• 责任者：Huang Qiangtai (Guangzhou Institute of Geochemistry ; Chinese Academy of Sciences ; Guangzhou 510640 ; China) ; Xia Bin
• 刊名：Chinese Journal of Geology
• 出版年：2013
• 卷期：48(3)
• 关键词：碱性花岗岩 ; alkali granite ; 山东 ; Shandong Province
• 页码：p.773-786
• 图表：7 illus., 3 tables, 24 refs.
• 分类号：0801
• issnNo：ISSN0563-5020
• isbnNo：CN11-1937/P

     The field and indoor results show that the gneissic alkali granite from Lanshantou was converted from paleozoic sedimentary rock. Its chemical composition presents high Sihansi-font-family: ’times new roman’">（ SiO2 = 75%- 77%hansi-font-family: ’times new roman’">）,alkali-richhansi-font-family: ’times new roman’">（Na20hansi-font-family: ’times new roman’">＋K20 = 8.38% - 8.60%hansi-font-family: ’times new roman’">）,1ow AIhansi-font-family: ’times new roman’">（A1203 = 11.72% - 12.05% hansi-font-family: ’times new roman’">） ,and poor in Cahansi-font-family: ’times new roman’">（ CaO = 0.09% - 0.53% hansi-font-family: ’times new roman’">）. It was rich in the large-ion lithophile elements such as Rb,Ba,Th, U,Pb and poor in the high field strength elements such as Nb, Ta,Zr, Hf and Ti. The gneissie alkali granite presents relatively high LREE hansi-font-family: ’times new roman’">（ LREE/HREE = 6.32 - 9.86 hansi-font-family: ’times new roman’">） elements and obviously Eu hansi-font-family: ’times new roman’">（SEu = 0.42 - 0.64 hansi-font-family: ’times new roman’">） negative abnormality. Based on the base of studying the zircons CL images,The age of mantle of zircon with three-tier structure hansi-font-family: ’times new roman’">（core, mantle, shell hansi-font-family: ’times new roman’">） is 245 Ma or 235 Ma which reflects the first ultra-high pressure metamorphic time and also is the time of forming of the gneissie alkali granite and equivalent to the Early-Middle Triassic. The age of new shell of metamorphic composite zircon is 222 - 198 Ma which reflected the second metamorphic time and equivalent to Late Triassic. The U-Pb dating results of old nuclear of metamorphic composite zircon reveal that the ages of magmatic and detrital zircons have both proterozoic era hansi-font-family: ’times new roman’">（864 Ma -781 Ma - 701 Ma -688 Ma - 631 Ma-598 Ma -592 Mahansi-font-family: ’times new roman’">）and paleozoic erahansi-font-family: ’times new roman’">（544 Ma-500 Ma-447 bla -339 Ma- 306 Mahansi-font-family: ’times new roman’">）. In summary, the ear of protolith of host rock can not be proterozoic and may be palaeozoic.