本文選題：鋯石U-Pb年齡 + 變沉積巖��； 參考：《巖石學(xué)報》2017年09期

【摘要】：南遼河群里爾峪組主要分布在華北克拉通膠-遼-吉活動帶的大石橋-岫巖-鳳城-寬甸一帶,主要巖性為各類長英質(zhì)粒狀巖石(淺粒巖-變粒巖組合)。通過前人長期深入研究,在區(qū)域構(gòu)造、地球化學(xué)、同位素年代學(xué)研究、變質(zhì)作用以及構(gòu)造演化等方面積累了大量資料,取得了一系列重要進(jìn)展。但是,有關(guān)其變質(zhì)作用特征、沉積時代、源區(qū)特征以及遼河群乃至整個膠-遼-吉活動帶的大地構(gòu)造屬性和形成的構(gòu)造演化過程長期以來存在著裂谷開啟-閉合模式、弧-陸碰撞模式和陸-陸碰撞模式的爭論。本文在遼南地區(qū)1∶5萬變質(zhì)巖區(qū)專題填圖的基礎(chǔ)上,選擇三家子地區(qū)南遼河群里爾峪組的疙瘩狀長英質(zhì)粒狀巖石、黑云斜長片麻巖和含黑云母長英質(zhì)粒狀巖石為重點研究對象。通過鋯石陰極發(fā)光圖像特征和鋯石LA-ICP-MS U-Pb年代學(xué)測試,綜合限定研究區(qū)南遼河群里爾峪組變質(zhì)沉積巖的物質(zhì)來源和原巖形成時代,進(jìn)而探討其形成的構(gòu)造背景。3件樣品中鋯石陰極發(fā)光圖像顯示核-邊結(jié)構(gòu),核部具振蕩環(huán)帶,Th/U比值較高(Th/U=0.12~4.95),表明其巖漿來源;U-Pb年代學(xué)測試分別得到2140Ma、2170Ma和2150Ma的年齡峰值。綜合前期研究成果,鋯石U-Pb年代學(xué)測試結(jié)果在年齡直方圖中顯示明顯的2137Ma的峰值。該組年齡與區(qū)域上大量出露的遼吉花崗巖的年齡具有一致性,表明南遼河群里爾峪組的物質(zhì)來源于遼吉花崗巖,其沉積時限應(yīng)晚于古元古代。
[Abstract]:The Lianyu formation of the South Liaohe Group is mainly distributed in the Dashiqiao Xiuyan Fengcheng Kuandian area of the North China Craton Jiaoliao Liaoji active belt. The main lithology is felsic granular rock (shallow-granulite-granulite assemblage). Through a long period of in-depth studies by predecessors, a great deal of data have been accumulated in regional tectonics, geochemistry, isotopic chronology, metamorphism and tectonic evolution, and a series of important advances have been made. However, the characteristics of metamorphism, sedimentary epoch, source area, tectonic attributes of Liaohe Group and even the whole Jiao-Liaojia-Ji active belt, and the tectonic evolution process of formation have long existed rift opening and closing mode. Arc-land collision model and land-land collision model are controversial. Based on the topographic mapping of the 1: 50 000 metamorphic rock area in southern Liaoning Province, this paper selects the keloid felsic granulated rocks of the Liliyu formation of the South Liaohe Group in Sanjiazi area. The study of biotite-feldspar granulite and biotite-bearing feldspar granulite is the main research object. Based on the characteristics of zircon cathodoluminescence images and zircon LA-ICP-MS U-Pb geochronology, the material source and the age of origin of the metamorphic sedimentary rocks in the Liliyu formation of the South Liaohe Group in the study area are comprehensively limited. Furthermore, the zircon cathodoluminescence images of the 3 samples formed in the tectonic setting show a nucleus-edge structure with a high Th-P / U ratio of the oscillatory ring zone (Th/ UU 0.12U 4.95), indicating that the dating peaks of 2140 Ma, 2170 Ma and 2150 Ma are obtained from the U-Pb geochronological measurements of their magma origin, respectively. Combined with the previous results, the zircon U-Pb dating results show an obvious peak value of 2137 Ma in the age histogram. The age of this group is consistent with that of the Liaoji granite, which indicates that the material of the Lianyu formation of the South Liaohe Group originates from the Liaoji granite, and its sedimentary time is later than that of the ancient Gu Yuan.
【作者單位】： 中國地質(zhì)科學(xué)院地質(zhì)研究所;
【基金】：國家自然科學(xué)基金重點項目(41430210) 中國地質(zhì)調(diào)查局項目(DD20160121) 中國地質(zhì)科學(xué)院基本科研業(yè)務(wù)費項目(YYWF201703、J1614)聯(lián)合資助
【分類號】：P588.3;P597.3

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