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1.
高山林  刘士林  张仲培 《地质论评》2022,68(4):2022082004-2022082004
铁马河玄武安山岩位于鄂尔多斯地块西南缘,沿六盘山东麓断裂带出露。岩石发育气孔和杏仁状构造,具有斑状结构—间隐结构,斑晶主要为长条状斜长石和少量蚀变暗色矿物。岩石地球化学呈现富Na2O、FeOT、Al2O3,贫MgO、TiO2、K2O的特点,稀土配分曲线为右倾轻稀土富集型,LREE/ HREE=6. 50~7. 01,(La/Yb)N为5. 62~7. 14,富集Ba、Th、U、K等大离子亲石元素,Nb、Sr和Ti相对亏损,δEu= 0. 69~0. 91。样品n(87Sr)/n(86Sr)i为0. 70587~0. 70934,εNd(t)介于-6. 9 ~ -4. 8之间,TDM为2562~2730 Ma,Nb/Ta(6. 60~8. 25)低于大陆地壳的平均值,指示了受俯冲流体改造的古老富集地幔参与了岩浆形成。SHRIMP锆石U- Pb定年结果显示铁马河玄武安山岩形成于中元古代早期(~1740 Ma),其形成与研究区中元古代早期陆内伸展作用引起的古老岩石圈地幔减压熔融有关,是华北克拉通陆内裂谷发育过程在鄂尔多斯地块西南缘的体现。  相似文献   

2.
阿拉善地块的大地构造属性是近年来地质界激烈争论的科学问题:是华北克拉通的一部分,还是在前寒武纪尚未与华北克拉通拼合?研究阿拉善地块的基底并与华北克拉通主体进行对比,对探讨这一问题具有重要启示。阿拉善地块的基底仅在其东部和西南缘零星出露,且前人的研究主要集中在地块东部。在阿拉善地块西部的合黎山地区,有正长岩侵入龙首山群,并被震旦系不整合覆盖。该正长岩强烈富钾(K_2O=13.77%),轻、重稀土明显分异((La/Yb)_N=46.62),显示Nb-Ta负异常和Pb-Zr-Hf正异常,并具有高Sr低Nd的同位素特征(ε_(Nd)(t)=-5.05),表明该岩体源于玄武质下地壳的部分熔融。LA-ICP-MS锆石U-Pb定年表明,该正长岩形成于(1872±12) Ma,即古元古代,并记录了~2.7 Ga的地壳生长以及~2.5 Ga和~1.95 Ga的岩浆活动。合黎山古元古代正长岩的发现补充了阿拉善地块前寒武纪基底的组成,进一步完善了阿拉善地块新太古代—古元古代基底和构造热事件的时代格架,且与华北克拉通主体十分相似,指示二者具有明显的亲缘性。  相似文献   

3.
承德三岔口基性岩墙地球化学特征及地质意义   总被引:1,自引:0,他引:1  
对承德三岔口基性岩墙进行了锆石LA-ICP-MS U-Pb年代学和岩石地球化学研究。定年结果表明岩墙属晚印支期(222.1±1.6)Ma岩浆活动的产物;地球化学特征显示岩墙具有拉斑玄武岩特征,轻稀土(LREE)和大离子亲石元素(LILE)相对富集岩墙,亏损Nb、Ta和Ti等。同位素组成特征显示,岩墙具有正的初始Sr比值和负的εNd(t)值。以上特征都暗示三岔口基性岩墙可能来源于富集的岩石圈地幔。根据年代学、地球化学和前期研究成果认为,与三岔口基性岩墙同期位于华北北缘的东西向侵入岩带,可能是华北克拉通减薄的最初表现。  相似文献   

4.
三门峡市高庙石英闪长玢岩的激光探针等离子质谱(LA-ICP-MS)锆石U-Pb同位素年代测定获得了135Ma的年龄,与华北地块南缘早白垩世岩石圈伸展和减薄事件的时间一致.高庙岩体中继承锆石的形成年龄为2768Ma,该年龄和模式年龄均与华北克拉通早期地壳演化的峰期时间一致.石英闪长玢岩的SiO2含量为62.93%~65.54%,铝指数A/CNK=0.90 ~ 1.03,属于准铝质-弱过铝质系列.富钠(Na2O/K2O=1.29~1.46)、镁指数偏低(Mg#=33.5~42.4< 45),属于高钾钙碱性岩系.岩石稀土含量∑REE=197.09×10-6 ~234.41×10-6(平均216.00×10-6),轻重稀土明显分异[(La/Yb)N=15.86~20.55],基本不显示铕异常(δEu =0.96~1.02).岩石富集大离子亲石元素Rb、Ba、Sr、K等和轻稀土,高Sr/Y值(Sr/Y =41.99 ~56.71),亏损高场强元素Nb、Ta、Ti、重稀土和Y等.该石英闪长玢岩具有较低的n(143Nd)/n(144Nd) (t)值(0.5116)和较高的n(87Sr)/n86Sr) (t)值(0.7080),εNd(t)=-19.08,εsr(t) =49.89,TDM =2.15Ga.岩石的地球化学特点反映岩体由下地壳部分熔融形成.综合分析认为,高庙石英闪长玢岩源自加厚的基性下地壳的部分熔融作用,是华北克拉通的岩石圈在早白垩世减薄和破坏作用的产物,华北克拉通早白垩世期间的岩石圈减薄和破坏作用影响到了华北克拉通中-南部一带.  相似文献   

5.
本文收集大量锆石U-Pb年代学数据,通过制作年龄-频数图谱,简略探讨了西伯利亚克拉通、华北克拉通、东北地区微地块以及内蒙古大石寨地区的演化史,并对大石寨二叠系与其周边块体的锆石年龄作比较分析,进而探讨了大石寨地区二叠系的物源问题。碎屑锆石年龄-频数图表明,大石寨地区二叠系碎屑锆石年龄可以划分出古生代年龄段(500~250 Ma),中—新元古代年龄段(1.6~0.8 Ga),新太古一古元古代年龄段(2.6~1.7 Ga)。华北克拉通北缘与西伯利亚克拉通南缘基底年龄均1.6 Ga,其二者都不能反映大石寨地区二叠系物源年龄信息,而大石寨地区二叠系碎屑锆石年龄峰值与东北地区地块年龄峰具有很好一致性,说明二者锆石年龄峰值反映的构造岩浆事件一致,表明大石寨地区二叠系物源应来源于东北地块而不是华北克拉通和西伯利亚克拉通。同时,东北地区大量古老基底锆石年龄数据的存在,暗示东北地块可能独立于上述两大板块而存在,并响应中亚造山带内存在古老微大陆的观点;东北地块由诸多微小块体拼贴而成,并分别与西伯利亚克拉通和华北克拉通碰撞拼接,缝合线分别是贺根山一黑河缝合带与西拉木伦缝合带。  相似文献   

6.
中生代基性辉绿岩墙广泛分布于华北克拉通东部山东地区。本研究给出代表性岩墙的U-Pb锆石年龄、地球化学和Sr-Nd-Hf同位素证据,4个代表性锆石的LA-ICP-MS年龄范围处于121.9±0.6Ma和124.3±0.5Ma之间(早白垩纪)。岩石的主量元素组成变化较小,岩石富集轻稀土元素和大离子亲石元素(如,Rb、Ba、U、K和Pb),以及亏损高场强元素(如,Nb、Ta和Ti)。另外,基性岩墙具有相对一致的(87Sr/86Sr)i比值(~0.7098),负的εNd(t)值(-14.7~-14.5)、εHf(t)值(-31.4~-26.7)和高的Hf模式年龄(tDM1=1817~2024Ma)。研究显示基性岩墙来自富集岩石圈地幔的部分熔融作用,并在上升侵位过程中经历了一定程度的地壳混染作用影响。总体研究表明,基性岩墙的成因机制与扬子克拉通与华北克拉通的碰撞有关,岩浆源区为晚中生代前受俯冲扬子地壳沉积物交代后的富集岩石圈地幔。  相似文献   

7.
徐欢  赵慧  罗金海  程佳孝  尤佳  王师迪 《地质论评》2014,60(6):1284-1296
在华北地块西南缘陇县保家山西部铁马河剖面出露钾长花岗斑岩,与其伴生的有蚀变辉绿玢岩,整体沿六盘山断裂带分布。保家山钾长花岗斑岩富钾(Na2O/K2O=1.66~3.36),具钙碱性和准铝—弱过铝质特征(A/CNK=0.85~1.18)。富集轻稀土元素且轻重稀土元素分异明显(LREE/HREE=4.08~12.03),Eu负异常明显(δEu=0.50~0.53)。富集大离子亲石元素K、Rb、Ba、Th,亏损高场强元素Nb、Ta、Ti、Hf,强烈亏损P、Sr,且具有较高的Rb/Sr和Ga/Al比值,表现出A型花岗质岩石的特征。对两个样品进行锆石U-Pb LA-ICP-MS测年,分别获得n(206Pb)/n(207Pb)加权平均年龄1814±12Ma和1781±12Ma,说明岩体属于古元古代岩体。结合区域地质资料的研究表明,华北地块西南缘在古元古代期间处于强烈伸展背景,推测应该与古元古代贺兰坳拉槽的向南延伸有关。  相似文献   

8.
杨浩田  杨德彬  师江朋  许文良  王枫  谌瑛 《岩石学报》2018,34(11):3327-3340
大昆仑辉长岩和辉绿岩锆石LA-ICP-MS U-Pb年代学、锆石Hf同位素和全岩地球化学及全岩Sr-Nd-Pb同位素的研究为探讨鲁西地区早白垩世岩石圈地幔的属性提供了制约。结果表明,大昆仑辉长岩中少量锆石和辉绿岩中锆石发育条痕状吸收,具有相对高的Th/U比值(0.11~3.12),暗示它们均为岩浆成因,辉长岩中多数为岩浆成因的捕获锆石。辉长岩和辉绿岩中岩浆锆石的~(206)Pb/~(238)U加权平均年龄分别为132±3Ma和112±1Ma;辉长岩中捕获锆石的谐和年龄主要介于2469~1752Ma之间,暗示古老地壳物质的存在。辉长岩和辉绿岩整体具有低Si O_2(49.08%~52.61%)、高MgO(4.52%~9.67%)、Na_2O含量(2.58%~3.49%)以及高Mg~#值(45~65)特征;富集轻稀土元素和大离子亲石元素(Rb、Ba、Th)、贫重稀土元素和高场强元素(Nb、Ta、Zr和Hf),其(La/Yb)_N=8.98~10.2,Eu负异常不明显(δEu=0.83~0.93)。辉长岩的初始~(87)Sr/~(86)Sr比值变化于0.7046~0.7060之间,ε_(Nd)(t)值介于-16.71~-15.54之间,~(206)Pb/~(204)Pb、~(207)Pb/~(204)Pb和~(208)Pb/~(204)Pb初始比值分别为16.596~16.776、15.255~15.290和36.328~36.648。辉绿岩中岩浆锆石的ε_(Hf)(t)值介于-12.0~-2.5之间。上述结果表明,大昆仑辉长岩和辉绿岩形成于早白垩世,与华北克拉通东部早白垩世岩石圈减薄的峰期时间一致;起源于受华北克拉通古老下地壳物质改造的富集岩石圈地幔的部分熔融,形成于岩石圈减薄的伸展构造背景。  相似文献   

9.
吉林通化地区中元古代辉绿岩墙的发现及其地质意义   总被引:1,自引:0,他引:1  
报道了吉林通化地区中元古代辉绿岩墙LA-ICP-MS锆石U-Pb定年结果及地球化学特征,进而探讨了华北板块东北部中元古代辉绿岩墙形成的构造背景及其与哥伦比亚超大陆裂解事件的关系。辉绿岩中锆石呈自形,具有较高的Th/U值(0.21~1.45),其稀土配分型式显示轻稀土(LREEs)亏损、重稀土(HREEs)富集以及正Ce异常和负Eu异常,上述特征暗示所测锆石为岩浆锆石。锆石U-Pb定年结果显示: 7个分析点构成一条不一致线,上交点年龄为(1 244±28) Ma,该年龄代表了辉绿岩的形成时代,即中元古代。辉绿岩的SiO2质量分数为49.3%~49.5%,Mg#值为42.2~42.6,TFe2O3为13.6%~14.1%,属于拉斑玄武岩系列。微量元素特征显示: LREEs及大离子亲石元素(LILEs)相对富集,HREEs相对亏损,具有弱的Nb、Ta的亏损和Ti的富集,无明显Eu异常,Ba/Nb和La/Nb值分别为15.8~17.3和1.15~1.20,上述特征暗示通化地区中元古代辉绿岩来源于岩石圈地幔的部分熔融,并有软流圈组分的涉入。结合前人对华北板块北缘前寒武纪地质事件的研究成果,认为通化地区中元古代辉绿岩墙形成于强烈伸展环境,其形成与哥伦比亚超大陆的裂解有关。  相似文献   

10.
耿显雷  高山  陈晨 《地球科学》2011,36(3):483-499
来自年轻沉积物或现代河流的碎屑锆石是研究大陆地壳生长演化的理想载体.为揭示华北克拉通东部和苏鲁造山带大陆地壳的生长演化, 采集了中国东部大清河、潮白河、辽河、大沽河和胶莱河的5个地方的河沙样品, 并对分选出来的碎屑锆石进行了LA-ICP-MS和MC-LA-ICP-MS U-Pb定年和Hf同位素微区原位分析, 获得了396个锆石U-Pb谐和年龄及其对应的Hf同位素组成.2.4~2.5 Ga和1.8~1.9 Ga两个年龄特征峰指示大清河、潮白河和辽河的碎屑锆石来源于华北克拉通东部.辽河一部分100~500 Ma的锆石具有正的εHf(t)值和年轻的Hf模式年龄, 显示出显生宙的地壳生长.苏鲁造山带大沽河和胶莱河的碎屑锆石U-Pb年龄分布相对比较复杂, 但锆石U-Pb年龄和Hf同位素特征表明其为华北克拉通和扬子克拉通的混合来源.来自大清河、潮白河和辽河的锆石U-Pb年龄和Hf同位素证据, 表明华北克拉通东部地壳生长的主要时期为2.4~3.0 Ga, 并在2.6~2.7 Ga时处于生长的最高峰, 次一级的生长期为1.3~2.3 Ga, 而在其他阶段几乎没有地壳的生长或者不明显.华北克拉通东部现存大陆地壳的80%来源于太古代和古元古代的生长, 而自古元古代开始大陆地壳的演化就以古老地壳的重熔再改造为主.此外, 大沽河碎屑锆石的Hf同位素组成揭示出苏鲁造山带在古生代(300~500 Ma)存在明显的地壳生长.   相似文献   

11.
The Cimmerian terrane forms an almost unbroken chain stretching >13,500 km, from central southern Europe to western Indonesia, via SE Europe, the Middle East, Afghanistan, Tibet, SW China and Myanmar. Ar-guably, it is Earth’s most spectacular example of a “sliver” terrane, dwarfing in size more recently devel-oped examples, for instance the Palawan Block in the western Philippines, and the Lord Howe Rise in the Tasman Sea. The presentation will first outline the in-triguing geological features associated with this unique tectonic entity. Following that, recently obtained results following paleomagnetic investigations of two lower Permian rift-related basalt suites will be summarized (Abor Volcanics in northeastern India and Woniusi Ba-salts in Yunnan, China). The two studies are part of a larger programme of ongoing research aimed at deducing (I) the geodynamic configuration that generated the un-usual rifting system, and (II) exactly how Cimmeria fit-ted against Gondwana prior to its dispersal in the Early Permian. The critical unit is Baoshan, which we fit against Gondwana within a narrow longitudinal belt close to where northern India and northwestern Australia were once in close proximity (Fig. 1). Furthermore, we suggest that Sibumasu lay to directly the east, offshore of Australia; Qiangtang and Lhasa almost certainly sat to the west (off northern Greater India-SE Arabia), but we are uncertain as to their exact configuration. Our findings will be compared with several rather different models that have been published in recent years. The new pa-leomagnetic constraint highlights the flexibility authors currently have in reconstructing the region, principally because of the overall lack of similar high-quality data from the various blocks. We explain how new data could resolve these ambiguities, thereby offering more robust explanations for eastern Gondwana’s late Paleozoic de-velopment.  相似文献   

12.

Nd isotope studies of the oldest metasedimentary rocks from the Wonominta Block, western New South Wales reveal that these samples have a model age (TDM) of 1780–2010 Ma, slightly younger than that of low‐grade Willyama Supergroup metasediments (1920–2160 Ma), and significantly younger than those ages previously reported from high‐grade rocks of the Broken Hill Block (2200–2300 Ma). These differences have important implications for tectonic reconstruction in this region and support a model of transitional tectonics from the Broken Hill to Wonominta Blocks, as suggested by earlier geochemical studies of mafic rocks. Those studies revealed that the mafic rocks from the basal sequence of the Wonominta Block may have formed in a back‐arc basin, developed from a propagating rifting, an environment contiguous to that in which Willyama Supergroup was deposited. These results also carry significant implications for tectonic reconstruction of eastern Australia.  相似文献   

13.
The coals of the upper part of the Mansfield, Brazil, and the lower part of the Staunton Formations (Atokan and Desmoinesian, Pennsylvanian) in Indiana (Illinois Basin) are characteristically thin and discontinuous. As a result, problems with correlation and identification of the seams have persisted for both researchers and industry. These discrepancies affect coal exploration, mine planning, and subsequently coal-fired utilities. This study presents exploration and operational examples demonstrating some of the correlation problems associated with the coals of the Brazil Formation, and the Upper Block and Lower Block, in particular, and the surrounding upper part of the Mansfield Formation and lower part of the Staunton Formations. Based on exploration boreholes, mine scale observations, and coal quality and petrographic data, this study suggests that (1) the coal mapped as the Upper Block Coal Member of Clay County may, in fact, be the same seam as the Lower Block Coal Member of Daviess County; and (2) the Lower Block coal of Clay County is not present south of the Switz City area of central Greene County, IN.  相似文献   

14.
15.
钦-杭接合带之构造特征   总被引:2,自引:0,他引:2  
华南大陆壳由扬子地块和华夏地块两个主要的地质构造单元组成,其间发育一条板块碰撞拼接带——钦-杭接合带,依据地层组成、构造变形差异,进一步划分为鄣公山构造混杂岩带、绍兴-江山对接带,前者叠加发育在扬子地块南部陆缘江南古岛弧之上,后者代表两地块间消减了的大洋及边缘海混杂体,经历了晋宁-加里东多期碰撞拼贴:晋宁期华夏陆块向扬子陆块俯冲、碰撞、走滑,形成了透镜-网结状韧性剪切系统争三期褶皱变形;加里东运动,华夏陆块再次与扬子陆块碰撞、仰冲,导致华南加里东造山带逆冲推覆在晋宁期造山带之上。至此,两者最终焊接成一体,形成了统一的晚古生代沉积盖层。  相似文献   

16.
针对古生代中国中西部华北、华南和塔里木三大陆块在全球洋-陆格局中的古地理位置还存在的争议问题,本论文以国际最新的古地理位置重建研究方法和思路,在对中国三大陆块盆地(鄂尔多斯、四川和塔里木盆地)古生界钻井岩心的古地磁实测研究、全球古生代古地磁数据收集与有效性筛选处理、全球主要地质事件约束等多参数融合分析的基础上,采用最新的 GPlates 板块重建方法,对中国华北、华南和塔里木三大陆块在全球洋-陆格局中的古地理位置进行了重建和定位。研究结果表明:古生代三大陆块主要在全球 ±30° 之间的南北中低纬度之间迁移;三大陆块在古生代至少发生了 3 次不同的顺时针旋转和方位角转换;三大陆块运移速率至少经历了 3 次以上不同高、低速度间的转换与变化过程;响应于古生代全球洋-陆形成与演化,中国三大陆块古构造格局总体上经历了洋盆扩张下的“多岛洋”离散、俯冲碰撞下的离散-汇聚并存、俯冲消减下的差异汇聚隆升、新旧洋盆转换下的差异汇聚-离散、拼合与地幔柱控制下的差异汇聚-离散内部拉张的差异性演变过程。古生代中国三大陆块在全球洋-陆格局中的位置与差异性演变,奠定了中国三大陆块古生代不同性质盆地的形成与演化、不同层系油气烃源、储集原始物质差异性发育的基础。  相似文献   

17.
The Hukawng Basin is bounded on its east by splays of the still-active Sagaing Fault. Palinspastically restoring Myanmar's blocks to their positions before the widely-accepted c.400?km dextral strike-slip fault displacement, places the Hukawng Block alongside the Tengchong Block, suggesting they were formerly connected. Additionally the Cretaceous–Paleogene Medial-Myanmar Shear Zone then aligns with the NW-SE Jade Mines Belt. Jadeitite formed there under HP/LT conditions in a Mesozoic subduction zone. It was exhumed at the intersection of the dextral Medial-Myanmar Shear Zone with the subduction-zone at the continental margin of Sundaland. The later Sagaing Fault played no part in that exhumation.  相似文献   

18.
对华南地块、塔里木地块和基墨里大陆(包括保山、缅泰和羌塘地块)进行了古纬度和纬度运移量的对比分析,以确定古特提斯洋盆的闭合时代。结果表明:①保山与华南地块于晚二叠世碰撞,然后继续和华南地块、缅泰地块一起向北漂移,直到晚三叠世,并导致华南地块与华北地块碰撞和秦岭—大别造山带的形成;②羌塘地块与塔里木地块碰撞发生在晚三叠世;古特提斯洋沿着保山地块东缘和羌塘地块北缘的闭合是不同时的,东早西晚;③华南地块向北漂移,可能引起了华南地块西部和东昆仑—柴达木地块南部的古特提斯洋北岸的凹入,这为松潘—甘孜海底扇的发育提供了空间;古特提斯洋闭合引起的俯冲造成了华南地块西部大陆边缘的裂离,也共同为海底扇的发育提供了空间。包括塔里木地块、华南地块、东昆仑—柴达木地块和羌塘地块在内的几个地块的合围,导致了松潘—甘孜地块三角形的构造形状。支持以前的假设:松潘—甘孜三叠纪复理石杂岩的物源来自华北地块南缘或秦岭—大别造山带。  相似文献   

19.
华北、秦岭及扬子陆块的若干古地磁研究结果   总被引:13,自引:1,他引:13       下载免费PDF全文
本文对华北陆块、秦岭陆块以及扬子陆块内的70个采样点,474个标本进行了古地磁研究,利用16个采样点,112个标本中所获得的原生剩磁,重点分析了三陆块自寒武纪以来的古地磁极位置、古地磁偏角以及古纬度的变化特点。结果表明,三陆块为不同地质构造单元;寒武纪以来,华北陆块、秦岭陆块以及扬子陆块自北到南顺序排列;寒武纪时,秦岭陆块北侧和南侧分别存在一古洋盆,此时华北陆块和扬子陆块相距约1060km,三陆块向北漂移的过程中伴随着旋转运动,其中华北陆块和秦岭陆块以反时针旋转占优势,扬子陆块以顺时针旋转占优势;三陆块完全拼合时间在早三叠世至晚白垩世之间。  相似文献   

20.
Central Asian Orogenic Belt(CAOB) is one of the largest accretionary orogenic belts in the world. The eastern segment of CAOB is dominated by Paleozoic Paleo Asian Ocean tectonic regime, Mesozoic Paleo-Pacific tectonic regime and Mongolian-Okhotsk tectonic regime. The Songliao and Jiamusi blocks are located in the easternmost part of the CAOB and are the key region to solve the problem about overprinting processes of multiple tectonic regimes. It is generally believed that the Mudanjiang Ocean between the two blocks was finally closed in the Mesozoic, but the Paleozoic magmatism also developed along the Mudanjiang suture zone, while on both sides of the suture zone, there were comparable Paleozoic strata, indicating that the two blocks had converged during the Paleozoic, and the evolution history of the two blocks in the Late Paleozoic remains controversial. The Carboniferous-Permian terrestrial strata mainly developed in Binxian, Wuchang and Tieli on Songliao Block, Baoqing and Mishan on Jiamusi Block. Samples from the Songliao and Jiamusi blocks in the Late Carboniferous-Early Permian and Late Permian are collected for comparative analysis. The LAICP-MS zircon U-Pb dating results show that the maximum depositional age of Middle Permian Tumenling Formation and Late Permian Hongshan Formation in Songliao Block is ~260 Ma, while that of Tatouhe Formation and Carboniferous strata in Jiamusi Block are ~290 Ma and ~300 Ma, respectively, which supports the previous stratigraphic division scheme. The age peaks of ~290–300 Ma, ~400 Ma, ~500 Ma appeared in the Late Carboniferous to Early Permian strata of Jiamusi Block and the Middle Permian strata of Songliao Block. The age peak of ~500 Ma in the Middle Permian strata of Songliao Block may come from the Cambrian basement, Mashan Complex, of Jiamusi Block, while the age peaks of ~420–440 Ma in the Carboniferous strata of Jiamusi Block may come from the Silurian magmatic arc in Zhangguangcai Range in the eastern margin of Songliao Block, reflects the history that they had been potential sources of each other, indicating that they may have combined in the Paleozoic. The Hongshan Formation of Songliao Block in the Late Permian lacks the age peak of ~500 Ma, which indicate that Jiamusi Block was not the provenance of Songliao Block in the Late Permian, that is, there was a palaeogeographic isolation between the two blocks. Combined with the ~210 Ma bimodal volcanic rocks developed along the Mudanjiang suture zone reported previously, we believe that the oceanic basin between the Songliao and Jiamusi blocks should have been connected in Late Permian and reopened during Late Permian to Late Triassic.  相似文献   

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