• 责任者：Li Wuping (School of Civil Engineering ; Guangzhou University ; Guangzhou 510006 ; China)
• 刊名：Earth Science
• 出版年：2013
• 卷期：38(6)
• 关键词：火山岩 ; volcanic rocks ; 岩石地球化学 ; lithogeochemistry ; 辽宁 ; Liaoning Province
• 页码：p.1153-1168
• 图表：7 illus., 2 tables, 76 refs.
• 分类号：0801
• issnNo：ISSN1000-2383
• isbnNo：CN42-1233/P

     <font size="3"><font face="Times New Roman">The Middle Jurassic volcanic rocks of Haifanggou formation from the western Liaoning Province is an important component of Mesozoic volcanic rocks in the Yanshan Orogenic belt. The volcanic rocks of Haifanggou formation, which are mainly composed of traehyandesite with dacite and andesite, are metaluminous calc-alkaline and high-K series. Geochemical data indicate that the Middle Jurassic volcanic rocks of Haifanggou from the western Liaoning province have the low Mg adakitie volcanic features, such as SiO2font>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">≥<font face="Times New Roman">51.98%, Al2O3 font>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">≥<font face="Times New Roman">15.0 %, MgO font>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">〈<font face="Times New Roman">4. 18% font>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">（<font face="Times New Roman">Mg^#font>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">〈<font face="Times New Roman">0. 48font>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">）<font face="Times New Roman">, Srfont>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">≥<font face="Times New Roman">436 X 10-6, Ybfont>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">≤<font face="Times New Roman">2. 25font>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">×<font face="Times New Roman">10^-6, Yfont>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">≤<font face="Times New Roman"> 23. 14font>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">×<font face="Times New Roman">10^-6, Crfont>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">≤<font face="Times New Roman">81.09font>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">×<font face="Times New Roman">10^-6, Nifont>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">≤<font face="Times New Roman">34. 66font>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">×<font face="Times New Roman">10^-6 , Y/Ybfont>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">≤<font face="Times New Roman">14. 25, Sr/Yfont>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">≥<font face="Times New Roman">39, and Nb/Tafont>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">≈<font face="Times New Roman">20. The rocks are enriched in light rare earth elements font>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">（<font face="Times New Roman">LREEfont>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">）<font face="Times New Roman">, Ba, U, Sr and Pb, and are depleted in heavy rare earth elements font>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">（<font face="Times New Roman">HREEfont>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">）<font face="Times New Roman"> and high field strength elements font>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">（<font face="Times New Roman">such as Nb, Ta, Tifont>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">）<font face="Times New Roman"> ,and strongly fractionated font>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">（（<font face="Times New Roman">La/Ybfont>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">）<font face="Times New Roman">Nfont>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">≥<font face="Times New Roman">10. 37font>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">）<font face="Times New Roman"> with weak negative Eu anomaly or positive Eu anomaly font>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">（<font face="Times New Roman">0. 79 to 1.05 in Eu/Eu^font>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">＊<font face="Times New Roman"> font>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">）<font face="Times New Roman">. In addition, these adakitic volcanic rocks also have that low font>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">（<font face="Times New Roman">^143 Nd/^144 Ndfont>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">）<font face="Times New Roman"> initial ratios font>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">（<font face="Times New Roman">0. 511 603 to o. 511 733, -15.84 to -13. 30 in epsilon end font>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">（<font face="Times New Roman">tfont>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">））<font face="Times New Roman">, moderate font>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">（<font face="Times New Roman">^87 Sr/^86 Srfont>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">）<font face="Times New Roman"> initial ratios font>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">（<font face="Times New Roman">0. 704 9 to 0. 705 6, 8. 64 to 18. 11 in epsilon font>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">ε<font face="Times New Roman">Sr font>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">（<font face="Times New Roman">tfont>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">））<font face="Times New Roman"> and a higher depleted mantle model ages font>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">（<font face="Times New Roman">1. 81 to 1. 99 Ga in TDMfont>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">）<font face="Times New Roman">, showing enriched mantle end-member font>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">（<font face="Times New Roman">EMIfont>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">）<font face="Times New Roman"> characteristics. These features indicate that Haifanggou adakitic magma were derived from the partial melting of a thickened eclogite from the lower crust, and its origin is related to underplating of the basaltic magma. Combining with geochemistry of Mesozoic volcanic rocks in Yanshan Orogenic belt, the Early-Middle Jurassic in the Yanshan orogenic belt is a conversion period from the ancient Asian Ocean tectonic system to the paleo-Pacific tectonic system, while the generation of the Middle Jurassic adakitic volcanic rocks of Haifanggou formation font>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">（<font face="Times New Roman">174 Mafont>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">）<font face="Times New Roman"> shows that the Yanshan orogenic belt has come into font>font-family: 宋体; mso-ascii-font-family: ’times new roman’; mso-hansi-font-family: ’times new roman’">＊<font face="Times New Roman">he evolution stage of the paleo-Pacific tectonic system. The research results can facilitate the understanding of the deep mechanism of Yanshan movement and lithospheric thinning process.font>font>