CMIP5模式对AMO与PDO模拟评估及未来预估          下载免费PDF全文

宋晗  刘鹏  陶丽 《大气科学学报》2021,44(3):473-484

利用1880—2009年海表温度(Sea Surface Temperature, SST)观测资料以及耦合模式比较计划第五阶段(Coupled Model Intercomparison Project phase 5,CMIP5)中4种情景(piControl、historical、RCP2.6、RCP4.5)下的模拟资料,通过资料对比,评估了CMIP5模式对两个最为重要年代际尺度模态——北大西洋年代际振荡(Atlantic Multidecadal Oscillation, AMO)和太平洋年代际振荡(Pacific Decadal Oscillation, PDO)的模拟性能,并分析了在不同增暖情景下,这两个海洋年代际模态的变化特征。结果表明:在historical和piControl情景下,多模式集合可以再现北太平洋、东太平洋和北大西洋海表温度的年代际变化中心,但模拟的AMO和PDO模态的振幅都偏弱,特别是PDO模态在东太平洋强度的再现能力较弱。与观测资料相比,在historical情景下对AMO和PDO时空特征模拟较好的模式有:CESM1-CAM5、FGOALS-g2、GISS-E2-H-CC、MIROC5和NorESM1-ME,多模式集合则有更好的模拟效果。在不同增暖情景下,AMO与PDO的空间特征基本一致且振幅差随增暖变化不明显,但是伴随全球增暖加强,两模态都呈现方差贡献减小的特征,尤其AMO模态。  相似文献   

华北克拉通北缘中段赤峰撰山子矿区石炭纪-二叠纪侵入岩年代学和地球化学:对古亚洲洋构造演化的制约SCIEI北大核心CSCD     

杨帆  姜艳艳  陈井胜  韩兴 《岩石学报》2022,(8):2467-2488

本文对华北克拉通北缘中段赤峰撰山子矿区二长闪长岩、花岗(斑)岩等进行了岩相学、地球化学、锆石U-Pb定年以及Hf同位素研究,以期对古亚洲洋演化形成制约。锆石U-Pb定年显示,二长闪长岩和花岗岩形成于早石炭世(341.0±2.2Ma、324.1±4.3Ma),花岗斑岩形成于晚二叠世(252.8±3.2Ma、252.0±1.5Ma)。岩石地球化学及Hf同位素表明,二长闪长岩为高钾钙碱性I型花岗岩,形成于火山弧环境,其源区可能是俯冲板片脱水交代的地幔楔部分熔融产生玄武质岩浆上涌,导致新生地壳物质的部分熔融,并有部分玄武质岩浆加入形成的产物;花岗岩及花岗斑岩均为高钾钙碱性A型花岗岩,花岗岩形成于火山弧环境,花岗斑岩形成于造山后伸展环境,二者皆为新生地壳部分熔融的产物。综合前人研究认为,早石炭世-晚二叠世,研究区经历了古亚洲洋俯冲、弧-陆碰撞以及造山后伸展等阶段。  相似文献   

加拿大纽芬兰岛Indian Head Range地块格林威尔期二长花岗岩年龄、Nd-Hf同位素特征——块体属性与演化新证据     

王朝阳  王涛  张颖慧 《岩石矿物学杂志》2022,41(4):714-726

加拿大阿巴拉契亚造山带纽芬兰岛Humber带基底地块属性及地壳生长演化是近年来关注的科学问题,尤其是岛内西南部的Indian Head Range地块,其年龄组成与同位素特征研究对区域基底构造属性划分与对比至关重要。本文对Indian Head Range地块内的二长花岗岩岩体进行了锆石U-Pb定年,得到其²⁰⁶Pb/²³⁸U加权平均年龄值为1 149±4 Ma,代表该岩体的侵位年龄。这一定年结果表明该岩体具有中元古代晚期的年龄,为该地块格林威尔期岩浆事件的存在提供了新的年龄证据。Nd-Hf同位素分析结果显示,该二长花岗岩岩体εNd值为-2.3,εHf值介于+1.93～+3.65之间,两阶段Hf模式年龄介于1.84～1.73 Ga之间。结合前人研究,我们认为Humber带内各地块发育约1.5 Ga、1.15 Ga和1.0 Ga的3期花岗质岩浆事件,它们具有相似的Hf模式年龄值,暗示它们均来源于古元古代新生地壳物质的再造。带内格林威尔基底地块均为原地基底,且与劳伦大陆远端东部边缘具有一致的岩浆-构造演化史。以上研究对Humber带内格林威尔基底...  相似文献   

Discovery of the Late Carboniferous alkaline volcanic rocks in the Guyang area,eastern Yinshan Block,and its geological implicationsSCIEI北大核心CSCD     

朱伟鹏  田伟  魏春景 《岩石学报》2023,(3):670-688

在华北克拉通北缘阴山地块东部固阳地区发现了假白榴石粗面玄武岩和钾质粗面岩两种高钾准铝质碱性火山岩。地质年代学数据显示,假白榴石粗面玄武岩的磷灰石U-Pb年龄为322±14Ma,钾质粗面岩的锆石U-Pb年龄为315.6±7.5Ma,说明其形成时代均为晚石炭世。岩石地球化学特征显示,二者均富Al、Fe,贫Mg;富集大离子亲石元素(如Rb、Ba和K),相对亏损高场强元素(如Ta、Nb和Ti),轻重稀土分异明显,富集轻稀土,相对亏损重稀土,Eu异常不明显;高(87Sr/86Sr)i比值(0.710028~0.714745),低εNd(t)值(-9.0~-17.2),表现出相似的交代岩石圈地幔源区和地壳混染特征。将该碱性火山岩与兴蒙造山带晚石炭世-早二叠世中基性火山岩和阴山地块白垩纪中基性火山岩进行岩石类型对比,发现华北克拉通北缘产出的火山岩多为高钾碱性系列,而兴蒙造山带中产出的火山岩则多为钙碱性系列;与兴蒙造山带晚石炭世-早二叠世中基性火山岩进行岩石成因对比,发现它们的岩浆源区和混染程度并不相同,即固阳地区碱性火山岩为受到早古生代俯冲沉积物交代的岩石圈地幔部分熔融所形成的岩浆在上升过程中混染华北克拉通TTG片麻岩后喷发的产物,而兴蒙造山带中火山岩的产出则多为亏损地幔部分熔融所形成的岩浆在上升过程中轻度混染地壳物质后喷发的结果。在固阳地区发现晚石炭世碱性火山岩,代表着古亚洲洋在该时期的后造山伸展作用范围已延伸至华北克拉通北缘。  相似文献   

Discovery of Early Tonian Calc-alkaline and Shoshonitic Metamafic Rocks from the North Purulia Shear Zone, Chhotanagpur Gneissic Complex, Eastern India: Implications of Proterozoic Sub-continental Lithospheric Mantle     

Bapi GOSWAMI  Susmita DAS  Ankita BASAK  Chitta BHATTACHARYYA 《《地质学报》英文版》2023,97(1):68-89

Reports of shoshonitic rocks in Precambrian terrains are relatively rare. Pl-Grt amphibolites and Hbl-Bt mafic granulites occurring in the migmatitic gneisses of the Chhotanagpur Gneissic Complex(CGC) show calc-alkaline and shoshonitic characteristics. Relict porphyritic, sub-ophitic and poikilitic textures are noted in these rocks. Their parent magma was emplaced during the waning phase of the regional metamorphism. Geochemically, these metamafics are similar to the Group Ⅲ potassic and ultrapo...  相似文献   

Determination of the early Paleozoic accretionary complex in Southwestern Yunnan,China: Implications for the tectonic evolution of the Proto-Tethys Ocean     

《China Geology》2023,6(2):322-337

Accretionary complex study provides important knowledge on the subduction and the geodynamic processes of the oceanic plate, which represents the ancient ocean basin extinction location. Nevertheless, there exist many disputes on the age, material source, and tectonic attribute of the Lancang Group, located in Southwest Yunnan, China. In this paper, the LA-ICP-MS detrital zircon U–Pb chronology of nine metamorphic rocks in the Lancang Group was carried out. The U–Pb ages of the three detrital zircons mainly range from 590–550 Ma, 980–910 Ma, and 1150–1490 Ma, with the youngest detrital zircons having a peak age of about 560 Ma. The U–Pb ages of the six detrital zircons mainly range from 440–460 Ma and 980–910 Ma, and the youngest detrital zircon has a peak age of about 445 Ma. In the Lancang Group, metamorphic acidic volcanic rocks, basic volcanic rocks, intermediate-acid intrusive rocks, and high-pressure metamorphic rocks are exposed in the form of tectonic lens in schist, rendering typical melange structural characteristics of “block + matrix”. Considering regional deformation and chronology, material composition characteristics, and the previous data, this study thinks the Lancang Group may be an early Paleozoic tectonic accretionary complex formed by the eastward subduction of the Changning-Menglian Proto-Tethys Ocean, which provides an important constraint for the Tethys evolution.©2023 China Geology Editorial Office.  相似文献   

西藏松多地区晚白垩世末期弧岩浆岩岩石成因及构造意义     

刘金恒  解超明  范建军  王明  罗安波  高忠维  王斌  曾孝文 《地质通报》2018,37(8):1477-1491

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Si O_2含量为68.5%~80.6%,K_2O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T_(DM)~C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。  相似文献   

大兴安岭北段伊勒呼里山晚侏罗世二长花岗岩LA-ICP-MS锆石U-Pb年龄、地球化学特征及其地质意义     

尹志刚  宫兆民  张跃龙  曹忠强  李敏  李海娜  王阳  韩宇  张圣听 《地质通报》2018,37(7):1291-1301

对大兴安岭北段伊勒呼里山地区二长花岗岩进行了LA-ICP-MS锆石U-Pb年龄和岩石地球化学研究,确定其形成时代、岩石成因,揭露区域大地构造环境。测年数据显示,二长花岗岩于158.1±0.7Ma前形成,为晚侏罗世早期岩浆演化事件的产物。地球化学结果显示,二长花岗岩具有高Si、富Na、K、Al,低Fe、Mg的特点,A/CNK值为0.83~1.09,属高钾钙碱性花岗岩;富集大离子亲石元素K、Rb,贫高场强元素Hf、Th;稀土元素总量较高,稀土元素配分曲线右倾,具弱的负Eu异常,为Ⅰ型花岗岩。岩浆起源于下地壳玄武质成分的岩石部分熔融,为同碰撞期陆壳加厚过程的产物。研究区晚侏罗世早期二长花岗岩的形成与蒙古-鄂霍茨克缝合带闭合过程中的陆-陆碰撞环境有关,其形成时代限定了大兴安岭北段伊勒呼里山地区蒙古-鄂霍茨克洋的闭合时间应为晚侏罗世早期。  相似文献   

Zircon U-Pb-Hf isotopic and geochemical characteristics of the Xierzi biotite monzogranite pluton,Linxi, Inner Mongolia and its tectonic implications   总被引：1，自引：0，他引：1  

Qing-Bin Guan  Zheng-Hong Liu  Xing-An Wang  Bin Wang  Shi-Jie Wang  Yu-Song Chen  Zhi-Qiang Feng 《地学前缘(英文版)》2018,9(2):505-516

The opening, subduction and final closure of the Paleo-Asian Ocean led to the formation of the Central Asian Orogenic Belt. Controversy has long surrounded the timing of final closure of the Paleo-Asian Ocean. Here we present zircon U-Pb ages and petrological, geochemical and in situ Hf isotope data for the Xierzi biotite monzogranite pluton, Linxi, SE Inner Mongolia. U-Pb dating of zircon by LA-ICP-MS yields a middle Permian emplacement age(268.7 ± 2.3 Ma) for the Xierzi pluton that is dominated by biotite monzogranites with high SiO_2(71.2-72.8 wt.%),alkali(Na_2 O + K_2 O =8.05-8.44 wt.%), Al_2 O_3(14.4-15.2 wt.%) and Fe_2 O_3~T relative to low MgO contents, yielding Fe_2 O_3~T/MgO ratios of 2.87-3.44, and plotting within the high-K calc-alkaline field on a SiO_2 vs. K_2 O diagram. The aluminum saturation indexes(A/CNK) of the biotite monzogranites range from 1.06 to 1.19, corresponding to weakly to strongly peraluminous. They are enriched in rare earth elements(REE), high field strength elements(HFSEs; Zr,Hf). and large ion lithophile elements(LILEs; Rb, U, Th). The LREEs are enriched relative to the HREEs,with a distinct negative Eu anomaly in a chondrite-normalized REE diagram. Geochemically, the Xierzi biotite monzogranite is classified as an aluminous A-type granite, with all samples plotting within the A2-type granite field on a Y/Nb vs. Rb/Nb diagram. Zircon ε_(Hf)(t) values and two-stage modal ages of the zircons within the pluton range from +4.80 to +13.65 and from 983 to 418 Ma, respectively, indicating that the primary magma was generated through partial melting of felsic rocks from juvenile crust.Consequently, these results demonstrate that the Xierzi pluton formed under the post-orogenic extensional setting after arc-continent collision in the middle Permian.  相似文献   

Voyage of the Indian subcontinent since Pangea breakup and driving force of supercontinent cycles: Insights on dynamics from numerical modeling     

Masaki Yoshida  M.Santosh 《地学前缘(英文版)》2018,9(5):1279-1292

Recent advances in three-dimensional numerical simulations of mantle convection have aided in approximately reproducing continental movement since the Pangea breakup at 200 Ma. These have also led to a better understanding of the thermal and mechanical coupling between mantle convection and surface plate motion and predictions of the configuration of the next supercontinent. The simulations of mantle convection from 200 Ma to the present reveals that the development of large-scale cold mantle downwellings in the North Tethys Ocean at the earlier stage of the Pangea breakup triggered the northward movement of the Indian subcontinent. The model of high temperature anomaly region beneath Pangea resulting from the thermal insulation effect support the breakup of Pangea in the real Earth time scale, as also suggested in previous geological and geodynamic models. However, considering the low radioactive heat generation rate of the depleted upper mantle, the high temperature anomaly region might have been generated by upwelling plumes with contribution of deep subducted TTG(tonalite-trondhjemite-granite) materials enriched in radiogenic elements. Integrating the numerical results of mantle convection from 200 Ma to the present, and from the present to the future, it is considered that the mantle drag force acting on the base of continents may be comparable to the slab pull force, which implies that convection in the shallower part of the mantle is strongly coupled with surface plate motion.  相似文献