華北克拉通南緣中-新元古代沉積演化：以豫西地區(qū)黃連垛組和董家組為例*

左鵬飛 李雨 劉思聰 鄭德順**

1. 河南理工大學資源環(huán)境學院，焦作 4540002. 山東省沉積成礦作用與沉積礦產(chǎn)重點實驗室，山東科技大學，青島 266590

前人認為華北克拉通在中元古代到早古生代總體上處于伸展狀態(tài)，未參與Rodinia超大陸的演化過程(Luetal., 2002，2008；陸松年等，2004；Zhaietal., 2015)。然而，大量古地磁及巖墻群的相關(guān)研究表明，華北在中元古代到新元古代早期與Laurentia、Siberia、Australia、India克拉通可能相鄰(Hallsetal., 2000；Li and Powell，2001；Zhaietal., 2003；Peietal., 2006；Zhangetal., 2006，2009；相振群，2014；徐慧茹，2015；彭澎等，2018)。最新研究認為華北克拉通最可能與Laurentia存在某種聯(lián)結(jié)(Wangetal., 2016；丁繼凱，2017)，而Laurentia處于Rodinia超大陸的核心部分，發(fā)育完整的Grenville造山帶(Rainbirdetal., 1992，1997，2012；Lietal., 2008；Mosheretal., 2008；Peaseetal., 2008；Spenceretal., 2015)。華北克拉通在中元古代末期發(fā)育了“芹峪抬升”和“蔚縣抬升”，之后在燕遼地區(qū)缺失中元古代晚期地層(1350Ma到1100Ma)(杜汝霖等，1979；曲永強等，2010，2012；潘建國等，2013)，新元古代沉積作用也主要發(fā)育在徐淮、白云鄂博-渣爾泰-化德、熊耳地區(qū)(Huetal., 2016；潘桂棠等，2016；張克信等，2018)，最終形成了四個中-新元古代沉積盆地(圖1a)。最近又在以上三個地區(qū)的中-新元古代地層中報道了大量的Grenville時期的碎屑鋯石(胡波等，2009；高林志等，2010；Gaoetal., 2011；Yangetal., 2012；胡波，2013； Huetal., 2014a； Liuetal., 2014，2019；Caoetal., 2016；Heetal., 2017；楊敏，2017)。

由于華北克拉通(華北)南緣熊耳盆地內(nèi)熊耳群形成時代限定于約1800～1750Ma(Zhaoetal., 2004；Heetal., 2009；Cuietal., 2011)，通過洛峪口組凝灰?guī)r和下伏地層碎屑鋯石年齡的約束，汝陽群-洛峪群的沉積時代基本限定于約1750～1600Ma，即熊耳群-汝陽群-洛峪群均形成于長城系(1800～1600Ma)(蘇文博等，2012；蘇文博，2016；李承東等，2017)。洛峪口組上覆黃連垛組和董家組為1980年河南地科所于魯山下湯九女洞建立，在葉縣、方城、陜縣等地均有分布，時代為中元古代到新元古代早期(潘澤成，1980；關(guān)保德等，1988；河南省地質(zhì)礦產(chǎn)局，1989)。因此，洛峪群-汝陽群被下壓到長城系，導致傳統(tǒng)上對華北南緣中-新元古代沉積和構(gòu)造演化的認識需要重新調(diào)整，而上覆黃連垛組和董家組沉積環(huán)境和物源分析可為該區(qū)沉積-構(gòu)造演化提供新的約束。

結(jié)合前人工作，本次通過對華北南緣黃連垛組和董家組巖石學和沉積學特征的研究，借助黃連垛組、董家組和早古生界辛集組碎屑鋯石年代學分析，對比華北南緣中-新元古代沉積地層物源變化，揭示華北南緣中元古代到新元古代大地構(gòu)造演化歷史。

1 區(qū)域地質(zhì)背景

華北南緣中元古代早期經(jīng)歷熊耳火山事件(1800～1750Ma)后，發(fā)育陸源碎屑巖-碳酸鹽巖沉積體系(關(guān)保德等，1988；河南省地質(zhì)礦產(chǎn)局，1989)。根據(jù)該地區(qū)中-新元古代不同沉降作用將其自北向南分為三個地層分區(qū)：嵩箕、澠池-確山和盧氏-欒川(圖1b)(關(guān)保德等，1988；河南省地質(zhì)礦產(chǎn)局，1989；河南省地質(zhì)調(diào)查院，2009)。

圖1 華北克拉通和北秦嶺前寒武紀地質(zhì)簡圖(a，據(jù)Dengetal., 2014a, b；Dongetal., 2014，2015；Huetal., 2014a，2016；Peng，2015修改)及豫西地區(qū)前寒武紀地質(zhì)簡圖(b，據(jù)河南省地質(zhì)調(diào)查院，2009[注]河南省地質(zhì)調(diào)查院. 2009. 河南省礦產(chǎn)資源潛力評價；陜西省地質(zhì)調(diào)查院，2009[注]陜西省地質(zhì)調(diào)查院. 2009. 陜西省礦產(chǎn)資源潛力評價修改)

Fig.1 The location of the study area within the North China Craton(NCC)and North Qinling Terrane(NQT)(a，modified after Dengetal., 2014a, b；Dongetal., 2014，2015；Huetal., 2014a，2016；Peng，2015)，and simplified geological map of the western Henan(b)

澠池-確山地區(qū)在發(fā)育熊耳群火山-沉積巖之后，發(fā)育了沖積扇-扇三角洲相沉積地層(兵馬溝組或小溝背組)，與上覆汝陽群呈平行不整合接觸(圖2a)。汝陽群下部(云夢山組和白草坪組)由河流-濱海相石英砂巖過渡為潮間-潮上帶的砂巖、粉砂巖和頁巖，上部(北大尖組)發(fā)育了潮間帶泥質(zhì)粉砂巖，頂部為白云巖及白云質(zhì)砂巖。上覆整合覆蓋的洛峪群(崔莊組、三教堂組和洛峪口組)自下而上分別為外陸棚、濱海和潮坪沉積，其頂部發(fā)育疊層石白云巖。黃連垛組為三角洲-濱淺海-碳酸鹽巖沉積或濱海-潮坪沉積，董家組為三角洲-濱淺海-海灣瀉湖或濱淺海-潮坪沉積，二者均與上下地層呈平行不整合接觸(潘澤成，1980；周洪瑞等，1999)。上覆平行不整合覆蓋的羅圈組和東坡組總體上屬于冰湖相沉積(Guanetal.，1986；Le Heronetal.，2018)。早古生界辛集組不整合上覆蓋于東坡組或董家組之上，為濱海相含少量碳酸鹽巖的硅質(zhì)碎屑巖(劉印環(huán)，1986；劉印環(huán)等，1991；劉群等，1994)。

圖2 華北南緣熊耳地區(qū)中-新元古代盆地巖性柱狀對比(據(jù)關(guān)保德，1996；河南省地質(zhì)調(diào)查院，2009)MC-澠池；YC-伊川；LS-魯山；LB-靈寶. 澠池兵馬溝組和云夢山組古流向數(shù)據(jù)依據(jù)李文超(2013); 黃連垛組和董家組古流向據(jù)張玲華(1994); 高山河組古流向據(jù)河南省地質(zhì)調(diào)查院(2009)Fig.2 General stratigraphic sequences and correlation of the Meso-Neoproterozoic strata of the Xiong’er Basin (after Guan, 1996)MC-Mianchi area; YC-Yichuan area; LS-Lushan area; LB-Lingbao area. Paleocurrents data of Yunmenshan and Bingmagou formations in MC from Li(2013); Huoliangudo and Dongjia formations from Zhang(1994)

嵩箕地區(qū)主要地層自下而上為兵馬溝組、五佛山群、羅圈組及東坡組(圖2b)。兵馬溝組為一套扇三角洲相的礫巖、含礫砂巖、粗-細砂巖和粉砂巖沉積組合(張元國等，2011；趙太平等，2015；鄭德順等，2016a；Mengetal.，2018)。五佛山群(馬鞍山組、葡峪組和何家寨組)自下而上沉積于河流-濱淺海-碳酸鹽巖臺地環(huán)境(河南省地質(zhì)礦產(chǎn)局，1989；席文祥和裴放，1997)。最南部的盧氏-欒川地區(qū)自下而上發(fā)育了中元古界高山河組(群)和官道口群，以及新元古界欒川群(圖2c)(河南省地質(zhì)礦產(chǎn)局，1989；高林志等，2002；Gaoetal.，2009)。高山河組(群)不整合于熊耳群之上，主要為河流-濱海相的含礫石英砂巖。官道口群(龍家園組、巡檢司組、杜關(guān)組、馮家灣組和白術(shù)溝組)主要為一套潮坪-內(nèi)陸棚-潮間帶-淺海相的碳酸鹽巖(Lietal.，2019；河南省地質(zhì)調(diào)查院，2009)。欒川群沉積于潮下帶-淺海環(huán)境(河南省地質(zhì)礦產(chǎn)局，1989；蔣干清，1993；蔣干清等，1994；關(guān)保德，1996；席文祥和裴放，1997；王躍峰，2000)。古生界陶灣群不整合上覆于欒川群，巖性為變質(zhì)礫巖、碎屑巖及條帶狀不純大理巖，原巖可能沉積于深水斜坡相(張維吉和李育敬，1989；王宗起等，2007，2009)。

華北南緣古-中元古代(1850～1500Ma)巖漿事件，包括熊耳群火山巖、鎂鐵質(zhì)巖墻群和A型花崗巖，記錄了華北南緣在最終克拉通化之后的構(gòu)造演化歷史(陸松年等，2003；Pengetal.，2008；Baoetal.，2011；Peng，2015；鄧小芹等，2015；Deng and Wang，2016； Dengetal.，2016；Zhao and Deng，2016；師江朋，2017)。新元古代堿性粗面巖(860Ma)、輝長巖(830Ma)和正長巖(844Ma)，代表了伸展背景下的巖漿活動(柳永清等，2005；Baoetal.，2008；閻國翰等，2010；Wangetal.，2011)。

圖3 黃連垛組野外特征及微觀特征(a)黃連垛組底部含燧石條帶石英礫巖(下湯)；(b)黃連垛組底部石英礫巖微觀特征(正交偏光)(下湯)；(c)黃連垛組含硅質(zhì)條帶白云巖與泥晶白云巖(葉縣)；(d)黃連垛組泥晶白云巖與含硅質(zhì)條帶白云巖(葉縣)；(e)黃連垛組泥晶白云巖微觀特征(正交偏光)(葉縣)；(f)黃連垛組含硅質(zhì)條帶白云巖中存在的軟沉積物變形(葉縣). Q-石英Fig.3 Outcrop photographs and micrographs of the Huanglainduo Formation(a) pebbly quartz sandstones in the bottom of the Huanglianduo Formation(Xiatang)；(b)micrographs of pebbly quartz sandstones of the Huanglianduo Formation(crossed polars)(Xiatang)；(c) siliceous banded dolomites and dolomicrites of Huanglianduo Formation(Yexian)；(d) dolomicrites and siliceous banded dolomites of the Huanglianduo Formation(Yexian)；(e)micrographs of dolomicrite of the Huanglianduo Formation(crossed polars)(Yexian)；(f)siliceous banded dolomites of the Huanglianduo Formation，interbeded with soft-sediment deformation(Yexian). Q-quartz

圖4 董家組野外沉積特征與鏡下特征(a)董家組底部砂礫巖(葉縣)；(b)董家組下段長石石英砂巖(葉縣)，向上變細；(c)董家組下段長石石英粗砂巖微觀特征(正交偏光)(葉縣)；(d)董家組中段長石石英砂巖與泥質(zhì)粉砂巖互層(葉縣)；(e)董家組中段長石石英砂巖，夾泥質(zhì)粉砂巖(葉縣)；(f)董家組上段紫紅色鈣質(zhì)泥巖(葉縣). F-長石；L-巖屑Fig.4 Outcrop photographs and micrographs of the Dongjia Formation(a)glutenites in the bottom of the Dongjia Formation(Yexian)；(b)fining-upward feldspar-quartz sandstones in the lower unit of the Dongjia Formation(Yexian)；(c)micrographs of feldspar-quartz sandstone from the lower unit of the Dongjia Formation(crossed polars)(Yexian)；(d)feldspar-quartz sandstones with interbedding pelitic siltstone in the middle unit of the Dongjia Formation(Yexian)；(e)feldspar-quartz sandstones of the Dongjia Formation interlayered with pelitic siltstone in the middle unit(Yexian)；(f)purple-red calcareous marls in the upmost of the Dongjia Formation(Yexian). F-feldspar；L-fragment

2 黃連垛組和董家組沉積特征

黃連垛組巖性自下而上主要為礫巖-砂礫巖-硅質(zhì)條帶白云巖，頂部為條帶狀硅質(zhì)層，與上下地層均為平行不整合接觸(席文祥和裴放，1997)。董家組巖性自下而上主要為礫巖-含礫粗砂巖-長石石英砂巖-粉晶白云巖夾泥晶灰?guī)r，與上覆羅圈組或辛集組呈平行不整合接觸(席文祥和裴放，1997)。黃連垛組總體上為一套海進序列的三角洲、濱海、淺海相的陸源碎屑及碳酸鹽巖沉積建造，海侵方向為自西向東；董家組是另一套海進序列的三角洲、濱海、淺海相陸源碎屑和海灣瀉湖相碳酸鹽巖建造，海侵方向為自南向北或自西南向北，后期沉積的碳酸鹽巖形成于蒸發(fā)大于補給的沉積環(huán)境(潘澤成，1980；鄭偉和劉順喜，2012)。

本次研究主要選取魯山下湯地區(qū)和葉縣地區(qū)兩條剖面。下湯地區(qū)黃連垛組下段巖性為土黃色含礫石英砂巖和長石砂巖，礫石粒徑0.2～8cm，平均粒徑約2cm，分選磨圓較差，礫石沿軸向存在定向排列，礫石成分主要為燧石、石英巖等(圖3a)，基底-孔隙式膠結(jié)，雜基支撐為主(圖3b)；中段巖性為具楔狀交錯層理的土黃色長石石英砂巖，接觸式膠結(jié)，分選差，長石風化嚴重；上段巖性為成層性較好的含硅質(zhì)條帶白云巖。下湯東南葉縣地區(qū)黃連垛組主要巖性為灰白色厚層泥晶白云巖與淺黃色厚層具紋層狀含硅質(zhì)條帶白云巖，二者具多期次旋回性(圖3c, d)。葉縣地區(qū)黃連垛組泥晶白云巖強烈變形(圖3d)，內(nèi)部發(fā)育棱角狀硅質(zhì)碎屑，偶見石膏假晶(圖3e)；含硅質(zhì)條帶白云巖內(nèi)多發(fā)育軟沉積物變形(圖3f)。下湯地區(qū)黃連垛組底部礫巖多為棱角狀，少數(shù)為滾圓狀，分選差，磨圓較差，沿長軸方向具定向排列特征(圖3a)，沉積于河口灣環(huán)境，缺乏沖積扇-河流相沉積。因此，下湯地區(qū)黃連垛組沉積于河口灣-潮坪沉積環(huán)境，南部葉縣地區(qū)沉積于潮坪沉積環(huán)境，整體表現(xiàn)為自南向北的海進序列。

圖5 黃連垛組、董家組和辛集組樣品野外和微觀特征(a)黃連垛組下段英砂巖，具不明顯楔狀交錯層理(下湯)；(b)黃連垛組下段長石石英砂巖微觀特征(正交偏光)(下湯)；(c)董家組下段長石石英砂巖(下湯)；(d)董家組下段長石石英砂巖微觀特征(正交偏光)(下湯)；(e)辛集組底部薄板狀石英砂巖，夾薄層粉砂質(zhì)泥巖(下湯)；(f)辛集組底部石英砂巖微觀特征(正交偏光)(下湯)Fig.5 Outcrop photographs and micrographs of the Huanglianduo Formation, the Dongjia Formation and the Xinji Formation(a)feldspar-quartz sandstones in the lower unit of the Huanglianduo Formation(Xiatang)；(b)micrographs of feldspar-quartz sandstone in the lower unit of the Huanglianduo Formation (crossed polars)(Xiatang)；(c)feldspar-quartz sandstones in the lower unit of the Dongjia Formation(Xiatang)；(d)micrographs of feldspar-quartz sandstone in the lower unit of the Dongjia Formation (crossed polars)(Xiatang)；(e)quartz sandstones in the lower part of Xinji Formation，interbeded with mudstone(Xiatang)；(f)micrographs of quartz sandstone in the lower part of the Xinji Formation (crossed polars)(Xiatang)

圖6 華北南緣黃連垛組、董家組和辛集組碎屑巖代表性碎屑鋯石CL圖像Fig.6 Cathodoluminescence (CL) images of representative detrital zircon grains from the Huanglianduo, Dongjia and Xinji formations clastic rocks in the southern margin of North China Craton

圖7 華北南緣黃連垛組、董家組和辛集組碎屑鋯石U-Pb諧和曲線圖和年齡分布柱狀圖Fig.7 U-Pb concordia diagrams and age probability histograms for detrital zircons from the Huanglianduo, Dongjia and Xinji formations clastic rocks in the southern margin of North China Craton showing their age distributions

葉縣地區(qū)董家組底部巖性主要為灰白色中細粒石英砂巖和含長石石英砂巖；下段為土黃色中細粒石英砂巖，分選較好，磨圓較好；中段為灰白色粗-中粒石英砂巖或含長石石英砂巖，巖屑及云母含量較少，顆粒支撐，分選較好，磨圓一般；上段為青灰色或暗紅色薄層狀泥質(zhì)灰?guī)r及薄板狀泥頁巖。該區(qū)辛集組為紫紅色含礫砂巖-土黃色薄板狀石英砂巖，夾極薄層粉砂質(zhì)泥巖，石英顆粒分選較好磨圓中等，呈輕微定向排列。葉縣董家組底部巖性為黃褐色塊狀中-細礫砂礫巖，礫徑2～5mm，平均粒徑3mm，礦物成分主要為石英、燧石和長石，硅質(zhì)膠結(jié)，磨圓好，分選中等(圖4a)；下段巖性為黃褐色或暗紅色中厚層粗-中粒含石英長石砂巖(圖4b)，石英顆粒偶見溶蝕邊(圖4c)；中段巖性為中-細粒長石石英砂巖與土黃色粉砂質(zhì)泥巖互層(圖4d)，砂巖具楔狀交錯層理和浪成層理，泥巖具水平層理(圖4e)；上段巖性為厚層紫紅色薄板狀鈣質(zhì)泥巖(圖4f)。因此，葉縣地區(qū)董家組底部礫巖可能為濱海沉積礫巖，董家組總體上應(yīng)沉積于局限海盆的濱淺海環(huán)境。

3 測年樣品和分析

3.1 樣品采集與處理

黃連垛組下部樣品(17HLD-04)采集自魯山縣下湯鎮(zhèn)(圖1c、圖5a)。該樣品為黃色中細粒長石石英砂巖，主要礦物為石英(63%～65%)、長石(31%～35%)，具少量巖屑，顆粒支撐，接觸式膠結(jié)，次棱角狀-次圓狀，石英具次生加大邊，可見條紋長石、微斜長石及斜長石；巖屑多呈次棱角狀(圖5b)。

董家組底部樣品(17DJ-02)采集自魯山縣下湯鎮(zhèn)(圖1c)，中下部樣品(MLA-04-2)采集自葉縣常村鎮(zhèn)(圖1c)。董家組樣品(17DJ-02)為黃色長石石英砂巖(圖5c)，主要礦物為石英(51%～55%)、長石(40%～43%)、巖屑(4%～6%)，偶見云母，分選較好，磨圓一般，顆粒支撐，接觸式膠結(jié)；石英為次棱角狀-圓狀，部分石英具次生加大邊；長石為次棱角狀-次圓狀，偶見圓狀，可見具格子雙晶微斜長石，表面風化嚴重(圖5d)。另一樣品(MLA-04-2)為黃褐色粗-中粒長石石英砂巖(圖4b)，主要礦物為石英(61%～65%)、長石(19%～23%)、巖屑(6%～8%)，少見燧石，部分石英具溶蝕邊，長石具格子雙晶和條紋結(jié)構(gòu)(圖4c)。辛集組樣品(LTXJ-1-1)采集自魯山縣下湯鎮(zhèn)(圖5e)，為薄板狀石英砂巖，分選好，磨圓中等(圖5f)。

鋯石首先由南京宏創(chuàng)地質(zhì)勘探技術(shù)服務(wù)有限公司選取，采用場發(fā)射掃描電子顯微鏡(TESCAN，Mira 3 LMH)對其進行高分辨率陰極發(fā)光(CL)成像; 通過CL和透反射圖像識別鋯石內(nèi)部結(jié)構(gòu)并選擇合適位置進行碎屑鋯石U-Pb年代學分析。鋯石U-Pb定年由武漢上譜分析技術(shù)有限公司采用激光剝蝕電感耦合等離子體質(zhì)譜法(LA-ICP-MS)完成。激光剝蝕系統(tǒng)為Geolas 2005，激光脈沖頻率為5Hz，剝蝕點直徑為32μm。黃連垛組樣品(17HLD-04)和董家組樣品(17DJ-02)采用Agilent 7500a；董家組樣品(MLA-04-2)和辛集組樣品(LTXJ-1-1)采用Agilent 7900。鋯石標樣91500作為本次試驗標樣每6次進行兩次分析。利用ICP-MS Datacal軟件對鋯石數(shù)據(jù)進行離線選擇、背景分析及信號整合，以及時間漂移校正、定量校準(Liuetal., 2010；Spenceretal., 2016)。鋯石的U-Pb年齡結(jié)果使用Isoplot 3.0軟件(Ludwig，2003)計算。對鋯石206Pb/238U年齡小于1500 Ma，使用206Pb/238U年齡做頻率直方圖，207Pb/206Pb年齡用于年齡比較老的樣品(206Pb/238U>1500Ma)(Spenceretal.，2016)。選擇諧和度(206Pb/238U-207Pb/235U或206Pb/238U-207Pb/206Pb)大于90%的測值進行年齡分布統(tǒng)計。

3.2 分析結(jié)果

黃連垛組樣品(17HLD-04)中碎屑鋯石多為半自形或圓形，粒徑為40～250μm(圖6)，絕大多數(shù)鋯石具有環(huán)帶結(jié)構(gòu)，表明其為巖漿鋯石，對其隨機挑選96個點位進行測試。碎屑鋯石中，1顆碎屑鋯石偏離U-Pb演化曲線(圖7a)，諧和度低于90%(表1)。統(tǒng)計95顆鋯石年齡主峰值為1800Ma和2350Ma，次要峰值為2650Ma和2900Ma(圖7b)。

表1 華北克拉通南緣下湯地區(qū)黃連垛組碎屑鋯石U-Pb同位素年齡

Table 1 Zircon U-Pb isotopic data of sedimentary rocks from the Huanglianduo Formation in the Xiatang

測點號ThU(×10-6)Th/U同位素比值同位素年齡(Ma)207Pb/206Pb207Pb/235U206Pb/238U207Pb/206Pb207Pb/235U206Pb/238U比值2σ比值2σ比值2σ比值2σ比值2σ比值2σ不協(xié)和度(%)17HLD-04 (長石石英砂巖)-176870.90.16050.010110.2940.67440.46340.011324611082462612455501-244341.30.15390.01049.71590.65670.45810.012923911172408622431571-3107721.50.18430.00913.4820.66390.52790.01212692812714472732511-4841350.60.15480.0079.94160.45670.46220.01012399782429422449441-530181.70.10630.00974.79780.42150.32830.011417361671785741830553-647600.80.16970.008911.6130.57970.49260.01352555882574472582581-782621.30.15160.00859.52870.52830.45110.01182365962390512400531-8692020.30.11180.0055.38690.240.34550.00771829801883381913372-9911120.80.18610.007514.0280.58210.54130.01182709672752392789492-1070322.20.11610.00815.70260.38660.35670.009918981261932591966472-11102631.60.10530.00614.71460.26910.3230.007117201111770481804342-1219310.60.17660.009612.540.71120.51240.01392621912646532667591-13961070.90.10630.00574.7140.25190.32040.00651739981770451791322-14424210.11140.00645.00260.30660.32390.007818331051820521809381-1530251.20.11030.00794.96170.34820.32710.007918061301813591824381-16798310.1430.00578.69050.36510.43980.00892265682306382350402-171211570.80.10590.00454.77620.21070.32650.00621731781781371822303-1874920.80.14720.00659.16840.42190.45160.00932314752355422402412-1973890.80.13930.00637.99290.37930.41590.00922220782230432242421-2024580.40.14050.00638.61760.40560.44380.01042235772298432368463-2158870.70.14910.00629.3090.39860.4510.00882336722369392400392-22103941.10.15340.00729.61950.47130.45140.00942384802399452402421-2364850.80.17640.008612.170.56490.49780.01052620812618442604451-2485531.60.15510.00939.64480.53110.44940.010524031022401512392471-251721850.90.16550.007811.3150.52620.49180.01072513802549432579462-261431830.80.10870.00584.96620.25670.32980.00771777971814441837372-272185070.40.13850.00528.03830.31730.41770.00752209652235362250341-283365600.60.14970.00579.3380.38130.44910.00812342652372372391361-294143001.40.10640.00534.77180.23960.32530.00691739921780421816342-3020720610.15530.00799.89250.53410.46020.00912405922425502440401-312523170.80.15090.00749.29120.49080.44450.00872367832367482371391-32330963.40.17270.01067.05680.41720.29820.007258410321195316833523-332533000.80.15680.006310.0850.42520.46430.00852421682443392459371-342094500.50.1090.00455.00510.20550.33190.00621783761820351847302-354192621.60.15480.008810.0170.54050.47030.01412400982436502485622-361591810.90.11160.00595.03710.27390.32490.00661825971826461814321-371601740.90.19910.009215.4950.70250.56140.01132818752846432872471-387154621.60.10970.0055.04440.22810.33120.00581795831827381844281-3912011610.11480.00715.20760.30920.32890.007318771121854511833362-40991620.60.17240.009211.9260.6260.50060.01082581842599492616461-412286540.40.13730.00767.6910.46380.40160.0092194962196542176411-4221320710.19210.012214.6480.96040.54870.011227611052793622820461-431992530.80.11290.00775.230.35550.33520.007318561241858581863351-443872401.60.16010.009510.5580.64030.47540.009324571002485562507411-45731060.70.18690.010314.120.77950.5470.01222715902758522813512-462093220.70.14650.00648.86930.4040.43610.00852306802325422333381-472673440.80.11520.00695.67750.3420.35630.007518831091928521965362

續(xù)表1

Continued Table 1

測點號ThU(×10-6)Th/U同位素比值同位素年齡(Ma)207Pb/206Pb207Pb/235U206Pb/238U207Pb/206Pb207Pb/235U206Pb/238U比值2σ比值2σ比值2σ比值2σ比值2σ比值2σ不協(xié)和度(%)-481292290.60.11140.00545.2310.25820.33840.0071833871858421879342-4911711610.11090.00634.94630.27850.3230.007918151021810481805381-502263510.60.1090.00444.94690.20140.32750.0061783731810341826291-514936860.70.10890.00394.97770.1850.32940.00571781711816311836282-521531980.80.11340.00525.44430.25540.34690.00781854881892401920372-532171891.20.18780.007114.270.570.5480.01092724622768382817452-5469372710.15990.0069.92820.38550.44780.00842455632428362385382-552585120.50.11120.00475.43030.23470.35250.00741820771890371947353-561241650.80.13940.00628.26660.37420.42920.00932220772261412302422-573172921.10.10440.00454.68810.19620.32530.00711706811765351815343-581221800.70.14890.0069.29130.3620.45230.00872344702367362405382-592032980.70.1420.00528.53940.32310.43490.00862251632290342328392-6032580.60.21030.010317.0090.77640.58980.01512909792935442989612-612232420.90.15610.006910.2030.47460.47210.00992415742453432493432-62129991.30.15120.00879.56350.5350.45950.0112359982394512437492-633212141.50.17980.008513.2760.62790.5320.01032651782699452750432-642483990.60.14860.00849.52030.5250.46050.00872331962390512442383-6590521.70.10.01074.49520.47220.32520.011216252011730871815555-661421770.80.16130.014111.0330.90180.4920.011824691482526762579513-672481861.30.1440.01318.97930.77980.44710.010722761582336792382482-682086030.40.1080.00815.1680.37370.34250.00717661321847621899343-692653230.80.1890.020214.3611.54490.54420.0103274417727741022801431-70193862.20.11470.00825.70170.39740.35940.008818761301932601979413-713231931.70.10350.00594.71860.26630.3290.007716871071771471834374-7256900.60.17630.009112.7010.690.51920.01392618852658512696592-732823090.90.10680.00534.82720.23630.32590.00621746911790411819302-7412712610.11210.0065.05890.28270.32490.00691835981829471814341-7591741.20.11150.00715.03930.31950.32730.007718241151826541825371-762192320.90.1440.00568.78660.34610.44050.00782276672316362353352-773574600.80.10690.00434.81410.2030.32490.00571748741787351813282-782252770.80.14870.00629.16690.40010.44530.008423312712355402374371-792112550.80.14270.00628.22450.37710.41590.00892261802256422242411-80721700.40.14360.00658.83510.40530.44450.00972272772321422371433-811772680.70.15020.00589.30990.36420.44680.00772348662369362381341-822992711.10.15380.00659.70760.43270.45350.00882389722407412411391-831952550.80.1770.007612.250.50380.49870.00952625722624392608411-842591571.70.15070.00799.41490.45670.45120.00932354912379452401411-8569880.80.16460.008110.440.48140.45510.01132503822475432418503-86861590.50.15870.006510.020.38640.45270.00982442692437362407432-87892000.40.12720.00526.48990.26010.36610.00722061712045352011342-8868332.10.16120.008710.2190.56320.4560.01042469912455512422462-89571380.40.14150.00598.05750.35090.40960.0092256722237392213412-9043580.70.11360.00645.12780.29550.32580.007818571081841491818382-91731010.70.1520.00759.25020.46370.43940.01012368832363462348451-92701260.60.14720.00698.68880.40860.42630.00862313802306432289391-9316111.50.12160.02465.36811.05750.3250.0158198936818801691814774-94585710.15660.00749.83510.4680.45470.01032419802419442416461-9531570.60.21340.009116.4740.72630.5580.01122932692905422858462-96403910.15790.0089.94560.50110.4570.01072433852430472426471

表2 華北克拉通南緣下湯地區(qū)董家組碎屑鋯石U-Pb同位素年齡

Table 2 Zircon U-Pb isotopic data of sedimentary rocks from the Dongjia Formation in the Xiatang

測點號ThU(×10-6)Th/U同位素比值同位素年齡(Ma)207Pb/206Pb207Pb/235U206Pb/238U207Pb/206Pb207Pb/235U206Pb/238U比值2σ比值2σ比值2σ比值2σ比值2σ比值2σ不協(xié)和度(%)17DJ-02 (長石石英砂巖)-11091610.70.11440.00535.12190.23270.32380.0061872851840391808292-226300.90.11280.00835.14380.37220.33160.008518561331843621846411-360910.70.11360.00535.15580.24320.32790.00661857831845401828321-437920.40.10730.00514.92490.23570.33090.00611755871807401843302-543650.70.13880.00687.97480.36480.41590.00872213852228412242401-639660.60.11090.0065.15220.28220.3350.00741814931845471863361-757471.20.11470.00695.64540.32970.35560.007818761091923501961372-865920.70.11240.0065.15390.26070.33190.00731839961845431848351-9981790.60.10840.00485.11660.22030.3410.0071773751839371892343-1027380.70.11020.00685.13610.30380.33840.008318031181842501879402-1119240.80.11390.00825.4390.38650.3470.010118651291891611920482-12681010.70.11030.00585.16120.27380.33830.00721806961846451878352-1352680.80.10490.00634.65280.26710.32230.007417131111759481801363-14871360.60.10960.00495.10380.23540.33610.00661792821837391868322-1522270.80.12360.00845.90930.39930.3470.009320101211963591920443-16521070.50.12160.00536.14930.26750.36520.00811980771997382007381-1734010050.30.14030.00553.59810.18630.18580.008122316915494110984435-1832410.80.11310.00655.33760.30980.340.008318501041875501887401-1951680.80.11480.00635.48270.29510.34490.00871877981898461910421-2058960.60.15640.006510.2440.42940.47150.0092417712457392490402-21401020.40.13020.00587.18660.33430.39720.0082102772135412156371-2224201.20.11930.00975.53240.44040.33830.010819461451906681878522-231122360.50.13380.00585.75830.26630.31010.007721508119404017413811-2423290.80.11270.00825.11810.34960.3310.008818421311839581843431-2553441.20.15890.008710.34350.5540.47060.010224441262466502486451-2619270.70.16710.009510.9540.62150.47520.01312528962519532506571-271501021.50.10190.00714.47660.28860.31920.009516611291727541786464-2834301.10.11140.00734.97730.31450.32550.009318221191815531816451-2945600.80.10930.00644.9950.29150.33040.007817881071818491840382-3040440.90.1150.00655.26150.28830.33140.008218801061863471845401-3114131.10.11670.0115.33170.50120.33530.012219061691874801864591-3219280.70.10840.00764.86170.35290.32480.009317721281796611813451-3323211.10.1140.00775.16920.35540.32840.009518651221848591830461-3423340.70.10910.00665.01670.30740.33350.009417841161822521855452-35581330.40.14390.00548.84320.34110.44350.00862276652322352366382-3663581.10.11290.00585.24630.26910.33650.00811856931860441870391-37982130.50.10850.00494.46920.26710.29760.01271776771725501679633-3826201.30.21760.121214.8637.9050.50460.01322965104628075062633567-3924390.60.1110.00655.05560.27930.33120.008118171061829471844391-4051610.80.11170.00625.240.28270.33980.007118281011859461886342-4126300.90.11290.00785.18940.3360.33530.009618471251851551864461-42778110.11850.00596.05090.31530.36830.00821933891983452021392-4343510.80.20610.19369.46858.03570.36030.008328751033238477919843919-4423320.70.10920.00715.12690.32540.3420.009517871201841541896463-45891130.80.11830.0055.88580.25260.35920.00651931751959371978311-4670800.90.10910.00545.03220.24020.33440.0081785901825401859382-47601550.40.13960.00528.52950.34920.44080.00962222602289372354433

續(xù)表2

Continued Table 2

測點號ThU(×10-6)Th/U同位素比值同位素年齡(Ma)207Pb/206Pb207Pb/235U206Pb/238U207Pb/206Pb207Pb/235U206Pb/238U比值2σ比值2σ比值2σ比值2σ比值2σ比值2σ不協(xié)和度(%)-4875900.80.10780.00515.06520.24970.33920.00771763861830421883373-491421281.10.15180.00639.53530.42060.45410.01082366702391412413481-5065511.30.10650.0064.75890.27570.32480.009817401041778491813482-51232210.11260.00825.11740.37180.33140.010418431331839621845501-52126881.40.17930.007112.8260.52020.51620.00972647662667382683411-5323310.80.10880.00814.83530.33630.32380.008917891351791591808431-541041470.70.11190.00575.16170.26690.33260.00691831601846441851341-5519151.30.11230.01065.2090.50020.33550.011718391711854821865561-5643590.70.11340.00625.25130.2950.33390.00841855981861481857411-5718260.70.11870.00925.49350.38470.34510.01919361391900601911911-5830540.60.11280.00615.17050.28010.33060.00661844981848461841321-5929330.90.14670.03918.08182.17520.39770.0085230947222402432158394-6021610.30.11260.00595.11790.27140.32780.00711843951839451828341-6157620.90.1660.008611.2890.57580.48960.01152518872547482569501-6248620.80.10880.00634.99090.2840.33090.008417891061818481843402-63721740.40.14080.00578.15140.3370.41570.00792239702248372241361-641111880.60.15230.0069.59640.38780.45270.00852372682397372407381-651471061.40.10980.00564.93610.23760.32460.00721798931808411812351-66727110.15830.008510.1150.52380.46040.00982437912445482441431-67791040.80.15460.00789.60870.48190.44720.00932398862398462383421-68452213293.40.18020.01147.48380.45150.30090.0081265511021715416964025-69861030.80.15950.006710.2270.42860.46170.00912450712456392447401-70691510.50.11070.00485.12410.21750.33350.00651813781840361855321-71139891.60.15140.00659.87180.43070.46960.00982362732423402482433-7254610.90.110.00634.96420.29220.32480.007318001051813501813351-7354600.90.1960.009415.1150.73930.55590.01242794742822472850511-742351541.50.10910.00545.05210.25060.33380.00611785911828421857302-75403910.11310.00765.16060.34230.33080.008318501231846561842401-7633540.60.17440.010612.1340.7370.50340.011226111022615572628481-77792360.30.13250.00857.06250.49070.38280.008721311132119622089412-78727010.19140.014514.61.15460.54920.012227541252789752822512-7967860.80.11190.00895.21390.42430.3370.007718311441855691872371-80132841.60.1860.05411.8463.090.46680.0087270649825922442469385-8124360.70.18430.011613.9560.8730.54920.012126921042747592822513-82721130.60.14550.00738.72720.46580.43250.00912294862310492317411-83931200.80.11320.00595.48920.29030.35050.00761854941899451937362-8442740.60.11140.00625.16880.2960.33480.007718331011847491862371-85393910.11030.00674.81160.28380.31650.007518061051787501773371-86781210.60.11020.00484.93930.22150.32370.00641802801809381808311-871702390.70.10770.00424.83130.19330.32410.00641761721790341810312-8851680.80.11170.00585.29060.27720.34310.00791828941867451901382-8974651.10.18540.007913.9090.6150.54240.01212702692744422794502-9023524810.15950.00689.88440.42840.44760.00892450722424402385402-91871750.50.11090.00525.4410.26190.35450.00761815851891411956364-9241560.70.13810.00698.2010.41730.430.00992203872253462306443-93102961.10.10420.0054.76150.22450.33150.00761702891778401846374-9441610.70.1520.00769.38430.4630.44760.00922368862376452385411-95681010.70.14490.00728.75020.44820.43650.00932287852312472335421-9611200.50.21970.01417.5641.08850.58190.01629791032966602957651

表3 華北克拉通南緣葉縣地區(qū)董家組碎屑鋯石U-Pb同位素年齡

Table 3 Zircon U-Pb isotopic data of sedimentary rocks from the Dongjia Formation in the Yexian

測點號ThU(×10-6)Th/U同位素比值同位素年齡(Ma)207Pb/206Pb207Pb/235U206Pb/238U207Pb/206Pb207Pb/235U206Pb/238U比值2σ比值2σ比值2σ比值2σ比值2σ比值2σ不協(xié)和度(%)MLA-04-2 (長石石英砂巖)-1751340.60.11530.0055.92160.23860.36840.00651885781964352022313-2642410.30.11190.00445.61560.20550.360.00521831711918321982254-3541160.50.11620.00476.07180.2330.37540.00581898681986332055274-4441540.30.14840.00539.73650.3370.47110.00692327612410322488304-524600.11090.00615.30120.27830.34540.00718131011869451913333-649870.60.1360.00648.44850.37840.44750.00712176832280412384325-7757210.14560.00679.37020.42070.46360.00792295782375412456354-81111770.60.13950.00538.48030.31670.43810.00662220652284342342293-9571760.30.15180.00569.94660.3630.47220.00712366632430342493313-10611620.40.14110.0058.51470.30140.43480.0062240562287322327272-11272810.15730.008310.1070.50920.46560.00942427892445472464411-12951300.70.15540.00669.94740.42290.46180.00792406722430392447351-1369730.90.15390.00739.76240.4640.4580.00762391812413442431341-1414131.10.17360.011811.4020.70150.48230.01425921132557572537611-15631360.50.13680.0057.71540.29410.40710.0072187642198342202321-1650770.60.14820.0069.1920.3580.44950.00762325712357362393342-1761850.70.16030.006610.5170.42480.47480.00812459702481372505361-18911500.60.13940.00588.11370.34860.42070.00782220722244392263351-1914600.12070.00686.08360.34260.36610.007919661011988492011372-2064700.90.15720.006310.0650.42140.46320.00872428642441392454381-21971300.80.14610.00528.82330.31820.43680.00642302612320332336291-221801081.70.19980.006715.5510.53640.56370.00922824562850332882382-2348670.70.16480.00710.970.47590.48280.00912505712521402539401-2417300.60.18090.009112.080.67230.48240.01172661842611522538513-2550570.90.15870.007610.0410.4530.46330.01452443812439422454641-26801080.70.16210.006210.8040.43830.48170.00822477652506382534362-2770790.90.15810.00610.0450.38850.45930.00792435642439362436351-28565810.14090.00597.79640.33920.39980.00772239722208392168362-29541030.50.13970.00578.14780.32830.42120.00752224712248362266341-30121450.10.11990.00496.05150.24760.36370.00651955741983362000311-31791330.60.14250.0068.32080.36190.420.0082258722267392261361-3249830.60.12510.00526.56690.26820.37920.00672031732055362072311-33691060.70.1410.00538.14430.30190.41730.00672239652247342248311-3434241.40.15580.008710.3080.56630.48040.01032410942463512529453-35641000.60.15810.005610.3950.37580.47510.00742435602471342506322-36671410.50.13980.00577.86860.32060.40770.00742224702216372204341-3750610.80.11110.00575.31660.26640.34760.00721818941872431923343-381591481.10.16370.005811.1070.40640.49020.00822494612532342572352-39741480.50.11830.00455.99710.230.36590.00651931681975332010312-4047451.10.1610.006610.5370.43990.47220.009224661022483392493401-411612870.60.11580.00415.72430.19580.35650.00621892631935301965302-42881.10.11550.01195.40260.51510.34630.012418881811885821917602-43858510.15730.006510.3170.42350.47230.00932428712464382494412-44921020.90.20590.007417.0860.58780.59920.01252873592940333027503-452081351.50.11270.00425.01330.20810.32030.00741844671822351791362-461492520.60.15160.00519.7820.32890.46580.00822365582414312465363-47931410.70.15930.005810.58920.38620.48010.00832448622488342528362

續(xù)表3

Continued Table 3

測點號ThU(×10-6)Th/U同位素比值同位素年齡(Ma)207Pb/206Pb207Pb/235U206Pb/238U207Pb/206Pb207Pb/235U206Pb/238U比值2σ比值2σ比值2σ比值2σ比值2σ比值2σ不協(xié)和度(%)-4846640.70.16170.00710.83750.4970.4840.01052473732509432544462-4960830.70.19270.008214.58440.64090.54650.00972765702789422811401-50721450.50.15420.00579.70660.36010.45560.00822394632407342420361-511171061.10.1580.005710.25170.38080.46940.00812434612458342481361-5225320.80.19030.008313.82680.62230.52690.01122746732738432728471-5351820.60.15790.006210.2560.40130.47040.00752435662458362486332-54923220.30.11310.00475.30010.22530.33890.0051850751869361881241-55929310.13510.00647.58010.36530.40740.00912166832183432203421-56868410.16210.006710.71840.47630.47770.00862477702499412517371-5747630.70.14320.00658.4010.380.42470.00662266782275412282301-5850550.90.12890.00596.75910.31050.37940.00652084482080412074301-591122570.40.11940.00436.08950.21550.36860.00541947631989312023252-6060770.80.23630.008420.73960.73910.63410.01053095563127353166412-611941551.30.15730.007510.06050.45480.46230.00842428812440422450371-625790.10.12370.00836.13990.39880.36050.008520101201996571985401-632703210.80.16430.00610.76560.39390.47220.00732502612503342493321-641882370.80.15920.006510.03620.40350.45490.00772447692438372417341-651831731.10.11830.00615.46030.27130.33430.00651931931894431859312-661723610.50.13340.00617.2010.32340.38970.00652143802137402121301-6760650.90.14250.00938.06590.52650.41070.010822581122238592218491-681481960.80.15820.00699.90860.41820.45270.00772436742426392407341-692684830.60.12240.00466.09190.23090.35930.00571990681989331979271-703215290.60.16540.005710.9550.37970.47750.00652522572519322516291-712354440.50.14720.00558.75250.33270.42870.00642314632313352300291-7221421110.11710.00595.45660.26590.33790.0071922911894421876341-731251061.20.16490.008310.9450.52410.4820.01062506842518452536461-741931631.20.16020.007210.4880.46070.47350.00922458762479412499401-751723650.50.14810.00539.27320.33130.45210.00742324612365332404332-766321554.10.12010.00556.13150.26760.37060.00771958831995382032362-773895330.70.15470.005510.3760.36780.48380.00732398602469332544323-7814014510.11420.00625.4050.29450.3430.00771866981886471901371-792333990.60.13460.00548.15060.32990.43760.00912158712248372340415-802623490.80.15220.00559.87590.35350.46860.00742372612423332477323-811031300.80.11010.00555.14620.2530.33850.00671811901844421879322-822322540.90.11810.0055.91130.24170.36230.005919271081963361993282-832782171.30.2090.007716.7810.61030.58030.00922898592922352950371-842803750.80.15850.006510.480.42610.47860.00882440702478382521392-852380.10.1390.01277.4480.62040.39780.014222151592167752159651-861943910.50.15850.005810.410.38650.47510.0082440632472342506352-871032010.50.17510.007212.5040.51470.51790.01012607702643392690432-881321710.80.1680.007211.2740.51040.48530.00912538722546422550391-893172791.10.16340.007110.9380.50790.48430.00832491732518432546362-903084990.60.14950.00729.50390.49460.460.00922340812388482439413-913325550.60.14710.00689.4080.4790.46190.00872313802379472448393-921382220.60.1570.007110.3310.48940.47610.00942424762465442510412-9339241210.12070.00516.23730.25430.37490.00751966762010362053353-942552341.10.12020.00575.42450.27450.32640.00851959851889431821414-955006040.80.14650.00629.21530.38390.45360.00812305722360382411363

表4 華北克拉通南緣下湯地區(qū)辛集組碎屑鋯石U-Pb同位素年齡

Table 4 Zircon U-Pb isotopic data of sedimentary rocks from the Xinji Formation in the Xiatang

測點號ThU(×10-6)Th/U同位素比值同位素年齡(Ma)207Pb/206Pb207Pb/235U206Pb/238U207Pb/206Pb207Pb/235U206Pb/238U比值2σ比值2σ比值2σ比值2σ比值2σ比值2σ不協(xié)和度(%)LTXJ-1-1 (石英砂巖)-11201720.70.16260.007811.20.51020.49760.00932482812540422603403-242741410.11040.00464.77570.19760.31170.00571806761781351749282-311011310.11060.00725.01620.3110.32940.007618091171822521835371-47707291.10.1140.0045.63120.19360.35630.00521865641921301964253-51991831.10.10780.00584.92680.24950.33090.00611765981807431843302-642845210.1570.006610.40.4220.4780.00752424722471382519332-72173360.60.10790.00494.41880.23170.29540.00961765881716431669483-82525900.40.17860.006812.5790.50620.50760.01132640632649382647491-93328590.40.11160.00463.23320.12820.2090.003818287514653112232018-10781200.70.1590.00710.5710.48590.47880.00962456752486432522422-11811050.80.11120.00645.07950.27710.33060.00721820991833461841351-121967420.30.11410.00532.44880.16090.15540.00841866791257479314730-1347411510.40.17390.0076.72640.3390.27830.0125956620764515835027-1456790.70.11280.00745.13280.32240.32920.007418561191842531835361-152143110.70.16170.006210.9320.43790.48680.01092474642517372557472-16652040.30.17860.007113.3250.52330.53830.01092640662703372776463-171042790.40.16620.01272.44330.23430.10870.007825201291255696654662-181241380.90.16550.00811.1390.52480.48570.012513812535442552441-19771040.70.11160.00764.83230.35160.31580.011718281241791611769572-201541740.90.16070.007110.80.48560.48440.01112465752506422547482-21871110.80.10780.00634.84230.26980.32620.007817621071792471820382-221203440.40.13770.00528.33120.31620.43570.00672198672268342331303-23115881.30.16610.00811.4390.5460.49770.00952520812560452604412-241743370.50.12250.00485.9230.24770.34850.00741994701965361927352-251752090.80.17450.007112.5530.53630.51990.00932602682647402699392-2626410.60.17520.008112.8050.60310.530.01112609772665442741473-271251590.80.13760.00547.22620.27730.38020.00542198682140342077253-2841440.90.11220.00625.04890.29410.32530.006518361001828491815321-2948740.70.17460.007112.4550.51040.5170.00962603342639392687412-301061820.60.13650.00557.36460.32420.39010.0082183642157392123372-31461080.40.13420.00577.66740.32420.4140.00752153752193382233342-3224310.80.17320.008311.5430.53920.48380.00992589802568442544431-331341930.70.09820.00394.01990.15830.29570.00471591731638321670232-3421300.70.11770.00715.32730.30480.32950.007519221091873491836373-3529580.50.11330.0065.33140.26760.34290.00911854961874431901442-3642371.10.16870.008611.4670.57820.49040.01062544852562472572461-37781180.70.16440.007110.8850.49670.47620.01132501722513422511491-3832291.10.16610.008611.6290.58370.50540.01022520872575472637443-3945680.70.16020.006610.8270.44940.48690.00832457692508392557362-4034311.10.18390.008713.4180.6430.52680.01122689782710452728471-41542100.30.12790.0054.96390.20710.27990.006620696918133515913314-42911390.70.14620.00618.91460.40650.43970.01152302722329422349521-43561000.60.16460.007310.5170.47720.46080.00952503742481422443422-4427350.80.16410.007910.9260.49870.48290.01052498812517422540461-4538460.80.1730.007312.0780.50040.50420.00942587702610392632401-461019810.11310.00495.1980.22610.33130.00571850801852371845281-47531260.40.1420.00657.78520.3580.39480.00782254782206412145363-4826290.90.12410.00825.860.36310.34460.010420171171955541909503

續(xù)表4

Continued Table 4

測點號ThU(×10-6)Th/U同位素比值同位素年齡(Ma)207Pb/206Pb207Pb/235U206Pb/238U207Pb/206Pb207Pb/235U206Pb/238U比值2σ比值2σ比值2σ比值2σ比值2σ比值2σ不協(xié)和度(%)-4951401.30.17580.008912.0140.59810.49350.01062613842605472586461-50951280.70.26870.010123.7390.87030.63690.01013298593258363177403-51781360.60.12040.00495.90210.22680.35440.00581962731962331956271-5242391.10.11160.0065.1510.26550.33510.00691826981845441863341-5363461.40.16940.007911.5990.55610.49550.01162551782573452594501-5472531.40.1710.007811.4860.53370.48530.00922568712563432550401-5514121.20.14380.0128.34740.68250.42480.012822741432269742282581-5644530.80.1090.00564.990.26270.33170.00831783931818451847402-5738910.40.16270.006311.0450.40570.49170.00852484652527342578373-581401141.20.16850.006111.6910.41870.50140.00822542602580342620352-5952680.80.56570.022549.0062.62290.62340.022844335839725331249024-6039331.20.16840.008511.990.59640.51580.01152543842604472681493-6119260.70.11280.00765.39560.36640.34610.008918561231884581916432-621661940.90.1020.00414.26420.17450.30180.00511661751686341700251-6323590.40.15850.006610.070.4440.45890.00962439702441412435431-64781020.80.11220.00465.2030.20830.3360.00631836741853341867301-6511712310.16660.006111.5280.43450.5000.00852524622567352614362-6639730.50.14570.00769.01010.53630.44410.00852296902339542369382-6758930.60.14120.00628.25410.37030.42310.00882243762259412275401-68132592.20.12290.00596.30590.2870.37250.0071999792019402041332-6933770.40.16360.006111.2430.42280.49730.00862494622544352602373-70781800.40.13790.00497.94750.29260.41660.00732211612225332245331-7154620.90.13690.0067.78860.35970.41130.00892188762207422221411-7250940.50.14770.00629.4560.39620.46320.00822320712383392454363-7387541.60.15990.007411.1390.52140.50390.01052455782535442630454-74431070.40.13520.00527.94070.31130.42400.00722166672224352279333-7534530.70.1090.00595.00270.27310.33140.00651783991820461845312-7638530.70.18890.007314.5020.57810.55310.01022733632783382838422-77484810.11110.00585.10990.26620.33240.0071817941838441850341-7874810.90.1630.007211.2820.48680.49870.00922487752547402608393-7976541.40.16520.008311.520.55030.50380.01052510792566452630453-8063920.70.18950.007814.4880.58840.55090.00982738682782392829412-81831440.60.07820.0042.22860.1090.2060.00371154981190341207202-8249930.50.13480.00537.98610.31690.42670.00722162682229362291323-8335440.80.11450.00615.3880.2890.34010.0071873961883461887341-84591190.50.17140.008211.8520.55310.49920.0082572752593442610341-852233290.70.17130.007211.9230.49390.50190.00882572702598392622381-863553930.90.13240.00516.91830.26240.37660.0062131682101342060282-871391051.30.1020.00714.15170.27190.29620.007116611281665541672361-881712050.80.11130.00535.03780.23330.32720.0071821871826391825341-891101570.70.18740.007913.9090.58810.53480.0112719692743402762461-903313790.90.17010.00711.5530.48060.48870.00992558692569392565431-912366080.40.15440.00648.51410.35050.39680.00812395712287372154376-921582260.70.11280.00515.36780.2390.34320.00731856821880381902352-931212940.40.11480.00475.6110.23150.35150.00661877691918361942322-942655450.50.15010.00529.40640.31780.45090.00822347592378312399371-95118951.20.11360.00735.41160.32580.34540.008218581151887521913392-9694913890.70.13680.0063.84170.18160.20190.006721877616023811863630-971792010.90.10910.00555.09330.24560.33670.00671784921835411871322-981952630.70.15660.006110.1390.38490.46630.00772420662448352467341

圖8 華北南緣中-新元古界碎屑鋯石年齡組成對比Fig.8 Comparison of age distribution patterns of detrital zircon from Meso- to Neoproterozoic sediments in the southern margin of North China Craton

下湯地區(qū)董家組長石石英砂巖樣品(17DJ-02)中碎屑鋯石多為半自形或圓形，粒徑50～200μm(圖6)，該樣品鋯石具有明顯環(huán)帶結(jié)構(gòu)，應(yīng)為巖漿成因，少量鋯石具變質(zhì)環(huán)帶，對其隨機選取96個點位。其中4顆鋯石207Pb/206Pb年齡誤差較大，分別為2965±1046Ma(-38)、2875±1033Ma(-43)、2209±472Ma(-59)、2707±498Ma(-80)(表2、圖7c)，盡管編號為-59和-80的206Pb/238-207Pb/206Pb年齡的諧和度大于90%，但由于207Pb/206Pb年齡誤差較大，也未在年齡頻率分布圖中使用。因此，董家組樣品(17DJ-02)92顆碎屑鋯石主峰值年齡為1800Ma，其次為2250Ma、2400Ma、2650Ma(圖7d)。

董家組長石石英砂巖樣品(MLA-04-2)中碎屑鋯石多為半自形或圓形，粒徑100～300μm(圖6)，鋯石具明顯環(huán)帶構(gòu)造，部分鋯石具一定磨圓，對其隨機選取95個點位。分析結(jié)果顯示碎屑鋯石U-Pb年齡諧和度均大于90%(表3)，均落在年齡演化曲線上(圖7e)，峰值年齡主要為2450Ma，次要峰值為1900Ma、2250Ma、2900Ma和3100Ma(圖7f)。

辛集組石英砂巖樣品(LTXJ-1-1)中碎屑鋯石多為自形、半自形或圓形，粒徑50～150μm(圖6)，鋯石具明顯環(huán)帶結(jié)構(gòu)，部分鋯石磨圓較好，部分具溶蝕邊，對其隨機選取98個點位。結(jié)果顯示其中有7顆鋯石協(xié)和度比較低，年齡分別為1223±24Ma(-09)、931±47Ma(-12)、1582±50Ma(-13)、665±46Ma(-17)、1591±33Ma(-41)、4433±58Ma(-59)、1186±36Ma(-96)(表4、圖7g)，未在頻率分布圖中使用(圖7h)。91顆碎屑鋯石主峰年齡為1850Ma和2500Ma，次要峰值為1200 Ma、2200 Ma、2700 Ma和3300 Ma(圖7h)。

圖9 華北克拉通中-新元古界碎屑鋯石年齡對比圖(a)華北克拉通(Zhou et al.，2008；胡波等，2009；Gao et al.，2011；Wan et al.，2011；Ying et al.，2011；Zhu et al.，2011；胡國輝等，2012；Hu et al.，2012，2014a，b；Yang et al.，2012；李猛等，2013；Lan et al.，2014；Liu et al.，2014，2017a, 2019；馬銘株等，2014；Zhong et al.，2015；Zhang et al.，2016a；Dong et al.，2018；王振濤等，2017；賈超，2018；Li et al.，2019；Meng et al.，2018；Zuo et al.，2019)；(b)徐淮盆地(Zhou et al.，2008；Gao et al.，2011；Hu et al.，2012；Yang et al.，2012；He et al.，2017)；(c)渣爾泰-白云鄂博-化德盆地(胡波等，2009；Hu et al.，2014a；馬銘株等，2014；Liu et al.，2014，2019；Zhong et al.，2015；Li et al.，2019)；(d)燕遼盆地(Gao et al.，2011；Wan et al.，2011；Ying et al.，2011；王振濤等，2017)；(e)熊耳盆地(Zhu et al.，2011；胡國輝等，2012；李猛等，2013；Hu et al.，2014b；Lan et al.，2014；Zhang et al.，2016a；Liu et al.，2019；賈超，2018；Meng et al.，2018；Zuo et al.，2019)Fig.9 Comparison of age distribution patterns of detrital zircon from Meso- to Neoproterozoic sediments in the North China Craton(a)the North China Craton(Zhou et al.，2008；Hu et al.，2009，2012，2014a，b；Gao et al.，2011；Wan et al.，2011；Ying et al.，2011；Zhu et al.，2011；Yang et al.，2012；Li et al.，2013；Lan et al.，2014；Liu et al.，2014，2017a，2019；Ma et al.，2014；Zhong et al.，2015；Zhang et al.，2016a；Dong et al.，2018；Jia，2018；Li et al.，2019；Meng et al.，2018；Zuo et al.，2019)；(b)the Xuhuai Basin(Zhou et al.，2008；Gao et al.，2011；Hu et al.，2012；Yang et al.，2012；He et al.，2017)；(c)the Zhaertai-Bayan Obo-Huade Basin(Hu et al.，2009，2014a；Liu et al.，2014，2017a；Ma et al.，2014； Zhong et al.，2015；Li et al.，2019)；(d)the Yanliao Basin(Gao et al.，2011；Wan et al.，2011；Ying et al.，2011；Wang et al.，2017)；(e)the Xiong’er Basin(Zhu et al.，2011；Hu et al.，2012，2014b；Li et al.，2013；Lan et al.，2014；Zhang et al.，2016a；Liu et al.，2019；Dong et al.，2017；Jia，2018；Meng et al.，2018；Zuo et al.，2019)

4 討論

4.1 碎屑鋯石物源分析

華北克拉通在若干太古代陸核的花崗質(zhì)片麻巖和變質(zhì)沉積砂巖中發(fā)現(xiàn)3800～3000Ma的古老鋯石(Liuetal.，1992，2007；萬渝生等，2001，2009；翟明國，2006；Wuetal.，2008)。華北克拉通整體存在～2500Ma的構(gòu)造-巖漿事件的證據(jù)，2350～1950Ma發(fā)育有多個古元古代構(gòu)造活動帶，如晉-豫活動帶等(Zhaietal.，2003；翟明國和彭澎，2007；翟明國，2011)，在華北南緣發(fā)育有2350～1960Ma的嵩山群輕微變質(zhì)碎屑巖夾碳酸鹽巖(Liuetal.，2012)。小秦嶺地區(qū)和熊耳山地區(qū)太華群碎屑鋯石U-Pb年齡主要為2300～2000Ma(Huangetal.，2012；Yuetal.，2013；第五春榮等，2018)。1900～1850Ma期間，華北克拉通變質(zhì)巖大部分經(jīng)歷混合巖化作用或鉀化交代作用(Zhaietal.，2003，2015；Zhaoetal.，2010)。華北克拉通在1850～1500Ma期間，經(jīng)歷了伸展作用(Luetal.，2002，2008；Zhaietal.，2003；Zhaoetal.，2003；Zhangetal.，2009；翟明國，2013)，發(fā)育了非造山巖漿巖以及與裂谷有關(guān)的巖漿/火山活動和退變質(zhì)作用(趙太平等，2001；Zhaoetal.，2004，2009)，其中包括熊耳群和基性巖墻群(趙太平等，2002；Zhaoetal.，2004，2009；Pengetal.，2007，2008；翟明國，2010)以及豫西南和陜東南部近年來發(fā)現(xiàn)的中元古代花崗巖帶(Wangetal.，2003；鄧小芹等，2015；Dengetal.，2016)。同時黃連垛組和董家組與下伏地層兵馬溝組、云夢山組、白草坪組、三教堂組碎屑鋯石年齡峰值分布類似(圖8)，因此推斷華北克拉通為黃連垛組和董家組的物源區(qū)。

早古生界辛集組年齡分布與黃連垛組和董家組存在區(qū)別，與何家寨組碎屑鋯石相比存在少量中元古代晚期到新元古代早期碎屑鋯石(圖8)，同時近年來在華北南緣盧氏-欒川地區(qū)中元古代晚期地層以及在華北克拉通新元古-早古生代地層中也報道了大量同時期的碎屑鋯石(初航等，2011；Huetal.，2012；Yangetal.，2012；胡波等，2013，2015；張文龍等，2016；Liuetal.，2019；Zuoetal.，2019)(圖9)，辛集組發(fā)育的少量該時期碎屑鋯石可能源于沉積物的再循環(huán)。

4.2 澠池-確山地區(qū)中-新元古代沉積演化分析

華北南緣中元古代早期約1800～1750Ma發(fā)育熊耳火山-沉積作用之后(趙太平等，2002；崔敏利等，2010；Cuietal.，2011；翟明國等，2014)，局部地區(qū)快速沉積兵馬溝組(小溝背組)沖積扇-(扇)三角洲-濱海沉積(鄭德順等，2016b；岳亮和劉自亮，2017；Mengetal.，2018；Yueetal.，2018)，兵馬溝組沉積結(jié)束后，澠池-確山地區(qū)發(fā)生短暫地殼抬升，形成兵馬溝組與上覆汝陽群的區(qū)域平行不整合。汝陽群總體上由一套河流-濱海-潮坪相沉積組成，其頂部的北大尖組和洛峪群的崔莊組共同構(gòu)成了潮間帶到外陸棚帶沉積，洛峪群的三教堂組和洛峪口組組成了濱海-潮坪沉積。通過洛峪群頂部洛峪口組斑脫巖夾層獲得U-Pb諧和年齡約為1611Ma和1634Ma(蘇文博等，2012；李承東等，2017)，其應(yīng)劃為中元古界長城系。因此，中元古代早期(1750～1600Ma)華北南緣澠池-確山地區(qū)發(fā)育的汝陽群-洛峪群可能為一套陸相過渡到海相的被動大陸邊緣沉積。

之后，華北克拉通南緣發(fā)生區(qū)域構(gòu)造抬升，黃連垛組沉積初期發(fā)育了河口灣沉積環(huán)境。伴隨海侵擴大，在下湯地區(qū)沉積了潮上帶長石石英砂巖與泥質(zhì)粉砂巖，而葉縣地區(qū)發(fā)育了潮間帶泥晶白云巖。晚期下湯和葉縣地區(qū)發(fā)育潮下帶泥晶白云巖與含硅質(zhì)條帶白云巖。董家組與下伏黃連垛組為平行不整合接觸，董家組沉積初期為陸源碎屑物質(zhì)供給充分的濱海相，在下湯和葉縣地區(qū)沉積底部細礫巖及長石石英砂巖。隨后，下湯地區(qū)沉積濱海相長石石英砂巖，在葉縣地區(qū)沉積潮坪相具交錯層理長石石英砂巖與泥質(zhì)粉砂巖。最后在下湯和葉縣地區(qū)沉積局限臺地鈣質(zhì)泥巖。盡管古流向顯示黃連垛組和董家組存在多個方向的物源區(qū)(張玲華，1994；崔新省等，1996；董文明等，1999)，而碎屑鋯石顯示其物源均為華北克拉通，沒有明顯的變化，符合該套地層發(fā)育在局限盆地(海盆)的沉積環(huán)境。

4.3 對華北南緣中-新元古代沉積演化的啟示

黃連垛組在豫西陜縣、山西永濟地區(qū)仍有分布，依據(jù)不同地區(qū)該套地層的巖性組合、疊層石、碳同位素負偏等特征以及區(qū)域內(nèi)存在的不整合接觸關(guān)系認為黃連垛組可能與官道口群龍家園組或巡檢司組為同期沉積物(武鐵山，1982，2002；Xiaoetal.，1997；高維等，2011；徐文超等，2015；蘇文博，2016)。而董家組一般認為沉積于新元古代早期(武鐵山，1982，2002；Guanetal.，1986；Yin and Guan, 1999；胡國輝等，2013；蘇文博，2016)，碎屑鋯石顯示兩套地層物源區(qū)沒有明顯的變化，均為華北克拉通。黃連垛組和董家組發(fā)育在局限盆地(海盆)的沉積環(huán)境一致，分布范圍大體一致。通過區(qū)域地層對比，中元古代早期華北南緣沉積首先發(fā)育在嵩箕地區(qū)和澠池-確山地區(qū)，主要為五佛山群中下部和汝陽群-洛峪群濱淺海-潮坪沉積。之后沉積中心向盧氏-欒川地區(qū)遷移，沉積了中元古界官道口群和新元古界欒川群，而董家組和黃連垛組可能為該段時期盆地的邊緣相沉積。

新元古界欒川群以及羅圈組和東坡組顯示其沉積和構(gòu)造環(huán)境發(fā)生了明顯的變化(Zuoetal.，2019)。欒川群中發(fā)育的新元古代巖漿巖地化特征顯示其處于伸展背景(孫樞等，1981，1982；蔣干清，1993；石銓曾等，1996)或碰撞后的伸展(閻國翰等，2010)。此外，華北南緣白術(shù)溝組和何家寨組中發(fā)現(xiàn)了大量中元古代末期到新元古代早期碎屑鋯石，峰值年齡集中在1800～1000Ma(賈超，2018；Liuetal.，2019)。徐淮和渣爾泰-白云鄂博-化德地區(qū)中-新元古代地層中也發(fā)現(xiàn)了大量中元古代到新元古代的碎屑鋯石(圖9b, c)。盡管華北克拉通發(fā)育中元古代末期到新元古代早期(1300～900Ma)的鎂鐵質(zhì)巖漿巖(Zhangetal.，2009，2016b，2017，2018；Yangetal.，2011；Pengetal.，2011; Peng，2015; Wangetal.，2016；Cope，2017)，但缺乏該時期的長英質(zhì)巖漿活動。裂解模式認為，華北在中元古代(～1300Ma)和新元古代(～900Ma)，分別與Australian和West Congo-S?o Francisco裂開(Pengetal.，2011；Zhangetal.，2017，2018；彭澎等，2018)。此外，也有認為華北與Laurentia、Australia、Baltica、Siberia共同參與了Grenville-Sveconorwegian-Sunsas造山帶作用(喬秀夫等，2007；曲永強等，2010，2012；蘇文博等，2010；潘建國等，2013；Liuetal.，2019)，或者華北南緣中元古代末期到新元古代可能發(fā)生增生或者拼貼事件(Wangetal.，2011；Shietal.，2013；Dongetal.，2014，2015；Dong and Santosh，2016；Liuetal.，2019)。無論哪一種觀點都認為，沉積物源的變化和區(qū)域抬升可能與該期構(gòu)造事件有關(guān)。

5 結(jié)論

華北南緣中元古代早期發(fā)育熊耳期火山-沉積作用之后，局部地區(qū)快速沉積兵馬溝組，隨后發(fā)生大規(guī)模海侵，發(fā)育了一套河流-濱海-潮坪相沉積(汝陽群)和淺海-濱海-潮坪相沉積(洛峪群)。中元古代末期到新元古代早期發(fā)生了沉積盆地中心的轉(zhuǎn)移，洛峪群上覆黃連垛組和董家組為局限海灣體系下濱淺海-潮坪沉積，可能構(gòu)成了該時期盆地的邊緣相沉積。黃連垛組和董家組碎屑鋯石年齡主要峰值為1800Ma、2250Ma、2350Ma、2650Ma，兩者物源均為華北克拉通。但早古生界辛集組碎屑鋯石除1850Ma、2500Ma、2200Ma、2700Ma的主要峰值年齡外，還包括1200Ma的峰值。結(jié)合本次澠池-確山地區(qū)黃連垛組、董家組、辛集組以及嵩箕和盧氏-欒川地區(qū)的中-新元古代地層碎屑鋯石年齡分布變化，指示了華北南緣在中元古代晚期到新元古代沉積物源變化以及沉積間斷可能與華北克拉通該時期的構(gòu)造演化有關(guān)。

致謝 本論文在野外工作中得到翟明國院士、趙太平研究員、蘇文博教授和彭澎研究員的有益指導；在成文過程得到團隊成員張碧云、孫江濤、祁帥帥、谷華昱以及楊東亮等研究生的幫助；審稿人王世炎教授級高工、柳永清研究員、胡國輝博士提出了建設(shè)性的修改意見。在此對他們一并表示衷心感謝！