CAJ | 학술논문

本文首次测得江西弋阳中元古界铁沙街组石英角斑岩SHRIMP 锆石U-Pb年龄为1154±5 Ma。测定发现铁沙街组石英角斑岩和流纹岩高SiO2（73.53％～81.11％），低CaO（0.06％～0.11％）、Na2O（0.05％～2.77％），K2 O为2.16％～6.43％和Al2 O3为11.06％～13.96％；在Zr／TiO2—Nb／Y微量元素分类图解上绝大多数样品落于碱性流纹岩区域；在SiO2—FeO／MgO图解中绝大多数样品位于钙碱性岩石系列区域；稀土总量（ΣREE）为182.48×10－6～818.82×10－6，轻稀土较富集，铕明显负异常（δEu ＝0.20～0.45）；在原始地幔标准化图解中，表现出亏损大离子亲石元素（Ba、Sr、Ti、P）和富集高场强元素（Nb、Ta、La、Ce、Zr、Hf、Sm）。铁沙街组石英角斑岩和流纹岩的锆石的εHf（t）值分别为－6.1～5.3和－2.3～4.8，两阶段Hf模式年龄分别为1653～2380 Ma和1675～2132 Ma。锆石Hf同位素特征显示铁沙街组石英角斑岩、流纹岩的成因主要为岩石圈拆沉，深部地幔物质上涌，并由此造成的古元古代晚期下地壳物质的部分熔融。综上认为，铁沙街组石英角斑岩和流纹岩形成于中元古界后造山阶段的板内环境，可能与华夏陆块板内裂谷减薄开裂阶段的地幔物质上涌有关。
본문수차측득강서익양중원고계철사가조석영각반암SHRIMP 고석U-Pb년령위1154±5 Ma。측정발현철사가조석영각반암화류문암고SiO2（73.53％～81.11％），저CaO（0.06％～0.11％）、Na2O（0.05％～2.77％），K2 O위2.16％～6.43％화Al2 O3위11.06％～13.96％；재Zr／TiO2—Nb／Y미량원소분류도해상절대다수양품락우감성류문암구역；재SiO2—FeO／MgO도해중절대다수양품위우개감성암석계렬구역；희토총량（ΣREE）위182.48×10－6～818.82×10－6，경희토교부집，유명현부이상（δEu ＝0.20～0.45）；재원시지만표준화도해중，표현출우손대리자친석원소（Ba、Sr、Ti、P）화부집고장강원소（Nb、Ta、La、Ce、Zr、Hf、Sm）。철사가조석영각반암화류문암적고석적εHf（t）치분별위－6.1～5.3화－2.3～4.8，량계단Hf모식년령분별위1653～2380 Ma화1675～2132 Ma。고석Hf동위소특정현시철사가조석영각반암、류문암적성인주요위암석권탁침，심부지만물질상용，병유차조성적고원고대만기하지각물질적부분용융。종상인위，철사가조석영각반암화류문암형성우중원고계후조산계단적판내배경，가능여화하륙괴판내렬곡감박개렬계단적지만물질상용유관。
Zircon SHRIMP U-Pb dating of quartz keratophyre is first time to report from the Tieshajie Formaion (1 154 ±5 Ma),Mesoproterozoic.The quartz keratophyre and rhyolite from the Tieshajie Formaion,with high SiO2 (73.53%~81.11%),low CaO (0.06%~0.11%),low Na2O (0.05%~2.77%),Al2O3 (11.06%~13. 96%),and K2O (2.16%~6.43%).The quartz keratophyre and rhyolite belongs to alkali rhyolite rock series showed in the classification diagram of Zr/TiO2—Nb/Y and calc-alkaline rock series showed in the SiO2— FeO/MgO diagram.The rocks have higher REE contents (182.48 ×10 -6 ~818.82 ×10 -6)with relative enrichment of LREE and negative Eu anomaly (δEu=0.20~0.45).The primitive mantle normalized trace element patterns are characterized by the depletion of the LILE (Ba,Sr,Ti,P)and enrichment of the HFSE (Nb,Ta,La,Ce,Zr, Hf,Sm).TheεHf(t)values and two-staged Hf model ages of the quartz keratophyre and rhyolite from the Tieshajie Formaion are -6.1 ~5.3 and -2.3 ~4.8,1653 ~2380 Ma and 1675 ~2132 Ma.Zircon Hf isotopes characteristic shows that,the quartz keratophyre and rhyolite from the Tieshajie Formaion are products from the lithosphere delamination and mantle material upwelling,and partial melting of late paleoproterozoic crust materials. Synthetical analyze,the Tieshajie Formaion formed in a continental intraplate setting,postorogenic stage.It may be formed in cracking stage of intraplate rift of the Cathaysia,and products of mantle material upwelling.