Compositional and temperature variations of the Pacific upper mantle since the Cretaceous

IOCAS-IR

	Compositional and temperature variations of the Pacific upper mantle since the Cretaceous
	ZHANG Guoliang
发表期刊	Acta Oceanologica Sinica
ISSN	0253-505X
	2016-04-15
出版年	2016
卷号	v.35 期号:04 页码:23-29
文献类型	CNKI期刊论文
摘要	The geological evolution of the Earth during the mid-Cretaceous were shown to be anomalous, e.g., the pause of the geomagnetic field, the global sea level rise, and increased intra-plate volcanic activities, which could be attributed to deep mantle processes. As the anomalous volcanic activities occurred mainly in the Cretaceous Pacific, here we use basalt chemical compositions from the oceanic drilling(DSDP/ODP/IODP) sites to investigate their mantle sources and melting conditions. Based on locations relative to the Pacific plateaus, we classified these sites as oceanic plateau basalts, normal mid-ocean ridge basalts, and near-plateau seafloor basalts. This study shows that those normal mid-ocean ridge basalts formed during mid-Cretaceous are broadly similar in average Na8, La/Sm and Sm/Yb ratios and Sr-Nd isotopic compositions to modern Pacific spreading ridge(the East Pacific Rise). The Ontong Java plateau(125–90 Ma) basalts have distinctly lower Na8 and143Nd/144 Nd, and higher La/Sm and 87Sr/86 Sr than normal seafloor basalts, whereas those for the near-plateau seafloor basalts are similar to the plateau basalts, indicating influences from the Ontong Java mantle source. The super mantle plume activity that might have formed the Ontong Java plateau influenced the mantle source of the simultaneously formed large areas of seafloor basalts. Based on the chemical data from normal seafloor basalts, I propose that the mantle compositions and melting conditions of the normal mid-ocean ridges during the Cretaceous are similar to the fast spreading East Pacific Rise. Slight variations of mid-Cretaceous normal seafloor basalts in melting conditions could be related to the local mantle source and spreading rate.
关键词	mantle temperature mantle source super mantle plume Cretaceous mid-ocean ridge basalt
CNKI专辑号	A;
CNKI专辑名称	基础科学;
CNKI专题号	A010;A011;
CNKI专题名称	海洋学;地质学;
分类号	P736
收录类别	中科院核心 ; 中科院扩展
语种	英文;
资助项目(基金）	The Strategic Priority Research Program of the Chinese Academy of Sciences under contract No.XDA11030103 ; the National Natural Science Foundation of China under contract Nos 41376065,41176043 and 41522602 ; the project of“Ao Shan”excellent scholar for Qingdao National Laboratory for Marine Science and Technology
文献类型	CNKI期刊论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/189716
专题	中国科学院海洋研究所
作者单位	1.KeyLaboratoryofMarineGeologyandEnvironment,InstituteofOceanology,ChineseAcademyofSciences 2.LaboratoryforMarineGeology,QingdaoNationalLaboratoryforMarineScienceandTechnology
推荐引用方式 GB/T 7714	ZHANG Guoliang. Compositional and temperature variations of the Pacific upper mantle since the Cretaceous. 2016.