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平邑盆地的官庄群是我国罕见的富含碳酸盐岩和石膏岩的非海相河湖沉积,中生界-新生界界线连续,孢粉和其他微体生物化石丰富,对研究我国华北地区晚白垩世与古新世生物群及其演变、白垩系-古近系界线以及晚白垩世晚期的地质事件等具有十分重要的意义,引起众多地质学者的关注。通过对平邑盆地官庄群岩石地层的详细考察及对其赋存的生物群的研究,对固城组和卞桥组的定义进行了厘定。固城组为下粗上细的红色砂砾岩和砂泥岩,含砾石,其成分基本为火山岩,含晚白垩世孢粉和其他微体化石,时代为晚白垩世晚期;卞桥组为一套富含碳酸盐岩和石膏的地层,富含晚白垩世晚期至古新世孢粉和其他微体化石,可分为3个岩性段,白垩系-古近系界线在卞桥组一段的一、二亚段之间。  相似文献   

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中巴公路沿线溜石坡   总被引:2,自引:0,他引:2  
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As a connection region between North Atlantic and Arctic Oceans, the Nordic Sea plays a critical role in global climate system. In the Nordic Seas, surface water converts into intermediate water and deep water after cooling and other effects. These waters transport southward, and enter into North Atlantic as a form of overflow, therefore, they are the main source of the North Atlantic Deep Water(NADW), which play a key role in global ocean conveyor. The causes and processes of the deep water formation in the Nordic Seas are still uncertain. Based on a review of current and historical research results of the deep water in the Nordic Seas, the most important process for deep water formation convection is addressed. Factors and physical processes that may have impact on deep water formation are summarized. The transport of deep water in the Nordic Seas is summed up. Multi year variation of the deep water is described with the aim of giving some instructions and research directions to the readers.  相似文献   

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