The petrogenesis and tectonic significance of the latest Late Cretaceous arc igneous rocks in Sumdo area, Tibet
-
摘要:
新特提斯洋在晚白垩世末期(68Ma左右)的构造演化一直饱受争议。西藏松多地区晚白垩世末期弧岩浆岩包括花岗斑岩和二长花岗岩。锆石定年结果显示，二长花岗岩和花岗斑岩年龄均为68Ma。松多花岗斑岩和二长花岗岩的SiO2含量为68.5%~80.6%，K2O含量为4.1%~6.5%，P2O5含量为0.011%~0.058%。花岗斑岩Mg#值较低，为11.3~19.0，二长花岗岩Mg#值为24.2~43.5。花岗斑岩和二长花岗岩样品均显示轻稀土元素富集、重稀土元素亏损和明显的Eu(δEu=0.15~1.21)负异常。两者均富集大离子亲石元素Rb、Th、U、K、Pb等，亏损高场强元素Nb、Ta、Ti。花岗斑岩εHf(t)值为-0.9~+2.9，二阶段模式年龄TDMC在955~1196Ma之间; 二长花岗岩εHf(t)值为-17.1~+7.9(只有1个点为负值)，二阶段模式年龄在633~2219Ma之间。最终认为，松多地区晚白垩世末期二长花岗岩和花岗斑岩岩浆源区为新生下地壳，但花岗斑岩更靠近古老下地壳。结合区域资料，认为新特提斯洋在晚白垩世末期68Ma左右属于洋脊俯冲结束阶段。
Abstract:The tectonic evolution of the Neo-Tethys Ocean in the last phase of Late Cretaceous around 68Ma has been controversial. This paper firstly reports the last phase of Late Cretaceous arc igneous rocks in the Sumdo area of Tibet. They consist of granite porphyry and monzogranite. Zircon dating results show that the age of granite porphyry and monzogranite is 68Ma. The granite porphyry and monzogranite have the data SiO2(68.5%~80.6%), K2O (4.1%~6.5%), and P2O5 (0.011%~0.058%). The granite porphyry contains low Mg# values (11.3~19.0), and the monzogranite has high Mg# values (24.2~43.5). The granite porphyry and monzogranite show light REE enrichment, heavy REE depletion, and obvious negative Eu anomalies. They both are enriched in large-ion lithophile elements such as Rb, Th, U, K and Pb, and depleted in high-field-strength elements such as Nb, Ta and Ti. The granite porphyry has εHf(t) values ranging between -0.9 and +2.9, corresponding to TDMC model ages 955~1196Ma. The εHf(t) values of the monzogranite are -17.1~+7.9, with only one point being negative, corresponding to TDMC model ages 633~2219Ma. The authors have thus drawn the conclusion that the magma source of the granite porphyry and monzogranite in the Songdo area was new lower crust, but the granite porphyry was closer to the ancient lower crust. Combined with regional data, the authors hold that the Neo-Tethys Ocean belongs to the end stage of ocean ridge subduction in the last phase of Late Cretaceous around 68Ma.
-
班公湖-怒江结合带(BNS)位于青藏高原北部, 西起班公湖, 向东经改则、东巧、丁青与昌宁-孟连带相连, 向西延伸向克什米尔, 与东地中海特提斯蛇绿岩相连, 在中国境内长达2000km, 是青藏高原一条重要的结合带[1]。班公湖-怒江结合带中存在规模巨大的蛇绿岩、增生杂岩, 以及夹持其中的残余弧或岛弧变质地块, 发育韧性剪切带、逆冲断层、构造混杂岩、复杂褶皱等多种构造行迹, 沿断裂还发育晚白垩世-新近纪陆相火山岩、新生代陆相走滑拉分盆地和第四纪谷地[2]。为更好地认识班公湖-怒江结合带内物质的形成机制及相关的构造背景, 需要对其开展深入的研究。
通过对沉积岩中的碎屑锆石进行U-Pb定年分析, 可有效地探讨其源区并开展历史时期的古大陆重建。本文对该地区早白垩统多尼组(原1:25万区调划为上三叠统巫嘎组)砂岩的碎屑锆石开展了形态学及U-Pb年代学研究, 为揭示班公湖-怒江缝合带内该地层单元的物源区提供新的证据, 同时为探讨班公湖-怒江结合带的构造演化史提供一定的依据。
1. 地质特征
多尼组出露于改则县南西的洞错一带(图 1), 呈近东西向带状分布, 区域上为一套灰色-深灰色含煤碎屑岩地层。岩性主要为泥岩、砂岩、板岩、页岩、粉砂岩、石英砂岩、长石石英砂岩, 局部含火山岩, 产植物、菊石、双壳类、腹足类、珊瑚、层孔虫、海胆、腕足类、介形类等化石。根据野外实测剖面特征, 研究区多尼组主要岩性为深灰色、灰色泥质粉砂岩、粉砂岩, 局部夹灰色钙质岩屑石英砂岩、长石石英砂岩及少量灰岩等, 在灰岩中局部可见生物碎屑, 未见完整化石。
2. 样品采集与分析方法
样品采集于西藏改则县洞错乡南约15km处欧仁一带的PM009地层剖面上。样品岩性主要为灰色中细粒长石石英砂岩, 主要由石英(84%)、长石(13%)、岩屑(2%)、胶结物等组成, 颗粒大小以0.15~ 0.60mm为主, 分选性好, 磨圆度一般, 呈次棱角状, 次圆状。石英主要为单晶石英, 长石类以斜长石为主, 岩屑成分主要为灰岩、泥岩、粉砂岩等, 孔隙式胶结(图 2)。
样品锆石的分离和挑选由廊坊市地岩矿物分选有限公司完成, 在双目镜下挑选出晶形和透明度好的锆石颗粒, 粘贴在环氧树脂表面, 抛光后将锆石进行透射光、放射光和阴极发光显微照相。锆石制靶及阴极发光图像制备由北京中美美科科技有限公司完成, LA-ICP-MS锆石U-Pb定年测试分析在中国地质大学(武汉)地质过程与矿产资源国家重点实验室完成。其中LA-ICP-MS锆石U-Pb同位素年龄分析仪器为Elan6100DRC型激光剥蚀系统, 激光器为193nmArF准分子激光器。激光剥蚀斑束直径为32μm, 激光剥蚀深度为20~40μm。实验中采用氦气为剥蚀物质的载气, 采用标准锆石91500为外标, 采用美国国家标准物质局人工合成硅酸盐玻璃NIST SRM610为内标。详细的实验原理、流程和仪器参数见Yuan等[3]的文献。
3. 分析结果
多尼组砂岩碎屑锆石U-Pb年龄数据见表 1。在多尼组砂岩样品中, 随机挑选71粒锆石进行分析。从阴极发光(CL)图像(图 3)看出, 锆石颗粒大小在50~180μm之间。研究表明, 不同成因的锆石具有不同的Th/U值, 岩浆锆石的Th/U值较大(一般大于0.4);而变质锆石的Th/U值较小(一般小于0.1)[4]。多尼组砂岩碎屑锆石的Th/U值较大, 51颗锆石的Th/U值大于0.4, 平均值约为0.64, 说明锆石大部分为岩浆成因, 部分可能为变质成因。
表 1 洞错地区多尼组砂岩碎屑锆石U-Th-Pb同位素年龄数据Table 1. Detrital zircons U-Th-Pb data of sandstones in the Duoni Formation from Dongcuo area
![]()
图 3 洞错地区多尼组砂岩碎屑锆石阴极发光图（年龄单位为Ma）Figure 3. Cathodoluminescene images of detrital zircons of sandstones in the Duoni Formation from Dongcuo area4. 分析与讨论
4.1 测年结果
对于年轻锆石而言, 207Pb/206Pb年龄误差较大, 而对于古老锆石而言, 206Pb/238U年龄的误差较大。本文在年龄选取时, 对小于1000Ma的锆石, 选取206Pb/238U计算年龄值; 年龄大于1000Ma的锆石, 选取207Pb/206Pb计算年龄值[5]。从碎屑锆石年龄分布频率直方图(图 4)可以看出, 多尼组砂岩碎屑锆石年龄值分布在125~3261Ma之间。其中125~1000Ma的锆石有37粒, 最年轻年龄值为125Ma(测点号为PM009/26-17, 和谐度为97%); 大于1000Ma的年龄值为34个, 最老年龄值为3261Ma(测点号为PM009/26-35, 和谐度为96%)。碎屑锆石主要年龄区间(或峰值)为3261Ma、2739~2335Ma、1880~ 1750Ma、1006~657Ma、577~510Ma、456~409Ma和252~202Ma(表 1)。
![]()
图 4 青藏高原碎屑锆石U-Pb年龄频率图（据参考文献[15]修改）Figure 4. Age distributions of detrital zircons from the Tibetan Plateau4.2 讨论
多尼组的碎屑锆石年龄数据跨度较大, 不同的年龄峰值代表不同的地质意义。
(1) 3261Ma, 大于3000Ma的碎屑锆石在样品中仅出现1粒, 表明物源区存在古老地壳的残留[6], 为研究班怒带物源区的形成和演化奠定了物质基础。
(2) 2739~2335Ma年龄组包含10颗碎屑锆石, 代表物源区可能存在构造-岩浆事件。从全球地质背景看, 华北、北美、瑞芬及其他克拉通在2.5Ga左右发生了大规模的拼合事件(如Grenville事件、Pan-Afriean事件等), 形成有记载的最古老的超级大陆[7]。近年来, 众多学者在羌塘盆地发现1.8~ 2.7Ga的锆石, 如盆地中央隆起带差桑-茶布一带的戈木日群[8], 盆地西南部龙木错-双湖缝合带南侧荣玛温泉地区石英岩[9], 以及羌塘盆地北部唐古拉山温泉地区雁石坪群[10]。暗示羌塘盆地有太古宙的地壳物质, 支持羌塘盆地存在前寒武纪结晶基底的可能性。这也说明, 研究区多尼组的物源很可能为北部的南羌塘地块。
(3) 1880~1750Ma年龄组包含16颗碎屑锆石, 指示源区存在古元古代早期的构造热事件。研究表明[11-12], Columbia超级大陆各个组成陆块是在2.1~ 1.8Ga碰撞事件中拼合在一起的, 并在中元古代早-中期Columbia超级大陆边缘向外增生, 随后开始裂解, 1880~1750Ma可能也是羌塘结晶基底的主期变质年龄。
(4) 1006~657Ma年龄组包含13颗碎屑锆石, 该期是全球构造运动演化的一系列重大热事件时期, Grenvillian碰撞造山期(1000~900Ma)形成了罗迪尼亚超大陆, 在850~750Ma开始隆升、裂解[13]。在700Ma发生分解, 反映了早期的泛非碰撞, 中国大陆主要的构造表现为普遍存在张裂, 在羌塘结晶基底的戈木日群中发现1016~929Ma的热事件, 说明此时羌塘地块存在构造热事件[1]。
(5) 577~510Ma年龄组包含5颗碎屑锆石, 指示了新元古代晚期的一次构造热事件, 该组年龄值可能是泛非造山运动(550±100Ma)在物源区的记录。
(6) 456~409Ma年龄组包含8颗碎屑锆石, 可能指示了冈瓦纳大陆北缘在早泥盆世-奥陶纪的增生过程[14]。
(7) 252~202Ma年龄组包含5颗碎屑锆石, 指示拉萨地块与羌塘地块之间发生了俯冲消减及碰撞与缝合作用。
(8) 最小年龄125Ma和126Ma, 可能代表该套地层的沉积时代, 说明该套地层于早白垩世沉积形成。
班公湖地区中生代沙木罗组和日松组碎屑锆石显示, 其沉积物的物源区可能为北部的羌塘地块[1]。商旭地区中生代沉积物中含有部分来自其北部南羌塘地块中的物质, 暗示班公湖-怒江洋壳在中生代向北俯冲[15]。南羌塘与特提斯喜马拉雅沉积变质岩的碎屑锆石年龄具有相似的频率分布特征, 且二者的主要年龄峰值为530Ma、950Ma, 其与高喜马拉雅新元古代沉积变质岩碎屑锆石的年龄主峰一致, 表明其在古生代与高喜马拉雅相邻; 同时, 拉萨地块与澳大利亚西部的碎屑锆石具有一致的年龄峰值1170Ma, 表明拉萨地块可能在石炭纪-二叠纪与澳大利亚西北部毗邻[16]。从锆石年龄分布频率图可见, 研究区碎屑锆石年龄分布直方图与南羌塘更具相似性, 西藏洞错地区班公湖-怒江结合带早白垩世沉积物的物源可能来自北部的南羌塘地块。
5. 结论
(1) 班公湖地区早白垩世多尼组砂岩碎屑锆石LA-ICP-MS U-Pb测年结果显示, 碎屑锆石最年轻颗粒的年龄值为125Ma, 说明其形成时代晚于早白垩世; 最老碎屑锆石年龄值为3261Ma, 表明物源区存在古老地壳的残留。
(2) 将研究区早白垩世碎屑锆石的年龄分布频率图与南部的拉萨地块及北部的南羌塘地块对比, 其与南羌塘地块更具相似性, 说明研究区的早白垩世沉积物的物源可能来自北部的南羌塘地块。
致谢: 感谢吉林大学青藏高原科研团队所有成员。 -
![]()
图 1 冈底斯岩浆岩带构造地质简图(据参考文献[24]修改)
BNSZ—班公湖-怒江缝合带；SNMZ—狮泉河-永珠-嘉黎带；LMF—洛巴堆-米拉山断裂带；
IYZSZ—印度-雅鲁藏布缝合带；SL—南拉萨地块；CL—中拉萨地块；NL—北拉萨地块Figure 1. Tectonic map of the Gangdise belt
![]()
图 3 花岗斑岩与二长花岗岩野外照片(a、c)和镜下照片(b、d)
Qz—石英；Bit—黑云母；Or—正长石
Figure 3. Field photos (a, c) and microscope photographs(b, d) of granite porphyry and monzogranite
![]()
![]()
图 5 松多地区花岗斑岩和二长花岗岩球粒陨石标准化稀土元素配分曲线(a)和原始地幔标准化微量元素蛛网图(b)(标准化数据据参考文献[53])
Figure 5. Chondrite-normalized REE patterns(a) and primitive-normalized multi-element spider diagram(b) for granite porphyry and monzogranite from Sumdo area
![]()
图 6 松多地区花岗斑岩和二长花岗岩锆石U-Pb谐和图、206Pb/238U年龄图和锆石阴极发光（CL）图像
Figure 6. U-Pb concordia diagrams, plot of 206Pb/238U age and CL images for granite porphyry and monzogranite from Sumdo area
![]()
图 7 松多地区花岗斑岩和二长花岗岩YbN-(La/Yb)N(a)和Y-Sr/Y(b)图解[54]
Figure 7. YbN-(La/Yb)N(a) and Y-Sr/Y(b) diagrams for granite porphyry and monzogranite from Sumdo area
![]()
图 8 松多地区花岗斑岩和二长花岗岩（Zr+Nb+Ce+Y）-(K2O+Na2O)/CaO(a)[57]、100×(MgO+TFeO+TiO2)/SiO2-(Al2O3+ CaO)/(TFeO+Na2O+K2O)[58](b)，A/CNK-A/NK[67](c)，SiO2-P2O5 [60](d)，Rb-Y[61](e)和Rb-Th[61](f)图解
Figure 8. (Zr+Nb+Ce+Y)-(K2O+Na2O)/CaO (a), 100*(MgO+TFeO+TiO2)/SiO2-(Al2O3+CaO)/(TFeO+Na2O+K2O) (b), A/ CNK-A/NK (c), SiO2-P2O5 (d), Rb-Y(e), and Rb-Th(f) diagrams for granite porphyry and monzogranite from Sumdo area
![]()
图 9 松多地区花岗斑岩与二长花岗岩SiO2- MgO(a)、SiO2-V(b)、SiO2-TFe2O3(c)、SiO2-Co(d)、Sr-Ba(e)、Sr-Rb/Sr(f)和SiO2- Al2O3(g)图解[68]
Pl—斜长石；Amp—角闪石；Kfs—钾长石；Bi—黑云母
Figure 9. SiO2-MgO(a), SiO2-V(b), SiO2-TFe2O3 (c), SiO2-Co(d), Sr-Ba(e), Sr-Rb/Sr(f) and SiO2-Al2O3(g) diagrams for granite porphyry and monzogranite from Sumdo area
表 1 松多地区花岗斑岩和二长花岗岩主量、微量和稀土元素测试结果
Table 1 Major, trace and rare earth element data for granite porphyry and monzogranite from Sumdo area
样品号 S16T44H1 S16T44H2 S16T44H3 S16T44H4 S16T44H5 S16T44H6 S16T88H1 S16T88H2 S16T88H3 S16T88H4 S16T88H5 岩性 花岗斑岩 二长花岗岩 SiO2 76.12 78.10 80.57 72.94 68.45 76.24 76.38 74.68 75.57 77.79 77.23 TiO2 0.04 0.03 0.03 0.04 0.04 0.03 0.18 0.25 0.15 0.11 0.06 Al2O3 13.81 12.68 9.67 15.71 18.32 13.20 13.06 13.80 13.68 12.98 12.86 TFe2O3 1.50 1.26 1.12 1.58 1.59 1.19 0.88 1.37 0.92 0.48 0.38 MnO 0.06 0.05 0.06 0.07 0.06 0.06 0.07 0.06 0.05 0.02 0.09 MgO 0.13 0.08 0.06 0.16 0.12 0.09 0.29 0.41 0.24 0.10 0.05 CaO 0.32 0.05 0.36 0.49 0.89 0.56 0.99 1.09 0.89 0.87 0.37 Na2O 2.23 2.79 2.99 2.58 3.96 3.36 3.30 3.39 3.66 3.52 3.44 K2O 5.75 4.94 5.12 6.40 6.53 5.25 4.83 4.88 4.79 4.11 5.50 P2O5 0.02 0.02 0.02 0.03 0.04 0.02 0.03 0.06 0.04 0.01 0.01 Mg# 17.25 12.17 11.34 19.05 14.85 14.83 43.45 41.36 37.76 33.01 24.23 烧失量 1.52 1.06 1.13 1.70 1.70 1.24 0.46 0.63 0.51 5.85 0.20 Li 20.48 17.94 11.32 15.57 11.40 10.12 18.26 17.93 16.82 25.18 18.24 Sc 7.56 7.24 5.73 4.85 3.64 4.24 4.14 3.74 2.69 2.61 5.43 V 4.68 3.33 3.14 2.37 2.08 2.35 11.98 10.94 6.16 5.03 2.09 Cr 1.69 1.87 2.98 1.56 0.92 1.28 2.41 1.19 2.49 1.22 3.50 Co 0.40 0.42 0.59 0.37 0.38 0.38 1.43 1.41 0.73 0.48 0.33 Ni 1.25 1.16 1.64 1.30 0.71 0.56 2.25 0.87 0.72 0.78 2.60 Ga 18.91 18.57 18.52 17.13 15.65 16.45 14.58 9.10 8.09 9.99 13.44 Rb 245.8 214.2 254.0 242.2 212.6 215.4 192.1 119.6 104.2 87.5 231.4 Sr 16.25 26.38 29.28 18.47 25.45 30.09 128.06 87.50 69.46 54.90 19.36 Y 39.96 39.12 35.08 33.16 24.90 29.46 20.70 9.25 12.62 10.38 29.90 Zr 83.03 99.04 93.10 73.39 86.34 72.54 89.60 62.76 48.76 58.59 56.30 Nb 20.25 20.23 22.19 17.85 17.74 17.27 16.56 7.62 7.02 7.50 11.69 Cs 6.45 3.95 5.35 6.92 4.23 4.94 17.00 6.38 5.38 6.29 8.79 Ba 170.9 159.8 163.3 207.8 175.9 197.0 458.8 240.4 205.8 178.6 27.0 La 22.72 22.02 22.44 21.16 17.93 19.30 19.91 15.78 9.00 9.81 11.29 Ce 49.90 48.54 54.12 45.50 41.10 43.38 42.68 31.26 18.68 17.32 19.97 Pr 6.03 5.90 5.95 5.58 4.68 5.13 4.66 3.43 2.13 1.93 2.13 Nd 22.74 22.20 22.46 21.36 17.74 19.45 15.55 11.71 7.49 6.53 6.75 Sm 6.37 6.18 6.18 5.84 4.78 5.30 3.28 2.18 1.72 1.37 1.40 Eu 0.35 0.34 0.31 0.31 0.24 0.26 0.54 0.37 0.29 0.55 0.16 Gd 6.69 6.49 6.33 6.33 5.00 5.64 2.94 1.79 1.70 1.42 1.62 Tb 1.12 1.09 1.03 1.01 0.78 0.89 0.48 0.27 0.30 0.24 0.40 Dy 6.94 6.84 6.38 6.58 5.04 5.81 2.97 1.60 1.97 1.61 3.75 Ho 1.40 1.39 1.27 1.35 1.01 1.18 0.62 0.32 0.43 0.35 1.10 Er 4.06 4.05 3.67 3.66 2.74 3.22 1.88 0.98 1.36 1.15 4.23 Tm 0.57 0.57 0.51 0.54 0.40 0.47 0.30 0.15 0.21 0.18 0.74 Yb 3.64 3.68 3.25 3.47 2.52 3.05 2.13 1.06 1.42 1.25 5.63 Lu 0.52 0.52 0.45 0.52 0.38 0.46 0.32 0.16 0.22 0.19 0.87 Hf 2.34 2.59 2.62 2.18 2.34 2.11 2.21 1.57 1.22 1.59 1.67 Ta 1.14 1.17 1.28 1.15 1.13 1.10 1.03 0.44 0.44 0.45 0.69 Pb 44.16 40.54 38.86 74.04 65.95 56.21 23.68 11.32 11.18 18.13 20.90 Th 22.60 22.82 23.64 29.19 25.21 27.87 16.96 9.89 8.19 10.58 13.41 U 6.27 6.47 7.02 10.70 10.69 10.22 2.98 1.41 1.66 2.73 3.62 注：主量元素含量单位为%，微量和稀土元素为10-6 
下载: 导出CSV
表 2 松多地区花岗斑岩和二长花岗岩LA-ICP-MS锆石U-Th-Pb同位素测试结果
Table 2 LA-ICP-MS zircon U-Th-Pb isotopic data for granite porphyry and monzogranite from Sumdo area
点号 元素含量/10-6 Th/U 同位素比值（±1σ） 年龄/Ma（±1σ） Th U Pb 207Pb/206Pb 207Pb/235U 206Pb/238U 207Pb/206Pb 207Pb/235U 206Pb/238U ST44-01 978 2364 26.76 0.41 0.05049 0.07497 0.01077 218 73 69.1 ST44-02 298 306 3.97 0.98 0.05038 0.07492 0.01078 213 73 69.1 ST44-03 767 2146 23.99 0.36 0.05043 0.07494 0.01077 215 73 69.1 ST44-04 743 2161 24.37 0.34 0.04868 0.0715 0.01065 132 70 68.3 ST44-05 728 2274 24.91 0.32 0.04883 0.07151 0.01062 140 70 68.1 ST44-06 472 1149 13.29 0.41 0.05067 0.07531 0.01078 226 74 69.1 ST44-07 710 1530 20.22 0.46 0.04945 0.06893 0.01011 169 68 64.8 ST44-08 82 165 26.80 0.49 0.07691 1.50328 0.14174 1119 932 854 ST44-09 2675 4117 60.57 0.65 0.04697 0.06289 0.00971 48 62 62.3 ST44-10 577 1604 18.26 0.36 0.04909 0.0732 0.01081 152 72 69.3 ST44-12 818 1241 15.31 0.66 0.04698 0.06891 0.01064 48 68 68.2 ST44-13 318 444 5.54 0.71 0.04718 0.0697 0.01071 58 68 68.7 ST44-15 976 1856 23.37 0.53 0.05175 0.07449 0.01044 274 73 66.9 ST44-17 291 849 9.61 0.34 0.05123 0.07459 0.01056 251 73 67.7 ST44-18 798 1719 20.01 0.46 0.05023 0.07693 0.0111 206 75 71.2 ST44-19 870 1478 17.87 0.59 0.04863 0.0729 0.01087 130 71 69.7 ST44-20 449 1082 12.60 0.41 0.0473 0.07183 0.01101 65 70 70.6 ST88-01 2310 1821 25.74 1.27 0.04501 0.06733 0.01085 -19 66 69.6 ST88-02 343 615 7.51 0.56 0.04752 0.07121 0.01087 75 70 70 ST88-03 670 673 9.08 1.00 0.04744 0.07062 0.01079 71 69 69.2 ST88-04 224 414 5.04 0.54 0.04741 0.07103 0.01086 70 70 70 ST88-05 312 431 5.44 0.72 0.04728 0.07048 0.01081 63 69 69 ST88-06 687 829 10.73 0.83 0.04733 0.06995 0.01072 66 69 69 ST88-07 249 422 5.17 0.59 0.05174 0.07585 0.01063 274 74 68 ST88-08 358 676 8.14 0.53 0.04753 0.07117 0.01086 76 70 69.6 ST88-09 349 405 5.40 0.86 0.04734 0.07074 0.01083 66 69 69 ST88-10 674 1009 11.32 0.67 0.04762 0.06219 0.00947 80 61 60.8 ST88-11 238 284 3.78 0.84 0.04714 0.07076 0.01088 56 69 70 ST88-12 335 448 5.75 0.75 0.04756 0.07147 0.0109 77 70 70 ST88-13 306 562 6.87 0.55 0.04746 0.07098 0.01084 72 70 69.5 ST88-14 261 393 4.92 0.66 0.04746 0.0706 0.01079 72 69 69 ST88-16 161 243 2.95 0.66 0.04789 0.06939 0.01051 94 68 67 ST88-17 181 530 5.94 0.34 0.04721 0.06886 0.01058 60 68 68 ST88-18 265 483 5.62 0.55 0.04727 0.06726 0.01032 63 66 66 ST88-19 636 729 9.12 0.87 0.04891 0.07273 0.01078 144 71 69.1 ST88-20 591 732 9.43 0.81 0.04648 0.06824 0.01064 23 67 68.2
下载: 导出CSV
表 3 松多地区花岗斑岩和二长花岗岩锆石Hf同位素测试结果
Table 3 Zircon Hf isotopic data for granite porphyry and monzogranite from Sumdo area
No. 年龄/Ma 176Yb/177Hf 2σ 176Lu/177Hf 2σ 176Hf/177Hf 2σ 176Hf/177Hfi εHf(0) εHf(t) εHf(t)' 2σ TDM/Ma TDMC/Ma fLu/Hf 花岗斑岩(S16T44) S16T44-1 68 0.069947 0.000398 0.002207 0.000016 0.282743 0.000014 0.282740 -1.0 0.4 0.9 0.5 746 1113 -0.93 S16T44-2 68 0.155669 0.006944 0.003912 0.000145 0.282708 0.000017 0.282703 -2.2 -0.9 -0.3 0.6 836 1196 -0.88 S16T44-3 68 0.064932 0.001864 0.001924 0.000047 0.282813 0.000015 0.282810 1.4 2.9 3.4 0.5 639 955 -0.94 S16T44-4 68 0.056115 0.000799 0.001757 0.000020 0.282777 0.000015 0.282775 0.2 1.6 2.1 0.5 688 1036 -0.95 S16T44-5 68 0.054526 0.000254 0.001709 0.000011 0.282780 0.000014 0.282778 0.3 1.7 2.2 0.5 683 1029 -0.95 二长花岗岩(S16T88) S16T88-1 68 0.038688 0.000547 0.001284 0.000019 0.282248 0.000024 0.282247 -18.5 -17.1 -16.3 0.8 1428 2219 -0.96 S16T88-1 68 0.038688 0.000547 0.001284 0.000019 0.282248 0.000024 0.282247 -18.5 -17.1 -16.3 0.8 1428 2219 -0.96 S16T88-3 68 0.043073 0.000823 0.001484 0.000023 0.282946 0.000023 0.282944 6.1 7.6 8.4 0.8 440 653 -0.96 S16T88-4 68 0.034688 0.000824 0.001210 0.000029 0.282897 0.000022 0.282896 4.4 5.9 6.6 0.8 506 763 -0.96 S16T88-5 68 0.067824 0.001599 0.002260 0.000052 0.282932 0.000022 0.282930 5.7 7.1 7.8 0.8 469 686 -0.93
下载: 导出CSV
-
莫宣学, 董国臣, 赵志丹, 等.西藏冈底斯带花岗岩的时空分布特征及地壳生长演化信息[J].高校地质学报, 2005, 11(3):281-290. doi: 10.3969/j.issn.1006-7493.2005.03.001 Wang R, Richards J P, Hou Z Q, et al. Zircon U-Pb age and Sr-Nd-Hf-O isotope geochemistry of the Paleocene-Eocene igneous rocks in western Gangdese:Evidence for the timing of Neo-Tethyan slab breakoff[J]. Lithos, 2015, 224/225:179-194. doi: 10.1016/j.lithos.2015.03.003
Chu M F, Chung S L, Song B, et al. Zircon U-Pb and Hf isotope constraints on the Mesozoic tectonics and crustal evolution of Southern Tibet[J]. Geology, 2006, 34(9):745. doi: 10.1130/G22725.1
Ji W Q, Wu F Y, Chung S L, et al. Zircon U-Pb geochronology and hf isotopic constraints on petrogenesis of the Gangdese batholith, Southern Tibet[J]. Chemical Geology, 2009, 62(3/4):229-245. doi: 10.1016-j.chemgeo.2009.01.020/
Mo X, Niu Y L, Dong G, et al. Contribution of syncollisional felsic magmatism to continental crust growth:a case study of the paleogene linzizong volcanic succession in Southern Tibet[J]. Chemical Geology, 2008, 250(1/4):49-67. http://linkinghub.elsevier.com/retrieve/pii/S0009254108000582
管琪, 朱弟成, 赵志丹, 等, 西藏南部冈底斯带东段晚白垩世埃克岩:新特提斯洋脊俯冲的产物?[J].岩石学报, 2010, 26(7):2165-2179. http://d.old.wanfangdata.com.cn/Periodical/ysxb98201007018 孟繁一, 赵志丹, 朱弟成, 等.西藏冈底斯东部门巴地区晚白垩世埃达克质岩的岩石成因[J].岩石学报, 2010, 26(7):2180-2192. http://d.old.wanfangdata.com.cn/Periodical/ysxb98201007019 Wen D R, Chung S L, Song B, et al. Late cretaceous gangdese intrusions of adakitic geochemical characteristics, Tibet:petrogenesis and tectonic implications[J]. Lithos, 2008, 105(1):1-11.
Ma L, Wang Q, Wyman D.A, et al. Late cretaceous(100-89 Ma) magnesian charnockites with adakitic affinities in the milin area, eastern gangdese:partial melting of subducted oceanic crust and implications for crustal growth in Southern Tibet[J]. Lithos, 2013, 175/176(8):315-332.
Zhang Q, Jin W, Li C, et al. Revisiting the new classification of granitic rocks based on whole-rock Sr and Yb contents:index[J]. Acta Petrologica Sinica, 2010, 26(4):985-1015. http://en.cnki.com.cn/Article_en/CJFDTOTAL-YSXB201004002.htm
Mo X X, Hou Z, Niu Y L, et al. Mantle contributions to crustal thickening during continental collision:evidence from cenozoic igneous rocks in southern Tibet[J]. Lithos, 2007, 96(1):225-242. doi: 10.1016-j.lithos.2006.10.005/
李才, 程立人, 胡克, 等.西藏羌塘南部地区的冰海杂砾岩及其成因[J].吉林大学学报, 1995, (4):368-374. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=QK199500183653 李才, 黄小鹏, 翟庆国, 等.龙木错-双湖-吉塘板块缝合带与青藏高原冈瓦纳北界[J].地学前缘, 2006, 13(4):136-147. doi: 10.3321/j.issn:1005-2321.2006.04.011 李才, 李永铁, 林源贤, 等.西藏双湖地区蓝闪片岩原岩Sm-Nd同位素定年[J].中国地质, 2002, 29(4):355-359. doi: 10.3969/j.issn.1000-3657.2002.04.004 李才, 翟庆国, 董永胜, 等.青藏高原羌塘中部榴辉岩的发现及其意义[J].科学通报, 2006, 51(1):70-74. doi: 10.3321/j.issn:0023-074X.2006.01.014 李才.龙木错-双湖-澜沧江板块缝合带与石炭二叠纪冈瓦纳北界[J].吉林大学学报:地球科学版, 1987, (2):155-166. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=QK000001164867 李才.青藏高原龙木错-双湖-澜沧江板块缝合带研究二十年[J].地质论评, 2008, 54(1):105-119. doi: 10.3321/j.issn:0371-5736.2008.01.012 王立全, 潘桂棠, 李才, 等.藏北羌塘中部果干加年山早古生代堆晶辉长岩的锆石SHRIMP U-Pb年龄—兼论原-古特提斯洋的演化[J].地质通报, 2008, 27(12):2045-2056. doi: 10.3969/j.issn.1671-2552.2008.12.010 潘桂棠.东特提斯地质构造形成演化[M].北京:地质出版社, 1997. 潘桂棠, 郑海翔, 徐跃荣, 等.初论班公湖-怒江结合带[C]//青藏高原地质文集.北京: 地质出版社, 1983: 229-242. 潘桂棠, 莫宣学, 侯增谦, 等.冈底斯造山带的时空结构及演化[J].岩石学报, 2006, 22(3):521-533. http://d.old.wanfangdata.com.cn/Periodical/ysxb98200603001 Zhu D C, Zhao Z D, Niu Y L, et al. The origin and pre-cenozoic evolution of the Tibetan plateau[J]. Gondwana Research, 2013, 23(4):1429-1454. doi: 10.1016/j.gr.2012.02.002
Yin A, Harrison T M. Geologic evolution of the Himalayan-Tibetan orogen[J]. Annual Review of Earth & Planetary Sciences, 2000, 28(28):211-280. doi: 10.1146/annurev.earth.28.1.211
Zhu D C, Zhao Z D, Niu Y L, et al. The Lhasa terrane:record of a microcontinent and its histories of drift and growth[J]. Earth & Planetary Science Letters, 2011, 301(1/2):241-255. doi: 10.1016-j.epsl.2010.11.005/
Harris N B W, Inger S, Ronghua X. Cretaceous plutonism in central Tibet:an example of post-collision magmatism?[J]. Journal of Volcanology & Geothermal Research, 1990, 44(1):21-32. doi: 10.1016-0377-0273(90)90009-5/
Coulon C, Maluski H, Bollinger C, et al. Mesozoic and cenozoic volcanic rocks from central and southern Tibet:39Ar-40Ar dating, petrological characteristics and geodynamical significance[J]. Earth & Planetary Science Letters, 1986, 79(3):281-302. doi: 10.1016-0012-821X(86)90186-X/
Lee H Y, Chung S L, Lo C H, et al. Eocene neotethyan slab breakoff in southern Tibet inferred from the linzizong volcanic record[J]. Tectonophysics, 2009, 477(1):20-35. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=JJ0211361861
Pearce J A, Mei H. Volcanic rocks of the 1985 Tibet geotraverse:Lhasa to golmud[J]. Philosophical Transactions of the Royal Society of London, 1988, 327(1594):169-201. doi: 10.1098/rsta.1988.0125
Turner S, Arnaud N, Liu J, et al. Post-collision, shoshonitic volcanism on the Tibetan plateau:implications for convective thinning of the lithosphere and the source of ocean island basalts[J]. Journal of Petrology, 1996, 37(1):45-71. doi: 10.1093/petrology/37.1.45
Zhu D C, Zhao Z D, Niu Y, et al. Cambrian bimodal volcanism in the Lhasa terrane, southern Tibet:record of an early paleozoic andean-type magmatic arc in the australian proto-tethyan margin[J]. Chemical Geology, 2012, 328(11):290-308. https://linkinghub.elsevier.com/retrieve/pii/S0009254112000034
刘敏.青藏高原中部聂荣微陆块侏罗纪早期富碱侵入岩的岩石成因及构造意义[D].中国地质大学(北京)博士学位论文, 2012. 董彦辉, 许继峰, 曾庆高, 等.存在比桑日群弧火山岩更早的新特提斯洋俯冲记录么?[J].岩石学报, 2006, 22(3):661-668. http://d.old.wanfangdata.com.cn/Periodical/ysxb98200603015 Zhu D C, Mo X X, Niu Y L, et al. Geochemical investigation of early cretaceous igneous rocks along an east-west traverse throughout the central Lhasa terrane, Tibet[J]. Chemical Geology, 2009, 268(3/4):298-312. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=JJ0211291457
Zhu D C, Pan G T, Zhao Z D, et al. Early Cretaceous subductionrelated adakite-like rocks in the Gangdese, south Tibet:Products of slab melting and subsequent melt-peridotite interaction?[J]. Journal of Asian Earth Sciences, 2009, 34(3):298-309. doi: 10.1016/j.jseaes.2008.05.003
董国臣, 莫宣学, 赵志丹, 等.拉萨北部林周盆地林子宗火山岩层序新议[J].地质通报, 2005, 24(6):549-557. doi: 10.3969/j.issn.1671-2552.2005.06.012 董国臣.林周盆地林子宗火山岩及其所含的印度-欧亚大陆碰撞信息研究[D].中国地质大学(北京)博士学位论文, 2002. 周肃, 莫宣学, 董国臣, 等.西藏林周盆地林子宗火山岩40Ar/39Ar年代格架[J].科学通报, 2004, 49(20):2095-2103. doi: 10.3321/j.issn:0023-074X.2004.20.014 Miller C, Schuster R, Klötzli U, et al. Post-collisional potassic and ultrapotassic magmatism in sw Tibet:geochemical and Sr-Nd-PbO isotopic constraints for mantle source characteristics and petrogenesis[J]. Journal of Petrology, 1999, 40(9):699-715.
朱弟成, 赵志丹, 牛耀龄, 等.拉萨地体的起源和古生代构造演化[J].高校地质学报, 2012, 18(1):1-15. doi: 10.3969/j.issn.1006-7493.2012.01.001 张泽明, 王金丽, 赵国春, 等.马拉雅造山带东构造结南迦巴瓦岩群地质年代学和前寒武纪构造演化[J].岩石学报, 2008, 24(7):1477-1487. http://d.old.wanfangdata.com.cn/Periodical/ysxb98200807005 Xu R H, Schärer U, Allègre C J. Magmatism and metamorphism in the Lhasa block(Tibet):a geochronological study[J]. Journal of Geology, 1985, 93(1):41-57. doi: 10.1086/628918
何世平, 李荣社, 王超, 等.青藏高原冈底斯北缘嘉玉桥群形成时代的确定[J].中国地质, 2012, 39(1):21-28. http://d.old.wanfangdata.com.cn/Periodical/zgdizhi201201003 解超明, 李才, 范建军, 等.青藏高原羌塘中部中-上奥陶统达瓦山组的建立及意义[J].地质通报, 2015, 34(10):1812-1820. doi: 10.3969/j.issn.1671-2552.2015.10.005 于红.陕西商南松树沟橄榄岩矿物地球化学特征及成因机理示踪[D].中国地质大学(北京)博士学位论文, 2011. Yuan H L, Gao S, Liu X M, et al. Accurate U-Pb Age and Trace Element Determinations of Zircon by Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry[J]. Geostandards and Geoanalytical Research 2004, 28:353-370. doi: 10.1111/ggr.2004.28.issue-3
Anderson T. Correction of common lead in U-Pb analyses that do not report 204Pb[J]. Chemical Geology, 2002, 192(1):59-79. https://www.sciencedirect.com/science/article/pii/S000925410200195X
Ludwig K R. User's Manual for Isoplot 3.00:A Geochronological Toolkit for Microsoft Excel[M]. Berkeley Geochronology Center Special Publication, Berkeley, No.4.7. 2003. http://www.scirp.org/reference/ReferencesPapers.aspx?ReferenceID=598741
侯可军, 李延河, 邹天人, 等. LA-MC-ICP-MS锆石Hf同位素的分析方法及地质应用[J].岩石学报, 2007, 23(10):2595-2604. doi: 10.3969/j.issn.1000-0569.2007.10.025 Bouvier A, Vervoort J D, Patchett P J. The Lu-Hf and Sm-Nd isotopic composition of CHUR:Constraints from unequilibrated chondrites and implications for the bulk composition of terrestrial planets[J]. Earth & Planetary Science Letters, 2008, 273(1/2):48-57. https://www.deepdyve.com/lp/elsevier/the-lu-hf-and-sm-nd-isotopic-composition-of-chur-constraints-from-BgXIQd5Lar
Griffin W L, Pearson N J, Belousova E, et al. The Hf isotope composition of cratonic mantle:LA-MC-ICPMS analysis of zircon megacrysts in kimberlites[J]. Geochimica Et Cosmochimica Acta, 2000, 64(1):133-147. doi: 10.1016/S0016-7037(99)00343-9
Winchester J A, Floyd P A. Geochemical discrimination of different magma series and their differentiation products using immobile elements[J]. Chemical Geology, 1977, 20(4):325-343. doi: 10.1016-0009-2541(77)90057-2/
Peccerillo A, Taylor S R. Geochemistry of eocene calc-alkaline volcanic rocks from the Kastamonu area, Northern Turkey[J]. Contributions to Mineralogy & Petrology, 1976, 58(1):63-81. doi: 10.1007-BF00384745/
Sun S S, Mcdonough W F. Chemical and isotopic systematics of oceanic basalts:implications for mantle composition and processes[J]. Geological Society London Special Publications, 1989, 42(1):313-345. doi: 10.1144/GSL.SP.1989.042.01.19
Defant M J, Drummond M S. Derivation of some modern arc magmas by melting of young subducted lithosphere[J]. Nature, 1990, 347(6294):662-665. doi: 10.1038/347662a0
Hu X, Garzanti E, Wang J, et al. The timing of india-asia collision onset-facts, theories, controversies[J]. Earth-Science Reviews, 2016, 160:264-299. doi: 10.1016/j.earscirev.2016.07.014
王强, 赵振华.桐柏-大别造山带燕山晚期A型花岗岩的厘定[J].岩石矿物学杂志, 2000, 19(4):297-306. doi: 10.3969/j.issn.1000-6524.2000.04.002 Joseph B. Whalen, Kenneth L. Currie, Bruce W. Chappell. Atype granites:geochemical characteristics, discrimination and petrogenesis[J]. Contributions to Mineralogy & Petrology, 1987, 95(4):407-419. doi: 10.1007%2FBF02831067
Sylvester P J. Post-collisional alkaline granites[J]. The Journal of Geology, 1989:261-280. http://d.old.wanfangdata.com.cn/Periodical/kxtb-e200523013
Li S M, Zhu D C, Wang Q, et al. Northward subduction of Bangong-Nujiang Tethys:insight from late Jurassic intrusive rocks from Bangongtso in western Tibet[J]. Lithos, 2014, 205(9):284-297.
Li X H, Li W X, Li Z X. On the genetic classification and tectonic implications of the early Yanshanian granitoids in the nanling range, south China[J]. Chinese Science Bulletin, 2007, 52(14):1873-1885. doi: 10.1007/s11434-007-0259-0
Chappell B W. Aluminium saturation in I-and S-type granites and the characterization of fractionated haplogranites[J]. Lithos, 1999, 46:535-551. doi: 10.1016/S0024-4937(98)00086-3
Green T H, Watson E B. Crystallization of apatite in natural magmas under high pressure, hydrous conditions, with particular reference to 'orogenic' rock series[J]. Contributions to Mineralogy and Petrology, 1982, 79(1):96-105. doi: 10.1007/BF00376966
Watson E B. Apatite saturation in basic to intermediate magmas[J]. Geophysical Research Letters, 1979, 6(12):937-940. doi: 10.1029/GL006i012p00937
Watson E B, Capobianco C J. Phosphorus and the rare earth elements in felsic magmas:an assessment of the role of apatite[J]. Geochimica Et Cosmochimica Acta, 1981, 45(12):2349-2358. doi: 10.1016/0016-7037(81)90088-0
Wolf M B, London D. Apatite dissolution into peraluminous haplogranitic melts:an experimental study of solubilities and mechanisms[J]. Geochimica Et Cosmochimica Acta, 1994, 58(19):4127-4145. doi: 10.1016/0016-7037(94)90269-0
Clemens J D. S-type granitic magmas-petrogenetic issues, models and evidence[J]. Earth-Science Reviews, 2003, 61(1/2):1-18. http://d.old.wanfangdata.com.cn/NSTLQK/NSTL_QKJJ025210617/
Maniar P D, Piccoli P M. Tectonic discrimination of granitoids[J]. Geological Society of America Bulletin, 1989, 101(5):635-643. doi: 10.1130/0016-7606(1989)101<0635:TDOG>2.3.CO;2
Liu J H, Xie C M, Li C, et al. Early Carboniferous adakite-like and I-type granites in central Qiangtang, northern Tibet:Implications for intra-oceanic subduction and back-arc basin formation within the Paleo-Tethys Ocean[J]. Lithos, 2018. 296/299:265-280. doi: 10.1016/j.lithos.2017.11.005
张旗, 潘国强, 李承东, 等.花岗岩构造环境问题:关于花岗岩研究的思考之三[J].岩石学报, 2007, 23(11):2683-2698. doi: 10.3969/j.issn.1000-0569.2007.11.002 吴浩.青藏高原羌塘中部375-200 Ma多期次岩浆作用[D].吉林大学博士学位论文, 2016. Taylor S R, Mclennan S M. The geochemical evolution of the continental crust[J]. Reviews of Geophysics, 1995, 33(2):241-265. doi: 10.1029/95RG00262
唐功建, 王强.高镁安山岩及其地球动力学意义[J].岩石学报, 2010, 26(8):2495-2512. http://d.old.wanfangdata.com.cn/Periodical/ysxb98201008021 王金丽, 张泽明, 石超.拉萨地体东南缘的多期深熔作用及动力学[J].岩石学报, 2008, 24(7):1539-1551 http://d.old.wanfangdata.com.cn/Periodical/ysxb98200807011 Kamei A. An adakitic pluton on Kyushu island, southwest Japan arc[J]. Journal of Asian Earth Sciences, 2004, 24(1):43-58. doi: 10.1016/j.jseaes.2003.07.001
赵振华, 王强, 熊小林, 等.新疆北部的富镁火成岩[J].岩石学报, 2007, 23(7):1696-1707. doi: 10.3969/j.issn.1000-0569.2007.07.015 Geng H, Sun M, Yuan C, et al. Geochemical, Sr-Nd and zircon U*-Pb-Hf isotopic studies of Late Carboniferous magmatism in the west Junggar, Xinjiang:implications for ridge subduction?[J]. Chemical Geology, 2009, 266(3/4):364-389. https://www.researchgate.net/publication/232205578_Geochemical_Sr-Nd_and_zircon_U-Pb-Hf_isotopic_studies_of_Late_Carboniferous_magmatism_in_the_West_Junggar_Xinjiang_Implications_for_ridge_subduction
Tang G, Wang Q, Wyman D A, et al. Ridge subduction and crustal growth in the Central Asian Orogenic Belt:evidence from Late Carboniferous adakites and high-Mg diorites in the western Junggar region, northern Xinjiang (west China)[J]. Chemical Geology, 2010, 277(3/4):281-300.
胡洋, 王居里, 王建其, 等.新疆西准噶尔庙尔沟岩体的地球化学及年代学研究[J].岩石学报, 2015, 31(2):505-522. http://d.old.wanfangdata.com.cn/Periodical/ysxb98201502016 Cole R B, Nelson S W, Layer P W, et al. Eocene volcanism above a depleted mantle slab window in southern Alaska[J]. Geological Society of America Bulletin, 2006, 118(1):140-158. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=JJ027973447
Kinoshita O. Possible manifestations of slab window in Cretaceous southwest Japan[J]. Tectonophysics, 2002, 344(1):1-13. doi: 10.1016-S0040-1951(01)00262-1/
-
期刊类型引用(0)
其他类型引用(4)
计量
- 文章访问数: 3299
- HTML全文浏览量: 294
- PDF下载量: 2407
- 被引次数: 4
