新生代时期受太平洋板片俯冲影响,华北克拉通中东部广泛发育具有洋岛玄武岩特征的板内岩浆活动。然而华北克拉通西段目前并无新生代火山岩年代学及地球化学相关的研究。本文首次报道华北克拉通西部阿拉善巴隆乌拉新生代岩浆活动。来自巴隆乌拉玄武岩和粗玄岩锆石U-Pb定年限定这些岩石形成于始新世时期(37.2~36.5 Ma)。新生代玄武岩和粗玄岩SiO2(50.38%~51.65%)和Al2O3(16.9%~17.5%)含量,富集轻稀土元素和大离子亲石元素,无Eu负异常和Nb、Ta亏损,显示洋岛玄武岩特征。玄武岩和粗玄岩样品87Sr/86Sr值为0.7054~0.7057、全岩εNd(t )值及锆石εHf(t )值分别为-7.2~-6.7和-3.2~-1.1之间,显示富集的同位素组成。地球化学研究揭示这些新生代岩石在上升过程中经历了有限的地壳混染作用。与华北克拉通东部新生代玄武岩相比,阿拉善新生代玄武岩具有更高的大离子亲石元素和更加富集的同位素组成。阿拉善地块北部地区的新生代玄武岩和粗玄岩起源于部分熔融曾被俯冲熔体交代富集的石榴子石二辉橄榄岩,新生代由于岩石圈伸展和软流圈地幔上涌导致交代富集的地幔源区发生部分熔融,在阿拉善地区形成具有洋岛玄武岩地球化学特征的火山岩。

Cenozoic continental basalts with oceanic island basalt(OIB)-like geochemical compositions in the middle and eastern North China craton (NCC) are associated with the subduction of the Pacific slab. However, the geochronological and geochemical data of Cenozoic volcanic rocks in the western part of the North China craton are rarely reported.This paper reports for the first time the Cenozoic magmatism in Balongwula, northern Alxa block,western NCC. The basalts and dolerites in the Balongwula are constrained to the Eocene (37.2~36.5 Ma) by zircon U-Pb dating.These basalts and dolerites show high SiO2(50.38%~51.65%) and Al2O3(16.9%~17.5%) contents, are characterized by enrichment in light rare earthelements (LREEs) and large ion lithophile elements (LILEs), without negative Eu anomalies and Nb, Ta depletion, indicating an affinity with OIB. These rocks also display enriched isotopic compositions with initial 87Sr/86Sr ratios (0.7054~0.7057), εNd(t )(-7.2 to -6.7) and εHf(t ) (-3.2 to -1.1). Geochemical analyses reveal that crustal contamination in these Cenozoic rocks has been negligible. Compared with the Cenozoic basalts in the eastern NCC,the Cenozoic basalts in the northern Alxa block have more enriched isotopic compositions and higher LILEs contents.The Cenozoic basalts and dolerites in the northern margin of the Alxa block were derived from the partial melting of garnet lherzolite that was metasomatized by subducted-related melts. During the Cenozoic, the extension of the lithosphere drove the upwelling of the asthenospheric mantle, leading to partial melting of the metasomatized enriched mantle,forming volcanic rocks with OIB-like geochemical features in the Alxa block.

阿拉善地块 ； 新生代 ； 洋岛玄武岩 ； 古亚洲洋板片

Alxa block ； Cenozoic ； oceanic island basalt ； Paleo-Asian Ocean

克拉通岩石圈具有厚度大、刚性和热流值低的特点,除了有少量非造山岩浆活动和深部地幔起源的金伯利岩、碳酸岩岩浆活动记录外,克拉通很少有地壳变形和岩浆活动记录(Lee et al., 2011)。华北克拉通是世界上最古老的克拉通之一,具有超过3.8Ga的构造演化历史(Liu et al., 1992; Ma Qiang et al., 2020)。华北克拉通在1.8Ga前由东西陆块碰撞完成克拉通化,在晚古生代之前一直处于稳定状态,其上覆盖了中元古代—晚古生代未变质的沉积地层。中生代以来,华北克拉通遭受克拉通破坏,发育广泛陆内变形和岩浆-火山活动(朱日祥, 2012;Ma Qiang et al.,2021)。在华北克拉通东部和中部地区中—新生代时期(＜110Ma)发育较大规模陆内玄武质岩浆活动,这些玄武质岩石富集大离子亲石元素(LILE)和轻稀土元素(LREE)元素,具有相对富集的同位素组成显示洋岛玄武岩(OIB)地球化学特征(Xu Zheng et al., 2017; 徐义刚等, 2018)。

前人对中国东部中—新生代陆内玄武岩进行了大量的岩石学和地球化学研究,提出了不同的成因机制,包括地幔柱作用(Wang Xuance et al., 2012, 2015)、软流圈地幔的部分熔融(Zhou Xinghua et al., 1982)、下地壳组分加入到软流圈地幔中(Chen Lihui, 2009)。大多数研究者支持华北克拉通中东部具有洋岛玄武岩特征的中—新生代岩浆岩石与俯冲洋壳组分(包括蚀变大洋壳和之上的俯冲沉积物)加入到亏损地幔有关(Wang Yan et al., 2011;Xu Yigang et al., 2012; Xu Zheng et al., 2012; Huang Jian et al., 2015;徐义刚等, 2018)。这些中—新生代板内玄武岩源区普遍包含再循环洋壳组分和相对正常地幔较低的Mg同位素组成,其成因与太平洋板片俯冲有关(Huang Jian et al., 2015; Tian Hengci et al.,2016; Li Shuguang et al., 2017)。地震层析成像研究也表明大兴安岭太行山重力梯度带以东的地区地幔过渡带存在俯冲滞留板片(Huang Jinli et al., 2006),古太平洋-太平洋俯冲板片可能自晚中生代以来就对上覆的地幔楔进行了持续的化学交代改造并控制了板内玄武岩的成因(Zhao Dapeng et al., 2004; Li Shuguang et al., 2017; 徐义刚等, 2018; 徐峥等, 2019;Ma Qiang et al., 2021)。然而对于华北克拉通最西段的阿拉善地区,目前缺乏新生代火山岩年代学和地球化学数据。与中国大陆东部地区一样,早白垩世时期阿拉善地区发育广泛的北东—南西走向伸展盆地、南东向拆离断层以及陆内火山作用,指示广泛的岩石圈减薄过程。Hui Jie et al.(2021)认为阿拉善地区的早白垩世玄武岩与古太平洋板片回卷有关。而大多数研究者则认为这些火山岩由岩石圈拆沉导致俯冲的古亚洲洋板块的物质重熔对亏损的软流圈地幔进行交代富集而形成(徐操等, 2014;Dai Hongkun et al., 2019, 2021a); 也有研究者认为这些火山岩形成于陆内伸展环境可能与区域上阿尔金断裂带的再活化有关(汤文豪,2012)。

本次研究中,笔者首次报道了阿拉善地块北部巴隆乌拉新生代玄武岩和粗玄岩岩石学、地质年代学、全岩主微量、Sr-Nd同位素和锆石Hf同位素数据,限定了岩浆作用的时代、岩石成因以及阿拉善地块深部地幔特征。通过对比阿拉善地块中生代火山岩和华北板块中东部新生代火山岩地球化学数据,讨论华北克拉通最西段新生火山岩成因及地质意义。

阿拉善地块位于华北板块西段,南北被中亚造山带和中国中央造山带所夹持,记录了特提斯洋和古亚洲洋复杂的多期次俯冲增生演化历史。阿拉善地块北缘分布恩格尔乌苏和查干楚鲁两条蛇绿岩带,进一步将阿拉善地块划分为三个次一级的构造单元,从北到南分别为珠斯楞-雅干构造带、宗乃山-沙拉扎山构造带和诺尔公-狼山构造带(图1b)。

研究区位于阿拉善地块东北缘巴隆乌拉地区(图1c)。古亚洲洋在晚古生代末沿着阿拉善地块北缘恩格尔乌苏缝合最终消亡,阿拉善地块进入陆内构造演化阶段。中生代以来阿拉善地块记录了多期次的陆内变形事件。三叠纪时期阿拉善地块发育富碱性侵入岩带,包括石英正长岩和正长花岗岩,形成于古亚洲洋增生造山后伸展的构造背景(任康绪等, 2005a; 田健, 2019)。侏罗纪时期阿拉善地块有零星的陆相碎屑及含煤沉积。进入早白垩纪,整个东亚大陆经历了强烈的伸展事件,形成伸展沉积盆地、变质核杂岩,强烈的地壳伸展减薄也导致广泛的火山-岩浆作用(Wang Tao et al., 2011)。阿拉善地块在白垩纪时期广泛发育沉积盆地,包括潮水盆地、银根盆地和额济纳盆地等。银根盆地沉积广泛的白垩纪地层(图1c), 自下而上命名为巴音戈壁组、苏宏图组和乌兰素海组,其中苏宏图组发育碱性玄武岩系列, 40Ar/39Ar定年揭示这套火山岩石形成于114~105Ma,时代为早白垩世晚期(Zhu Rixiang et al., 2008;钟福平等, 2011)。

1 ∶20万银根幅地质图将本次研究的巴隆乌拉地区的火山岩也定名为苏宏图组,不整合覆盖在下伏巴音戈壁组泥岩、页岩和碳质页岩之上,时代为早白垩世。卫星影像图显示清晰且完整的火山口地形(图2a),火山口呈椭圆形,坍塌形成破火山口,其长轴约为4 km,短轴约为3 km,覆盖面积达约9 km2。20A03为玄武岩,样品地理坐标N40°57′44″,E105°47′22″(图1c),岩石露头较好,表面被沙漠漆覆盖,呈灰黑色,位于火山口顶部的玄武岩表面可见气孔构造(图2c)。岩石呈致密块状,新鲜面呈灰绿色,来自火山口的玄武岩呈层状结构(图2b)。岩石中矿物粒径较粗,自形长条状的斜长石呈放射状杂乱分布,其间充填有橄榄石和辉石,形成间粒结构(图2d、e)。玄武岩之下逐渐过渡为粗玄岩(20A04)(图2f),地理坐标N40°57′45″,E105°47′24″。野外及镜下观察显示全晶质结构,矿物粒径大多＞0.5 mm,具特征的间粒结构,肉眼见辉石和斜长石,斜长石发生较强烈的绢云母化(图2g、h)。本次研究选取新鲜、无风化且没有岩脉侵入的岩石样品进行地质年代学、全岩主微量和Sr-Nd同位素分析。

锆石挑选、制靶和CL照相在河北廊坊诚信地质服务有限公司完成。根据CL照片和透射光照片选择没有包裹体和裂隙的锆石颗粒用于年龄测试。锆石U-Pb-Hf同位素测试实验在南京大学内生金属成矿研究国家重点实验室完成,测试的仪器为Agilent 7500a电感耦合等离子体质谱仪(ICP-MS)。详细的实验参数及方法见Tian Rongsong et al.(2021)。全岩主量和微量元素测试在广州奥室分析检测有限公司完成完成。主量元素采用X射线荧光光谱仪熔融法分析,样品烧失量(LOI)则根据马弗炉1000℃有氧灼烧,冷却后再精确称重,试样灼烧前、灼烧后的重量差计算所得。微量元素则是往试样中加入硼酸锂熔剂,混合均匀,在熔炉中于1025℃熔融。待熔融液冷却后,然后用等离子体质谱仪分析。详细的分析程序见Dai Fuqiang et al.(2017)。Sr-Nd同位素分析在南京聚谱检测科技有限公司完成,Sr-Nd同位素比值用Nu Plasma II MC-ICP-MS测定。测试过程中,分别采用86Sr/88Sr=0.1194和Sr同位素国际标准物质NIST SRM 987校正仪器质量分馏和仪器漂移;而Nd同位素仪器质量分馏采用146Nd/144Nd=0.7219校正,同时用Nd同位素国际标准物质JNdi-1作为外标校正仪器漂移,详细的实验分析流程见Muhtar et al.(2019)。

图1 华北克拉通地质简图显示新生代玄武岩分布(a)(底图据Guo Pengyuan et al., 2014)、阿拉善地块构造单元划分简图显示研究区位置(b)(底图据Tian Rongsong et al., 2021)及巴隆乌拉玄武岩分布和样品位置(c)

Fig.1 Sketch map of the North China craton, showing the distribution of the Cenozoic basalts (a) (after Guo Pengyuanet al., 2014); sketch map of major tectonic divisions of the Alxa block, showing the location of the study area (b) (modified after Tian Rongsong et al., 2021); the distribution and sample locations of the Balongwula basalts (c)

图2 阿拉善新生代火山口卫星影像图(a)、巴隆乌拉新生代火山岩露头(b)、巴隆乌拉新生代玄武岩野外和镜下岩石学特征(c)~(e)及巴隆乌拉新生代粗玄岩野外和镜下岩石学特征(f)~(h)

Fig.2 Satellite image showing the Cenozoic crater of Alxa block (a),volcanic rock outcrop in Balongwula, northern Alxablock (b), field and microscopic petrological characteristics of Cenozoic basalt in Balongwula (c)~(e), field and microscopic petrological characteristics of Cenozoic dolerites in Balongwula (f)~(h)

来自玄武岩中的锆石颗粒细小,大多在50~120 μm之间,大多数锆石呈自形柱状特征,长宽比大多介于3∶1到2∶1之间。锆石显示较密集韵律环带,Th/U比值都大于0.8,显示基性岩浆锆石特征(图3)。玄武岩之下的粗玄岩锆石大多为自形柱状,显示较密集的岩浆震荡环带(图3)。

两个样品的锆石U-Pb年龄数据分析结果见表1,巴隆武拉玄武岩共分析18颗锆石,这些锆石具有谐和的U-Pb年龄(表1),大多投在谐和线上,其中12颗具有自形柱状的锆石颗粒获得了一致加权平均年龄为36.5±0.8Ma (MSWD=1.3),可能代表玄武岩的喷出年龄(图4a)。此外,玄武岩中也携带了较多的捕获锆石信息,锆石U-Pb定年结果显示这些捕获锆石大多形成于中生代和早古生代时期,与区域岩浆活动记录一致。粗玄岩样品中也获得最小的谐和锆石年龄为37.2±1.2Ma (MSWD=1.5) (图4b),与玄武岩最小年龄组在误差范围内较一致,可能代表其形成时代或时代下限。粗玄岩中捕获大量早古生代的锆石,此外也有少量晚古生代和新元古代锆石。

玄武岩和粗玄岩中的锆石具有一致的Hf同位素组成,其εHf(t)值在-3.2~-1.1之间(图6a,表2), 对应的亏损地幔模式年龄在823~736Ma之间,显示富集的锆石Hf同位素组成(表2)。

表1 阿拉善巴隆乌拉地区新生代玄武岩和粗玄岩锆石原位U-Pb定年结果

Table1 Zircon U-Pb dating results of the Cenozoic basalts and dolerites in the Balongwula, Alxa block

来自巴隆乌拉玄武岩和粗玄岩的10个样品的主微量元素含量分析数据见表3。这些样品显示较高的SiO2(50.38%~51.65%), K2O+Na2O(7.2%~8.6%),Al2O3(16.9%~17.5%)和TiO2含量(1.94%~2.18%)及相对较低的MgO含量(4.30%~5.65%),对应的Mg#在49~53之间。TiO2含量与同时代华北克拉通西部集宁地区玄武岩相似,但高于阿拉善地区早白垩世玄武岩(Hui Jie et al., 2021)。由于粗玄岩烧失量(LOI: 3.21%~3.47%)较高,将主量数据归一化后用于投图和讨论。在TAS图解和Zr/TiO2×10000-Nb/Y不活动元素投图中,这些新生代玄武岩和粗玄岩都分别落在了玄武质粗面安山岩和碱性玄武岩区域(图5a、b)。玄武岩和粗玄岩样品总稀土含量在153×10-6~173×10-6之间,在球粒陨石标准化稀土元素配分图上,显示轻稀土富集((La/Yb)N=10.8~12.6), 无明显的Eu异常(δEu=0.95~1.04),而在原始地幔微量元素标准化蛛网图解中,玄武岩和粗玄岩显示富集大离子亲石元素(Rb、Ba、K和Sr),而高场强元素(Nb、Ta、Ti、P)不亏损的特征(图5c、d)。巴隆乌拉地区的新生代玄武岩和粗玄岩显示高度一致的主微量元素组成,表明这些岩石具有相同的起源和演化过程。除了相对较高的大离子亲石元素外,这些岩石与洋岛玄武岩(OIB)显示非常一致的微量与稀土元素特征(图5c、d)。

图3 阿拉善新生代玄武岩(20A03)和粗玄岩(20A04)代表性阴极发光CL照片

Fig.3 Representative cathodoluminescence (CL) images of zircons from the Cenozoic basalts (20A03) and dolerites (20A04) in Alxa block

红色圆圈代表U-Pb年龄分析点,黄圈代表Hf同位素分析点

Redcircles stand for the LA-ICP-MS U-Pb analysis spots, yellow circles represent the Hf isotope analysis spots

图4 阿拉善新生代玄武岩(a、b)和粗玄岩(c、d)锆石U-Pb定年结果

Fig.4 Zircon U-Pb dating results of the Cenozoic basalts (a, b) and dolerite (c, d) in Alxa block

表2 阿拉善巴隆乌拉地区新生代玄武岩和粗玄岩原位锆石Hf同位素分析结果

Table2 In situ zircon Hf isotopic compositions of the Cenozoic basalts and dolerites in the Balongwula, Alxa block

图5 阿拉善地块巴隆乌拉地区新生代玄武岩和粗玄岩主微量数据投图

Fig.5 Diagrams for the major and trace elements of the Cenozoic basalts and dolerites in the Balongwula, Alxa block

(a)—Zr/TiO2与Nb/Y分类图解(底图据Winchester et al.,1977); (b)—TAS图解(底图据Le Maitre, 1989); (c)—稀土元素球粒陨石标准化图解;(d)—微量元素原始地幔标准化图解;球粒陨石和原始地幔标准化值和OIB, N-MORB以及E-MORB组成引自Sun et al.(1989), 华北克拉通西部集宁新生代玄武岩数据引自Ho Kungsuan et al.(2011), 阿拉善地块早白垩世玄武岩来自Hui Jie et al.(2021)

(a)—Zr/TiO2 versus Nb/Y classification diagram after Winchester et al.(1977); (b)—TAS diagram, after Le Maitre (1989); (c)—chondrite normalized rare earth element diagram; (d)—primitive mantle normalized incompatible element diagram; chondrite and primitive mantle values and OIB, N-MORB, and E-MORB compositions are from Sun et al.(1989); Cenozoic Jining basalts of the western NCC are from Ho Kungsuan et al.(2011) and Early Cretaceous basalts in the Alxa block are from Hui Jie et al.(2021)

表3 阿拉善北部巴隆乌拉地区新生代玄武岩和粗玄岩全岩主量、微量元素分析结果

Table3 Whole rock major and trace elements of the Cenozoic basalts and dolerites in the Balongwula, Alxa block

与阿拉善地区下白垩统苏宏图组玄武岩和华北克拉通西部集宁地区新生代玄武岩相比,阿拉善地区新生代玄武岩和粗玄岩具有较高的轻稀土和大离子亲石元素(图5c、d)。

阿拉善巴隆乌拉新生代玄武岩和粗玄岩具有均一的Sr-Nd同位素组成,显示较富集的初始87Sr/86Sr比值(0.7054~0.7057), 和初始143Nd/144Nd比值(0.51222~0.51224),对应的εNd(t)值在-7.2~-6.7之间,亏损地幔模式年龄为1.74~1.62Ga(表4),这些新生代玄武岩和粗玄岩Sr-Nd同位素投图落在靠近I型富集地幔区域(图6b),指示这些基性岩石源区可能为富集地幔。与华北东部地区新生代玄武岩相比,阿拉善地区的中—新生代玄武岩更加富集Sr-Nd同位素组成。

表4 阿拉善巴隆乌拉地区新生代玄武岩和粗玄岩全岩Sr-Nd同位素数据

Table4 Whole-rock Sr-Nd isotopic compositions the Cenozoic basalts and dolerites in the Balongwula, Alxa block

图6 阿拉善新生代玄武岩和粗玄岩锆石Hf同位素组成 (a)、阿拉善和华北克拉通中—新生代玄武岩Sr-Nd同位素组成(b)

Fig.6 Zircon Hf isotope compositions of Cenozoic basalts and dolerites in Alxa block (a) and Sr-Nd isotope compositions of Mesozoic and Cenozoic basalts (b) in the Alxa block and NCC

华北克拉通东部新生代玄武岩数据来自Xu Zheng et al.(2017), 华北西部四子王旗早白垩世钾玄岩和阿拉善苏宏图早白垩世火山岩数据引自徐操等(2014)

Cenozoic basalts from the eastern NCC are from Xu Zheng et al.(2017); Early Cretaceous shoshonites from the Siziwangqi, western NCC, and Early Cretaceous volcanic rocks from Alxa block, are after Xu Cao et al.(2014)

由于玄武岩硅不饱和,用锆石U-Pb定年限定其喷发时代相对较难。然而本次采样的巴隆乌拉玄武岩和粗玄岩显示较高的SiO2含量(50.38%~51.65%),接近中性岩浆岩石组分。锆石CL图像显示这些锆石颗粒较小、晶形发育较好,大多呈柱状且发育较密集的环带(图3),反映经历了较长的冷却结晶过程,同时也具有较高的Zr含量(214×10-6~242×10-6)。锆石U-Pb定年获得的206Pb/238U年龄为37.2~36.5Ma可能代表了玄武岩的喷发年龄,即使这些锆石是捕获锆石,也代表巴隆乌拉玄武岩和粗玄岩形成时代晚于37.2~36.5Ma,支持这些岩石形成于新生代时期。

尽管巴隆乌拉地区新生代玄武岩存在丰富的捕获锆石,表明岩浆上升过程中受到地壳混染。然而,新生代玄武岩和粗玄岩样品具有高的TFe2O3(8.75%~9.83%)、 TiO2(1.94%~2.10%)含量和均一的全岩Sr-Nd和锆石Hf同位素组成,在微量元素蛛网图上缺乏Nb、Ta亏损,且存在明显的Th、U槽,表明有限的大陆地壳物质混染。此外,来自玄武岩和粗玄岩样品有较高的Nb/U比值(69.4~80.5),高于大洋中脊玄武岩(MORB)和洋岛玄武岩(OIB)的Nb/U比值(47±10; Hofmann et al., 1986), 而大陆地壳Nb/U比值相对较低(Nb/U=12; Taylor et al.,1985)。因此巴隆乌拉碱性玄质岩没有经历明显的地壳混染,其较高的全碱含量和富集的同位素组成基本反映了源区特征。相似地,华北克拉通中-西部新生代玄武岩,包括汉诺坝、大同和太行山地区玄武岩从深部喷发到地表过程中大多也没有遭受地壳混染(Xu Yigang et al.,2005; Tang Yanjie et al.,2006)。

阿拉善地区巴隆乌拉新生代玄武岩较高SiO2(50.38%~51.65%),低MgO(4.30%~5.65%)和Cr(80×10-6~110×10-6)含量,缺乏幔源橄榄岩包体,Mg#为49~53,不同于原生幔源岩浆组分,表明经历了分离结晶过程。此外,野外及镜下薄片观察到岩石中矿物粗大,结晶较好且缺乏玻璃质成分,也进一步支持这个观点。玄武岩和粗玄岩主量元素TFe2O3、CaO、MgO与SiO2呈负相关(图7),表明单斜辉石在岩浆演化过程中分离结晶。

阿拉善新生代玄武岩显示高的初始87Sr/86Sr比值 (0.7054~0.7057)普遍高于原始地幔值(0.7044)这些新生代岩石都显示负的εNd(t)值(-7.2~-6.7)。在初始87Sr/86Sr比值与εNd(t)值图解中投在第四象限的区域,表明这些玄武质岩浆来自于富集地幔源区。这些岩石富集轻稀土元素和大离子亲石元素,具有古老的Nd模式年龄和锆石Hf模式年龄暗示岩浆源区存在富集组分。一些研究者支持这些富集组分可能来源于循环的大洋地壳(Sobolev et al., 2007)或者俯冲的陆壳物质(Hofmann, 1997)。有的研究者则认为循环洋壳太亏损,大陆地壳尽管和OIB一样富集不相容元素,但是大陆地壳显著亏损Nb和Ta,因此认为循环大洋壳和俯冲的陆壳物质可能不是重要的组成(牛耀龄, 2010),而认为地幔交代作用是OIB富集的重要途经 (McKenzie et al., 1995; Niu Yaoling, 2008)。研究表明俯冲洋壳俯冲到达深部时(100~300km), 俯冲带组分包括蚀变大洋壳和之上的沉积物会发生部分熔融,形成的熔体具有富集轻稀土元素和大离子亲石元素,而不亏损高场强元素(如Nb和Ta)的特征,并与上俯冲带之上的地幔橄榄岩发生反应形成富含角闪石或辉石的地幔交代岩(Pilet et al., 2008)。后期这些地幔交代岩由于岩石圈伸展减薄发生部分熔融形成具有OIB微量元素特征及较高的Fe/Mn比值的岩浆。阿拉善地块东北缘地区巴隆乌拉新生代玄武岩和粗玄岩具有较高的Fe/Mn比值(57~68),并显示俯冲的印迹, 因此笔者认为这些具有洋岛玄武岩特征的岩石源区为受到古老板块俯冲组分交代的富集地幔。

这些新生代火山岩没有显示负的Eu异常(Eu/Eu*=0.95~1.04)表明斜长石在源区不是主要的残留阶段。一般认为玄武质岩浆起源于部分熔融地幔二辉橄榄岩,这些岩石的稀土模式通常受源区石榴子石和尖晶石含量的控制(McKenzie et al., 1991;Oyan et al., 2017)。一般来说,起源于尖晶石二辉橄榄岩源区的玄武质岩石显示平坦的球粒陨石标准化稀土模式,缺乏或具有弱的轻重稀土分离特征。由于重稀土元素与石榴子石更相容,玄武质岩石起源于石榴子石二辉橄榄岩源区会显示强烈的轻重稀土分异特征,因此也具有高的(La/Yb)N和(Ce/Yb)N比值(McKenzie et al., 1991)。来自阿拉善地块东北缘巴隆乌拉地区的新生代玄武质岩石显示强烈的轻重稀土分离和高的(La/Yb)N和(Ce/Yb)N比值,与含石榴子石二辉橄榄岩地幔起源的玄武质岩石相似。此外,在Sm/Yb与La/Sm投图上这些岩石也投在石榴子石二辉橄榄岩地幔源区(图8c)。因此,这些数据支持阿拉善地块东北缘新生代玄武岩起源于部分熔融曾被俯冲熔体交代的石榴子石二辉橄榄岩。

图7 阿拉善地块新生代火山岩SiO2 与主要氧化物CaO、TFe2O3和MgO变化图解(a~c)

Fig.7 The variation diagrams of SiO2 vs.CaO, TFe2O3 and MgO (a~c) for the Cenozoic volcanic rocks in the Alxa block

巴隆乌拉地区新生代火山岩的稀土元素配分曲线(图5c)以及微量元素特征(图5d)与典型的洋岛玄武岩非常相似。在Th/Yb与Ta/Yb图解和TiO2-MnO×10-P2O5×10三角图解上,所有玄武岩样品都分别落在了洋岛玄武岩区域(图8b)和洋岛碱性玄武岩区域(图8d),而在TiO2与Zr图解中,这些样品都落在了板内玄武岩区域(图8a),反映这些岩石形成于与洋岛玄武岩类似的板内构造背景。然而,这些火山岩位于银根盆地白垩系巴音戈壁组砂砾岩之上,岩石中发育气孔构造。此外,大量的研究表明古亚洲洋沿阿拉善地块北缘在晚古生代晚期完成最终拼合(Song Dongfang et al., 2018;Tian Rongsong et al., 2021),阿拉善地块进入陆内演化阶段。阿拉善地块北缘火山岩虽然具有类似于OIB的地球化学特征,但形成于陆内构造背景。

在华北克拉通东部,古太平洋板块俯冲驱动岩石圈减薄、克拉通破坏(朱日祥, 2012;Ma Qiang et al., 2021),来自太平洋俯冲板片旋回的俯冲组分在新生代玄武岩中被广泛识别(Xu Zheng et al., 2012; Li Shuguang et al.,2017;徐义刚等, 2018),大多数研究者支持中国东部新生代具有洋岛玄武岩特征的板内玄武岩是由于太平洋板片俯冲交代,大陆岩石圈拉张和软流圈地幔上涌,发生部分熔融而形成(Wang Yan et al.,2011;Huang Jian et al., 2015;徐义刚等, 2018)。由于新生代时期华北克拉通已经发生破坏和岩石圈减薄,中国东部地区岩石圈厚度普遍小于80km,形成的岩浆大多为中等碱性程度的玄武岩。与华北克拉通东部广泛分布的新生代玄武岩不同,本次在阿拉善地块东北缘地区发现的新生代玄武岩显示相对富集同位素特征,同时也更加富集大离子亲石元素(Rb、Ba、Sr和K)和更高的全碱含量。阿拉善地块远离太平洋构造域,新生代时期太平洋板块俯冲很可能没有影响到阿拉善地区。阿拉善地块靠近古亚洲洋缝合带,来自狼山地区晚白垩世玄武岩岩石地球化学特征表明岩石圈地幔受到古亚洲洋俯冲板片的交代(Dai Hongkun et al., 2019, 2021b)。碱性玄武岩中深源捕虏体也支持华北克拉通西北部岩石圈地幔和深部地壳被俯冲的古亚洲洋板片改造(Chen Chunfei et al., 2017; Liu Yongsheng et al., 2010; Dai Hongkun et al., 2018)。

图8 阿拉善巴隆乌拉新生代玄武岩和粗玄岩构造判别图解

Fig.8 Tectonic discrimination diagrams for the Balongwula basalts and dolerites, Alxa block

(a)—TiO2-Zr图解(据Pearce,1982);(b)—Th/Yb-Ta/Yb图解(据Wilson,1989)显示巴隆乌拉玄武岩具有洋岛玄武岩特征;(c)—Sm/Yb-La/Sm图解(据Aldanmaz et al.,2000);(d)—TiO2-MnO×10-P2O5×10三角图解(据Mullen, 1983);gt—石榴子石;sp—尖晶石;gt-lherzolite—石榴子石二辉橄榄岩;sp-lherzolite—尖晶石二辉橄榄岩;DM—亏损地幔;PM—原始地幔;N-MORB—正常大洋中脊玄武岩

(a)—TiO2 versus Zr diagram (after Pearce, 1982); (b)—Th/Yb versus Ta/Yb diagram (modified from Wilson, 1989) showing the oceanic-island basalt (OIB)-like features of the Cenozoic Balongwula basalts; (c)—Sm/Yb versus La/Sm diagram (after Aldanmaz et al., 2000); (d)—TiO2-MnO×10-P2O5×10ternary diagrams (after Mullen, 1983); gt—garnet;sp—spinel;gt-lherzolite—garnet lherzolite; sp-lherzolite—spinel lherzolite;DM—depleted mantle; PM—primitive mantle; N-MORB—normal-mid-ocean-ridge basalt

始新世晚期—中新世早期,鄂尔多斯地块西北缘开始强烈的地壳伸展形成沉积盆地(施炜等, 2018)。阿拉善地块东北缘地区这些玄武岩代表新生代早期该地区处于地壳伸展环境,区域上同时期也发育伸展盆地沉积乌兰布拉格组地层。研究显示鄂尔多斯地块周缘的主边界断裂均切穿地壳,岩石圈发生强烈破坏减薄(Tang Youcai et al., 2011)。此外,中亚造山带内宗巴彦断裂(Zuunbayan Fault)为一条巨型走滑断裂,该断裂呈NE—SW走向沿中蒙边界延伸到研究区附近,中生代晚期,该断裂活动在阿拉善地块北缘地区形成英巴变质核杂岩(Zhou Yinzhang et al., 2012; Yin Congyuan et al., 2017),新生代早中期时期可能再一次活化,形成区域上左行走滑剪切变形。有研究者认为这些大规模走滑剪切可能通过阿拉善和河西走廊地区与阿尔金断裂活动联系起来(Lamb et al., 1999; Yue Yongjuan et al, 1999),导致强烈的区域地壳伸展。因此新生代时期鄂尔多斯西北缘以及陆内大型走滑断裂活动可能形成广泛的地壳伸展,导致岩石圈减薄和软流圈地幔上涌,驱动交代的地幔源区发生部分熔融,喷出地表在巴隆乌拉地区形成新生代玄武岩。

(1)锆石U-Pb定年揭示阿拉善地块北部巴隆乌拉玄武岩和粗玄岩形成于始新世时期(37.2~36.5Ma)或始新世之后,指示阿拉善地块可能存在新生代岩浆活动。

(2)巴隆乌拉新生代玄武岩和粗玄岩具有富集的Sr-Nd-Hf同位素组成,富集轻稀土和大离子亲石元素,无Eu负异常和Nb、Ta亏损,显示洋岛玄武岩特征。

(3)阿拉善地块北缘新生代玄武岩起源于部分熔融曾被俯冲熔体交代富集的石榴子石二辉橄榄岩,新生代时期由于岩石圈伸展,软流圈上涌,导致被交代的地幔部分熔融形成新生代玄武岩和粗玄岩。

致谢:野外地质工作中得到南京大学张庆龙教授的悉心指导,审稿专家提出了宝贵的修改意见,在此一并表示衷心的感谢!

Aldanmaz E, Pearce J A, Thirlwall M F, Mitchell J G. 2000. Petrogenetic evolution of late Cenozoic, post-collision volcanism in western Anatolia, Turkey. Journal of Volcanology and Geothermal Research, 102: 67~95.

Chen Lihui, Zeng Gang, Jiang Shaoyong, Hofmann A W, Pan Mingbao. 2009. Sources of Anfengshan basalts: subducted lower crust in the Sulu UHP belt, China. Earth and Planetary Science Letters, 286(3-4): 426~435.

Chen Chunfei, Liu Yongsheng, Foley S F, Ducea M N, Geng Xianlei, Zhang Wen, Xu Rong, Hu Zhaochu, Zhou Lian, Wang Zaicong. 2017. Carbonated sediment recycling and its contribution tolithospheric fertilization under the northern North China craton. Chemical Geology, 466: 641~653.

Dai Fuqiang, Zhao Zifu, Zheng Yongfei. 2017. Partial melting of the orogenic lower crust: geochemical insights from post-collisional alkaline volcanics in the Dabie orogen. Chemical Geology, 454: 25~43.

Dai Hongkun, Zheng Jianping, Xiong Qing, Su Yuping, Pan Shaokui, Ping Xianquan, Zhou Xing. 2018. Fertile lithospheric mantle underlying ancient continental crust beneath the northwesternNorth China craton: significant effect from the southward subduction of the Paleo-Asian Ocean. Geological Society of America Bulletin, 131: 3~20.

Dai Hongkun, Zheng Jianping, O'Reilly S Y, Griffin, W L, Xiong Qing, Xu Rong, Su Yuping, Ping Xianquan, Chen Fukun. 2019. Langshan basalts record recycled Paleo-Asian oceanic materials beneath the northwestern North China craton. Chemical Geology, 524: 88~103.

Dai Hongkun, Oliveira B, Zheng Jianping, Griffin W L, Afonso, J C, Xiong Qing, O'Reilly S Y. 2021a. Melting dynamics of Late Cretaceous lamprophyres incentral Asia suggest a mechanism toexplain many continental intraplatebasaltic suite magmatic provinces. Journal of Geophysical Research: Solid Earth, 126: 2021JB021663.

Dai Hongkun, Zheng Jianping, Xiong Qing, O'Reilly S Y, Griffin W L. 2021b. Deep lithosphere of the North China Craton archives the fate of the Paleo-Asian Ocean. Earth-Science Reviews, 215: 103554.

Guo Pengyuan, Niu Yaoling, Ye Lei, Liu Jinju, Sun Pu, Cui Huixia, Zhang Yu, Gao Junping, Su Li, Zhao Jianxin, Feng Yuexing. 2014. Lithosphere thinning beneath west North China craton: evidence from geochemical and Sr-Nd-Hf isotope compositions of Jining basalts. Lithos, 202-203: 37~54.

Ho Kungsuan, Liu Yan, Chen Juchin, You Chenfeng, Yang Huaijen. 2011. Geochemical characteristics ofCenozoic Jining basalts of the western North China craton: evidence for the roleof the lower crust, lithosphere, and asthenosphere in petrogenesis. Terrestrial, Atmospheric and Oceanic Sciences, 22: 15~40.

Hofmann A W. 1997. Mantle geochemistry: the message from oceanic volcanism. Nature, 385: 219~229.

Hofmann A W, Jochum K P, Seufert M, White W M. 1986. Nb and Pb in oceanic basalts: new constraints onmantle evolution. Earth and Planetary Science Letters, 79: 33~45.

Hui Jie, Cheng Hongyi, Zhang Jin, Zhang Kaijun, Qu Junfeng, Zhang Beihang. 2021. Early Cretaceous continent basalts in the Alxa block, NW China: geochronology, geochemistry, and tectonic implications. International Geological Reviews, 63(7): 882~899.

Huang Jinli, Zhao Dapeng. 2006. High-resolution mantle tomography of China and surrounding regions. Journal of Geophysical Research: Solid Earth, 111 (B9): B09305.

Huang Jian, Li Shuguang, Xiao Yilin, Ke Shan, Li Wangye, Tian Ye. 2015. Origin of low δ26 Mg Cenozoicbasalts from South China block and their geodynamic implications. Geochimica ET Cosmochimica Acta, 164: 298~317.

Lamb M A, Hanson A D, Graham S A, Badarch G, Webb L E. 1999. Left-lateral sense offset of upper Proterozoic to Paleozoic features across the Gobi Onon, Tost, and Zuunbayan faults in southern Mongolia and implications for other Central Asian faults. Earth and Planetary Science Letters, 173: 183~194.

Le Maitre R W. 1989. A Classification of Igneous Rocks and Glossary of Terms (IUGS): Recommendations of the IUGS Subcommission on the Systematics of Igneous Rocks. Oxford: Blackwell.

Lee C T, Luffi P, Chin E J. 2011. Building and destroying continental mantle. Annual Review of Earth and Planetary Sciences, 39: 59~90.

Li Shuguang, Yang Wei, Ke Shan, Meng Xuan, Tian Hengci, Xu Lijuan, He Yongsheng, Huang Jian, Wang Xuance, Xia Quanke, Sun Weidong, Yang Xiaoyong, Ren Zhongyuan, Wei Haiquan, Liu Yongsheng, Meng Fancong, Yan Jun. 2017. Deep carbon cyclesconstrained by a large-scale mantle Mg isotope anomaly in eastern China. National Science Review, 4: 111~120.

Liu Dunyi, Nutman A P, Compston W, Wu J S, Shen Q H. 1992. Remnants of ＞3800 Ma crust in the Chinese part of the Sino-Korean craton. Geology, 20: 339~342.

Liu Yongsheng, Gao Shan, Hu Zhaochu, Gao Changgui, Zong Keqing, Wang Dongbing. 2010. Continental and oceanic crust recycling-induced melt-peridotite interactions in the Trans-North China orogen: U-Pb dating, Hf isotopes and trace elements in zircons from mantle xenoliths. Journal of Petrology, 51: 537~571.

Ma Qiang, Xu Yigang, Huang Xiaolong, Zheng Jianping, Ping Xianquan, Xia Xiaoping. 2020. Eoarchean to Paleoproterozoic crustal evolution in the North China craton: evidence from U-Pb and Hf-O isotopes of zircons from deep-crustal xenoliths. Geochimica et Cosmochimica Acta, 278: 94~109.

Ma Qiang, Xu Yigang. , 2021. Magmatic perspective on subduction of Paleo-Pacific plate and initiation of big mantle wedge in East Asia. Earth-Science Reviews, 213: 103473.

McKenzie D, O'Nions R K. 1991. Partial melt distributions from inversion of rare earth element concentrations. Journal of Petrology, 32: 1021~1091.

McKenzie D, O'Nions R K. 1995. The source regions of oceanic island basalts. Journal of Petrology, 36: 133~159.

Mullen E D. 1983. MnO-TiO2-P2O5: a minor element discriminantfor basaltic rocks of oceanic environments and itsimplications for petrogenesis. Earth and Planetary Science Letters, 62: 53~62.

Muhtar M N, Wu Changzhi, Santosh M, Lei Ruxiong, Gu Lianxing, Wang Simeng, Gan Kai. 2019. Late Paleozoic tectonic transition from subduction to post-collisional extension in eastern Tianshan, Central Asian orogenic belt. Geological Society of America Bulletin, 132: 1756~1774.

Niu Y L. 2008. The origin of alkaline lavas. Science, 320: 883~884

Niu Y L. 2010. Some basic concepts and problems on the petrogenesis of intra-plate ocean island basalts. Chinese Science Bulletin, 55(2): 103~114 (in Chinese with English abstract).

Oyan V, Keskin M, Lebedev V A, Chugaev A V, Sharkow E V, Unal E. 2017. Petrology and geochemistry of the Quaternary mafic volcanism to the NE of Lake Van, Eastern Anatolian Collision Zone, Turkey. Journal of Petrology, 58: 1701~1728.

Pearce J A. 1982. Trace element characteristics of lavas from destructive plate boundaries. In: Thorpe R S eds. Andesites: Orogenic Andesites and Related Rocks. Chichester: John Wiley and Sons, 528~548.

Ren Kangxu, Yan Guohan, Mu Baolei, Xu Baoliang, Tong Ying, Chen Tingli, Cai Jianhui. 2005a. Rb-Sr age and geological implication of the Alxa alkaline-rich intrusive rocks, western Inner Mongolia. Acta Scientiarum Naturalium Universitatis Pekinensis, 41(2): 204~211 (in Chinese with English abstract).

Ren Kangxu, Yan Guohan, Mu Baolei, Cai Jianhui, Tong Ying, Li Fengtang, Zhao Fengsan, Gu Libing, Yang Bin, Chu Zhuyin. 2005b. Geochemistry and Nd, Sr, Pb isotopic characteristics of the alkali-rich intrusive rocks in Alxa fault block, Western Inner Mongolia and their implications. Earth Science Frontiers, 2005, 12(2): 292~301 (in Chinese with English abstract).

Pilet S, Baker M B, Stolper E M. 2008. Metasomatized lithosphere and the origin of alkaline lavas. Science, 320: 916~919.

Shi Wei, Hu Jianmin, Chen Hong. 2018. Cenozoic structure around the Ordos block China. Earth Sciences Joint Academic Conference, 290~292.

Sobolev A V, Hofmann A W, Kuzmin D V, Yaxley D M, Arndt N T, Chung S L, Danyushesky L V, Elliott T, Fery F A, Garica M O. 2007. The amount of recycled crust in sources of mantle derived melts. Science, 316: 412~417.

Song Dongfang, Xiao Wenjiao, Collins A S, Glorie S, Han Chunming, Li Yongchen. 2018. Final subduction processes of the Paleo-Asian Ocean in the Alxa tectonic belt (NW China): constraints from field and chronological data of Permian arc-related volcano-sedimentary rocks. Tectonic, 37: 1658~1687.

Sun S S, McDonough W F. 1989. Chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes. In Saunders A D, Norry M J, ed. Magmatism in the Ocean basins. Geological Society of London, Special Publication: 313~345.

Tang Yanjie, Zhang Hongfu, Ying Jifeng. 2006. Asthenosphere-lithospheric mantle interaction in an extensional regime: implication from the geochemistry of Cenozoic basalts from Taihang Mountains, North China craton. Chemical Geology, 233: 309~327.

Tang Youcai, Chen Y John, Zhou Shiyong, Ning Jieyuan, Ding Zhifeng. 2011. Lithosphere structure and thickness beneath the North China craton from joint inversion of ambient noise and surface wave tomography. Journal of Geophysical Research, 118(5): 2333~2346.

Tang Wenhao, Zhang Zhicheng, Li Jianfeng, Chen Chen, Li Ke. 2012. Geochemical characteristics and tectonic significance ofthe Cretaceous volcanic rocks in the eastern terminal of the Altyn Tagh fault zones. Earth Science Frontiers, 19: 51~62 (in Chinese with English abstract).

Taylor S R, Mclennan S M. 1985. The continental crust: Itscomposition and evolution. Journal of Geology, 94: 632~633.

Tian Hengci, Yang Wei, Li Shuguang, Ke Shan, Chu Zhuyin. 2016. Origin of low δ26 Mg basalts with EM-I component: evidence for interaction between enriched lithosphere and carbonated asthenosphere. Geochimica ET Cosmochimica Acta, 188: 93~105.

Tian Jian, Xin Houtian, Teng Xuejian, Liu Yang, Guo Shuo, Teng Fei, He Peng, Wang Wenlong. 2019. Tectonic significance of Carboniferous-Triassic magmatism in Langshan area, Inner Mongolia. Earth Science, 44(1): 206~219 (in Chinese with English abstract).

Tian Rongsong, Xie Guoai, Zhu Wenbin, Gao Shuang. 2021. Late Paleozoic magmatic flare-up in the Nuoergong-Langshan Belt, Alxa block: insights into tectonic evolution of the southern Paleo-Asian Ocean. Lithos, 398-399: 106310.

Wang Tao, Zheng Yadong, Zhang Jinjiang, Zeng Lingsen, Donskaya T, Guo Lei, Li Jianbo. 2011. Pattern and kinematic polarity of Late Mesozoic extension in continental NE Asia: perspectives from metamorphic core complexes. Tectonics, 30: TC6007.

Wang Yan, Zhao Zifu, Zheng Yongfei, Zhang Junjun. 2011. Geochemical constraints on the nature of mantle source for Cenozoic continental basalts in East-Central China. Lithos, 125(3-4): 940~955.

Wang Xuance, Li Zhengxiang, Li Xianhua, Li Jie, Liu Ying, Long Wenguo, Zhou Jinbo, Wang Wei. 2012. Temperature, pressure, and composition of the mantle source region of Late Cenozoic basalts in Hainan Island, SE Asia: a consequence of a young thermal mantle plume closeto subduction zones? Journal of Petrology, 53(1): 177~233.

Wang Xuance, Wilde S A, Li Qiuli, Yang Yanan. 2015. Continental flood basalts derived from the hydrous mantle transition zone. Nature Communications, 6: 7700.

Wilson, M. , 1989. Igneous Petrogenesis. London: Harper CollinsAcademic, 466.

Winchester J A, Floyd P A. 1977. Geochemical discrimination of different magma series and their differentiation products using immobile elements. Chemical Geology, 20: 325~343.

Xu Yigang, Ma Jinlong, Frey F A, Feigenson M D, Liu Jiangfeng. 2005. Role of lithosphere-asthenosphere interactionin the genesis of Quaternary alkali and tholeiitic basalts from Datong, western North China craton. Chemical. Geology, 224: 247~271.

Xu Yigang, Zhang Huihuang, Qiu Huaning, Ge Wenchun, Wu Fuyuan. 2012. Oceanic crust components in continental basalts from Shuangliao, Northeast China: derived from the mantle transition zone? Chemical Geology, 328: 168~184.

Xu Yigang, Li Hongying, Hong Lubing, Ma Liang, Ma Qiang, Sun Mingdao. 2018. Generation of Cenozoic intraplate basalts in the big mantle wedge under eastern Asia. Science China Earth Sciences, 61: 869~886.

Xu Zheng, Zhao Zifu, Zheng Yongfei, 2012. Slab-mantle interaction for thinning of cratonic lithospheric mantle in North China: geochemical evidence from Cenozoic continental basalts in central Shandong. Lithos, 146-147: 202~217.

Xu Chao, He Yuankai, Wu Tairan, Zheng Rongguo, Zhang Wen, Meng Qingpeng, Zhang Zhaoyu. 2014. Geochemical characteristics of Early Cretaceous shoshonites in the middle and western northern margin of the North China craton and a comparative study. Acta Scientiarum Naturalium Universitatis Pekinensis, 50: 301~315 (in Chinese with English abstract).

Xu Zheng, Zheng Yongfei. 2017. Continental basalts record the crust-mantle interaction in oceanic subduction channel: a geochemical case study from Eastern China. Journal of Asian Earth Sciences, 145: 233~259.

Xu Zheng, Zheng Yongfei. 2019. Crust-mantle interaction in the Paleo-Pacific subduction zone: geochemical evidence from Cenozoic continental basalts in Eastern China. Earth Science, 44(12): 4135~4143 (in Chinese with English abstract).

Yin Congyuan, Zhang Bo, Han Baofu, Zhang Jinjiang, Wang Yang, Ai Sheng. 2017. Structural analysis and deformation characteristics of the Yingba metamorphic core complex, northwestern margin of the North China craton, NE Asia. Journal of Structural Geology, 94: 195~212.

Yue Yongjun, Liou J G. 1999. Two-stage evolution model for the Altyn Tagh fault, China. Geology, 27: 227~230.

Zhao Dapeng, Lei Jianshe, Tang Rongyut. 2004. Origin of the Changbai intraplate volcanism in Northeast China: evidence from seismic tomography. Chinese Science Bulletin, 49: 1401~1408.

Zhong Fuping, Zhong Jianhua, Wang Yi, You Weifeng, Yang Weili, Zheng Menglin. 2011. The Early Cretaceous volcanic rocks in Suhongtu depression in Yingen-Ejina Qi basin: its scientific significance to the research of Altun fault. Earth Science Frontiers, 18(3): 233~240 (in Chinese with English abstract).

Zhu Rixiang, Pan Yongxin, He Huaiyu, Qin Huafeng, Ren Shoumai. 2008. Palaeomagnetism and 40Ar/39Ar age from a Cretaceousvolcanic sequence, Inner Mongolia, China: implications for the field variation during the Cretaceous normalsuperchron. Physics of the Earth and Planetary Interiors, 169: 59~75.

Zhu Rixiang, Xu Yigang, Zhu Guang, Zhang, Hongfu, Xia Quanke, Zheng, Tianyu. 2012. Destruction of the North China craton. Science China Earth Sciences, 42(8): 1135~1159 (in Chinese with English abstract).

Zhou Yinzhang, Han Baofu, Zhang Bo, Xu Zhao, Ren Rong, Li Xiaowei, Su Li. 2012. The Yingba shear zone on the Sino-Mongolian border: southwestern extension of the Zuunbayan fault from Mongolia to China and implications for Late Mesozoic intracontinental extension in eastern Asia. Tectonophysics, 574: 118~132.

Zhou Xinghua, Armstrong R. 1982. Cenozoic volcanic rocks of eastern China: secular and geographic trends in chemistry and strontium isotopic composition. Earth and Planetary Science Letters, 58(3): 301~329.

牛耀龄. 2010. 板内洋岛玄武岩(OIB)成因的一些基本概念和存在的问题. 科学通报, 55(2): 103~114.

任康绪, 阎国翰, 牟保磊, 许保良, 童英. 2005a. 阿拉善断块富碱侵入岩Rb-Sr年龄及其地质意义. 北京大学学报(自然科学版), 41(2): 204~211.

任康绪, 阎国翰, 牟保磊, 蔡剑辉, 童英, 李凤棠, 赵凤三, 古丽冰, 杨斌, 储著银. 2005b. 阿拉善断块富碱侵入岩岩石地球化学和Nd、Sr、Pb同位素特征及其意义. 地学前缘, 12(2): 292~302.

施炜, 胡健民, 陈虹. 2018. 鄂尔多斯地块周缘新生代构造. 中国地球科学联合学术年会, 290~292.

汤文豪, 张志诚, 李建锋, 晨辰, 李可. 2012. 阿尔金断裂东端白垩纪火山岩地球化学特征及其地质意义. 地学前缘, 19: 51~62.

田健, 辛后田, 滕学建, 刘洋, 郭硕, 滕飞, 何鹏, 王文龙. 2019. 内蒙古狼山地区石炭纪-三叠纪岩浆作用及其构造意义. 地球科学44: 206~219.

徐操, 贺元凯, 吴泰然, 郑荣国, 张文, 孟庆鹏, 张昭昱. 2014. 华北板块北缘中-西段早白垩世钾玄岩地球化学特征及对比研究. 北京大学学报(自然科学版), 50: 301~315.

徐峥, 郑永飞. 2019. 中国东部新生代玄武岩记录古太平洋俯冲带壳幔相互作用. 地球科学, 44: 4135~4143.

徐义刚, 李洪颜, 洪路兵, 马亮, 马强, 孙明道. 2018. 东亚大地幔楔与中国东部新生代板内玄武岩成因. 中国科学: 地球科学, 48: 825~843.

钟福平, 钟建华, 王毅, 由伟丰, 杨伟利, 郑孟林. 2011. 银根-额济纳旗盆地苏宏图坳陷早白垩世火山对阿尔金断裂研究的科学意义. 地学前缘, 18(3): 233~240.

朱日祥, 徐义刚, 朱光, 张宏福, 夏群科, 郑天愉. 2012. 华北克拉通破坏. 中国科学: 地球科学, 42(8), 25: 1135~1159.