永安盆地有机碳同位素特征与古环境意义

晚古生代永安盆地位于华夏块体武夷山隆起南缘,发育在前泥盆纪基底之上,是在政和—大埔断裂带基础上经伸展作用而成的一个沉积断陷盆地。盆内不同时代含碳层位样品δ13Corg值的变化及其与邻区样品δ13Corg值的对比研究显示了盆地本身乃至整个中国东南部沉积环境在不同地质时期以及同一时期不同区段沉积相变化的异同特征;永安盆地晚...

ORGANIC CARBON ISOTOPE CHARACTERISTICS OF THE YONGAN BASIN AND THEIR PALAEO-ENVIRONMENTAL IMPLICATIONS

The late Paleozoic Yongan Basin is located in the southern margin of the Wuyi Mt.uplift of the Cathaysia block.It was developed on pre-Devonian basement,and was formed as an extensional basin following the Zhenghe-Dapu fault zone.δ13Corg data from the Yongan Basin and other basins in southeastern China are compared to illustrate the similiarities and differences between different basins and between rocks of different ages.δ13Corg values of the Yongan Basin Palaeozoic sediments range from-15‰ to-25‰,similar to δ13Corg values(-20‰~-30‰)of equivalent rocks in the northern Jinhua-Quzhou basin.TOC values of the Yongan Basin are similar to those of equivalent sediments in the Ping-Le Basin.These similarities indicate that the sedimentary environment of the Yongan Basin is similar to other basins in the region,representing a marine-terrestrial transitional environment.There are also differences in TOC contents among sediments of different ages.Most organic-rich sediments in the ZM(Zhejiang-Fujian coast) area are of Mesozoic-Cenozoic age.During the Paleozoic time,the ZM area was an uplifted area and,together with the Wuyi Mt.uplife,it supplied sediments to the Yongan Basin.This interpretation is consistent with regional palaeocurrent data.