Petrogenesis of Paleoproterozoic diorite porphyries inLuojiazhuang, western Shandong： constraints fromLA-ICP-MS zircon U-Pb geochronology and geochemistry

作     者：YANG Haotian SHI Jiangpeng HUO tengfei YANG Donghong 

作者机构：College of Earth Sciences Jilin University Changchun 130061 China Research Center of Palaeontology & Stratigraphy Jilin University Changchun 133026 China 

出 版 物：《Global Geology》 (世界地质（英文版）)

年 卷 期：2016年第19卷第2期

页      面：78-84页

学科分类：070902[理学-地球化学] 0709[理学-地质学] 070901[理学-矿物学、岩石学、矿床学] 07[理学] 

基　　金：Supported by the Program for New Century Excellent Talents in University(No.NCET-12-0237) the Natural Science Foundation of China(No.41472052) Basic Scientific Research Foundation of Central Universities of China 

主　　题：Paleoproterozoic diorite porphyry geochronology geochemistry western Shandong 

摘      要：Based on the study of LA-ICP-MS zircon U-Pb geochronology and whole-rock geochemistry for theLuojiazhuang diorite porphyries in Menying , western Shandong , the analyzed zircons exhibit oscillatory zoning in the cathodoluminescence images and have high Th/U ratios （0. 15-1.53） , indicating a magmatic *** addition, most of the zircons have narrow metamorphic edges, suggesting that late metamorphic eventsmay exist. The youngest group of magmatic zircon 207Pb/206Pb ages rangng from 2 384 Ma to 2 234 Ma, yieldinga weighted mean age of 2 353 ± 14 Ma, which represents the forming age of the diorite porphyries, as theEarly Paleoproterozoic. Geochemically , the samples are characterized by low Si〇2（54. 54% and 55. 47% ）,high MgO （5.22% and 5.49% ） and Mg# values （58 and 59） . Moreover , they show enrichment of light rareearth elements and large ion lithophile elements （ Rb , Ba and K） , depletion of heavy rare earth elements andhigh field strength elements （Nb, Ta , Zr and Hf） , positive anomaly of Pb , and negative anomaly of Ti. Thefact implies that the Luojiazhuang diorite porphyries might derive from partial melting of mantle and mixed with an amount of continental crust material. In summary , they may tectonic setting that stretching along the east-＂west direction at the North China Craton in the Early Paleoproterozoic.