line-level: 2" class=MsoNormal>Geochemical Characteristics and Petrogenesis of Late Paleozoic Mafic Rocks from
详细信息
- 责任者：Feng Guangying (State Key Laboratory of Ore Deposit Geochemistry ; Institute of Geochemistry ; Chinese Academy of Sciences ; Guiyang 550002 ; China) ; Liu Shen
- 刊名：Geochimica
- 出版年：2010
- 卷期：39(5)
- 关键词：基性岩 ; basic rocks ; 岩石地球化学 ; lithogeochemistry ; 吉林 ; Jilin Province
- 页码：p.427-438
- 图表：9 illus., 4 tables, 41 refs.
- 分类号：0801
- issnNo：ISSN0379-1726
- isbnNo：CN44-1398/P
摘要
Yumuchuan sillites located in the Zhangguangcailing Block of the Xingmeng orogenic belt, K-Ar dating yields the ages ranging from 262 to 264 Ma, geochemical data show that the SiO2 contents of the sillites vary from 47.02% to 52.60%, these rocks belong to low potassium tholeiite series, and are characterized by low K2O(0.13%~0.47%) and Na2O>K2O. Chondrite-normalized patterns for the sillites exhibit flat but moderate depletion in LREE ((La/Yb)N = 0.65-0.87), and the primitive mantle-normalized spidergrams show relatively enrichment in Rb and Ba, but without depletion in the HSFE, such as Nb and Ta. Strontium and Nd isotopic compositions of the representative sillites are characterized by low initial 87Sr/86Sr ratios (0.704 958-0.705 631), high and constant εNd(t) values (7.2-8.1), suggesting that they were derived from a depleted mantle source without significant crustal contamination.