塔里木盆地晚奥陶世大洋红层研究

Abnormal marine environment and major regional tectonic events can be recorded by the oceanic red beds, which is of great significance to study the oceanic environmental evolution in the region and even the whole world. Since the study of the Cretaceous oceanic red beds，their coloration mechanism, paleo-ocean environment and genetic mechanism have made great progress, the key scientific problems of “paleoclimate and tectonic evolution lead to Cretaceous oceanic red beds deposited” has been solved, and the concept of “ocean oxygen enrichment”has been proposed firstly, but the Paleozoic especially Ordovician oceanic red beds is significantly weaker. The early Late Ordovician oceanic red beds has been reported in South China, Ordos, USA, France, Canada, Welsh and Portugal, which suggested that the event might be global. And early Late Ordovician marine red beds is also deposited in the Tarim basin, for the research of its genetic mechanism, the Kanling Formation of the Dawangou section distributed in the Keping is studied. The major element and diffuse reflectance spectroscopy analysis are used for the coloration mechanism. And the paleo-ocean environment can be studied by the redox sensitive element (such as Mn, U, V, Mo, Ce, et.) analysis. Combined with the test of the organic-inorganic carbon isotope, the genetic model of the Late Ordovician red beds can be revealed, and the response mechanism between the marine red beds and paleo-ocean evolution will be discussed.

大洋红层是异常古海洋环境和重大区域构造事件的信息载体，对了解地史时期区域甚至全球古海洋环境有重要的科学意义。白垩纪以来的大洋红层研究在其致色机制、古海洋环境及成因方面取得了巨大进展，解决了古气候及构造变化导致白垩纪大洋红层形成的重大关键科学问题，并首次提出了“大洋富氧”的概念，而古生代尤其是奥陶纪大洋红层研究明显较弱。晚奥陶世大洋红层可能具有全球性，在华南、鄂尔多斯、美国、威尔士、葡萄牙、法国和加拿大等地区均有报道。塔里木盆地也有同时期的红层记录，为了解该套大洋红层的成因，申请人拟以柯坪大湾沟剖面上奥陶统坎岭组红色瘤状灰岩及其上下层位为研究对象，通过主量元素及漫反射光谱测试，分析其致色机理，利用有机-无机碳同位素分析，获取古气候信息，根据氧化还原敏感元素（如Mn、Mo、V、U、Ce等）结果，分析古海洋氧化还原环境变化。综合以上结果，最终揭示研究剖面坎岭组大洋红层成因及其与古海洋变化的响应。