemperature and paleovegetation data, which will help to better constrain the climate and ecosystem dynamics of continental interiors during times of exceptional global warmth.

记录记录的气候和环境条件普遍在大陆古亚洲在早白垩世温室阶段是稀疏的，零碎的，往往是矛盾的。对于Aptian-Albian间隔，一小组代理人得出的大陆古温度估计显示相对较冷的平均气温，这与从海洋领域获得的异常温暖的海面温度形成对比。蒙古中部的大陆Choir-Nyurgy盆地含有厚的、富含褐煤的连续层，其中保存着一个非常完好的以针叶树为主的植物群，代表了中纬度的湿地生态系统。该研究计划旨在通过结合基于brGDGT的古测温和煤岩学与孢粉学分析来研究这些含褐煤矿床。调查将集中在三个露天褐煤矿的材料和在以前的实地考察中研究和取样的钻芯。初步的有机地球化学和孢粉学结果表明，低成熟煤和碎屑互层是非常适合所选择的方法。将陆地碳同位素地层学和孢粉地层学与凝灰质层的放射性U/Pb年代学相结合，将改善现有的时间框架。该项目将提供新的和重要的古温度和古植被数据，这将有助于在全球异常温暖的时期更好地限制大陆内部的气候和生态系统动态。