西藏南部晚白垩世红色灰岩层为大洋富氧条件下的沉积产物，红色灰岩层内有机碳极低，生物极其繁盛，碳同位素偏低，但从上往下又呈增高趋势。溶解氧含量在古海洋演化史中是非线形波动变化的，既有全球溶解氧含量偏低时期（缺氧条件），也有全球溶解氧含量偏高时期（富氧条件），古海洋溶解氧含量重建和富氧问题的解决对于理解大洋循环、古气候、生命绝灭、地质事件以及有机质演化具有十分重要的科学意义 The Late Cretaceous red limestone in southern Tibet is a sedimentary product under the conditions of oxygen enrichment in the oceans. The organic carbon in the red limestone is extremely low, its biology is extremely prosperous, its carbon isotope is low, but it shows an increasing trend from top to bottom. Dissolved oxygen content fluctuates nonlinearly in paleoceanographic evolution history. It includes not only the period of low dissolved oxygen (hypoxia), but also the period of high global dissolved oxygen (oxygen enrichment), the re-establishment of dissolved oxygen And the solution of the problem of oxygen enrichment have very important scientific significance for understanding the ocean circulation, paleoclimate, extinction of life, geological events and the evolution of organic matter