摘 要 早白堊世為中生代鄂爾多斯盆地演化的最晚階段,構(gòu)造環(huán)境與沉積物源體系發(fā)生了明顯的改變,對盆地演化及多能源礦藏(產(chǎn))賦存具有重要影響。以鄂爾多斯盆地南部下白堊統(tǒng)宜君組為主要研究對象,利用碎屑鋯石定年方法,結(jié)合周鄰地質(zhì)體鋯石U-Pb年齡譜峰及構(gòu)造演化特征,示蹤了宜君組沉積物質(zhì)來源并探討了其地質(zhì)意義。結(jié)果表明,宜君組砂巖碎屑鋯石U-Pb年齡主要集中分布于早中生代(195~250 Ma)和早古生代(400~500 Ma)時期,峰值年齡分別為218 Ma和450 Ma,與今北秦嶺地區(qū)廣泛出露巖體的時代具明顯的時空一致性,而元古宙—太古宙鋯石年齡不但數(shù)量少且較為分散。經(jīng)區(qū)域?qū)Ρ?,指出宜君組物源主要來自秦嶺造山帶,秦嶺造山帶早中生代巖體侵位后,最晚在早白堊世初已抬升剝露至地表,并開始向盆地南部提供大量物源。本研究在一定程度上間接約束了秦嶺晚中生代隆升剝露及渭北隆起發(fā)育的時限,對明確盆地南部中生代砂巖型鈾礦鈾源及成礦分布具有一定的指示意義。
關(guān)鍵詞 鄂爾多斯盆地南部;下白堊統(tǒng)宜君組;碎屑鋯石U-Pb定年;物源分析;地質(zhì)意義
第一作者簡介 李姣莉,女,1996年出生,碩士研究生,碎屑年代學(xué),E-mail: 874345188@qq.com
通信作者 王建強(qiáng),男,副教授,E-mail: wjq@nwu.edu.cn
中圖分類號 P618.13 文獻(xiàn)標(biāo)志碼 A
0 引言
鄂爾多斯盆地為我國最重要的多能源盆地之一,其南部與秦嶺造山帶和祁連造山相鄰,中古生代經(jīng)歷了多期復(fù)雜的沉積—構(gòu)造演化過程,新生代早期渭河盆地的發(fā)育以及中晚期以來受青藏高原演化和向東北擠出的明顯影響,構(gòu)造活動頻繁,后期改造強(qiáng)烈、地質(zhì)特征復(fù)雜多樣[1?2]。近年來,隨著鄂爾多斯盆地油氣、煤、砂巖型鈾礦等能源礦產(chǎn)勘探開發(fā)的不斷深入,盆地南部中生代以來的構(gòu)造屬性、物源體系及盆山關(guān)系等諸多問題,進(jìn)一步引起了許多地質(zhì)工作者關(guān)注和研究[3?4],但相對于富含石油、煤炭資源的中上三疊統(tǒng)延長組和侏羅系,下白堊統(tǒng)研究程度相對薄弱[4?8]。前人研究認(rèn)為,鄂爾多斯盆地南部下白堊統(tǒng)早期沉積物源主要來自秦嶺造山帶[2,5?6],但缺乏年代學(xué)的有效約束;同時,晚白堊世以來,鄂爾多斯盆地經(jīng)歷了整體抬升和差異剝蝕,加之渭河盆地的斷陷,盆地南部剝蝕改造強(qiáng)烈,下白堊統(tǒng)原有沉積格局發(fā)生改變,與相鄰造山帶的山盆關(guān)系不明[2,5]。此外,盆地南部下白堊統(tǒng)砂巖發(fā)育且具明顯放射性異常,為砂巖型鈾礦潛在的重要勘探層系[7?9],目前已發(fā)現(xiàn)了國家灣鈾礦及鎮(zhèn)原、崇信—彬縣等多個鈾異常礦化點(diǎn)[3,10?12],但因早白堊世物源體系及盆山關(guān)系研究的薄弱,在一定程度上制約了該區(qū)砂巖型鈾礦的進(jìn)一步勘查。宜君組為鄂爾多斯盆地下白堊統(tǒng)發(fā)育的第一套地層,主要分布于現(xiàn)今盆地西南部,以河流、沖積扇相的砂礫巖沉積為主,代表了快速堆積的山麓相沉積[2],因而,是開展源匯示蹤和盆山構(gòu)造演化的理想對象。
巖石中的鋯石因其強(qiáng)的抗物理和化學(xué)風(fēng)化能力,在沉積搬運(yùn)過程中能夠較好地保存下來,加之其穩(wěn)定的U-Pb同位素體系[13],使得鋯石U-Pb年齡譜特征已成為示蹤源區(qū)和開展盆地古構(gòu)造—古地理重建的重要紐帶和手段,當(dāng)前在相關(guān)研究中應(yīng)用廣泛[14?20]。本文主要針對盆地南部早白堊世沉積物質(zhì)來源問題,選擇渭北隆起麟游、彬縣地區(qū)典型下白堊統(tǒng)剖面,在野外考察的基礎(chǔ)上,開展了碎屑鋯石定年分析,并結(jié)合前人相關(guān)研究成果[2?6,21?27],厘定了早白堊世宜君組物源特征,初步探討了宜君期鄂爾多斯盆地南部的盆山關(guān)系,相關(guān)成果有望在蝕源區(qū)成礦物質(zhì)來源方面為盆地南部下白堊統(tǒng)砂巖型鈾礦勘查提供一定的依據(jù)。
1 地質(zhì)概況
鄂爾多斯盆地位于華北板塊西部,為中生界疊加在早、晚古生界之上的多重疊合盆地,除古生界志留系、泥盆系、下中石炭統(tǒng)及中生界上白堊統(tǒng)缺失外,地層發(fā)育相對齊全,具有多構(gòu)造體系、多旋回演化及多類型沉積的特點(diǎn)[1]。今盆地周緣被新生代斷陷盆地與諸多山系所分割,為一遭受多期改造的殘留盆地,其面積約25×104 km2,是我國重要的多能源勘探和生產(chǎn)基地[28]。盆地可進(jìn)一步劃分為六個一級構(gòu)造單元,其中,南部渭北隆起隔渭河新生代斷陷盆地與北祁連、秦嶺造山帶相鄰(圖1);由南至北,依次出露元古界、古生界,中生界三疊系、侏羅系及下白堊統(tǒng)志丹群地層,總體呈北東— 北東東向展布(圖2)。
下白堊統(tǒng)志丹群為中生代鄂爾多斯盆地沉積的最晚地層,最大殘留地層厚度1 400余米,由老到新依次沉積了宜君組、洛河組、環(huán)河—華池組、羅漢洞組及涇川組(圖2);其巖石類型和沉積相多樣,不僅有河湖相砂、泥巖,也有風(fēng)成及沖積扇相砂、礫巖等[21?25,29?30],主體經(jīng)歷了宜君組—環(huán)河華池組、羅漢洞組—涇川組2個由粗粒到細(xì)粒的沉積旋回[6]。盆地南部下白堊統(tǒng)各時代地層由東向西、由南向北出露依次變新(圖2)。早白堊世以來也是盆地演化—改造的關(guān)鍵時期,早白堊世盆地發(fā)生了最顯著的構(gòu)造熱事件[3],對下伏地層油氣的生烴、成藏均有明顯影響;早白堊世末期以來,盆地遭受了邊部強(qiáng)內(nèi)部弱的抬升剝蝕和改造[26,31],深刻地影響著盆地能源礦產(chǎn)的調(diào)整與最終定位,盆地南部、東部在早白堊世末期以來地層遭受剝蝕厚度可達(dá)2 000 m,下白堊統(tǒng)原始沉積范圍遠(yuǎn)大于今殘留范圍,向南可達(dá)渭河盆地,甚或秦嶺造山帶北麓[26]。
宜君組為早白堊世盆地最早沉積的地層,盆地南部主要沿宜君、旬邑、彬縣、麟游、隴縣一線出露(圖2),地層厚度在縱、橫向上變化明顯,介于0~203 m,與下伏不同時代地層呈角度不整合或平行不整合接觸(圖3,剖面位置見圖2),總體向盆地內(nèi)部呈楔形變薄尖滅或與上覆洛河組漸變。宜君組總體為一套粗碎屑沉積,呈灰紫、紫紅、橘紅色,礫石支撐,鈣質(zhì)、砂質(zhì)膠結(jié),砂巖透鏡體發(fā)育,為干旱—半干旱環(huán)境,局部時段出現(xiàn)溫暖、潮濕的氣候[32],具多物源和快速堆積的特點(diǎn)[26],屬盆地邊部山麓相沉積,是探索盆地南部源匯特征及盆山演化的理想對象。
2 樣品采集與分析方法
2.1 野外露頭及樣品信息
為分析和探討鄂爾多斯盆地南部早白堊世早期物源特點(diǎn),本文重點(diǎn)對宜君組出露較好的麟游老鐵鉤和彬縣虎家灣兩地剖面開展了研究和樣品采集(圖1~3)。
其中,麟游老鐵溝剖面位于麟游縣城西北約20 km處,該剖面宜君組厚約60 m,為棕紅—暗棕色塊狀礫巖,夾砂巖透鏡體(圖4a,b),礫石成分以花崗巖為主,平均含量高達(dá)65%,其次為片麻巖(15%)、片巖(10%)、石英巖(3%)等,礫石礫徑普遍在5~15 cm,最大可達(dá)50 cm,多見扁平度較高的礫石呈疊瓦狀排列,分選磨圓中等;下伏地層為侏羅系直羅組,呈淺灰紅色厚層狀含細(xì)礫石英砂巖夾少量紫紅色泥巖,兩者呈微角度不整合接觸(圖4c);本次在該剖面下部和中部各采集了1 件透鏡體砂巖樣品,分別為LY-28(N 34°43'26.7\",E 107°42'52.7\",H 1 092 m),LY-06(N 34°44'56.1\",E 107°42'32.9\",H 1 203 m)。彬縣虎家灣剖面,位于彬縣縣城北側(cè)10 km處,其宜君組為厚約30 m的紫紅色礫巖夾中厚層透鏡體砂巖(圖4d),礫石以石英巖為主,平均含量可達(dá)50%,花崗巖(34%)、片巖(12%)次之,礫石礫徑一般介于5~10 cm,最大可達(dá)30 cm,局部可見礫石呈疊瓦狀排列,偶見交錯層理。礫徑較麟游地區(qū)有所變小,磨圓度、分選性也相應(yīng)變好。下伏地層為安定組,呈紫紅色砂質(zhì)泥巖夾中厚層狀砂巖、砂礫巖,兩者之間亦呈微角度不整合接觸(圖4e)。在該剖面下部采集了1件透鏡體砂巖樣品,樣號為BX-13(N 35°02'57.2\",E 108°06'14.2\",H 826 m)。
2.2 分析方法
本文采用激光剝蝕電感耦合等離子體質(zhì)譜法(LA-ICP-MS)開展碎屑鋯石U-Pb定年。鋯石委托廊坊地調(diào)院分選,鋯石制靶、陰極發(fā)光(CL)圖像采集以及U-Pb定年測試則均在西北大學(xué)大陸動力學(xué)國家重點(diǎn)實(shí)驗(yàn)室完成。首先將分選的鋯石顆粒隨機(jī)挑選粘至有雙面膠的載玻片上,并用環(huán)氧樹脂灌注,待固結(jié)后拋磨制成鋯石樣靶;然后對制好的樣靶進(jìn)行反射光、透射光及陰極發(fā)光(CL)顯微圖像采集,揭示鋯石形態(tài)及內(nèi)部結(jié)構(gòu),以便更好地遴選測點(diǎn)位置;最后利用激光剝蝕電感耦合等離子體質(zhì)譜儀(GeoLas Pro+Agilent 7500a)進(jìn)行測定,激光束斑直徑為30 μm。測試過程采用國際標(biāo)準(zhǔn)鋯石91500作為外標(biāo)標(biāo)準(zhǔn)物質(zhì),元素含量采用NIST610作為外標(biāo),29Si作內(nèi)標(biāo),詳細(xì)實(shí)驗(yàn)步驟和方法參見文獻(xiàn)[33];數(shù)據(jù)處理采用Glitter4.0軟件,年齡計算及圖制作利用Isoplot 4.15程序。研究主要選擇諧和度介于90%~110%的碎屑鋯石年齡,其中小于1.0 Ga的采用206Pb/238U年齡,大于1.0 Ga的采用207Pb/206Pb年齡。
3 實(shí)驗(yàn)結(jié)果
從形態(tài)及顏色看,兩地區(qū)碎屑鋯石總體類似。大多數(shù)鋯石呈淺棕色及棕紅色,部分為無色透明或淺黃色;鋯石粒徑普遍在60~150 μm,主體呈次圓狀,可見凹坑、溝槽及斷口磨蝕痕跡,少量鋯石呈短柱狀,表面粗糙,顯示鋯石可能經(jīng)歷了一定距離的搬運(yùn)。從鋯石CL圖像可以看到大多數(shù)鋯石有核—幔結(jié)構(gòu),發(fā)育清晰規(guī)則的震蕩環(huán)帶,顯示出巖漿成因鋯石的特征;少量鋯石結(jié)構(gòu)表現(xiàn)出均勻或補(bǔ)丁狀,且無震蕩環(huán)帶,有的邊部還出現(xiàn)亮白色或暗色增生邊,可能為變質(zhì)成因鋯石(圖5)。
本次測試的3件宜君組砂巖樣品共獲得249顆鋯石諧和年齡數(shù)據(jù),其中麟游地區(qū)的LY-28樣品共獲得95顆鋯石年齡,LY-06樣品獲得67顆鋯石年齡;彬縣地區(qū)BX-13樣品獲得87顆鋯石年齡。相關(guān)樣品的鋯石U-Pb諧和圖、年齡直方圖如圖6。
(1) 麟游地區(qū)LY-28樣品的碎屑鋯石U-Pb年齡分布范圍介于193.8~2 657.2 Ma(n=95),主要集中于193.8~234.2 Ma(16顆)和386.7~507.1 Ma(68顆)2個年齡段,占到總量的88.4%,其峰值年齡分別為213 Ma 和455 Ma;其余鋯石年齡分布于947.6~2 657.2 Ma(11顆),數(shù)據(jù)點(diǎn)分散分布。
(2) 麟游地區(qū)LY-06樣品的碎屑鋯石U-Pb年齡分布范圍介于203.3~2 635 Ma(n=67),主要集中于203.3~238.9 Ma(25顆)和403.3~481.1 Ma(16顆)2個年齡段,占到總量的61%,峰值分別為220 Ma 和455 Ma,與LY-28 峰值年齡類似;其余年齡分布于597.4~2 635 Ma(25顆),亦未形成明顯峰值。麟游地區(qū)兩件樣品的鋯石Th/U比值介于0.07~2.01,其中大于0.4 的占90%,表明樣品鋯石普遍具巖漿成因特點(diǎn)。
(3) 彬縣地區(qū)BX-13樣品的碎屑鋯石U-Pb年齡分布范圍介于195~2 718 Ma(n=87),明顯集中于195.6~263.6 Ma(57顆)和421.8~448 Ma(10顆)2個年齡段,占到總量的77%,其峰值年齡分別為218 Ma和447 Ma;其余鋯石則較零散地分布于914.5~2 718 Ma(20顆)年齡段,數(shù)據(jù)點(diǎn)分散分布。該樣品鋯石Th/U比值介于0.06~2.06,比值大于0.4的占94%,表明樣品鋯石普遍具巖漿成因特點(diǎn)。
綜合分析上述3件宜君組砂巖樣品的碎屑鋯石U-Pb年齡直方圖,可以看出總體上呈類似的譜峰特點(diǎn),鋯石年齡均主要集中在早中生代(195~250 Ma)和早古生代(400~500 Ma)時期,且具有類似的峰值年齡,分別為218 Ma和450 Ma,而元古宙—太古宙鋯石年齡不但少且數(shù)據(jù)點(diǎn)分散分布。
4 討論
4.1 潛在物源區(qū)分析
有關(guān)鄂爾多斯盆地南部早白堊世物源問題,前人曾不同程度開展了研究。如對宜君組,王建強(qiáng)等[26]采用礫巖礫組方法,分析了宜君組礫性、礫度、古水流(圖2)等,指出宜君組沉積物源特征在橫向上存在差異性,認(rèn)為麟游—彬縣地區(qū)物質(zhì)主要來自北秦嶺造山帶,隴縣—千陽地區(qū)主要來自隴山地區(qū),同時指出渭北隆起南部及渭河地區(qū)早白堊世時期仍在接受沉積,其原始沉積南界至少在今渭河地區(qū)甚或達(dá)秦嶺北麓;禹江[6]同樣采用礫組分析方法,進(jìn)一步對鄂爾多斯盆地西南部宜君組沉積環(huán)境及物源特征開展了研究,指出宜君組為干旱—半干旱環(huán)境下山麓洪積扇相沉積,為快速堆積的產(chǎn)物,也認(rèn)為麟游地區(qū)主要來自北秦嶺造山帶,而彬縣地區(qū)除來自北秦嶺造山帶外,極少量地混入了來自其下伏的碳酸鹽巖地層。程先鈺等[7]對盆地西南部鎮(zhèn)原地區(qū)洛河組下段(即宜君組上覆地層)含鈾砂巖開展碎屑鋯石U-Pb定年,獲得了166~370 Ma、388~472 Ma、1 744~2 150 Ma、2 241~2 740 Ma、615~1 623 Ma五個年齡區(qū)間,峰值年齡主要有272 Ma、427 Ma、1 899 Ma 和2 493 Ma,認(rèn)為該區(qū)洛河組砂巖為多物源區(qū)混合(需要指出的是前人研究表明洛河期鄂爾多斯盆地廣泛發(fā)育風(fēng)成砂巖環(huán)境沉積[22?23,30])。上述研究均表明盆地南部下白堊統(tǒng)物源與其相鄰的造山帶存在密切的聯(lián)系。本次測試結(jié)果進(jìn)一步揭示,鄂爾多斯盆地南部宜君組砂巖碎屑鋯石U-Pb年齡譜主要集中于早中生代和早古生代(圖6),中新元宙—太古宙年齡較少且呈分散分布,本文重點(diǎn)以早古生代和早中生代2階段為重點(diǎn)開展討論。
前人大量研究表明,早古生代鋯石在北祁連東段巖體及相關(guān)地層中有大量發(fā)育,如草川鋪花崗巖體(434±10 Ma)[34]、黃門川花崗閃長巖體(440.5±4.4 Ma)[35]、王家岔閃長巖體(454.7±1.7 Ma)[36]、閻家店閃長巖體(440.2±0.92 Ma)[37]、新街花崗質(zhì)片麻巖(447±5.4 Ma)[38]、紅土堡巖組變基性火山巖(443.4.7±1.7 Ma)及葫蘆河群變質(zhì)砂巖(426~493 Ma)[39]等;此外,古生代巖體在北秦嶺地區(qū)廣泛分布,南秦嶺僅有零星出露(圖1),如黑河花崗巖(401±14 Ma)[40]、閃長巖(442±7 Ma)[40]、花崗閃長巖(470±9 Ma)[41],鳳縣紅花鋪云英閃長巖(414±1.5 Ma)[42]、唐藏石英閃長巖體(455±1.9 Ma)[43]等,據(jù)統(tǒng)計秦嶺古生代巖體鋯石U-Pb年齡集中于505~400 Ma,其中450~422 Ma年齡段在北秦嶺全區(qū)廣布[44]。上述巖體或地層鋯石年齡與本次樣品的早古生代峰值年齡具有較好的一致性。
早中生代相關(guān)鋯石年齡的巖體在秦嶺地區(qū)廣泛分布,如沙河灣巖體(214~207 Ma)、糜署嶺巖體(213±3 Ma和212±5 Ma)[45]、黃渚關(guān)花崗巖(214±1 Ma和 213± 3Ma)、廠壩花崗巖(213±2 Ma)[46]、江里溝復(fù)式巖體(229.1±1.8 Ma)[47]、寶雞巖體(216~210 Ma)、華陽巖體(214~195 Ma)、光頭山花崗巖(221~206 Ma)、老城花崗巖(221~210 Ma)[48]等。Wang et al.[49]根據(jù)巖石地球化學(xué)特征分析認(rèn)為秦嶺地區(qū)早中生代巖體可分為2期,其中250~240 Ma巖體相對較少,主要分布在西秦嶺地區(qū),而225~185 Ma巖體遍布于整個秦嶺造山帶,且集中分布于商州以西(圖1),這與本次研究樣品年齡峰值在時空上也具有明顯的一致性。
為了進(jìn)一步明確麟游和彬縣地區(qū)宜君組的物質(zhì)來源,筆者分區(qū)塊統(tǒng)計了鄂爾多斯盆地南部周緣相關(guān)地質(zhì)體的鋯石U-Pb年齡特征,具體包括北秦嶺地區(qū)[49?57]、南秦嶺地區(qū)[57?66]、北祁連地區(qū)[67?71]及華北地塊南緣[72?81],共統(tǒng)計了3 563個年齡數(shù)據(jù)(圖7),總體上可代表這些地區(qū)相關(guān)巖石的鋯石年齡組成,這些同位素測年數(shù)據(jù)主要采用SHRIMP和LA-ICP-MS U-Pb定年方法。從統(tǒng)計結(jié)果看,北秦嶺地區(qū)相關(guān)地質(zhì)體的鋯石年齡主要集中于190~250 Ma、400~500 Ma年齡段,大于500 Ma的鋯石年齡雖分布廣泛但未形成明顯的峰值年齡;南秦嶺地區(qū)相關(guān)地質(zhì)體的鋯石年齡主要集中在190~240 Ma、425~500 Ma和620~1 000 Ma年齡段,大于1 000 Ma的年齡亦分布,但峰值不明顯;北祁連造山帶地區(qū)相關(guān)地質(zhì)體的鋯石年齡主要集中于430~550 Ma、900~1 200 Ma、1 800~2 300 Ma 及2 500 Ma±年齡段;而華北板塊南緣地區(qū)相關(guān)地質(zhì)體的鋯石年齡主要集中于120~150 Ma,1 600~2 000 Ma及2 400~2 500 Ma年齡段。
綜合對比各地區(qū)年齡譜峰特征,可以看到麟游與彬縣宜君組的碎屑鋯石U-Pb年齡譜峰與北秦嶺地區(qū)年齡譜峰特征非常類似,與南秦嶺地區(qū)總體相似,但在研究區(qū)未出現(xiàn)620~1 000 Ma 的新元古代年齡峰;與北祁連地區(qū)相比較,可以看到古生代年齡峰特征相對一致,但元古宙—太古宙年齡譜峰特征明顯不同;而與華北板塊南緣在代表性峰值特征上則有比較明顯的差異(圖7)。綜述上述分析,并結(jié)合當(dāng)前研究區(qū)周邊地區(qū)地質(zhì)體出露的特點(diǎn)(圖1),本文認(rèn)為鄂爾多斯盆地南部麟游、彬縣地區(qū)下白堊統(tǒng)宜君組物源應(yīng)以北秦嶺中段地區(qū)為主,同時可能有來自南秦嶺北部地區(qū)的物源供給。
對于研究區(qū)出現(xiàn)的未成明顯峰值但廣泛分布的元古宙—太古宙碎屑鋯石年齡數(shù)據(jù)(圖7),從周鄰區(qū)域元古代巖體分布看,則主要分布于南秦嶺東南部及揚(yáng)子板塊北緣(圖1),很難成為本區(qū)的物源區(qū),為此,本文認(rèn)為宜君組中出現(xiàn)的元古宙—太古宙年齡的碎屑鋯石應(yīng)主要來自于北秦嶺地區(qū)如秦嶺群、寬坪群等巖系,這與研究區(qū)宜君組地層中礫石所展現(xiàn)的以花崗巖為主,同時含有石英巖、片巖及片麻巖等礫石的分布特征相一致(圖4),由于這些古老變質(zhì)巖系地層中鋯石礦物含量相對較低,同時由于下伏巖體在該時期或之前的隆升剝露、致使上覆變質(zhì)巖系地層出露范圍變小,物質(zhì)供應(yīng)可能相對較少有關(guān),也暗示著沉積區(qū)沉積物中碎屑鋯石含量可能與源區(qū)巖體出露關(guān)系更為密切。
4.2 地質(zhì)意義
4.2.1 對秦嶺造山帶及渭北隆起晚中生代以來隆升剝露的啟示
造山帶以高起伏為典型特征,使地質(zhì)體暴露于風(fēng)化和侵蝕之下,產(chǎn)生的碎屑物質(zhì)被輸送到毗鄰的洼陷區(qū)域(沉積盆地),這種沉積填充物包含了有關(guān)物質(zhì)從源到匯輸送過程的關(guān)鍵信息,記錄了盆山構(gòu)造格局形成和演化歷史,可用于探索沉積體系演化中構(gòu)造和沉積因素之間的相互關(guān)系[82]。前人大量研究表明,秦嶺造山帶是我國華北與揚(yáng)子兩大板塊于中晚三疊世(印支期)碰撞拼合形成的造山帶[83?84],碰撞造山后開始了更為強(qiáng)烈的陸內(nèi)調(diào)整演化,經(jīng)歷了晚三疊世—早中侏羅世垮塌演化、晚侏羅世—白堊紀(jì)大規(guī)模陸內(nèi)造山作用[85],上述演化過程在秦嶺造山帶內(nèi)部及南部揚(yáng)子板塊北緣有明顯的構(gòu)造—沉積響應(yīng),但由于新生代渭河地塹的發(fā)育,使得在北側(cè)的鄂爾多斯盆地表現(xiàn)不甚明了。
本次通過對鄂爾多斯盆地早白堊世宜君組砂巖碎屑鋯石U-Pb定年,一方面揭示了鄂爾多斯盆地南部下白堊統(tǒng)發(fā)育來自秦嶺造山帶的沉積物源;更為重要的是,宜君組碎屑鋯石年齡中廣泛記錄著秦嶺造山帶所特有的早中生代(195~250 Ma)巖漿活動,這表明秦嶺地區(qū)早中生代巖體最晚應(yīng)在早白堊世初已抬升剝露至地表,并開始大量向造山帶北側(cè)沉積區(qū)提供物源。此外,渭北隆起區(qū)下白堊統(tǒng)普遍與下伏不同時代地層呈不整合接觸關(guān)系,以及宜君組沖積扇相礫巖的發(fā)育(圖3,4),這在區(qū)域上與秦嶺造山帶同期演化具有較好的一致性,印證了秦嶺造山帶晚侏羅世開始的大規(guī)模陸內(nèi)造山作用已明顯影響到了鄂爾多斯盆地南部。同時,鄂爾多斯盆地南部下白堊統(tǒng)發(fā)育大量來自秦嶺造山帶的沉積物源,從側(cè)面也說明了此時渭北隆起區(qū)還未演化成阻隔秦嶺造山帶物質(zhì)到來的隆起構(gòu)造單元,支持渭北隆起主體隆升應(yīng)為早白堊世末以來的觀點(diǎn)[86?89]。
4.2.2 對鄂爾多斯盆地南部砂巖型鈾礦勘查的意義
蝕源區(qū)剝露的巖石類型和物質(zhì)組成,直接制約盆地內(nèi)的沉積建造和巖性特征,對沉積礦產(chǎn)的形成亦有重要影響[90]。就砂巖型鈾礦而言,若條件具備,來自蝕源區(qū)鈾源的成礦作用可發(fā)生在沉積、成巖和成巖后生作用的全過程[90]。眾所周知,中酸性巖漿巖、古老變質(zhì)巖系均為重要的富鈾地質(zhì)體,往往具有較高的放射性鈾元素含量。
研究表明,秦嶺地區(qū)古生代、早中生代巖漿巖鈾元素含量較高,鈾含量為(4.1~6.9)×10-6[10],其原始鈾含量最高可達(dá)10×10-6,而秦嶺群、寬坪群等鈾含量為(4~6)×10-6[91];結(jié)合上述物源分析,相關(guān)地層均可以成為鄂爾多斯盆地南部下白堊統(tǒng)重要的潛在鈾元素來源區(qū),然早白堊世沉積主體以高氧化環(huán)境為主,總體不利于砂巖型鈾礦的富集,但下白堊統(tǒng)局部層段如環(huán)河—華池組、涇川組仍發(fā)育還原環(huán)境,適于鈾元素發(fā)生還原沉淀[10];同時,U元素在氧化環(huán)境下較為活躍,極易被氧化而發(fā)生遷移[92],下白堊系砂體發(fā)育,透水性好,進(jìn)入盆地內(nèi)的鈾元素后期可以發(fā)生遷移,在其下伏地層如侏羅系中進(jìn)一步富集成礦。鄂爾多斯盆地南部砂巖型鈾礦總體勘查程度較低,但目前已在下白堊統(tǒng)中發(fā)現(xiàn)了如國家灣砂巖型鈾礦,鎮(zhèn)原、崇信—涇川、隴縣等鈾礦化點(diǎn)或異常區(qū)[10?12],在侏羅系中發(fā)現(xiàn)了店頭、雙龍鈾礦床,焦平、廟灣、照金、彬縣等鈾礦化點(diǎn)[8,91],指示盆地南部砂巖型鈾礦廣闊的勘探前景。從蝕源區(qū)成礦物質(zhì)來源角度探索礦藏形成,是深刻揭示成礦物質(zhì)聚集與分布,探討礦藏成巖和有效指導(dǎo)礦藏預(yù)測等內(nèi)容的重要組成部分,值得進(jìn)一步研究。
5 結(jié)論
(1) 鄂爾多斯盆地南部麟游、彬縣地區(qū)下白堊統(tǒng)宜君組碎屑鋯石U-Pb定年表明,主要集中分布于早中生代(195~250 Ma)和早古生代(400~500 Ma)時期,峰值年齡分別為218 Ma和450 Ma,而元古宙—太古宙鋯石年齡不但數(shù)量少且較為分散,與北秦嶺地區(qū)相關(guān)地質(zhì)體的鋯石U-Pb年齡具明顯的時空一致性,綜合認(rèn)為研究區(qū)物源主要來自于北秦嶺地區(qū)。
(2) 通過下白堊統(tǒng)宜君組碎屑鋯石年代學(xué)及物源分析,指出秦嶺造山帶早中生代巖體侵位后,最晚在早白堊世已抬升剝露至地表,并開始向盆地南部提供大量物源,這在一定程度上為約束秦嶺晚中生代隆升剝露及渭北隆起發(fā)育的時限提供間接的證據(jù);進(jìn)一步認(rèn)為秦嶺地區(qū)古生代及早中生代巖體為宜君組重要的物質(zhì)來源,可為盆地南部提供豐富的鈾元素,對該區(qū)鈾礦資源勘查具有一定的指導(dǎo)意義。
致謝 衷心感謝西北大學(xué)大陸動力學(xué)國家重點(diǎn)實(shí)驗(yàn)室張紅和戴夢寧高級工程師在實(shí)驗(yàn)和數(shù)據(jù)處理過程中的幫助。本文所采用鄂爾多斯盆地鋯石U?Pb 測年數(shù)據(jù)可通過Geochron 網(wǎng)站獲取http://www.geochron.org/viewfile.php?pkey=20092。
參考文獻(xiàn)(References)
[1] 劉池洋,趙紅格,桂小軍,等. 鄂爾多斯盆地演化—改造的時空
坐標(biāo)及其成藏(礦)響應(yīng)[J]. 地質(zhì)學(xué)報,2006,80(5):617-638.
[Liu Chiyang, Zhao Hongge, Gui Xiaojun, et al. Space-time coordinate
of the evolution and reformation and mineralization response
in Ordos Basin[J]. Acta Geologica Sinica, 2006, 80(5):
617-638.]
[2] 王建強(qiáng). 鄂爾多斯盆地南部中新生代演化—改造及盆山耦合
關(guān)系[D]. 西安:西北大學(xué),2010.[Wang Jianqiang. Mesozoic-
Cenozoic basin evolution-reforming and basin-mountain coupling
in southern Ordos Basin[D]. Xi'an: Northwest University,
2010.]
[3] 張?zhí)旄#缗嗌?,程先鈺,? 鄂爾多斯盆地早白堊世含鈾巖系
的新發(fā)現(xiàn)及其層序地層[J]. 大地構(gòu)造與成礦學(xué),2020,44(4):
633-647. [Zhang Tianfu, Miao Peisen, Cheng Xianyu, et al.
Stratigraphic characteristics of a newly discovered uraniumbearing
stratum in the Lower Cretaceous, Ordos Basin[J]. Geotectonica
et Metallogenia, 2020, 44(4): 633-647.]
[4] 任戰(zhàn)利,祁凱,劉潤川,等. 鄂爾多斯盆地早白堊世構(gòu)造熱事件
形成動力學(xué)背景及其對油氣等多種礦產(chǎn)成藏(礦)期的控制作
用[J]. 巖石學(xué)報,2020,36(4):1213-1234.[Ren Zhanli, Qi
Kai, Liu Runchuan, et al. Dynamic background of Early Cretaceous
tectonic thermal events and its control on various mineral
accumulations such as oil and gas in the Ordos Basin[J]. Acta
Petrologica Sinica, 2020, 36(4): 1213-1234.]
[5] 龐軍剛,李文厚,國吉安,等. 鄂爾多斯盆地白堊紀(jì)沉積體系及
古地理演化[J]. 西北大學(xué)學(xué)報(自然科學(xué)版),2021,51(2):
314-324.[Pang Jungang, Li Wenhou, Guo Ji'an, et al. Depositional
system and paleogeographic evolution of the Cretaceous of
Ordos Basin[J]. Journal of Northwest University (Natural Science
Edition), 2021, 51(2): 314-324.]
[6] 禹江. 鄂爾多斯盆地西南緣早白堊世宜君組沉積環(huán)境及構(gòu)造
意義[D]. 西安:長安大學(xué),2018.[Yu Jiang. Sedimentary environment
and tectonic significance of the Early Cretaceous Yijun
Formation in the southwestern Ordos Basin[D]. Xi'an: Chang'an
University, 2018.]
[7] 程先鈺,張?zhí)旄?,苗培森,? 鄂爾多斯盆地西南緣洛河組下段
含鈾砂巖鋯石U-Pb 年代學(xué):對巖石圈伸展作用的啟示[J]. 中
國地質(zhì),2023,50(3):853-871. [Cheng Xianyu, Zhang Tianfu,
Miao Peisen, et al. Detrital zircon U-Pb geochronology of uranium-
bearing sandstone in the Lower member of Luohe Formation
in the southwest margin of the Ordos Basin: Implications for the
lithospheric extension[J]. Geology in China, 2023, 50(3):
853-871.]
[8] 孫棟華,江民忠,陳江源,等. 鄂爾多斯盆地西南部多元地學(xué)特
征及其找鈾意義[J]. 鈾礦地質(zhì),2020,36(4):293-301.[Sun
Donghua, Jiang Minzhong, Chen Jiangyuan, et al. The characteristics
of multi-source geo-information and its significance to
uranium exploration in the southwest of Ordos Basin[J]. Uranium
Geology, 2020, 36(4): 293-301.]
[9] 朱強(qiáng),李建國,苗培森,等. 鄂爾多斯盆地西南部洛河組儲層特
征和深部鈾成礦地質(zhì)條件[J]. 地球科學(xué)與環(huán)境學(xué)報,2019,41
(6):675-690.[Zhu Qiang, Li Jianguo, Miao Peisen, et al. Reservoir
characteristics of Luohe Formation and metallogenic geological
conditions of deep uranium in the southwestern margin of
Ordos Basin, China[J]. Journal of Earth Sciences and Environment,
2019, 41(6): 675-690.]
[10] 徐陽,凌明星,薛碩,等. 鄂爾多斯盆地雙龍地區(qū)砂巖型鈾礦
富集、遷移和成礦機(jī)制[J]. 大地構(gòu)造與成礦學(xué),2020,44(5):
937-957.[Xu Yang, Ling Mingxing, Xue Shuo, et al. Enrichment,
transportation and ore forming mechanism of sandstonetype
uranium deposits in Shuanglong area, Ordos Basin[J].
Geotectonica et Metallogenia, 2020, 44(5): 937-957.]
[11] 陳江源,牛家驥,郭佳,等. 鄂爾多斯盆地南緣崇信—涇川地
區(qū)航放異常特征及鈾礦找礦前景分析[J]. 地質(zhì)與勘探,2020,
56(3):551-565.[Chen Jiangyuan, Niu Jiaji, Guo Jia, et al.
Characteristics of aerial radioactive anomalies and prospect of
uranium exploration in the Chongxin-Jingchuan area, southern
margin of Ordos Basin[J]. Geology and Exploration, 2020, 56
(3): 551-565.]
[12] 張字龍,范洪海,賀鋒,等. 鄂爾多斯盆地西南緣下白堊統(tǒng)鈾
成礦條件分析[J]. 鈾礦地質(zhì),2018,34(4):193-200.[Zhang
Zilong, Fan Honghai, He Feng, et al. Analysis of sandstone
type uranium metallogenic conditions of Lower Cretaceous in
the southwest margin of Ordos Basin[J]. Uranium Geology,
2018, 34(4): 193-200.]
[13] Kos?ler J, Sylvester P J. Present trends and the future of zircon
in geochronology: Laser ablation ICPMS[J]. Reviews in Mineralogy
and Geochemistry, 2003, 53(1): 243-275.
[14] 張岳橋,廖昌珍. 晚中生代—新生代構(gòu)造體制轉(zhuǎn)換與鄂爾多
斯盆地改造[J]. 中國地質(zhì),2006,33(1):28-40.[Zhang
Yueqiao, Liao Changzhen. Transition of the Late Mesozoic-
Cenozoic tectonic regimes and modification of the Ordos Basin
[J]. Geology in China, 2006, 33(1): 28-40.]
[15] Peng H, Liu C Y, Wang J Q, et al. Discovery of multiple tectonic
reformations of the eastern Yingen-Ejinaqi Basin: Evidence
from detrital chronology[J]. Acta Geologica Sinica (English
Edition), 2021, 95(2): 693-695.
[16] 趙紅格,劉池洋,王海然,等. 鄂爾多斯盆地西北緣早—中侏
羅世延安期碎屑鋯石LA-ICP-MS 定年及其物源意義[J]. 地
學(xué)前緣,2015,22(3):184-193.[Zhao Hongge, Liu Chiyang,
Wang Hairan, et al. LA-ICP-MS detrital zircon dating and its
provenance significance in Yan'an Formation of the Early-
Middle Jurassic in the northwestern margin of Ordos Basin[J].
Earth Science Frontiers, 2015, 22(3): 184-193.]
[17] Zhao X C, Liu C Y, Wang J Q, et al. Detrital zircon U-Pb ages
of Paleozoic sedimentary rocks from the eastern Hexi Corridor
Belt (NW China): Provenance and geodynamic implications
[J]. Sedimentary Geology, 2016, 339: 32-45.
[18] 彭恒,劉顯陽,劉池洋,等. 鄂爾多斯盆地西南緣中生代中晚
期構(gòu)造體制轉(zhuǎn)化過程及其動力學(xué)背景[J]. 地質(zhì)學(xué)報,2022,96
(2):387-402.[Peng Heng, Liu Xianyang, Liu Chiyang, et al.
Spatial-temporal evolution and the dynamic background of the
translation of Mid-Late Mesozoic tectonic regimes of the southwest
Ordos Basin margin[J]. Acta Geologica Sincia,2022,96
(2):387-402.]
[19] 張文龍,陳剛,章輝若,等. 唐王陵昭陵組礫巖碎屑鋯石U-Pb
年代學(xué)分析[J]. 沉積學(xué)報,2016,34(3):497-505.[Zhang
Wenlong, Chen Gang, Zhang Huiruo, et al. Detrital zircon UPb
geochronology from Zhaoling Formation in Tangwangling
[J]. Acta Sedimentologica Sinica, 2016, 34(3): 497-505.]
[20] 韓會平,武春英,白清華,等. 鄂爾多斯盆地烏審旗地區(qū)上古
生界砂巖碎屑鋯石U-Pb 年齡及其地質(zhì)意義[J]. 沉積學(xué)報,
2014,32(4):643-653.[Han Huiping, Wu Chunying, Bai Qinghua,
et al. Zircon U-Pb dating of clastic sandstone in the Upper
Paleozoic from Wushenqi area, Ordos Basin and its geological
significance[J]. Acta Sedimentologica Sinica, 2014, 32(4):
643-653.]
[21] 王建強(qiáng),賈楠,劉池洋,等. 鄂爾多斯盆地西南部下白堊統(tǒng)宜
君組礫巖礫組分析及其意義[J]. 沉積學(xué)報,2011,29(2):226-
234. [Wang Jianqiang, Jia Nan, Liu Chiyang, et al. Fabric
analysis of Yijun gravels of Lower Cretaceous in the southwestern
Ordos Basin[J]. Acta Sedimentologica Sinica, 2011, 29
(2): 226-234.]
[22] 龐軍剛,國吉安,李文厚,等. 古沙漠記錄的沉積體系及層序
地層研究進(jìn)展:以鄂爾多斯盆地白堊系為例[J]. 地層學(xué)雜志,
2011,35(1):95-102.[Pang Jungang, Guo Ji'an, Li Wenhou, et
al. Advance of depositional system and sequence stratigraphy in
paleo-desert record: Taking the Cretaceous strata in Ordos Basin
as an example[J]. Journal of Stratigraphy, 2011, 35(1):
95-102.]
[23] 李孝澤,董光榮,靳鶴齡,等. 鄂爾多斯白堊系沙丘巖的發(fā)現(xiàn)[J].
科學(xué)通報,1999,44(8):874-877.[Li Xiaoze, Dong Guangrong,
Jin Heling, et al. Discovery of Ordos Cretaceous dune rock and
its significance[J]. Chinese Science Bulletin, 1999, 44(8):
874-877.]
[24] 謝淵,王劍,李明輝,等. 鄂爾多斯盆地早白堊世巖相古地理
與地下水水質(zhì)和分布的關(guān)系[J]. 地質(zhì)通報,2004,23(11):
1094-1102.[Xie Yuan, Wang Jian, Li Minghui, et al. Relations
of the Early Cretaceous lithofacies-paleogeography to
groundwater quality and distribution in the Ordos Basin[J].
Geological Bulletin of China, 2004, 23(11): 1094-1102.]
[25] 王建強(qiáng). 鄂爾多斯盆地西南部早白堊世原盆恢復(fù)及其演化
[D]. 西安:西北大學(xué),2007.[Wang Jianqiang. Reconstruction
of the Early Crataceous basin and its evolution in southwest
Ordos[D]. Xi'an: Northwestern University, 2007.]
[26] 王建強(qiáng),劉池洋,劉鑫,等. 鄂爾多斯盆地南部下白堊統(tǒng)演化
改造特征[J]. 西北大學(xué)學(xué)報(自然科學(xué)版),2011,41(2):291-
297.[Wang Jianqiang, Liu Chiyang, Liu Xin, et al. Geologic
characteristic and its evolution and reformation of Lower Cretaceous
in southern Ordos Basin[J]. Journal of Northwest University
(Natural Science Edition), 2011, 41(2): 291-297.]
[27] 秦江鋒. 秦嶺造山帶晚三疊世花崗巖類成因機(jī)制及深部動力
學(xué)背景[D]. 西安:西北大學(xué),2010.[Qin Jiangfeng. Petrogenesis
and geodynamic implications of the Late-Triassic Granitoids
from the Qinling orogenic belt[D]. Xi'an: Northwest University,
2010.]
[28] 劉池洋,王建強(qiáng),張東東,等. 鄂爾多斯盆地油氣資源豐富的
成因與賦存—成藏特點(diǎn)[J]. 石油與天然氣地質(zhì),2021,42(5):
1011-1029.[Liu Chiyang, Wang Jianqiang, Zhang Dongdong,
et al. Genesis of rich hydrocarbon resources and their occurrence
and accumulation characteristics in the Ordos Basin[J].
Oil amp; Gas Geology, 2021, 42(5): 1011-1029.]
[29] 謝淵,王劍,李令喜,等. 鄂爾多斯盆地白堊系粘土礦物的分
布特征及其沉積—成巖環(huán)境意義[J]. 地質(zhì)通報,2010,29(1):
93-104.[Xie Yuan, Wang Jian, Li Lingxi, et al. Distribution of
the Cretaceous clay minerals in Ordos Basin, China and its implication
to sedimentary and diagenetic environment[J]. Geological
Bulletin of China, 2010, 29(1): 93-104.]
[30] 程守田,劉星,郭秀蓉,李志德. 古沙漠沉積及其層序單元:以
鄂爾多斯白堊紀(jì)內(nèi)陸古沙漠盆地為例[J]. 中國地質(zhì)大學(xué)學(xué)報
(地球科學(xué)版),2000(06):587-591.[Chen Shoutian,Liu Xin,
Guo, et al. Xiurong Palaeo-desert deposition and sequence
stratigraphic units:An example from cret aceous continent
palaeo-desert basin in Ordos[J]. Journal of China University of
Geosciences (Earth Science Edition) ,2000(06):587-591.]
[31] 何登發(fā),包洪平,開百澤,等. 鄂爾多斯盆地及其鄰區(qū)關(guān)鍵構(gòu)
造變革期次及其特征[J]. 石油學(xué)報,2021,42(10):1255-
1269.[He Dengfa, Bao Hongping, Kai Baize, et al. Critical
tectonic modification periods and its geologic features of Ordos
Basin and adjacent area[J]. Acta Petrolei Sinica, 2021, 42
(10): 1255-1269.]
[32] 黃永波. 早白堊世鄂爾多斯南部沙漠起源與演化:志丹群磁
性地層年代及沉積物磁化率測量[D]. 蘭州:蘭州大學(xué),2010.
[Huang Yongbo. The origin and evolution of the desert in southern
Ordos in Early Cretaceous: Constraint from magnetostratigraphy
of Zhidan Group and magnetic susceptibility of its sediment
[D]. Lanzhou: Lanzhou University, 2010.]
[33] Ballard J R, Palin J M, Williams I S, et al. Two ages of porphyry
intrusion resolved for the super-giant Chuquicamata copper
deposit of northern Chile by ELA-ICP-MS and SHRIMP[J].
Geology, 2001, 29(5): 383-386.
[34] Zhang H F, Zhang B R, Harris N, et al. U-Pb zircon SHRIMP
ages, geochemical and Sr-Nd-Pb isotopic compositions of
intrusive rocks from the Longshan-Tianshui area in the southeast
corner of the Qilian orogenic belt, China: Constraints on
petrogenesis and tectonic affinity[J]. Journal of Asian Earth
Sciences, 2006, 27(6): 751-764.
[35] 魏方輝,裴先治,李瑞保,等. 甘肅天水地區(qū)早古生代黃門川
花崗閃長巖體LA-ICP-MS 鋯石U-Pb 定年及構(gòu)造意義[J]. 地
質(zhì)通報,2012,31(9):1496-1509.[Wei Fanghui, Pei Xianzhi,
Li Ruibao, et al. LA-ICP-MS zircon U-Pb dating of Early Paleozoic
Huangmenchuan granodiorite in Tianshui area of Gansu
province and its tectonic significance[J]. Geological Bulletin of
China, 2012, 31(9): 1496-1509.]
[36] 陳雋璐,李好斌,王洪亮,等. 秦祁結(jié)合部位王家岔石英閃長
巖體鋯石LA-ICPMS 定年及地質(zhì)意義[J]. 吉林大學(xué)學(xué)報(地
球科學(xué)版),2007,37(3):423-431.[Chen Junlu, Li Haobin,
Wang Hongliang, et al. LA-ICPMS zircon U-Pb dating of a
quartz diorite pluton from Wangjiacha, the junction area between
the Qinling and Qilian orogenic belts and its tectonic significance
[J]. Journal of Jilin University (Earth Science Edition),
2007, 37(3): 423-431.]
[37] 裴先治,孫仁奇,丁仨平,等. 隴東地區(qū)閻家店閃長巖LA-ICPMS
鋯石U-Pb 測年及其地質(zhì)意義[J]. 中國地質(zhì),2007,34(1):
8-16.[Pei Xianzhi, Sun Renqi, Ding Saping, et al. LA-ICPMS
zircon U-Pb dating of the Yanjiadian diorite in the eastern
Qilian mountains and its geological significance[J]. Geology in
China, 2007, 34(1): 8-16.]
[38] 何艷紅,陳亮,孫勇,等. 隴縣地區(qū)新街片麻巖套鋯石年齡及
其地質(zhì)意義[J]. 西北大學(xué)學(xué)報(自然科學(xué)版),2005,35(5):
625-627,632.[He Yanhong, Chen Liang, Sun Yong, et al. Zircon
chronology of Xinjie complex in Longxian County and its
geological significance[J]. Journal of Northwest University
(Natural Science Edition), 2005, 35(5): 625-627, 632.]
[39] 裴先治,李佐臣,李瑞保,等. 祁連造山帶東段早古生代葫蘆
河群變質(zhì)碎屑巖中碎屑鋯石LA-ICP-MSU-Pb 年齡:源區(qū)特征
和沉積時代的限定[J]. 地學(xué)前緣,2012,19(5):205-224.[Pei
Xianzhi, Li Zuochen, Li Ruibao, et al. LA-ICP-MS U-Pb ages
of detrital zircons from the meta-detrital rocks of the Early Palaeozoic
Huluhe Group in eastern part of Qilian orogenic belt:
Constraints of material source and sedimentary age[J]. Earth
Science Frontiers, 2012, 19(5): 205-224.]
[40] Lerch M F, Xue F, Kr?ner A, et al. A Middle Silurian-Early
Devonian magmatic arc in the Qinling mountains of central China
[J]. The Journal of Geology, 1995, 103(4): 437-449.
[41] Xue F, Kr?ner A, Reischmann T, et al. Palaeozoic pre- and
post-collision calc-alkaline magmatism in the Qinling orogenic
belt, central China, as documented by zircon ages on granitoid
rocks[J]. Journal of the Geological Society, 1996, 153(3):
409-417.
[42] 徐學(xué)義,李婷,陳雋璐,等. 西秦嶺西段花崗巖漿作用與成礦
[J]. 西北地質(zhì),2012,45(4):76-82.[Xu Xueyi, Li Ting, Chen
Junlu, et al. The granitoids magmatism and mineralization in
west section of the Western Qinling, NW China[J]. Northwestern
Geology, 2012, 45(4): 76-82.]
[43] 陳雋璐,徐學(xué)義,王洪亮,等. 北秦嶺西段唐藏石英閃長巖巖
體的形成時代及其地質(zhì)意義[J]. 現(xiàn)代地質(zhì),2008,22(1):45-
52. [Chen Junlu, Xu Xueyi, Wang Hongliang, et al. LAICPMS
zircon U-Pb dating of Tangzang quartz-diorite pluton in
the west segment of North Qinling mountains and its tectonic significance
[J]. Geoscience, 2008, 22(1): 45-52.]
[44] 王濤,王曉霞,田偉,等. 北秦嶺古生代花崗巖組合、巖漿時空
演變及其對造山作用的啟示[J]. 中國科學(xué)(D輯):地球科學(xué),
2009,39(7):949-971.[Wang Tao, Wang Xiaoxia, Tian Wei, et
al. North Qinling Paleozoic granite associations and their variation
in space and time: Implications for orogenic processes in
the orogens of central China[J]. Science China (Seri. D):
Earth Sciences, 2009, 39(7): 949-971.]
[45] Qin J F, Lai S C, Grapes R, et al. Geochemical evidence for
origin of magma mixing for the Triassic monzonitic granite and
its enclaves at Mishuling in the Qinling orogen (central China)
[J]. Lithos, 2009, 112(3/4): 259-276.
[46] 王天剛,倪培,孫衛(wèi)東,等. 西秦嶺勉略帶北部黃渚關(guān)和廠壩
花崗巖鋯石U-Pb 年齡及源區(qū)性質(zhì)[J]. 科學(xué)通報,2010,55
(36):3493-3505.[Wang Tiangang, Ni Pei, Sun Weidong, et
al. Zircon U-Pb ages of granites at Changba and Huangzhuguan
in Western Qinling and implications for source nature[J]. Chinese
Science Bulletin, 2010, 55(36): 3493-3505.]
[47] 路東宇,葉會壽,曹晶,等. 西秦嶺江里溝復(fù)式巖體LA-ICP-MS
鋯石U-Pb 年齡、地球化學(xué)和Hf 同位素特征及其地質(zhì)意義[J].
巖石學(xué)報,2017,33(3):942-962.[Lu Dongyu, Ye Huishou,
Cao Jing, et al. LA-ICP-MS zircon U-Pb ages, Hf isotopic
compositions, geochemistry characteristics and its geological
significance of Jiangligou composite granite, West Qingling
orogen[J]. Acta Petrologica Sinica, 2017, 33(3): 942-962.]
[48] 劉樹文,楊朋濤,李秋根,等. 秦嶺中段印支期花崗質(zhì)巖漿作
用與造山過程[J]. 吉林大學(xué)學(xué)報(地球科學(xué)版),2011,41(6):
1928-1943.[Liu Shuwen, Yang Pengtao, Li Qiugen, et al. Indosinian
granitoids and orogenic processes in the middle segment
of the Qinling orogen, China[J]. Journal of Jilin University
(Earth Science Edition), 2011, 41(6): 1928-1943.]
[49] Wang X X, Wang T, Zhang C L. Neoproterozoic, Paleozoic,
and Mesozoic granitoid magmatism in the Qinling orogen, China:
Constraints on orogenic process[J]. Journal of Asian Earth
Sciences, 2013, 72: 129-151.
[50] Dong Y P, Zhang G W, Neubauer F, et al. Tectonic evolution
of the Qinling orogen, China: Review and synthesis[J]. Journal
of Asian Earth Sciences, 2011, 41(3): 213-237.
[51] 楊華,辛補(bǔ)社,付金華,等. 鄂爾多斯盆地西南緣崆峒山組礫
巖中的碎屑鋯石LA-ICP-MS U-Pb 定年及其構(gòu)造意義[J]. 地
質(zhì)論評,2014,60(3):677-692.[Yang Hua, Xin Bushe, Fu Jinhua,
et al. LA-ICP-MS U-Pb dating of detrital zircons from
Kongtongshan Formation conglomerate in the southwestern margin
of Ordos Basin and its tectonic significance[J]. Geological
Review, 2014, 60(3): 677-692.]
[52] 高春云,郭安林,李興輝,等. 北秦嶺柳葉河盆地石炭系—二
疊系含礫砂巖碎屑鋯石LA-ICP-MS U-Pb 年齡及其地質(zhì)意義
[J]. 地質(zhì)通報,2015,34(9):1689-1698.[Gao Chunyun, Guo
Anlin, Li Xinghui, et al. LA-ICP-MS U-Pb dating of detrital
zircon from Liuyehe Basin in North Qinling mountains[J]. Geological
Bulletin of China, 2015, 34(9): 1689-1698.]
[53] Li N, Chen Y J, Santosh M, et al. Compositional polarity of
Triassic granitoids in the Qinling orogen, China: Implication for
termination of the northernmost paleo-Tethys[J]. Gondwana Research,
2015, 27(1): 244-257.
[54] 宮相寬,蔡宏明,郭瑞清,等. 北秦嶺西段早侏羅世A型花崗
巖及其地質(zhì)意義[J]. 地質(zhì)科學(xué),2021,56(1):158-181.[Gong
Xiangkuan, Cai Hongming, Guo Ruiqing, et al. Early Jurassic
A-type granites in the western North Qinling orogen, central
China, and its geological significance[J]. Chinese Journal of
Geology, 2021, 56(1): 158-181.]
[55] 王元元,裴先治,劉成軍,等. 西秦嶺舒家壩地區(qū)泥盆紀(jì)舒家
壩群碎屑鋯石LA-ICP-MSU-Pb 年齡:源區(qū)特征與形成時代
[J]. 地質(zhì)通報,2014,33(7):1015-1027.[Wang Yuanyuan, Pei
Xianzhi, Liu Chengjun, et al. Detrial zircon LA-ICP-MS U-Pb
ages of the Devonian Shujiaba Group in Shujiaba area of the
West Qinling tectonic zone: Constraints on material source and
sedimentaryage[J]. Geological Bulletin of China, 2014, 33
(7): 1015-1027.]
[56] 周澍,張賀,陳福坤. 北秦嶺五垛山花崗巖鋯石U-Pb 年代學(xué)和
地球化學(xué)特征及成因[J]. 高校地質(zhì)學(xué)報,2019,25(6) :901-
913.[Zhou Shu, Zhang He, Chen Fukun. Zircon U-Pb geochronology,
geochemistry and petrogenesis of granites from the
Wuduoshan pluton, the North Qinling terrane[J]. Geological
Journal of China Universities,2019,25(6):901-913.]
[57] 張紅. 秦嶺北麓現(xiàn)代河流碎屑鋯石U-Pb年代學(xué)研究及其地質(zhì)
意義[D]. 西安:西北大學(xué),2008.[Zhang Hong. The chronological
study on U-Pb dating of modern river detrital zircon in
north piedmont of Qinling and its geological indication[D].
Xi'an: Northwest University, 2008.]
[58] Dong Y P, Liu X M, Neubauer F, et al. Timing of Paleozoic
amalgamation between the North China and South China
Blocks: Evidence from detrital zircon U-Pb ages[J]. Tectonophysics,
2013, 586: 173-191.
[59] Li Y Q, He D F, Li D, et al. Detrital zircon U-Pb geochronology
and provenance of Lower Cretaceous sediments: Constraints
for the northwestern Sichuan pro-foreland basin[J]. Palaeogeography,
Palaeoclimatology, Palaeoecology, 2016, 453: 52-72.
[60] 劉寶星,裴先治,李瑞保,等. 南秦嶺勉略構(gòu)造帶橫現(xiàn)河地
區(qū)變質(zhì)沉積巖形成時代及物源:來自LA-ICP-MS 碎屑鋯石
U-Pb 年齡的證據(jù)[J]. 西北地質(zhì),2020,53(2):77-101.[Liu
Baoxing, Pei Xianzhi, Li Ruibao, et al. Age and provenance of
the metasedimentary rocks of Hengxianhe area in Mianlue
tectonic belt of Southern Qinling: Evidence from detrital zircons
LA-ICP-MS U-Pb dating[J]. Northwestern Geology, 2020, 53
(2): 77-101.]
[61] 李振華. 南秦嶺泥盆紀(jì)與揚(yáng)子板塊北緣新元古代晚期—早古
生代碎屑鋯石研究及其地質(zhì)意義[D]. 西安:西北大學(xué),2019.
[Li Zhenhua. Research on detrital zircons from the Devonian
clatic sequence in the South Qinling belt and the Late Neoproterozoic
to Early Paleozoic sedimentary rocks at the northern
margin of the Yangtze Block and its geological significancence
[D]. Xi'an: Northwest University, 2019.]
[62] 楊貴才. 西秦嶺陽山金礦帶印支期花崗巖成因及金成礦作用
[D]. 北京:中國地質(zhì)大學(xué)(北京),2019.[Yang Guicai. Petrogenesis
of indosinian granites and gold metallogeny of Yangshan
gold belt in Western Qinling[D]. Beijing: China University of
Geosciences (Beijing), 2019.]
[63] 孟旭陽,王曉霞,柯昌輝,等. 南秦嶺華陽花崗巖LA-ICP-MS
鋯石U-Pb 年齡、地球化學(xué)和Hf 同位素組成:對五龍巖體群成
因的約束[J]. 地質(zhì)通報,2013,32(11):1704-1719.[Meng
Xuyang, Wang Xiaoxia, Ke Changhui, et al. LA-ICP-MS zircon
U-Pb age, geochemistry and Hf isotope of the granitoids
from Huayang pluton in South Qinling orogen: Constraints on
the genesis of Wulong plutons[J]. Geological Bulletin of China,
2013, 32(11): 1704-1719.]
[64] 毛世東,陳衍景,周振菊,等. 南秦嶺東河群碎屑鋯石U-Pb 年
齡及其板塊構(gòu)造意義[J]. 巖石學(xué)報,2013,29(1):67-82.
[Mao Shidong, Chen Yanjing, Zhou Zhenju, et al. U-Pb ages
of detrital zircon grains from the Donghe Group in the Southern
Qinling microcontinent: Implications for tectonic evolution[J].
Acta Petrologica Sinica, 2013, 29(1): 67-82.]
[65] 楊力,陳福坤,楊一增,等. 丹鳳地區(qū)秦嶺巖群片麻巖鋯石UPb
年齡:北秦嶺地體中—新元古代巖漿作用和早古生代變質(zhì)
作用的記錄[J]. 巖石學(xué)報,2010,26(5):1589-1603.[Yang
Li, Chen Fukun, Yang Yizeng, et al. Zircon U-Pb ages of the
Qinling Group in Danfeng area: Recording Mesoproterozoic and
Neoproterozoic magmatism and Early Paleozoic metamorphism
in the North Qinling terrain[J]. Acta Petrologica Sinica, 2010,
26(5): 1589-1603.]
[66] 弓虎軍,朱賴民,孫博亞,等. 南秦嶺地體東江口花崗巖及其
基性包體的鋯石U-Pb 年齡和Hf 同位素組成[J]. 巖石學(xué)報,
2009,25(11):3029-3042. [Gong Hujun, Zhu Laimin, Sun
Boya, et al. Zircon U-Pb ages and Hf isotopic composition of
the Dongjiangkou granitic pluton and its mafic enclaves in the
South Qiniing terrain[J]. Acta Petrologica Sinica, 2009, 25
(11): 3029-3042.]
[67] Yuan W, Yang Z Y. The Alashan terrane was not part of North
China by the Late Devonian: Evidence from detrital zircon U-Pb
geochronology and Hf isotopes[J]. Gondwana Research, 2015,
27(3): 1270-1282.
[68] Yan Z, Xiao W J, Windley B F, et al. Silurian clastic sediments
in the North Qilian Shan, NW China: Chemical and isotopic
constraints on their forearc provenance with implications for
the Paleozoic evolution of the Tibetan Plateau[J]. Sedimentary
Geology, 2010, 231(3/4): 98-114.
[69] Xu Y J, Du Y S, Cawood P A, et al. Provenance record of a
foreland basin: Detrital zircon U-Pb ages from Devonian strata
in the North Qilian orogenic belt, China[J]. Tectonophysics,
2010, 495(3/4): 337-347.
[70] Xu Y J, Du Y S, Cawood P A, et al. Detrital zircon record of
continental collision: Assembly of the Qilian orogen, China
[J]. Sedimentary Geology, 2010, 230(1/2): 35-45.
[71] Gehrels G E, Yin A, Wang Y F. Detrital-zircon geochronology
of the northeastern Tibetan Plateau[J]. GSA Bulletin, 2003,
115(7): 881-896.
[72] 柯昌輝,王曉霞,李金寶,等. 華北地塊南緣黑山—木龍溝地
區(qū)中酸性巖的鋯石U-Pb 年齡、巖石化學(xué)和Sr-Nd-Hf 同位素研
究[J]. 巖石學(xué)報,2013,29(3):781-800.[Ke Changhui, Wang
Xiaoxia, Li Jinbao, et al. Zircon U-Pb age, geochemistry and
Sr-Nd-Hf isotopic geochemistry of the intermediate-acid rocks
from the Heishan-Mulonggou area in the southern margin of
North China Block[J]. Acta Petrologica Sinica, 2013, 29(3):
781-800.]
[73] 盧仁,梁濤,劉小麗. 華北克拉通南緣南召縣郭莊巖體鋯石UPb
年齡報道[J]. 中國地質(zhì),2021,48(4):1296-1297.[Lu Ren,
Liang Tao, Liu Xiaoli. The report on zircon U-Pb age of the
Guozhuang intrusive in the Nanzhao county, southern margin of
the North China Carton[J]. Geology in China, 2021, 48(4):
1296-1297.]
[74] 段友強(qiáng),張正偉,楊曉勇. 華北克拉通南緣張士英巖體大陸動
力學(xué)背景:來自地球化學(xué)、鋯石U-Pb 年齡和Hf 同位素的證據(jù)
[J]. 巖石學(xué)報,2015,31(7):1995-2008.[Duan Youqiang,
Zhang Zhengwei, Yang Xiaoyong. The continental dynamics of
Zhangshiying pluton at the southern margin of the North China
Craton: Evidence from geochemical, zircon U-Pb geochronology
and Hf isotopic compositions[J]. Acta Petrologica Sinica,
2015, 31(7): 1995-2008.]
[75] 蘇文博,李懷坤,徐莉,等. 華北克拉通南緣洛峪群—汝陽群
屬于中元古界長城系:河南汝州洛峪口組層凝灰?guī)r鋯石LAMC-
ICPMSU-Pb年齡的直接約束[J]. 地質(zhì)調(diào)查與研究,2012,
35(2):96-108.[Su Wenbo, Li Huaikun, Xu Li, et al. Luoyu
and Ruyang Group at the south margin of the North China Craton
(NCC) should belong in the Mesoproterozoic Changchengian
system: Direct constraints from the LA-MC-ICPMS U-Pb
age of the tuffite in the Luoyukou Formation, Ruzhou, Henan,
China[J]. Geological Survey and Research, 2012, 35(2):
96-108.]
[76] 胡國輝,趙太平,周艷艷,等. 華北克拉通南緣五佛山群沉積
時代和物源區(qū)分析:碎屑鋯石U-Pb 年齡和Hf 同位素證據(jù)[J].
地球化學(xué),2012,41(4):326-342.[Hu Guohui, Zhao Taiping,
Zhou Yanyan, et al. Depositional age and provenance of the
Wufoshan Group in the southern margin of the North China Craton:
Evidence from detrital zircon U-Pb ages and Hf isotopic
compositions[J]. Geochimica, 2012, 41(4): 326-342.]
[77] 田雯,王永詩,馬立馳,等. 鄂爾多斯盆地西南緣二疊系上石
盒子組碎屑鋯石U-Pb 年齡與地質(zhì)意義[J]. 礦物學(xué)報,2017,
37(6):782-790.[Tian Wen, Wang Yongshi, Ma Lichi, et al.
U-Pb age and geological significance of detrital zircon in the Upper
Shihezi Formation Permian system from the southwestern
margin of Ordos Basin[J]. Acta Mineralogica Sinica, 2017, 37
(6): 782-790.]
[78] 師江朋,楊浩田,楊德彬,等. 華北克拉通南緣太古宙地殼生
長和再造:登封地區(qū)五指嶺組碎屑鋯石U-Pb-Hf 同位素制約
[J]. 大地構(gòu)造與成礦學(xué),2018,42(2):379-391.[Shi Jiangpeng,
Yang Haotian, Yang Debin, et al. Archean crustal growth
and reconstruction of the southern margin of North China Craton:
Constraints from the U-Pb-Hf isotopic compositions of de‐
trital zircon from the Wuzhiling Formation at the Dengfeng area
[J]. Geotectonica et Metallogenia, 2018, 42(2): 379-391.]
[79] 鐘焱,相振群,初航. 華北克拉通北緣的中元古代多旋回復(fù)合
盆地及其地質(zhì)意義:來自碎屑鋯石U-Pb 年齡的統(tǒng)計學(xué)證據(jù)
[J]. 巖石學(xué)報,2019,35(8):2377-2406.[Zhong Yan, Xiang
Zhenqun, Chu Hang. A Mesoproterozoic multi-cycled composite
basin in the northern margin of the North China Craton and
its geological implications: Constraints from statistics of the detrital
zircon U-Pb data[J]. Acta Petrologica Sinica, 2019, 35
(8): 2377-2406.]
[80] 譚聰,盧遠(yuǎn)征,宋昊南,等. 華北克拉通西南緣高山河組凝灰
巖鋯石U-Pb 年齡及其地質(zhì)意義[J]. 地質(zhì)學(xué)報,2019,93(5):
1113-1124.[Tan Cong, Lu Yuanzheng, Song Haonan, et al.
Zircon U-Pb dating of the Gaoshanhe Formation tuff in the
southwestern margin of the North China Craton, and its geological
singificance[J]. Acta Geologica Sinica, 2019, 93(5): 1113-
1124.]
[81] 張恒,高林志,周洪瑞,等. 華北克拉通南緣官道口群和洛峪
群的年代學(xué)研究新進(jìn)展:來自凝灰?guī)rSHRIMP鋯石U-Pb 年齡
的新證據(jù)[J]. 巖石學(xué)報,2019,35(8):2470-2486.[Zhang
Heng, Gao Linzhi, Zhou Hongrui, et al. Chronology progress
of the Guandaokou and Luoyu Groups in the southern margin of
North China Craton: Constraints on zircon U-Pb dating of tuff
by means of the SHRIMP[J]. Acta Petrologica Sinica, 2019,
35(8): 2470-2486.]
[82] Bernet M. Exhumation studies of mountain belts based on detrital
fission-track analysis on sand and sandstones[M]//Malusà M
G, Fitzgerald P G. Fission-track thermochronology and its application
to geology. Cham: Springer, 2019: 269-277.
[83] 朱日祥,楊振宇,馬醒華,等. 中國主要地塊顯生宙古地磁視
極移曲線與地塊運(yùn)動[J]. 中國科學(xué)(D輯):地球科學(xué),1998,
28(增刊1):1-16.[Zhu Rixiang, Yang Zhenyu, Ma Xinghua,
et al. Phanerozoic paleomagnetic apparent pole shift curve and
block movement of main blocks in China[J]. Science China
(Seri. D): Earth Sciences, 1998, 28(Suppl. 1): 1-16.]
[84] 張國偉,張本仁,袁學(xué)誠,等. 秦嶺造山帶與大陸動力學(xué)[M].
北京:科學(xué)出版社,2001.[Zhang Guowei, Zhang Benren, Yuan
Xuecheng, et al. Qinling orogenic beit and continental dynamics
[M]. Beijing: Science Press, 2001.]
[85] 梁文天. 秦嶺造山帶東西秦嶺交接轉(zhuǎn)換區(qū)陸內(nèi)構(gòu)造特征與演
化過程[D]. 西安:西北大學(xué),2009.[Liang Wentian. Characteristics
and evolution of intracontinental tectonics in the transition
area between East and West Qinling in Qinling orogenic belt
[D]. Xi'an: Northwest University, 2009.]
[86] 王建強(qiáng),劉池洋,閆建萍,等. 鄂爾多斯盆地南部渭北隆起發(fā)
育時限及其演化[J]. 蘭州大學(xué)學(xué)報(自然科學(xué)版),2010,46
(4):22-29.[Wang Jianqiang, Liu Chiyang, Yan Jianping, et
al. Development time and evolution characteristics of Weibei uplift
in the south of Ordos Basin[J]. Journal of Lanzhou University
(Natural Sciences), 2010, 46(4): 22-29.]
[87] 祁凱,任戰(zhàn)利,張夢婷,等. 渭河地區(qū)及周緣晚古生代—中生
代碎屑鋯石年代學(xué)、地球化學(xué)及構(gòu)造—沉積意義[J]. 巖石學(xué)報,
2020,36(6):1897-1912.[Qi Kai, Ren Zhanli, Zhang Mengting,
et al. Characteristics of geochronology, geochemistry of
Late Paleozoic and Mesozoic in Weihe region and its tectonicsedimentary
significance[J]. Acta Petrologica Sinica, 2020, 36
(6): 1897-1912.]
[88] 任戰(zhàn)利,崔軍平,郭科,等. 鄂爾多斯盆地渭北隆起抬升期次
及過程的裂變徑跡分析[J]. 科學(xué)通報,2015,60(14):1298-
1309.[Ren Zhanli, Cui Junping, Guo Ke, et al. Fission-track
analysis of uplift times and processes of the Weibei uplift in the
Ordos Basin[J]. Chinese Science Bulletin, 2015, 60(14):
1298-1309.]
[89] 任戰(zhàn)利,崔軍平,李進(jìn)步,等. 鄂爾多斯盆地渭北隆起奧陶系
構(gòu)造— 熱演化史恢復(fù)[J]. 地質(zhì)學(xué)報,2014,88(11):2044-
2056. [Ren Zhanli, Cui Junping, Li Jinbu, et al. Tectonicthermal
history reconstruction of Ordovician in the Weibei uplift
of Ordos Basin[J]. Acta Geologica Sinica, 2014, 88(11):
2044-2056.]
[90] 劉池洋,趙紅格,趙俊峰,等. 能源盆地沉積學(xué)及其前沿科學(xué)
問題[J]. 沉積學(xué)報,2017,35(5):1032-1043.[Liu Chiyang,
Zhao Hongge, Zhao Junfeng, et al. Sedimentology of energy
basins and the frontier scientific problems[J]. Acta Sedimentologica
Sinica, 2017, 35(5): 1032-1043.]
[91] 李曉翠,劉武生,賈立城,等. 鄂爾多斯盆地南部砂巖型鈾礦
成礦預(yù)測[J]. 鈾礦地質(zhì),2014,30(6):321-327.[Li Xiaocui,
Liu Wusheng, Jia Licheng, et al. Prognosis of sandstone hosted
uranium deposit in southern Ordos Basin[J]. Uranium Geology,
2014, 30(6): 321-327.]
[92] Spirakis C S. The roles of organic matter in the formation of
uranium deposits in sedimentary rocks [J]. Ore Geology
Reviews, 1996, 11(1/2/3): 53-69.