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| 燕山地区1.6～1.0Ga时期碳酸盐岩碳、氧同位素组成、演化及其地质意义 | |
| 引用本文： | 旷红伟,李家华,彭楠,罗顺社,岑超.燕山地区1.6～1.0Ga时期碳酸盐岩碳、氧同位素组成、演化及其地质意义[J].地学前缘,2009,16(5):118. |
| 作者姓名： | 旷红伟 李家华 彭楠 罗顺社 岑超 |
| 作者单位： | 1. 中国地质科学院,地质研究所,北京,100037;油气资源与勘探技术教育部重点实验室,长江大学,长江大学,地球物理与石油资源学院,湖北,荆州,434023 2. 中国地质科学院,地质研究所,北京,100037;长江大学,地球科学学院,湖北,荆州,434023 3. 长江大学,地球科学学院,湖北,荆州,434023 4. 中国地质科学院,地质研究所,北京,100037 |
| 基金项目： | 国家自然科学基金，中国地质科学院地质研究所基本科研业务费项目，中国石油化工股份有限公司海相油气勘探前瞻性项目，区带预测长江大学自然科学发展基金 |
| 摘 要： | 依据实测的燕山地区(1.6～1.0Ga)高于庄组—景儿峪组114个碳、氧同位素数据,研究、讨论了中、新元古界碳酸盐岩碳、氧同位素组成、演化及其地质意义。研究表明,燕山中、新元古界由下至上的地层序列上,碳、氧同位素表现明显的旋回性演化特征,二者多显正相关关系;δ13C在-3‰～3‰区间低幅、高频振荡;δ18O则表现为-2‰～-8‰的高幅、高频波动;δ13C值的增大与沉积环境由潮间向潮下演变、海平面上升、海水变淡、生物量增多相关;降低的δ13C多代表潮间—潮上环境。高于庄组瘤状灰岩及洪水庄组页岩δ13C为低负值,代表最大海泛期沉积。氧同位素组成和变化指示研究区总体为咸化环境,杨庄组上部和雾迷山组下部古海水盐度最高,之后盐度逐渐降低,至雾迷山组上部又有所升高。研究区与天津蓟县和北京十三陵地区的中、新元古代碳酸盐岩碳、氧同位素组成与演化表现出明显的相似性,反映了它们共同受燕山裂陷槽发育的控制;同时,与北美Belt超群和俄罗斯乌拉尔里菲期碳酸盐岩碳、氧同位素组成、演变的高度协同性,又说明了中、新元古代碳酸盐岩中碳、氧同位素组成、演化响应于全球古海洋背景和地球化学条件。 |
| 关 键 词： | 燕山 中、新元古代 碳酸盐岩 碳、氧同位素 地质意义 |
The C and O isotopic compositions and their evolution recorded in the carbonate interval of the Yanshan area from 1.6 to 1.0 Ga,and their geological implications |
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| Kuang Hongwei,Li Jiahua,Peng Nan,Luo Shunshe,Cen Chao.The C and O isotopic compositions and their evolution recorded in the carbonate interval of the Yanshan area from 1.6 to 1.0 Ga,and their geological implications[J].Earth Science Frontiers,2009,16(5):118. | |
| Authors: | Kuang Hongwei Li Jiahua Peng Nan Luo Shunshe Cen Chao |
| Abstract: | Based on the C and O isotopic profile of 114 analytic results obtained by the standard method of phosphorolysis,we have discussed the compositions and evolution of δ13C and δ18O recorded in the carbonates in the Yanshan area during the interval of 1.6-1.0 Ga and their geological implications.The C and O isotopic profile reveals a secular cyclic evolutionary trend in ascending order of carbonates,i.e.,δ13C shows a shift from-3‰ to +3.0‰ and δ18O shows a range from-2.0‰ to-8.0‰.An elevation of δ13C correlated with the relative variation from intertidal to subtidal sedimentary environments,the sea level rising,the flux of fresh water and the high organic productivity,whereas a decreasing shift corresponded to a transition from supratidal to intertidal facies or sedimentary boundaries in term of sequence stratigraphy.The nodular limestone or shalestone has negative δ13C excursion,representing the maximum sea flooding sediments from Gaoyuzhuang and Hongshuizhuang Formations respectively.The O isotopic composition and evolution suggests that a salted water paleoenvironment was prevailing over the research area during the synsedimentary period from the Upper Yangzhuang to Lower Wumishan Formations,i.e.,the more salted interval,which recovered later in Upper Wumishan Formation.The current study and C and O isotope evolution are consistent with the previous research results,which provides isotopic evidence supporting the existence of an aulacogen basin alone,and furthermore are highly concordant with the C and O isotope evolutions in Belt Supergroup in North America and Mid-Riphean in Ural,Russia,which suggests a response to a global paleo-ocean geochemical setting. |
| Keywords: | Yanshan area Meso-Neoproterozoic carbonates C and O isotope implications |
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