南京大学学报(自然科学版)
南京大學學報(自然科學版)
남경대학학보(자연과학판)
JOURNAL OF NANJING UNIVERSITY(NATURAL SCIENCES)
2015年
1期
73-86
,共14页
王浩%徐兆文%李海勇%赵增霞%陆建军
王浩%徐兆文%李海勇%趙增霞%陸建軍
왕호%서조문%리해용%조증하%륙건군
二长岩%岩石化学%Sr-Nd同位素%山东邹平%华北克拉通
二長巖%巖石化學%Sr-Nd同位素%山東鄒平%華北剋拉通
이장암%암석화학%Sr-Nd동위소%산동추평%화북극랍통
monzonite%petrochemistry%Sr-Nd isotope%Zouping county%Shandong Provine%North China Craton
山东邹平雪山二长岩岩体位于华北克拉通东南部邹平火山岩盆地内.本文通过对雪山二长岩年代学、岩石地球化学、同位素地球化学的研究,探讨邹平地区早白垩世岩浆作用.LA-ICP-MS 锆石 U-Pb 加权平均年龄为(128.5±1.2)Ma,属于燕山晚期岩浆活动产物.二长岩具有富碱(K2 O+Na2 O=9.92~10.35 wt.%)、富镁(Mg#=42.89~51.22),准铝质(ACNK=0.78~0.82)和钾玄质;轻稀土富集、重稀土亏损[(La/Yb)N=5.19~7.19],无明显 Eu异常(δEu=0.82~0.99);大离子亲石元素元素(Rb,Ba等)富集,高场强元素(Nb、Ta、Ti等)亏损等特征.二长岩具有较低的(87Sr/86Sr)i 比值(0.705188~0.705661),εNd(t)值(-14.79~-13.46)和老的两阶段Nd模式年龄TDM2(2.02~2.12 Ga).早白垩世俯冲的太平洋板片后撤拉张,软流圈上涌加热鲁西 EM1型富集岩石圈地幔,岩石圈地幔部分熔融产生的玄武质岩浆,经橄榄石、辉石结晶分异形成了雪山二长岩.
山東鄒平雪山二長巖巖體位于華北剋拉通東南部鄒平火山巖盆地內.本文通過對雪山二長巖年代學、巖石地毬化學、同位素地毬化學的研究,探討鄒平地區早白堊世巖漿作用.LA-ICP-MS 鋯石 U-Pb 加權平均年齡為(128.5±1.2)Ma,屬于燕山晚期巖漿活動產物.二長巖具有富堿(K2 O+Na2 O=9.92~10.35 wt.%)、富鎂(Mg#=42.89~51.22),準鋁質(ACNK=0.78~0.82)和鉀玄質;輕稀土富集、重稀土虧損[(La/Yb)N=5.19~7.19],無明顯 Eu異常(δEu=0.82~0.99);大離子親石元素元素(Rb,Ba等)富集,高場彊元素(Nb、Ta、Ti等)虧損等特徵.二長巖具有較低的(87Sr/86Sr)i 比值(0.705188~0.705661),εNd(t)值(-14.79~-13.46)和老的兩階段Nd模式年齡TDM2(2.02~2.12 Ga).早白堊世俯遲的太平洋闆片後撤拉張,軟流圈上湧加熱魯西 EM1型富集巖石圈地幔,巖石圈地幔部分鎔融產生的玄武質巖漿,經橄欖石、輝石結晶分異形成瞭雪山二長巖.
산동추평설산이장암암체위우화북극랍통동남부추평화산암분지내.본문통과대설산이장암년대학、암석지구화학、동위소지구화학적연구,탐토추평지구조백성세암장작용.LA-ICP-MS 고석 U-Pb 가권평균년령위(128.5±1.2)Ma,속우연산만기암장활동산물.이장암구유부감(K2 O+Na2 O=9.92~10.35 wt.%)、부미(Mg#=42.89~51.22),준려질(ACNK=0.78~0.82)화갑현질;경희토부집、중희토우손[(La/Yb)N=5.19~7.19],무명현 Eu이상(δEu=0.82~0.99);대리자친석원소원소(Rb,Ba등)부집,고장강원소(Nb、Ta、Ti등)우손등특정.이장암구유교저적(87Sr/86Sr)i 비치(0.705188~0.705661),εNd(t)치(-14.79~-13.46)화로적량계단Nd모식년령TDM2(2.02~2.12 Ga).조백성세부충적태평양판편후철랍장,연류권상용가열로서 EM1형부집암석권지만,암석권지만부분용융산생적현무질암장,경감람석、휘석결정분이형성료설산이장암.
A combined study of petrochemistry,Sr-Nd isotopes and zircon U-Pb ages of the late Mesozoic Xueshan monzonite in the Zouping volcanic basin,Shangdong Province,North China Craton (NCC),was carried out.The zircon U-Pb dating results reveal that the Xueshan monzonite was emplaced in Early Cretaceous((128.5±1.2)Ma). The Xueshan monzonite is alkaline(K2 O+Na2 O=9.92~10.35 wt.%),magnesium-rich(Mg#=42.89~51.22), metaluminous(ACNK=0.78~0.82)and shoshonitic in composition,and enriched in large ion lithophile elements (e.g.,Rb and Ba)and light rare earth elements((La/Yb)N=5.19~7.19),depleted in high field strength elements (e.g.,Nb,Ta,and Ti)and heavy rare earth elements,and have no Eu anomalies(δEu=0.82~0.99).Relatively low (87 Sr/86 Sr)i ratios(0.705188~0.705661)andεNd(t)values(-14.79~-13.46)indicate that the monzonitic magma was likely to be derived from partial melting of the Luxi EM1-type enriched lithospheric mantle and underwent fractional crystallization of olivine and pyroxene.The tectonic triggered the late Mesozoic large scale magmatism in eastern NCC,might be accompanied with the roll-back of the subducted paleo-Pacific plate.