气候变化领域集成服务门户(CCPortal): Re-Os isotopes of Dali picrite (Yunnan): New constraints on the formation of Emeishan Large Igneous Province

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	Re-Os isotopes of Dali picrite (Yunnan): New constraints on the formation of Emeishan Large Igneous Province
	Hao YanLi; Huang QiShuai; Zhang XiaoRan; Shi RenDeng
通讯作者	Hao, YL (通讯作者)
发表日期	2011
ISSN	1000-0569
EISSN	2095-8927
起始页码	2937
结束页码	2946
卷号	27 期号:10
英文摘要	Dali picrite in Yunnan Province occurs at the bottom of Emeishan basalt in the inner zone of Emeishan Large Igneous Province (ELIP). The picrite is highly porphyritic with 20% similar to 40% euhedral-subhedral olivine and clinopyroxenite phenocrysts, and the groundmass with diabasic texture is composed of microcrystalline olivine, clinopyroxenite and plagioclase with minor spinel. SiO2 content of most picrites ranges from 45. 94% to 46. 37%, lower than 47%, except for one sample, whose SiO2 content is up to 47. 35%. In all picrite samples, MgO is higher than 18%, varying between 19. 01% and 23. 77%, and total NO2O + K2O is lower than 2%, ranging narrowly from 1. 52% to 1. 97%, which indicates the features of typical picrites. Whole-rock Re content shows a narrow range from 0. 349 x 10(-9) to 0. 424 x 10(-9) while Os has a wide range from 0. 889 x 10(-9) to 4. 276 x 10(-9); in addition, the whole-rock Re-187/Os-188 and Os-187/Os-188 ratios vary from 0.437 +/- 0.012 to 2. 708 +/- 0.025 and from 0. 1283 +/- 0.0002 to 0. 1354 +/- 0.0004, respectively. The estimated Os-187/Os-188 ratios of the matrix range from 0. 1380 to 0. 1415 by the Mass Balance Calculation. By contrast, all Re (0. 030 x 10(-9) similar to 0. 049 x 10(-9)) and Os (0. 625 x 10(-9) similar to 0. 757 x 10(-9)) values of the olivines separated from the picrites are lower than those of whole-rock data, and the Os-187/Os-188 ratio of the olivines ranges from 0. 1254 +/- 0. 0005 to 0. 1268 +/- 0. 0005, lower than that of the whole-rock. The spinel separated from the picrites has the highest Os content up to 80. 6 x 10(-9) and the lowest Os-187/Os-188 ratio down to 0. 1252 +/- 0. 0003. Compared with features of the Primitive Upper Mantle (PUM), the matrix Re-Os isotopes have the crust lava affinity, while the olivine and spinel show residual mantle features. gamma Os values of the separated minerals (olivine and spinel) are between - 2. 01 and - 2. 59, indicating that the rock-forming materials might have originated from the depleted sources instead of from such rich or fertile areas as the boundary of the core-mantle, while the gamma Os values of whole-rock vary from -1. 11 to -3.24, obviously the mixing result of olivine, spinel and matrix. It is inferred that the formation of ELIP should be attributed to the interaction between the crust and the mantle.
关键词	FLOOD-BASALT PROVINCE LITHOSPHERIC MANTLE YANGTZE PLATFORM GEOCHEMISTRY SYSTEMATICS INSIGHTS ND ORIGIN
英文关键词	Picrite; Interaction of crust-mantle; Re-Os isotopes; Emeishan Large igneous Province; Dali
语种	英语
WOS研究方向	Geology
WOS类目	Geology
WOS记录号	WOS:000296655800013
来源期刊	ACTA PETROLOGICA SINICA
来源机构	中国科学院青藏高原研究所
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/257877
推荐引用方式 GB/T 7714	Hao YanLi,Huang QiShuai,Zhang XiaoRan,et al. Re-Os isotopes of Dali picrite (Yunnan): New constraints on the formation of Emeishan Large Igneous Province[J]. 中国科学院青藏高原研究所,2011,27(10).
APA	Hao YanLi,Huang QiShuai,Zhang XiaoRan,&Shi RenDeng.(2011).Re-Os isotopes of Dali picrite (Yunnan): New constraints on the formation of Emeishan Large Igneous Province.ACTA PETROLOGICA SINICA,27(10).
MLA	Hao YanLi,et al."Re-Os isotopes of Dali picrite (Yunnan): New constraints on the formation of Emeishan Large Igneous Province".ACTA PETROLOGICA SINICA 27.10(2011).