Ages and geological significance of the dark dykes emplaced in the Karamay pluton and adjacent area, in western Junggar, Xinjiang, NW China: Evidence form LA-ICP-MS zircon chronology and Ar-Ar amphibole chronology
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摘要:
新疆西准噶尔克拉玛依岩体以及周围地层中存在着大量暗色闪长玢岩岩墙，是岩浆物质贯入3组走向不同的裂隙形成的。对其中一个闪长玢岩岩墙样品进行锆石LA-ICP-MS年代学测试，得到303.1±1.2Ma的锆石206Pb/238U加权平均年龄，对从该闪长玢岩中分离出的角闪石进行Ar-Ar年代学测试，得到312.1±2.8Ma的坪年龄 (1120~1400℃) 和313.6±6.9Ma的反等时线年龄。对该闪长玢岩岩墙附近的含角闪石黑云母二长花岗岩进行的锆石LA-ICP-MS年代学测试，获得其206Pb/238U加权平均年龄为319.0±1.0Ma。对侵入石炭纪地层的一个花岗斑岩岩脉样品进行锆石LA-ICP-MS年代学测试，得到了315.3±1.0Ma的206Pb/238U加权平均年龄。上述年代学测试结果表明克拉玛依市以西地区的暗色岩墙形成时代是石炭纪末期，不是前人所说的二叠纪。在这些岩墙形成之前，该区在石炭纪晚期还发育以克拉玛依岩体及附近酸性岩脉为代表的花岗质岩浆活动。上述围岩和岩墙的年代学资料揭示出该区闪长玢岩岩墙所占据的裂隙形成时代在315~303Ma之间，为新疆西准噶尔地区晚古生代地球动力学背景及岩浆活动的深入研究，提供了时间方面的约束。
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关键词:
- 岩墙 /
- 锆石LA-ICP-MS年代学 /
- 角闪石Ar-Ar年代学 /
- 克拉玛依岩体 /
- 西准噶尔
Abstract:There are large number of dark diorite porphyrite dykes emplaced in the Karamay pluton and its adjacent area, western Junggar, Xinjiang, NW China. They are considered to be formed by magma filling into the existing fractures, which can be briefly classified into three groups with different strikes. The LA-ICP-MS U-Pb dating for zircons from a diorite porphyrite dyke sample yields 206Pb/238U age of 303.1±1.2Ma. The Ar-Ar plateau age and inverse isochron diagram age of amphiboles from the same sample, are 312.1±2.8Ma (1120~1400℃) and 313.6±6.9Ma respectively. The zircon 206Pb/238U age of host rock is determined, by LA-ICP-MS zircon U-Pb dating, as 319.0±1.0Ma, and zircon 206Pb/238U age of a granite porphyry vein is 315.3±1.0Ma. These chronology data show that the formation of the dykes in this area is not Permian, but Late Carboniferous, and that before filling of those dykes, the granitic magma intrusion occurred in western Junggar area, resulting in Karamay pluton and granite porphyry veins. The above dating data of the dykes and the host rock imply that the fractures, filled by the dykes, occurred from 315Ma to 303Ma. This study gives the new temporal constraint for further research in both Late Paleozoic geodynamical environment and magmatic intrusion of western Junggar, Xinjiang, NW China.
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Key words:
- Dykes /
- Zircon U-Pb chronology /
- Amphibole Ar-Ar chronology /
- Karamay pluton /
- Western Junggar
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图 1
西准噶尔位置和板块构造分区 (a) 以及主要岩体、断裂、蛇绿岩分布和克拉玛依岩体的位置 (b)
Figure 1.
Tectonic divisions of Central Asian area (after Li et al., 2006a) and location of western Junggar (a) and plutons, faults and ophiolites distribution in western Junggar, and location of the Karamay pluton (b)
图 2
克拉玛依岩体的岩石组合、岩墙分布、周围地质情况及采样位置
Figure 2.
Rock types of the Karamay pluton, distribution of the dark dykes, their surrounding geology, and sample locations
图 3
样品627KY1和627KY2的位置、野外产出关系及岩石学显微照片
Figure 3.
Location, field outcrops and microscopic photos of sample 627KY1 and 627KY2
图 4
样品627KY5的位置、野外产出关系和岩石显微照片
Figure 4.
Location of sample 627KY5, the contact relationship between vein and host rock and microscopic photo of dyke
图 5
岩墙和围岩锆石的阴极发光图像、测试点位置及测试结果
Figure 5.
CL images of zircons from dykes and host rock, testing point locations and results
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Chen W, Zhang Y, Jin GS, Zhang YQ and Wang QL.2006. Late Cenozoic episodic uplifting in southeastern part of the Tibetan Plateau: Evidence from Ar-Ar thermochronology. Acta Petrologica Sinica, 22(4): 867-872(in Chinese with English abstract)
Gao SL, He ZL and Zhou ZY. 2006. Geochemical characteristics of the Karamay granitoids and there significance in West Junggar, Xinjiang. Xinjiang Geology, 24(2): 125-130(in Chinese with English abstract)
Han BF, Ji JQ, Song B, Chen LH and Zhang L. 2006. Late Paleozoic vertical growth of continental crust around the Junggar Basin, Xinjiang, China(Part Ⅰ): Timing of post-collisional plutonism. Acta Petrologica Sinica, 22(5): 1077-1086(in Chinese with English abstract)
He GQ, Liu JB, Zhang YQ and Xu X. 2007. Keramay Ophiolitic mélange formed during Early Paleozoic in western Junggar basin. Acta Petrologica Sinica, 23(7): 1573-1576(in Chinese with English abstract)
He JB and Chen B. 2011. Pertogenesis of Karamay plutons in the West Junggar: Constraints from geochronology, petrology and geochemistry. Earth Science Frontiers, 18(2): 199-211(in Chinese with English abstract)
Jahn BM, Griffin WL and Windley BF. 2000. Continental growth in the Phanerozoic: Evidence from Central Asia. Tectonophysics, 328: 227
Kang L, Li YJ, Zhang B, Zhang HW and Wang JN. 2009. Petrographic evidence for magma mixing of Xiaerpu granite in West Junggar, Xinjiang. Acta Petrologica et Mineralogica, 28(5): 423-432(in Chinese with English abstract)
Kwon ST, Tilton GR, Coleman RG and Feng Y. 1989. Isotopic studies bearing on the tectonics of the West Junggar region, Xinjiang, China. Tectonics, 8(4): 719-727
Li JY, He GQ, Xu X, Li HQ, Sun GH, Yang YN, Gao LM and Zhu ZX. 2006a. Crustal tectonic framework of North Xinjiang and adjacent regions and its formation. Acta Geologica Sinica, 80(1): 148-168(in Chinese with English abstract)
Li JY, Wang KZ, Sun GH, Mo SG, Li WQ, Yang YN and Gao LM. 2006b. Paleozoic active margin slices in the Southern Turfan-Hami basin: Geological records of subduction of the Paleo-Asian Ocean plate in central Asian regions. Acta Petrologica Sinica, 22(5): 1087-1102(in Chinese with English abstract)
Li JY, Song B, Wang KZ, Li YP, Sun GH and Qi DY. 2006c. Permian mafic-ultramafic complexes on the southern margin of the Tu-Ha basin, Eastern Tianshan Mountains: Geological records of vertical crustal growth in Central Asia. Acta Geoscientica Sinica, 27(5): 424-446(in Chinese with English abstract)
Li JY, Zhang J, Yang TN, Li YP, Sun GH, Zhu ZX and Wang LJ. 2009. Crustal tectonics division and evolution of the southern part of the North Asian orogenic region and its adjacent areas. Journal of Jilin University(Earth Science Edition), 39(4): 584-605(in Chi敮潥汳潥朠祷?楴湨??桮楧湬慩???????????〩?????楩渠??栬椠湈敡獮攠?睆椬琠桊??湊村氬椠獌桩?慚扈猬琠牌慩捵琠??戠牡?奤椠湙??奧??央甠愲渰‰???升略湯????堬椠慧潥?坣??慭湩摳?婲桹愠潡?????休ひ????即愠湋畡歲楡瑭楡捹?摢祡歳敩獣?楩湮?坥敲獭瑥??畡湴来朠慤特??堠楳湷橡楲慭渠杦???攠潘捩桮敪浩楡据慧氬?晃敨慩瑮畡爮攠獇??灣敨瑩牭潩杣敡測攠猳椳猨?愩渺搠‵氷椴渭欵猸?琨潩??畃??畮?浳楥渠敷物慴汨椠穅慮瑧楬潩湳???敢潳捴桲楡浣楴挩愼??????????ㄠ??????椠湚??桮楧渠敊猬攠?睨極琠桚??渠杗污楮獧栠?愠扡獮瑤爠慘捵琠??戠爲?失椱渮??奩??奯畮愠湓????坐愠湕札?奢????漠湯杦?塔偡?慧湥摮??畯慮湺?奧????ぴ?ㄠ???慗来浳慴瑥楲据?牊敵据潧牧摡獲?漠湘?瑮桪敩??慧琬攠?偨慩汮敡漺稠潉楮捩?瑩敡捬琠潴湩業捥?敯癦漠汬略瑦楴漭湬?潴晥?睡敬猠瑳敬物湰??畦渠杴杨慥爠??塯楬湩樠楦慡湵杬???敇潥瑯敬捯瑧潩湣楡捬愠?敵瑬??整瑩慮氠汯潦朠敃湨楩慮?????㈨???㈠???有?ㄨ?楮渠??桩楮湥敳獥攠?睩楴瑨栠??湧杬汩楳獨栠?慢扳獴瑲牡慣捴琩??扲爾?婵桮愠湙材?????慧渠杈????坯慵渠杇?堠????楌?奵???娮栠愲渰朰??圠?慥湯摣?坥慭湩杳??乹????ち????敮慯瑵畳爠敁猭?慹湰摥?浧敲慡湮楩湴来?漠晡?浯慮晧椠捄?浲楡换牵潴朠牴慥湣畴汯慮物?攠湢捥汬慴瘠敩?椠湗?塳楴愠敊牵灮畧?条牲愬渠楘瑩敮?楩湡?坧攮猠瑇??畣湨杩杭慩牣??堠椳渵樨椱愩渺朠?‵堭椶渷樨楩慮渠权??敮潥汳潥朠祷??????????と??????楡湣??格楢湲放獗敥?眠楓瑎栬??湨来汮楧猠桊?愬戠獙瑵爠慄捂琬??扨牥?婧栠慂渠条?????塵椠慙潆?圠????愮渠??????畯潧?儠兡???慓潈?兒??慐渠摺??潣?卮????びㄠは???慮杴浲慵瑳楩獶浥?潢景?浹椠摢?潩据攠慂湡楯捧?牴極搠条敲?獡甬戠摘畩据瑪楩潡湮?搮甠牅楡湲杴??慓牣扩潥湮楣晥攠牆潲畯獮?楩湥?睳攬猠琱攸爨渲??甠渲朱朲愭爲???癩楮搠敃湨捩敮?晳牥漠海??慨氠楅祮慧?潩灳桨椠潡汢楳瑴敲???挩琼慢?倾敗瑩牮潤汬潥杹椠捂慆?匠楁湬楥捸慥??????ㄠ????㈠????????楥湲??栠楡湮敤猠敂?睤楡瑲档??湇朮氠椲猰栰?愮戠獔瑥牣慴捯瑮??戠牭?婤桥慬湳朠?奣???桴敩湯?圠???桴敨湥????慴湲摡??楁畳?塡奮???はで???卣琠畂摥祬?漮渠?瑯桵敲??牬??牦?慴杨敥?獇灥敯捬瑯牧畩浣?潬映?摯楣慩来整湹攬琠椱挶???匳?愭渴搷?瑢桲放?浩敡捯栠慗湊椬猠浈?潮映??猬甠灙?????猬甠灃??牮?版敌挬漠楓汵?氠潍猬猠?敩确愠浓灆氬攠獌?映牚潌洬?瑍桡敯?捑汇愬礠?浨楡湮敧爠慊汅猬?潓晵?倠?吠?扮潤甠湌摩愠牊祌?椠渲‰?栶愮渠杕确楩湱杵??婃桡敲橢楯慮湩杦?偲牯潵癳椭湐捥敲???敮漠汴潥杣楴捯慮汩?刭敭癥楴敡睬?????????????????椠湯??桎楯湲整獨敥?睮椠瑘桩??湩条汮楧猨桎?愠扃獨瑩牮慡挩琺??扯牮?婴桲潡畩?????楯??兴???慴湥??????慳?????潨湥朠?????塥畲?儠児?慬湥摯??畩潡?娠????どの????獴畡瀠??ぴ??獬畯灧??牡??獩畮灩?????猲用瀵??爠?朰收漲挭栱爰漷渶漨汩潮朠祃?潩普?浳慥映楷捩?摨礠歅敮獧?楩湳?丠潡牢瑳桴?塡楣湴権椼慢湲朾???捯琠慗?倬攠瑓牨潵氠潌杓椬挠慇?卯椠湊椬挠慘?????????????ㄠお???楇湵??桚楊測攠獌敩?睊楙琠桡??渠杓汵楮猠桍?愠戲猰琰爸愮挠瑃??扴物?婥桮畴??儠?慹湮摡??散湳朠?奦?????????偲污慬琠敁?瑩敡据琠潏湲楯捧獥?慩湣搠?敥癬潴氠畡瑮楤漠湩?楳渠?坥整獡瑬??畧湥杮杹愮爠?潩普?塩楡湮橧椠慇湥杯??塧楹測樠椲愶渨朱??攠漴氭漸木祩?????????????と??楮湧??桳楨渠敡獢敳?睲楡瑣桴??湢杲氾楘獵栠?慑戬猠瑊物愠捊瑑??扈牡?娠桂畆?夠??慵渠摍?堬甠?塨???す????吠桚敨?摵椠獊挮漠瘲攰爰礸?漠晐??慲牯汬祯?佹爬搠潧癥楯捣楨慥湭?潳灴桲楹漠污楮瑤攠?浥?汣慨湲杯敮?楬湯?呹愠敯牦戠慴桨慥琠慩楮??瑲獭???塡楴湥樠楴慯渠杭??乩坣??桹楫湥慳???挠瑮慯?側敨瑥牲潮氠潘杩楮捪慩?卮楧渠楳捩慮??㈠???????????????㈠?楣湴??桐楥湴敲獯敬?睧楩瑣桡??湩杮汩楣獡栬?愲戴猨琵爩愺挠琹??戭爹?娶栨畩?夠???塮略?塥???桴敨渠???慬湩摳?堠畡敢?奴塲???〩???￣?潵氠潘洬椠瑈敥?浇慑爬戠汌敩?慈湑搬?杄慩牮湧攠瑔?愬洠灌桩極戠潘汙椠瑡敮?椠湍?瑩栠敓?漮瀠栲椰漰氶椮琠楂捡?浩?氠慣湨条敲?楣湴?睲敩獳瑴敩牣湳??畦渠杴杨慥爠??割敡汭楡捹猠?潰晨?瑯桬敩??慣爠汭秩?偡慮汧敥漬稠潘楩据?潩捡敮慧測椠捡?捤爠畩獴瑳?慺湩摲?楯瑮猠?摈敒敉灍?猠畤扡摴畩据瑧椮漠湇???挀琀愀?倀攀琀爀漀氀漀最椀挀愀?匀椀渀椀挀愀????????????????????椀渀??栀椀渀攀猀攀?眀椀琀栀??渀最氀椀猀栀?愀戀猀琀爀愀挀琀?
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