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Timming of Lithospheric Extension in Northeastern China:Evidence from the Late Mesozoic Nianzishan A-Type Granitoid Complex
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作者 Jinhua Qin Cui Liu +1 位作者 Yuchuan Chen Jinfu Deng 《地球科学学刊:英文版》 SCIE CAS CSCD 2019年第4期689-706,共18页
New zircon U-Pb dates obtained by laser ablation inductively coupled plasma mass spectrometry(LA-ICP-MS),whole-rock geochemical data and Sm-Nd and Rb-Sr isotopic data are presented for miarolitic alkaline granites,por... New zircon U-Pb dates obtained by laser ablation inductively coupled plasma mass spectrometry(LA-ICP-MS),whole-rock geochemical data and Sm-Nd and Rb-Sr isotopic data are presented for miarolitic alkaline granites,porphyritic syenite and rhyolites of the Nianzishan A-Type granitoid complex(NAGC)in the Great Xing'an Range-Songliao Basin in Northeast(NE)China.New crystallization ages of 112.95±0.93 and 114.1±1.71 Ma for granite and 118.6±0.51 Ma for porphyritic syenite were determined by high-precision LA-ICP-MS.The εNd(t)of the rocks range from +1.85 to+2.06,with Nd model ages(T(DM1))from 671 to 821 Ma,indicating that the NAGC originated from juvenile source rocks and exhibits geochemical characteristics of A1-and A-Type granite which formed in an extensional setting.We attribute the magmatism to regional extension and lithospheric thinning caused by the subduction of the western Pacific Plate about 120 to 100 Ma. 展开更多
关键词 A-TYPE granitee new ZIRCON UU-Pb ZIRCON agees NE China LITHOSPHERIC exxtension
Petrogenesis of the Late Triassic shoshonitic Shadegai pluton from the northern North China Craton:Implications for crust-mantle interaction and post-collisional extension 预览
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作者 Liqiong Jia Liang Wang +2 位作者 Genhou Wang Shibin Lei Xuan Wu 《地学前缘:英文版》 CAS CSCD 2019年第2期595-610,共16页
Latest Permian to Triassic plutons are widespread in the northern North China Craton(NCC);most of them show calc-alkaline,high-K calc-alkaline,or alkaline geochemical features.The Shadegai pluton in the Wulashan area ... Latest Permian to Triassic plutons are widespread in the northern North China Craton(NCC);most of them show calc-alkaline,high-K calc-alkaline,or alkaline geochemical features.The Shadegai pluton in the Wulashan area has shoshonitic affinity and I-type character,and is composed of syenogranites containing abundant maficmicrogranular enclaves(MMEs).LA-MC-ICP-MS UePb data yieldweightedmean 206Pb/238U ages of 222±1 Ma and 221±1 Ma for the syenogranites and MMEs,respectively,suggesting their coeval formation during the Late Triassic.The syenogranites have high SiO2(70.42-72.30 wt.%),K2O(4.58-5.22 wt.%)and Na2O(4.19-4.43 wt.%)contents but lower concentrations of P2O5(0.073-0.096 wt.%)and TiO2(0.27-0.37 wt.%),and are categorized as I-type granites,rather than A-type granites,as previously thought.These syenogranites exhibit lower(87Sr/86Sr)i ratios(0.70532-0.70547)and strongly negative whole-rockεNd(t)values(-12.54 to-11.86)and zirconεHf(t)values(-17.81 to-10.77),as well as old Nd(1962e2017 Ma)andHf(2023-2092 Ma)model ages,indicating that theywere derived fromthe lower crust.Field and petrological observations reveal that the MMEs within the pluton probably represent magmatic globules commingled with their hostmagmas.Geochemically,theseMMEs have lowSiO2(53.46-55.91wt.%)but high FeOt(7.27-8.79 wt.%)contents.They are enriched in light rare earth elements(LREEs)and large ion lithophile elements(LILEs),and are depleted in heavy rare earth elements(HREEs)and high field strength elements(HFSEs).They have whole-rock(87Sr/86Sr)i ratios varying from 0.70551 to 0.70564,εNd(t)values of-10.63 to-9.82,and zirconεHf(t)values of-9.89 to 0.19.Their geochemical and isotopic features indicate that they were derived from the subcontinental lithospheric mantle mainly metasomatized by slab-derived fluids,with minor involvement of melts generated from the ascending asthenospheric mantle.Petrology integrated with elemental and isotopic geochemistry suggest that the Shadegai pluton was produced by crust-mantle interactions,i.e.,partial 展开更多
关键词 Magma mixing CRUST-MANTLE interaction LITHOSPHERIC delamination POST-COLLISION North China CRATON
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Petrogenesis and tectonic implications of Early Cretaceous andesitic-dacitic rocks,western Qinling(Central China):Geochronological and geochemical constraints 预览
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作者 Feifei Zhang Peter A. Cawood +1 位作者 Yunpeng Dong Yuejun Wang 《地学前缘:英文版》 CAS CSCD 2019年第4期1507-1520,共14页
40Ar/39Ar and zircon U-Pb geochronological and whole-rock geochemical analyses for the Laozanggou intermediate-acidic volcanic rocks from the western Qinling orogenic belt,Central China,constrain their petrogenesis an... 40Ar/39Ar and zircon U-Pb geochronological and whole-rock geochemical analyses for the Laozanggou intermediate-acidic volcanic rocks from the western Qinling orogenic belt,Central China,constrain their petrogenesis and the nature of the Late Mesozoic lithospheric mantle.These volcanic rocks yield hornblende or whole-rock 40Ar/39Ar plateau ages of 128.3-129.7 Ma and zircon U-Pb age of131.3±1.3 Ma.They exhibit SiO2 of 56.86-66.86 wt.%,K2 O of 0.99-2.46 wt.%and MgO of 1.03-4.47 wt.%,with Mg#of 42-56.They are characterized by arc-like geochemical signatures with significant enrichment in LILE and LREE and depletion in HFSE.All the samples have enriched Sr-Nd isotopic compositions with initial 87Sr/86Sr ratios ranging from 0.7112 to 0.7149 andεNd(t)values from 10.2 to 6.3.Such geochemical signatures suggest that these volcanic rocks were derived from enriched lithospherederived magma followed by the assimilation and fractional crystallization(AFC)process.The generation of the enriched lithospheric mantle is likely related to the modification of sediment-derived fluid in response to the Triassic subduction/collision event in Qinling orogenic belt.The early Cretaceous detachment of the lithospheric root provides a reasonable mechanism for understanding the petrogenesis of the Laozanggou volcanic sequence in the western Qinling orogenic belt. 展开更多
关键词 40AR/39AR and zircon U-Pb geochronology SR-ND isotopes Early Cretaceous AFC process Continental LITHOSPHERIC mantle WESTERN QINLING orogenic belt
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Magnetotelluric investigation of lithospheric electrical structure beneath the Dharwar Craton in south India: Evidence for mantle suture and plume-continental interaction 预览
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作者 D. Malleswari K. Veeraswamy +4 位作者 K.K. Abdul Azeez A.K. Gupta Narendra Babu Prasanta K. Patro T. Harinarayana 《地学前缘:英文版》 CAS CSCD 2019年第5期1915-1930,共16页
Broad-band and long period magnetotelluric measurements made at 63 locations along -500 km long Chikmagalur-Kavali profile,that cut across the Dharwar craton (DC) and Eastern Ghat Mobile Belt (EGMB) in south India,is ... Broad-band and long period magnetotelluric measurements made at 63 locations along -500 km long Chikmagalur-Kavali profile,that cut across the Dharwar craton (DC) and Eastern Ghat Mobile Belt (EGMB) in south India,is modelled to examine the lithosphere architecture of the cratonic domain and define tectonic boundaries.The 2-D resistivity model shows moderately conductive features that intersperse a highly resistive background of crystalline rocks and spatially connect to the exposed schist belts or granitic intrusions in the DC.These features are therefore interpreted as images of fossil pathways of the volcanic emplacements associated with the greenstone belt and granite suite formation exposed in the region.A near vertical conductive feature in the upper mantle under the Chitradurga Shear Zone represents the Archean suture between the western and eastern blocks of DC.Although thick (-200 km) cratonic (highly resistive) lithosphere is preserved,significant part of the cratonic lithosphere below the western DC is modified due to plume-continental lithosphere interactions during the CretaceouseTertiary period.A west-verging moderately conductive feature imaged beneath EGMB lithosphere is interpreted as the remnant of the Proterozoic collision process between the Indian land mass and East Antarctica.Thin (-120 km) lithosphere is seen below the EGMB,which form the exterior margin of the India shield subsequent to its separation from East Antarctica through rifting and opening of the Indian Ocean in the Cretaceous. 展开更多
关键词 MAGNETOTELLURIC LITHOSPHERIC structure MANTLE PLUME MANTLE SUTURE Dharwar CRATON
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Nature and evolution of the lithospheric mantle revealed by water contents and He-Ar isotopes of peridotite xenoliths from Changbaishan and Longgang basalts in Northeast China
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作者 Qinghu Xu Jiaqi Liu +1 位作者 Huaiyu He Yunhui Zhang 《科学通报:英文版》 SCIE EI CSCD 2019年第18期1325-1335,共11页
The nature and evolution of the lithospheric mantle underlying Northeast(NE)China were investigated by assessing the mineral chemistry,water contents,and noble gas(He-Ar)isotopes of peridotite xenoliths captured by Ce... The nature and evolution of the lithospheric mantle underlying Northeast(NE)China were investigated by assessing the mineral chemistry,water contents,and noble gas(He-Ar)isotopes of peridotite xenoliths captured by Cenozoic basalts from the Changbaishan and Longgang regions.The xenoliths,which have 863-1141℃ equilibration temperatures,primarily comprise spinel lherzolites and rare spinel harzburgites.The Mg^#(Fo)values of olivine in the peridotite xenoliths vary from 86.9 to 91.3.The clinopyroxenes have high Ti/Eu and low(La/Yb)N,and their chondrite-normalized rare earth elements(REEs)exhibit light REE-depletion to-enrichme nt patter ns,indicati ng that the mantle un derneath the investigated region was predominantly subjected to partial melting(1%-10%)and was metasomatized by silicate melts.The measured 3He/4He ratios of the Changbaishan xenoliths have a narrow range from 5.8 Ra to 8.4 Ra with an average of 7.4 Ra.The ^3He/^4He isotopic ratios of the Longgang xenoliths varied from 4.7 Ra to 8.1 Ra with an average of 5.9 Ra;slightly lower than the Changbaishan xenoliths.The whole-rock H2O contents of the studied peridotite ranged from 9 to 132 ppm.The high H2O con tents in excess of 50 ppm(up to 132 ppm)might represent newly accreted and cooled asthenospheric materials,while those with H2O contents lower than 50 ppm(as little as 9 ppm)may represent rhinned,relic,ancient lithospheric mantle.These geochemical evidences,in combi nation with published data,indicated that the lithospheric mantle beneath the Changbaishan and Longgang in NE China is dominated by the younger and more fertile lithospheric mantle with a minor ancient and refractory keel.In addition,the lithospheric mantle of this area was metasomatized by melts related to the recent subduction event(e.g..Pacific oceanic plate).Therefore,the westward-dipping Pacific oceanic plate subduction had an important contribution to the transformation of the lithospheric mantle beneath NE China. 展开更多
关键词 Subcontinental lithospheric mantle Peridotite xenoliths Mineral chemistry He-Ar isotopes Water contents Northeast China
Crustal strain rates of southeastern Tibetan Plateau derived from GPS measurements and implications to lithospheric deformation of the Shan-Thai terrane 预览
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作者 KeLiang Zhang ShiMing Liang WeiJun Gan 《地球与行星物理:英文版》 CSCD 2019年第1期45-52,共8页
The link between the crustal deformation and mantle kinematics in the Tibetan Plateau has been well known thanks to dense GPS measurements and the relatively detailed anisotropy structure of the lithospheric mantle.Ho... The link between the crustal deformation and mantle kinematics in the Tibetan Plateau has been well known thanks to dense GPS measurements and the relatively detailed anisotropy structure of the lithospheric mantle.However,whether the crust deforms coherently with the upper mantle in the Shan-Thai terrane(also known as the Shan-Thai block)remains unclear.In this study,we investigate the deformation patterns through strain rate tensors in the southeastern Tibetan Plateau derived from the latest GPS measurements and find that in the Shan-Thai terrane the upper crust may be coupled with the lower crust and the upper mantle.The GPS-derived strain rate tensors are in agreement with the slipping patterns and rates of major strike-slip faults in the region.The most prominent shear zone,whose shear strain rates are larger than 100×10^–9a^–1,is about 1000-km-long in the west,trending northward along Sagaing fault to the Eastern Himalayan Syntaxis in the north,with maximum rate of compressive strain up to–240×10^–9a^–1.A secondary shear zone along the Anninghe-Xiaojiang Fault in the east shows segmented shear zones near several conjunctions.While the strain rate along RRF is relatively low due to the low slip rate and low seismicity there,in Lijiang and Tengchong several local shear zones are present under an extensional dominated stress regime that is related to normal faulting earthquakes and volcanism,respectively.Furthermore,by comparing GPS-derived strain rate tensors with earthquake focal mechanisms,we find that 75.8%(100 out of 132)of the earthquake T-axes are consistent with the GPS-derived strain rates.Moreover,we find that the Fast Velocity Direction(FVDs)at three depths beneath the Shan-Thai terrane are consistent with extensional strain rate with gradually increasing angular differences,which are likely resulting from the basal shear forces induced by asthenospheric flow associated with the oblique subduction of the India plate beneath the Shan-Thai terrane.Therefore,in this region the upper crust d 展开更多
关键词 strain rate TENSOR GPS measurement LITHOSPHERIC deformation southeastern TIBETAN PLATEAU Shan-Thai TERRANE
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A Thickness Gauge for the Lithosphere Based on Ce/Yb and Sm/Yb of Mantle-Derived Magmatic Rocks 预览
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作者 WU Zhenhan Patrick J. BAROSH +2 位作者 ZHANG Qichao WU Jiwen YANG Yan 《地质学报:英文版》 SCIE CAS CSCD 2018年第6期2120-2135,共16页
A new method for determining the partial melting depth of mantle-derived magma and lithospheric thickness in continental regions is derived from REE geochemistry.This effective technique uses variations in the Ce/Yb a... A new method for determining the partial melting depth of mantle-derived magma and lithospheric thickness in continental regions is derived from REE geochemistry.This effective technique uses variations in the Ce/Yb and Sm/Yb ratios found in mainly volcanic rocks in continental China.The ratios change with the depth of origin consistent with the correlation between lithospheric thickness and the Ce/Yb and Sm/Yb ratios found in oceanic basalt.These ratios increase exponentially with the depth of origin,the lithospheric thickness,of a wide variety of Cenozoic volcanic basalt and Paleozoic kimberlite in the North China Craton,northeastern China continent and vicinity.This functional relationship with depth is shown in a plot of the ratios that forms a concordia curve,which is closely expressed by formulas using 8-degree polynomials.These provide a more accurate gage in measuring the lithospheric thickness than the traditional geophysical methods.When applied to volcanic rock of different ages it also reveals how the thickness has changed over time and thus,greatly aids the understanding of the tectonic history.Relations between the CO2 content,mineral reactions and pressure in the upper asthenosphere beneath the base of the lithosphere appears to affect the proportions of REE in partial melts and brings about a close correlation between lithospheric thickness and the Ce/Yb and Sm/Yb ratios in mantle-derived magmatic rock.This thickness gauge,for both continental and oceanic lithosphere,provides a new approach in analyzing the lithospheric thickness in different tectonic settings and geologic times. 展开更多
关键词 Ce/Yb and Sm/Yb ratios MANTLE-DERIVED magmatic rock LITHOSPHERIC thickness correlationanalysis North China CRATON
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Geochemistry,petrogenesis and tectonic implication of Early Cretaceous A-type rhyolites in Hailar Basin,NE China 预览
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作者 ZHENG Han SUN Xiaomeng 《世界地质:英文版》 2018年第2期77-90,共14页
Early Cretaceous A-type rhyolites of the Shangkuli Formation in the Hailar Basin of NE China exhibit geochemical characteristics of high silicon,alkali,Fe/Mg,Ga/Al,Zr,Pb,HFSEs,and REE contents but low Ca,Ba,Sr and Eu,... Early Cretaceous A-type rhyolites of the Shangkuli Formation in the Hailar Basin of NE China exhibit geochemical characteristics of high silicon,alkali,Fe/Mg,Ga/Al,Zr,Pb,HFSEs,and REE contents but low Ca,Ba,Sr and Eu,which meet the criteria of typical reduced A-type granite.The A-type rhyolites are most probably derived from magmatic underplating and partial melting of quartz-feldspathic lower crust,with the lithospheric mantle material involved,due to the extensional deformation of the Erguna-Hulun Fault.Although the A-type rhyolites show A1-type trace elements characteristics,they were formed in a post-orogenic extensional background together with the coeval widespread bimodal volcanic rocks,metamorphic core complexes,volcanic fault basins and metallogenic province in the Sino-Russia-Mongolia border tract.This extension event was related to the collapse of thickened region of the continental crust after the closure of the Mongol-Okhotsk Ocean. 展开更多
关键词 A-TYPE RHYOLITES Hailar BASIN Early Cretaceous PETROGENESIS LITHOSPHERIC extension
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辽东岫岩地区早白垩世侵入岩的年代学、地球化学及地质意义 被引量:3
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作者 刘杰勋 郭巍 朱凯 《岩石学报》 SCIE EI CAS CSCD 北大核心 2016年第9期2889-2900,共12页
本文对辽东岫岩地区帽盔山二长花岗岩、荒地花岗闪长岩和朝阳苏长辉长岩进行了岩相学、地球化学、LA-ICP-MS U-Pb定年。帽盔山二长花岗岩主量元素具有富Si、Al、K,贫Fe、Mg、Ca的特征;微量元素亏损Sr、P、Eu、Ti,富集K、Rb、Th等不相容... 本文对辽东岫岩地区帽盔山二长花岗岩、荒地花岗闪长岩和朝阳苏长辉长岩进行了岩相学、地球化学、LA-ICP-MS U-Pb定年。帽盔山二长花岗岩主量元素具有富Si、Al、K,贫Fe、Mg、Ca的特征;微量元素亏损Sr、P、Eu、Ti,富集K、Rb、Th等不相容元素,元素地球化学特征表明岩体为铝质A型花岗岩(A/CNK=1.03-1.06,A/NK=1.11-1.12)。荒地花岗闪长岩的SiO_2含量为64.1%-70.8%,K_2O/Na_2O的比值为0.87-1.08,含铝指数A/CNK和A/NK分别为0.98-1.02和1.31-1.55,微量元素富集K、Rb、Sr、Ba等大离子亲石元素,亏损Nb、P、Ti等高场强元素,轻重稀土分馏强烈,(La/Yb)N值为13.41-68.2,属于准铝质到过铝质I型花岗岩。朝阳苏长辉长岩的SiO_2含量为54.8%-58.3%,K2O/Na2O的比值为0.57-0.78,微量元素富集K、Ba、Sr等大离子亲石元素,亏损Nb、U、P、Ti等高场强元素,富集La、Ce、Pr、Nd等轻稀土元素。测年结果显示帽盔山二长花岗岩的锆石年龄为137Ma,荒地花岗闪长岩的锆石年龄为139Ma,朝阳苏长辉长岩的锆石年龄为139Ma,均形成于早白垩世。结合构造背景图解,帽盔山二长花岗岩、荒地花岗闪长岩和朝阳苏长辉长岩均为伸展构造环境下的岩浆活动产物。结合三个岩体的时空特点,表明在早白垩世时期,辽东岫岩地区处于非造山的伸展环境,且岩石圈减薄及伸展活动的发展有自深部至浅部的特点,是华北板块东部伸展地球动力学背景的具体体现。 展开更多
关键词 早白垩世侵入岩 地球化学 锆石U-PB测年 岩石圈减薄 伸展环境 辽东岫岩地区
2009~2010年大华北岩石圈磁异常分布及其变化特征 预览 被引量:9
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作者 陈斌 顾左文 +2 位作者 狄传芝 高金田 袁洁浩 《云南大学学报:自然科学版》 CAS CSCD 北大核心 2011年第5期548-553,共6页
使用曲面样条和球冠谐和方法,对2009年和2010年所测量的2期大华北地区218个地磁场测点的数据所描述的岩石圈磁场F,D,I3个要素进行分析.2期测量所得到的F,D,I3要素的宏观分布类似.D要素的值在华北东北部负值增强、正值减弱,在华北的中西... 使用曲面样条和球冠谐和方法,对2009年和2010年所测量的2期大华北地区218个地磁场测点的数据所描述的岩石圈磁场F,D,I3个要素进行分析.2期测量所得到的F,D,I3要素的宏观分布类似.D要素的值在华北东北部负值增强、正值减弱,在华北的中西部负值减弱、正值增强;在整个华北的大部分地区,F要素的负异常减弱,正异常增强,江苏滨海和辽冀附近的正异常减弱,负异常增强;I要素在华北大部分地区正值增强负值减弱,在辽宁东北部,山西东边界至晋豫交界附近的区域正值减弱负值增强. 展开更多
关键词 岩石圈 磁场 大华北地区
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云南潞西三台山超镁铁岩体Os-Nd-Pb-Sr同位素特征及地质意义 被引量:2
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作者 储著银 王伟 +3 位作者 陈福坤 王秀丽 李向辉 季建清 《岩石学报》 SCIE CAS CSCD 北大核心 2009年第12期,共8页
滇西地区特提斯造山带具有多块体拼合的构造特点,是东特提斯造山带的重要组成部分之一,其大地构造演化对理解全球特提斯造山带具有重要的地质意义.在腾冲和保山地块之间的龙陵-瑞丽断裂带中出露超镁铁质岩石,曾被解释为两个陆块缝合的证... 滇西地区特提斯造山带具有多块体拼合的构造特点,是东特提斯造山带的重要组成部分之一,其大地构造演化对理解全球特提斯造山带具有重要的地质意义.在腾冲和保山地块之间的龙陵-瑞丽断裂带中出露超镁铁质岩石,曾被解释为两个陆块缝合的证据.本文采用高灵敏度高精度超低本底Re-Os、Sm-Nd、Pb和Rb-Sr同位素分析技术,对采自该断裂带潞西三台山的超镁铁岩样品进行了Os-Nd-Pb-Sr同位素测定.分析结果表明,这些超镁铁岩石具有强烈富集特征.分析的5个岩石样品具有高的初始~(87)Sr/~(86)Sr值(0.71074~0.71444)、低的初始ε_(Nd)值(-6.2~-10.6)、低初始γ_(Os)值(-4.8~-8.8)和较高的初始铅同位素比值,其Os同位素模式年龄值(t_(RD))为0.97~1.71Ga.Nd-Os同位素组成特征表明,三台山超镁铁岩具有古老的富集大陆岩石圈地幔岩石的特征,不能作为腾冲和保山地块的缝合证据. Abstract: The western Yunnan Tethyan terrain that is formed by the amalgamation of multiple continental blocks represents an important part of the eastern Tethyan tectonic belt. Its tectonic evolution bears essential significances for understanding the formation of the global Tethyan orogenic belt. Along the Longling-Ruili fault zone between the Tengchong and Baoshan blocks, many small outcrops of ultramafic rocks are exposed, which have ever been interpreted as evidence for the suturing of these two blocks. Os-Nd-Pb-Sr isotopic compositions of ultramafic rocks sampled from Santaishan massif were analyzed by using low procedural blank and high precision analytical techniques in this study. Analytical results show that these ultrmafic rocks exhibit isotopic characteristics of strong enrichment. Five analyzed samples of ultramafic rock yield high initial ~(87)Sr/~(86)Sr values (0.71074 ~0.71444), low initial ε_(Nd) values (-6.2 ~ -10.6), low initial γ_(Os) values (-4.8 ~ -8.8) and relative high initial Pb isotopic ratios. Os isotopic mod 展开更多
关键词 云南潞西 超镁铁岩体 同位素特征 地质意义 western Yunnan initial isotopic characteristics 大陆岩石圈地幔 LITHOSPHERIC mantle 造山带 特提斯 tectonic evolution 同位素分析技术 high precision understanding 铅同位素比值 断裂带 大地构造演化 超镁铁质岩石 同位素组成
太行山南段符山高镁闪长岩的成因——拆沉陆壳物质熔融的熔体与地幔橄榄岩反应的结果 被引量:19
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作者 许文良 杨德彬 +1 位作者 裴福萍 于洋 《岩石学报》 SCIE CAS CSCD 北大核心 2009年第8期,共15页
本文对太行山南段符山高镁闪长岩进行了年代学与地球化学研究,结合其中地幔橄榄岩包体的研究,对符山高镁闪长岩的成因和中生代岩石圈地幔的性质进行了探讨.研究表明,符山闪长岩体是由一套含橄榄石角闪闪长岩-角闪闪长岩-闪长岩构成.含... 本文对太行山南段符山高镁闪长岩进行了年代学与地球化学研究,结合其中地幔橄榄岩包体的研究,对符山高镁闪长岩的成因和中生代岩石圈地幔的性质进行了探讨.研究表明,符山闪长岩体是由一套含橄榄石角闪闪长岩-角闪闪长岩-闪长岩构成.含橄榄岩包体的寄主岩--角闪闪长岩中的锆石可划分为两种:一是代表寄主岩浆结晶的锆石:内部结构均匀、呈条带状吸收、自形-半自形晶形,具有较高的Th/U比值(1.10~4.08),其~(206)Pb/~(238)U年龄介于123~128Ma之间,12个点的加权平均值为125±1Ma,这表明岩体的形成时代为早白垩世;二是捕获或继承锆石:具有核边结构、吸收程度不均匀、呈浑圆状和自形-半自形两种,它们的Th/U比值介于0.32~2.03之间,构成了3组~(207)Pb/~(206)Pb加权平均年龄:2503±11Ma、2181±26Ma和1778±36Ma.该类岩石的SiO_2和MgO含量分别介于56.69%~59.21%和3.60%~6.33%之间;且以高:Mg~#(0.51~0.64)、富Na(Na_2O/K_2O大于1)、高Cr(93.1×10~(-6)~420×10~(-6))、Ni(35.1×10~(-6)~137×10~(-6))为特征.该类岩石强烈富集轻稀土元素和大离子亲石元素、明显亏损高场强元素,(87Sr/86Sr)I、ε_(Nd)(t)值和(~(206)Pb/~(204)Pb)I分别变化于0.70581~0.70641、-8.30~-16.56和17.052~17.512之间.综合上述特征,同时结合地幔橄榄岩包体的特征和古元古代捕获锆石的大量存在,认为符山高镁闪长岩的原始岩浆起源于拆沉陆壳物质的部分熔融,其后经历了与地幔橄榄岩的反应过程. Abstract: This paper reports chronological and geochemical data of the Fushan high-Mg~# diorites from the southern Taihang Mts. And discusses its petrogenesis and nature of the Mesozoic lithospheric mantle beneath the central North China Craton together with the mantle peridotite xenoliths entrained by them. The Fushan dioritic intrusion is composed mainly of olivine-bearing hornblende-diorite, hornblende-diorite and diorite. Based on their shape and s 展开更多
关键词 山南 高镁闪长岩 成因 物质 熔融 熔体 地幔橄榄岩 橄榄岩包体 岩反应 结果 North China Craton central southern continental crust partial melting PERIDOTITE XENOLITHS high field strength rare earth elements crystallization time lithospheric mantle
南海北部深水区地热特征及其成因 预览 被引量:81
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作者 米立军 袁玉松 +3 位作者 张功成 胡圣标 何丽娟 杨树春 《石油学报》 EI CAS CSCD 北大核心 2009年第1期 27-32,共6页
对392个地温梯度数据和234个大地热流数据的统计结果显示:南海北部深水区地温梯度为2.94~5.22℃/hm,平均为3.91±074℃/hm;大地热流值为24.2~121mW/m2,平均为77.5±14.8mW/m2。南海北部地区现今地温场具“热盆... 对392个地温梯度数据和234个大地热流数据的统计结果显示:南海北部深水区地温梯度为2.94~5.22℃/hm,平均为3.91±074℃/hm;大地热流值为24.2~121mW/m2,平均为77.5±14.8mW/m2。南海北部地区现今地温场具“热盆”属性,且深水区比浅水区更“热”。大地热流总体变化趋势为:从陆架到陆坡(从北到南)逐渐增高,且增高趋势与地壳减薄趋势一致,同时,平面上存在显著的局部异常点。新生代岩石圈拉张减薄以及新构造运动引发的岩浆、断裂活动是南海北部深水区具“热盆”特征的根本原因,南北向岩石圈减薄程度控制了大地热流总体变化趋势,新构造运动引发的岩浆与断裂活动则是局部热流异常形成的根本原因。 展开更多
关键词 南海北部 深水区 地温梯度 大地热流值 岩石圈 岩浆活动 断裂活动
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Si- and alkali-rich melt inclusions in minerals of mantle peridotites from eastern China: Implication for lithospheric evolution 被引量:3
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作者 FAN Qicheng SUI Jianli XU Ping LI Ni SUN Qian WANG Tuanhua 《中国科学:地球科学英文版》 SCIE EI CAS 2006年第1期43-49,共7页
Minerals of spinel- and garnet-facies mantle xenoliths entrained in Cenozoic basalts from eastern China (North China, Northeastern China and Southeastern China coastal area) contains lots of melt inclusions. Studies o... Minerals of spinel- and garnet-facies mantle xenoliths entrained in Cenozoic basalts from eastern China (North China, Northeastern China and Southeastern China coastal area) contains lots of melt inclusions. Studies on these melt inclusions show that the glass inclusions are rich in SiO2 (60%―68%) and alkalis (K2O+Na2O=5%―11%, especially for K2O) as well as volatiles such as H2O and CO2 (2%―7%), which belong to dacites and andesites of the high-K calcic alkali series rocks with few shoshonites. High Al and Ca diopside in melt inclusion is the product of melt crystallization at high temperature and pressure, rather than the product of devitrification. Results show that these K-rich (in general K2O>3%) intermediate-acidic silicate melt inclusions have characteristics of continent without a genetical link to host basalts and their phenocrystic minerals. Thus, these trapped melt inclusions represent melts of Mesozoic lithospheric mantle-crust interaction and imply that the continental lithospheric mantle beneath eastern China had undergone fragmentation and recreation processes during the Mesozoic and Cenozoic periods. This result undoubtly provides important implication for the evolution of sub-continental lithosphere beneath eastern China. We propose that these Si- and alkalis-rich melts should be responsible for the mantle chemical heterogeneity underneath eastern China. 展开更多
关键词 Si- and alkali-rich MELT inclusion MANTLE peridotite LITHOSPHERIC evolution eastern China.
中国东部岩石圈地幔的富化和置换过程
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作者 郑建平 戴宏坤 张卉 《矿物岩石地球化学通报》 CAS CSCD 北大核心 2019年第2期201-216,共16页
中国东部大陆主要由华北和华南两个古老地块在早中生代沿秦岭-大别-苏鲁造山带拼合形成,在显生宙特别是晚中生代时,东部大陆特别是华北东部发生显著活化,表现为浅部强烈的构造变形、盆地形成、岩浆活动、巨量成矿和深部岩石圈地幔的改... 中国东部大陆主要由华北和华南两个古老地块在早中生代沿秦岭-大别-苏鲁造山带拼合形成,在显生宙特别是晚中生代时,东部大陆特别是华北东部发生显著活化,表现为浅部强烈的构造变形、盆地形成、岩浆活动、巨量成矿和深部岩石圈地幔的改造、减薄和增生作用,从而明显区别于全球其他稳定的克拉通地区。本文梳理了中国东部大陆演化历史和岩石圈地幔特征,认为华北和华南地块均由古老陆块拼合而成,块体初始规模小且内部发育薄弱带;显生宙以来华北、华南甚至整个中国东部都受到周边多个构造域的夹持影响,板片俯冲引起的软流圈上涌和熔流体活动沿大陆内部薄弱带和边缘有效侵蚀、改造上覆大陆岩石圈,使之发生减薄、再富集和置换作用,这种被改造的岩石圈地幔具有饱满的组成(富含玄武质组分)、较高的密度和较低的刚性程度,容易发生构造变形和部分熔融,使原本稳定的克拉通发生活化。因此,块体规模和内部薄弱带(内因)及周边构造环境(外因)是大陆稳定性的重要控制因素,中国东部大陆显生宙活化是这些因素协同作用的结果。 展开更多
关键词 中国东部 岩石圈地幔 富化与置换 块体规模 板内薄弱带 周边构造环境
利用S波接收函数研究下扬子及其邻区的岩石圈结构 预览
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作者 张耀阳 方慧 +2 位作者 仇根根 艾印双 赵亮 《中国地质》 CAS CSCD 北大核心 2019年第4期786-794,共9页
下扬子及其邻区位于欧亚板块、太平洋板块和菲律宾海板块的交汇地带,自中生代以来经历了广泛的伸展变形和岩浆活动,其岩石圈结构和性质对深入认识华南块体乃至整个中国东部的显生宙构造演化以及相关动力学过程都具有重要意义。本文使用... 下扬子及其邻区位于欧亚板块、太平洋板块和菲律宾海板块的交汇地带,自中生代以来经历了广泛的伸展变形和岩浆活动,其岩石圈结构和性质对深入认识华南块体乃至整个中国东部的显生宙构造演化以及相关动力学过程都具有重要意义。本文使用中国科学院地质与地球物理研究所地震台阵实验室在合肥-金华沿线布设的流动地震台阵数据,通过S波接收函数偏移成像方法对下扬子及其邻区岩石圈的速度间断面结构进行了研究。成像结果显示,主测线下方Moho面深度为32~42 km,岩石圈底界面深度为84~112 km,总体表现为西深东浅,且速度间断面结构与区域构造特征变化趋势相一致。这为下扬子及其邻区岩石圈中生代以来的改造和减薄提供了新的观测证据:华北南部盆地区下方Moho面结构复杂,岩石圈较厚(90~112 km),表明该区域的改造程度相对较低;下扬子克拉通与华夏块体北缘岩石圈结构特征相似,仅在江南造山带附近Moho面和岩石圈底界面有小尺度变化,表明它们自新元古代拼合以来可能作为一个整体被改造。进一步结合同剖面南段大地电磁测深成像结果,文章对研究区的岩石圈改造提出了与华北地区相似的地幔流模型,郯庐断裂带和江南造山带两侧断裂带等薄弱带在太平洋板块俯冲的作用下,可能成为软流圈物质上涌的通道。 展开更多
关键词 下扬子及邻区 接收函数 速度间断面 岩石圈改造 深部资源工程
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地幔再富集作用对岩石圈地幔Fe-Mg-Ca同位素组成的影响
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作者 赵新苗 《矿物岩石地球化学通报》 CAS CSCD 北大核心 2019年第4期713-724,共12页
本文对目前的大洋玄武岩和华北地幔橄榄岩捕虏体的Fe-Mg-Ca同位素研究结果进行了系统的归纳和总结,并在此基础上,探讨地幔再富集作用对岩石圈地幔Fe-Mg-Ca同位素组成的影响,以期为进一步认识华北岩石圈地幔物质组成转变的方式提供新途... 本文对目前的大洋玄武岩和华北地幔橄榄岩捕虏体的Fe-Mg-Ca同位素研究结果进行了系统的归纳和总结,并在此基础上,探讨地幔再富集作用对岩石圈地幔Fe-Mg-Ca同位素组成的影响,以期为进一步认识华北岩石圈地幔物质组成转变的方式提供新途径。统计结果表明,没有受到地幔交代作用影响的橄榄岩,其Fe-Mg-Ca同位素组成变化范围小,而地幔再富集作用会导致岩石圈地幔的Fe-Mg-Ca同位素组成明显不均一,说明地幔再富集作用是导致岩石圈地幔Fe-Mg-Ca同位素组成变化的重要机制。 展开更多
关键词 岩石圈地幔 地幔再富集作用 地幔捕虏体 Fe-Mg-Ca同位素
中国东部及邻区晚中生代伸展拆离构造——综述与新认识 预览 被引量:1
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作者 杨谦 施炜 侯贵廷 《地球学报》 EI CAS CSCD 北大核心 2019年第4期511-544,共34页
伸展构造是大陆岩石圈减薄破坏在上部浅层的一种重要表现。其中,低角度伸展拆离构造为中国东部以及邻区晚中生代地壳伸展变形的显著构造变形样式,是研究区域岩石圈浅层构造变形与深部减薄过程关系的重要窗口。结合相关的几何学、运动学... 伸展构造是大陆岩石圈减薄破坏在上部浅层的一种重要表现。其中,低角度伸展拆离构造为中国东部以及邻区晚中生代地壳伸展变形的显著构造变形样式,是研究区域岩石圈浅层构造变形与深部减薄过程关系的重要窗口。结合相关的几何学、运动学、年代学等资料的综述分析,本文对中国东部及邻区低角度伸展拆离构造时空展布、运动学极性、应变机制进行了系统论述。在空间展布上,这些伸展拆离构造在东亚大陆的分布不均一,指示岩石圈的不均匀伸展减薄作用。在形成时代上,伸展拆离活动主要集中在两个时代区间:140–125Ma为伸展拆离构造在中下地壳初始形成期,在水平伸展作用主导下,以简单剪切为主;125–110Ma为伸展拆离构造快速隆升剥露期,在垂向挤压的主导下,以纯剪切为主。相关的几何学和运动学标志表明这些伸展构造总体具有在NW–SE方向上单向低角度伸展拆离运动学特征,反映它们总体受NW–SE向伸展应力场作用控制。以大兴安岭—太行山—武陵山重力梯度带为界,东、西两侧区域伸展活动均具有从NW向SE传播的趋势,且这种趋势西部较东部明显,表现为不同的动力学背景特征。东部主要受到古太平洋板块后撤影响,而西部可能与蒙古—鄂霍茨克洋闭合之后,增厚地壳发生重力崩塌而引发区域大规模伸展活动以及同时发生的秦岭—大别构造带陆内造山后应力伸展的联合作用相关。 展开更多
关键词 东亚大陆 伸展拆离构造 重力梯度带 应变机制 岩石圈减薄 古太平洋板块
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川西拉拉含矿镁铁质层状岩体的成因及构造背景 预览
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作者 孙君一 于文佳 +2 位作者 崔加伟 李重 罗照华 《地质力学学报》 CSCD 2019年第1期139-150,共12页
川西拉拉含矿镁铁质层状岩体位于扬子地块西缘,构造环境复杂,关于其成因机制及岩浆源区的问题至今仍缺乏系统的研究。文章针对该岩体七个岩相带,进行了主、微量元素和Sr-Nd同位素分析,结果表明,七个岩相带(YWS-1—YWS-7)是岩浆经历不同... 川西拉拉含矿镁铁质层状岩体位于扬子地块西缘,构造环境复杂,关于其成因机制及岩浆源区的问题至今仍缺乏系统的研究。文章针对该岩体七个岩相带,进行了主、微量元素和Sr-Nd同位素分析,结果表明,七个岩相带(YWS-1—YWS-7)是岩浆经历不同的演化过程而形成的。其中,第五相带SiO2含量高(42.95%~44.07%),MgO含量低(1.62%~1.89%),稀土总量明显偏低(295.32×10^-6~366.36×10^-6),Cr、Ni含量偏低,87Sr/86Sr为0.7391~0.7812,是受到地壳混染所致;其它相带Mg^#值高(0.54~0.74),稀土总量偏高(672.53×10^-6~986.66×10^-6),87Sr/86Sr为0.7087~0.7097,显示岩石圈地幔源区特征。结合区域地质背景分析,认为该层状岩体产生于大陆裂谷构造环境,岩浆来源于岩石圈地幔源区,演化过程中结晶分异和多次脉动作用相伴。这一活动过程与新元古时期扬子板块西缘的超级地幔柱活动有关。 展开更多
关键词 拉拉矿区 层状岩体 主、微量元素 岩石圈地幔 岩石成因
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地幔橄榄岩中碳酸盐熔体交代作用及其鉴定特征
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作者 邓黎旭 刘勇胜 +2 位作者 宗克清 朱律运 胡兆初 《地球科学》 EI CAS CSCD 北大核心 2019年第4期1113-1127,共15页
碳酸盐熔体交代作用是指在地幔碳酸盐熔体与橄榄岩之间的相互作用,是改造地幔的重要方式之一.碳酸盐熔体交代会显著改变地幔橄榄岩的岩石学和地球化学特征.首先,碳酸盐熔体交代作用会改变地幔橄榄岩中的矿物组成和比例.尽管碳酸盐熔体... 碳酸盐熔体交代作用是指在地幔碳酸盐熔体与橄榄岩之间的相互作用,是改造地幔的重要方式之一.碳酸盐熔体交代会显著改变地幔橄榄岩的岩石学和地球化学特征.首先,碳酸盐熔体交代作用会改变地幔橄榄岩中的矿物组成和比例.尽管碳酸盐熔体与橄榄岩的反应结果受控于初始反应物成分和反应的温压条件,但多数反应会导致橄榄岩中辉石的比例增加,而且有时还会出现磷灰石、独居石等副矿物.另外,在有些受碳酸盐熔体交代显著的橄榄岩的矿物中不仅可发现大量CO2流体包裹体和碳酸盐熔体包裹体,也会出现特殊的反应边结构和熔体囊.其次,碳酸盐熔体在改造地幔橄榄岩过程中,会在地幔矿物中留下明显的地球化学指纹.在主量元素特征上,受到碳酸盐熔体交代的橄榄岩中的单斜辉石往往具有偏高的Mg#和Ca/Al比值(>5);而在微量元素组成特征上的变化更为显著,包括单斜辉石具有高的(La/Yb)N、Eu/Ti、Zr/Hf、Y/Ho比值,并显著亏损HFSE等.另外,值得注意的是,碳酸盐熔体与地幔橄榄岩反应的程度不同也会导致这些地球化学特征存在差异,因此在判别碳酸盐熔体交代作用时要采用岩石学和地球化学特征相结合,多方面对比分析.对于引起地幔碳酸盐熔体交代作用的交代介质来源的识别主要用Mg-Zn-Ca-Sr等多种同位素体系进行示踪研究,尤其是近年来微区Sr同位素分析方法的建立为地幔碳酸盐熔体交代作用研究提供了重要手段. 展开更多
关键词 碳酸盐熔体交代作用 岩石学 地球化学 岩石圈地幔
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