新疆地质
新疆地質
신강지질
XINJIANG GEOLOGY
2013年
1期
1-5
,共5页
东准噶尔%卡拉麦里%I型花岗岩%锆石LA-ICP MS定年%后碰撞
東準噶爾%卡拉麥裏%I型花崗巖%鋯石LA-ICP MS定年%後踫撞
동준갈이%잡랍맥리%I형화강암%고석LA-ICP MS정년%후팽당
East Junggar%Kalamaili%I-type granite%LA-ICP MS Dating of Zircon%Post-collision
新疆东准噶尔卡拉麦里构造带分布多种类型花岗岩,主要包括花岗闪长岩、二长花岗岩和钾长花岗岩.对处于卡拉麦里主断裂带西侧的奥塔乌克尔希花岗闪长岩体进行年代学和地球化学特征研究,岩体SiO2含量中等,相对富含钠,A/CNK在0.93~0.99,具准铝质中等钙碱性岩系特征.其轻稀土元素富集,具微弱铕负异常,明显富集Rb,Sr,Th等大离子亲石元素和Zr,Hf等高场强元素,强烈亏损元素Nb,Ta,Ti,为I型花岗岩.锆石LA-ICP MS测年为(329.1±1.3) Ma和(305.7±1.5) Ma,分属于早石炭世维宪期和晚石炭世卡西莫夫期,岩体定位于晚石炭世晚期.主微量及稀土元素综合分析表明该岩体具复杂成因,早石炭世晚期卡拉麦里地区洋壳消减,造山作用形成新生陆壳物质,晚石炭世后碰撞构造阶段地幔底侵岩浆引起地壳物质的部分熔融形成了奥塔乌克尔希岩体.综合研究表明,东准噶尔洋盆闭合发生在早石炭世维宪期,晚石炭世晚期准噶尔地区东部已进入新沉积盆地构造发育时期.
新疆東準噶爾卡拉麥裏構造帶分佈多種類型花崗巖,主要包括花崗閃長巖、二長花崗巖和鉀長花崗巖.對處于卡拉麥裏主斷裂帶西側的奧塔烏剋爾希花崗閃長巖體進行年代學和地毬化學特徵研究,巖體SiO2含量中等,相對富含鈉,A/CNK在0.93~0.99,具準鋁質中等鈣堿性巖繫特徵.其輕稀土元素富集,具微弱銪負異常,明顯富集Rb,Sr,Th等大離子親石元素和Zr,Hf等高場彊元素,彊烈虧損元素Nb,Ta,Ti,為I型花崗巖.鋯石LA-ICP MS測年為(329.1±1.3) Ma和(305.7±1.5) Ma,分屬于早石炭世維憲期和晚石炭世卡西莫伕期,巖體定位于晚石炭世晚期.主微量及稀土元素綜閤分析錶明該巖體具複雜成因,早石炭世晚期卡拉麥裏地區洋殼消減,造山作用形成新生陸殼物質,晚石炭世後踫撞構造階段地幔底侵巖漿引起地殼物質的部分鎔融形成瞭奧塔烏剋爾希巖體.綜閤研究錶明,東準噶爾洋盆閉閤髮生在早石炭世維憲期,晚石炭世晚期準噶爾地區東部已進入新沉積盆地構造髮育時期.
신강동준갈이잡랍맥리구조대분포다충류형화강암,주요포괄화강섬장암、이장화강암화갑장화강암.대처우잡랍맥리주단렬대서측적오탑오극이희화강섬장암체진행년대학화지구화학특정연구,암체SiO2함량중등,상대부함납,A/CNK재0.93~0.99,구준려질중등개감성암계특정.기경희토원소부집,구미약유부이상,명현부집Rb,Sr,Th등대리자친석원소화Zr,Hf등고장강원소,강렬우손원소Nb,Ta,Ti,위I형화강암.고석LA-ICP MS측년위(329.1±1.3) Ma화(305.7±1.5) Ma,분속우조석탄세유헌기화만석탄세잡서막부기,암체정위우만석탄세만기.주미량급희토원소종합분석표명해암체구복잡성인,조석탄세만기잡랍맥리지구양각소감,조산작용형성신생륙각물질,만석탄세후팽당구조계단지만저침암장인기지각물질적부분용융형성료오탑오극이희암체.종합연구표명,동준갈이양분폐합발생재조석탄세유헌기,만석탄세만기준갈이지구동부이진입신침적분지구조발육시기.
@@@@There are plenty types of granites around the Kalamaili structural belt in East Junggar of Xinjiang, mostly in-cluding granodiorite,monzonitic granite,alkali-feldspar granite and alkali granite.This paper studied the dating of the Ao-tawuke’erxi granodiorites in the west of principal structural belt and their geochemical compositions.The result shows that the granites are characterized by medium SiO2 contents,modicum K-feldspar,amphibole and blotite contents,compar-ative enrichment natrium, and dominated plagioclases among the feldspars. The ratio of A/CNK is varying from 0.93 to 0.99,showing characteristics of metaluminous and medium calc-alkalic rock series. The granites are characterized by en-richment in LREE,not obvious depletion in Eu.For the trace elements of granites,large-ion lithophile elements of Rb, Sr, Th etc.and high field strength elements of Zr,Hf etc.are rich obviously,but Nb,Ta,Ti appear strong depletion.The main body of granites are I-type granodiorite.The LA-ICP MS ages of zircon are (329.1±1.3) Ma and (305.7±1.5) Ma.Geo-chemical elementary and regional geology analysis indicated that the orogenic collision at east Junggar presented during the early late-carboniferous periods,and the orogenic movement ended at the teminal of late-carboniferous periods.
