Mineralogical, Geochronological and Geochemical Characteristics of Zhoukoudian Intrusion and Their Magmatic Source and Evolutionmas-microsoft-com:office:office" />
详细信息
- 责任者：Zhang Jinyang (Faculty of Earth Resources ; China University of Geosciences ; Wuhan 430074 ; China) ; Ma Changqian
- 刊名：Earth Science
- 出版年：2013
- 卷期：38(1)
- 页码：p.68-86
- issnNo：ISSN1000-2383
- isbnNo：CN42-1233/P
摘要
mary name="EnDivSummary">Zhoukoudian intrusion contains intermediate-acidic rocks with three magmatic pulses.LA-ICPMS zircon U-Pb ages of quartz diorite and diorite-porphyry are 131.6±2.1Ma and 128.1±1.4Ma,respectively.All kinds of rocks are metaluminous and show highK calc-alkaline affinity with high Mg #.Their LREE,Ba,K,and Sr contents are high and HREE,Ta,Nb,P,and Ti are low with no Eu anomaly,high(La/Yb)N and Sr/Y ratios.Zoned plagioclase with large mantle is common in granodiorite(second pulse)and mafic microgranular enclaves.Two such zoned plagioclase crystals are studied:One from granodiorite with high An compositions in cores and reverse,normal-zoning outwardly in well-developed mantles;the other from mafic microgranular enclave with low An compositions in cores and beginning with dusty zoning and then showing normal-zoning in mantles,together with shape,size,quantity,reverse vein,statistics of mineral contents,mineral compositions,geochemistry,zoned structure,dyke-like swarms of mafic microgranular enclaves,agenesis of magma mingling between basic and acid magma is suggested.Magma mingling attained local equilibrium around enclaves and happened during whole solidified process of granodiorite due to multiple pulses of basic magma.The rocks from Zhoukoudian intrusion are adakitic and are partially melted within thickened lower crust.(Er/Lu)N and Nb/Ta ratios increase from quartz diorite-granodiorite to intermediate-acidic dykes,which indicates that residual minerals in source region changed from amphibole+garnet to garnet+rutile and the source became deeper.
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