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Journal of Earth Science 2024年第1期35卷 29-40页

作者： Zhuang Li chunjing wei Chuan Yang Xi Zhang College of Geosciences China University of PetroleumBeijing 102249China MOE Key Laboratory of Orogenic Belts and Crustal Evolution School of Earth and Space SciencesPeking UniversityBeijing 100871China China Transport Telecommunications and Information Center Beijing 100011China

The basalts within the greenstone belt worldwide serve as an ideal target to decipher the nature of Archean mantle sources and further to extend the understanding of the early stages of Earth's *** provide important insights into the issues,we carried out a detailed investigation of whole-rock geochemistry and Sm-Nd isotopes,and zircon U-Pb-Hf isotopes for the Late Neoarchean metamorphosed basalts in eastern Hebei,North China Craton.U-Pb isotopic dating using the LA-ICPMS on zircons reveals that the basalts in eastern Hebei erupted at ca.2.48-2.51 Ga and subsequently experienced multiple regional metamorphic events at 2477 and 1798 Ma,*** metamorphosed basalts are featured by low SiO_(2),MgO,K_(2)O+Na_(2)O,and high Fe O contents,endowed with the subalkaline and high-Fe tholeiitic *** radiogenic initial Nd and Hf isotope values and correlations among V,Ni and Cr contents strongly imply that the basalts experienced significant clinopyroxene and olivine fractionation and minor crustal contamination during magma *** are also characterized by the relatively low total REE contents and exhibit significant depletions to moderate enrichments in the LREE contents,indicating the derivation from a deep mantle source in an Archean proto-mantle plume setting.

关键词： zircon U-Pb-Hf isotopes geochemistry Late Neoarchean basaltic magmatism North China Craton Archean proto-mantle plume

冀北红旗营杂岩多期变质作用:古元古代俯冲/碰撞—晚古生代伸展—早中生代挤压的记录

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地学前缘 2024年第1期31卷 95-110页

作者：魏春景赵亚男初航北京大学地球与空间科学学院造山带与地壳演化教育部重点实验室北京100871 中国地质调查局天津地质调查中心(华北地质科技创新中心) 天津300170

冀北红旗营杂岩记录了从古元古代到早中生代多期构造-热事件,并可能存在支持古元古代洋壳俯冲的关键证据,但是对其形成时代、变质演化历史和大地构造属性等众说纷纭。本文以总结红旗营杂岩变质作用和年代学研究为基础,探讨其复杂的多期... 详细信息

冀北红旗营杂岩记录了从古元古代到早中生代多期构造-热事件,并可能存在支持古元古代洋壳俯冲的关键证据,但是对其形成时代、变质演化历史和大地构造属性等众说纷纭。本文以总结红旗营杂岩变质作用和年代学研究为基础,探讨其复杂的多期构造演化过程。红旗营杂岩包括表壳岩、赤城混杂岩和正片麻岩三个岩石-构造单元。正片麻岩以古元古代(1.87~1.82 Ga)花岗闪长岩-二长花岗岩-正长花岗岩为主,出现少量新太古代(2.55~2.53 Ga)英云闪长质-花岗闪长质片麻岩。赤城混杂岩为典型蛇绿混杂岩,由退变榴辉岩(斜长角闪岩)和橄榄岩块体以及变质沉积岩组成,形成时代可能>1.88 Ga。表壳岩主要包括不同变质程度的碳质碎屑岩-碳酸盐岩和少量火山岩,可能形成于2.1~2.0 Ga。综合分析赤城混杂岩中的退变榴辉岩、斜长角闪岩和凤山地区含十字石石榴云母片岩的变质作用演化,可划分出5期变质作用。第一期变质作用(M1)存在于凤山地区的云母片岩中,为中压型,顺时针型p-T轨迹,峰期变质条件为1.0~1.1 GPa/>780℃,变质时间为约1.95 Ga。第二期变质作用(M2)见于退变榴辉岩中,顺时针型p-T轨迹,包括升温升压至峰期和峰后等温降压演化阶段,峰期p-T条件为>2.2 GPa/约750℃,地热梯度约为9℃/km。尽管退变榴辉岩中多数锆石限定晚古生代变质年龄,但榴辉岩相变质作用时间应>1.88 Ga。第三期变质作用(M3)出现于凤山地区的云母片岩中,以含十字石组合叠加在M1高级变质组合为特征,顺时针型p-T轨迹,峰期变质条件为0.6~0.7 GPa/610~630℃,变质年龄约为1.88 Ga。第四期变质作用(M4)出现于赤城混杂岩的斜长角闪岩中,由早期榴辉岩组合叠加变质形成,显示“大于号”形p-T轨迹,包括峰前减压升温和峰期后减压冷却变质过程,峰期p-T条件为0.5~0.7 GPa/780~830℃,地热梯度约为35℃/km(低压型),变质时间为晚古生代(354~289 Ma),并伴随广泛深熔作用。第五期变质作用(M5)以局部叠加绿片岩相组合为特征,为顺时针型p-T轨迹,推测变质作用时间为255~234 Ma。M1中压型变质作用与在华北克拉通西部2.0~1.95 Ga发生的碰撞造山事件有关;M2高压型变质作用与沿华北克拉通北缘1.95~1.88 Ga期间发生的洋壳俯冲有关,是支持现在样式板块构造启动的有力证据之一;M3中压型变质作用指示在华北克拉通北缘于1.88~1.83 Ga期间发生的另一次碰撞造山事件;M4低压型变质作用为晚古生代华北克拉通北缘区域伸展所致;M5低温型变质作用与沿索伦缝合带发生的碰撞闭合事件有关。可见,红旗营杂岩5期变质作用记录了古元古代碰撞-俯冲-碰撞、晚古生代伸展和早中生代挤压的复杂构造过程。红旗营杂岩在经历古元古代俯冲-碰撞事件之后位于不同地壳深度。西部红旗营表壳岩和赤城混杂岩位于中-下地壳层次,其中锆石记录了1.72~1.66 Ga、约450 Ma、354~289 Ma和255~234 Ma等多期热事件;而东部凤山地区表壳岩则位于中-上地壳,缺少后期热事件的锆石和独居石年龄记录。

关键词：多期变质作用古元古代混杂岩红旗营杂岩华北克拉通

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Electron microprobe analysis of Hf and Ti in ultrahigh temperature zircon:Optimized approaches and perspectives

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Science China Earth Sciences 2023年第5期66卷 985-996页

作者： Xiaoli LI Bin WANG chunjing wei Key Laboratory of Orogenic Belts and Crustal Evolution MOE School of Earth and Space SciencesPeking UniversityBeijing100871China

Zircon as a multi-objective typomorphic mineral commonly contains diverse trace elements with specific petrogenetic *** Hf abundance in zircon is sensitively indicative of melt fractionation during zircon growth on one hand,and on another,the Ti content is a robust temperature sensor of zircon crystallization and has been effectively u tilized in thermometric estimation.A Hf-Ti negative correlation was previously reported in igneous zircons,and thus a potential Hf thermometry was then *** this work,we performed reliable electron microprobe(EMP)measurements of Hf and Ti in ultrahigh temperature(UHT)zircons from the North China Craton,in optimizing point,line and grid *** EMP contents of Hf and Ti both show a wide range of fluctuation owing to the smaller probe spot,and some of them are higher than the LAICPMS *** Hf-Ti correlation in UHT zircons displays dual and thus complicated patterns in contrast with the previous consideration,which implicates some other factors controlling the geochemical behaviors of Hf and Ti in ***,the estimated Ti temperatures based on the EMP analyses are obviously higher than the LA-ICPMS outcomes,but are well consistent with the actual peak condition of the parent *** explains the common underestimation of Ti temperatures in hightemperature metamorphic rocks,by using LA-ICPMS analyses.

关键词： Ultrahigh-temperature Zircon Hf content Ti content Electron microprobe

不同麻醉方式用于手术治疗的糖尿病患者中的效果及对血流动力学的影响分析

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糖尿病新世界 2024年第3期27卷 13-15,32页

作者：李雪妮魏春景厦门市第五医院福建厦门361101

目的探讨不同麻醉方式用于手术治疗的糖尿病患者中的效果及对血流动力学的影响。方法选取2023年7—11月厦门市第五医院收治的68例糖尿病患者为研究对象,均接受手术治疗,按照麻醉方式不同对其进行分组。参照组34例应用全身麻醉方案,研究... 详细信息

目的探讨不同麻醉方式用于手术治疗的糖尿病患者中的效果及对血流动力学的影响。方法选取2023年7—11月厦门市第五医院收治的68例糖尿病患者为研究对象,均接受手术治疗,按照麻醉方式不同对其进行分组。参照组34例应用全身麻醉方案,研究组34例在此基础上联合硬外阻滞麻醉。比较两组不同时间节点的血糖、血压、心率水平。结果研究组T3(手术开始30 min)、T4(手术完成即刻)阶段收缩压、舒张压均比参照组低,差异有统计学意义(P均<0.05)。研究组T3、T4时间点心率(82.34±2.83)、(84.12±1.34)次/min较参照组低,差异有统计学意义(t=7.988、15.825,P均<0.05)。研究组T3、T4时间段血糖数值较参照组小,差异有统计学意义(P均<0.05)。结论不同麻醉方式应用于需要接受手术治疗的糖尿病患者中的效果存在差异。相较于全身麻醉而言,全身麻醉联合硬外阻滞麻醉对患者血流动力学的影响更小,并且能够稳定其术中血糖值,对确保手术顺利进行,维护手术安全性作用显著。

关键词：糖尿病麻醉方式硬外阻滞麻醉全身麻醉血流动力学血糖

The Caledonian low Al-TTD series from the Northern Qinling Orogenic Belt:Rock properties,genetic simulation and geological implication

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Science China Earth Sciences 2005年第11期48卷 1837-1847页

作者： TIAN wei wei chunjing School of Earth and Space Sciences Peking University Beijing 100871 China School of Earth and Space Sciences Peking University Beijing 100871 China

A belt of low Al-Trondhjemite-Tonalite-Diorite (TTD) series has been recognized along the Northern Qinling Orogenic Belt (NQOB), which is dated as 430―399 Ma and charac-teristic of positive εNd(t ) values. Geochemical features and trace elements simulation indicate that the TTD series was probably originated from differently partial melting of tholeiitic rocks from the Erlangping group. Thermodynamic analysis on the residue phases of the partial melting pro- cesses suggests that the TTD series may represent a dynamic process of temperature-increasing and pressure-decreasing, indicating an extension and thinning process of a thickened crust.

关键词： Northern Qinling, Caledonian movement, Erlangping group, TTD series, trace elements simulation, partial melting, isotopic dating, experimental petrology

Petrogenetic simulation of the Archean trondhjemite from Eastern Hebei, China

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Science China Earth Sciences 2017年第5期60卷 958-971页

作者： ZHANG Shiwei wei chunjing DUAN ZhanZhan Key Laboratory of Orogenic Belts and Crustal Evolution School of Earth and Space Sciences Peking University

It is generally believed that trondhjemitic rock, an important component of TTG rocks, is the anatectic product of mafic rocks. However, in many TTG gneiss terranes, for instance, the granulite facies terrane in Eastern Hebei, trondhjemites occur as small dikes, intrusions or leucosomes in tonalitic gneisses, suggesting their origin of in-situ partial melting. Based on the petrological analysis of a tonalitic gneiss sample from Eastern Hebei, in combination with zircon U-Pb dating, we investigated the petrogenesis of trondhjemite through simulating anatectic reactions and the major and trace element characteristics of the product melt at different pressures(0.7, 1.0 and 2.0 GPa). The results indicate that hornblende dehydration melting in a tonalitic gneiss at 0.9–1.1 GPa and 800–850°C, corresponding to the high-T granulite facies, with melting degrees of 5–10wt.% and a residual assemblage containing 5–10wt.% garnet, can produce felsic melts with a great similarity, for instance of high La/Yb ratios and low Yb contents to the trondhjemitic rocks from Eastern Hebei. However, the modelled melts exhibit relatively higher K2 O, and lower CaO and Mg~# than those in the trondhjemitic dikes and leucosomes from Eastern Hebei, suggesting that the leucosomes may not only contain some residual minerals but also be subjected to the effect of crystal fractionation. The zircon U-Pb dating for the tonalitic and trondhjemitic rocks in the Eastern Hebei yields a protolith age of 2518±12 Ma and a metamorphic age of 2505±19 Ma for the tonalitic gneiss. The latter age is consistent with a crystallization age of 2506±6 Ma for the trondhjemitic rock, confirming a close petrogenetic relation between them.

关键词：奥长花岗岩成岩模拟河北锆石U-Pb定年太古宙花岗质岩石变质年龄中国

Phase transition in the subducted oceanic lithosphere and generation of the subduction zone magma

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Chinese Science Bulletin 2008年第23期53卷 3603-3614页

作者： wei chunjing ZHANG YingHui Key Laboratory of Orogenic Belts and Crustal Evolution Ministry of Education of China School of Earth and Space Sciences Pe-king University Beijing 100871 China

Two metamorphic processes, i.e. subsolidus dehydration and partial melting occurring in MORB, metasediments and peridotite of subducted oceanic lithosphere are discussed on the basis of available experimental work and phase equilibrium modeling. Phase diagrams of hydrous MORB show that in most cold subduction P-T (pressure-temperature) regimes a large portion of water in the basic layer has released below the onset of blueschist facies (< 20 km), and at a depth (60―70 km) of transition from lawsonite blueschist to lawsonite eclogite facies through glaucophane dehydration; only a smaller portion of water will escape from the slab through dehydration of lawsonite and chloritoid in the depth range suitable for arc magma formation; and a very small portion of water stored in lawsonite and phengite will fade into the deeper mantle. The role of amphibole for arc magma formation is still arguable. In cold subduction P-T regimes, the dehydration of chlorite and talc in Al-poor metasediments, and chloritoid and carpholite in Al-rich metapelites at a depth around 80―100 km will make some con- tributions to the formation of arc magma. Comparatively, dehydration of serpentine in hydrated peridotite occurs at depths of 120―180 km, playing an important role in the arc magmatism. Subduction of oceanic crust along warm P-T regimes will cross the solidi at a depth over 80 km, resulting in partial melting under fluid-saturated and fluid-absent conditions in the metasediments involving biotite and phengite, and in the basic rocks involving epidote and amphibole. The melt compositions of the basic crust are adakitic at pressures < 3.0 GPa, but become peraluminous granitic at higher pressures.

关键词：脱水作用部分熔融海洋岩石圈俯冲带

Paleoproterozoic crustal evolution of the Hengshan-Wutai—Fuping region,North China Craton

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Geoscience Frontiers 2014年第4期5卷 485-497页

作者： chunjing wei Jiahui Qian Xiwen Zhou MOE Key Laboratory of Orogenic Belts and Crustal Evolution School of Earth and Space SciencesPeking University Institute of Geology Chinese Academy of Geological Sciences

An arguable point regarding the Neoarchean and Paleoproterozoic crustal evolution of the North China Craton（NCC）is whether the tectonic setting in the central belt during the mid-Paleoproterozoic（2.35-2.0 Ga）was dominated by an extensional regime or an oceanic subduction-arc regime.A review of the midPaleoproterozoic magmatism and sedimentation for the Hengshan-Wutai-Fuping region suggests that a back-arc extension regime was dominant in this *** conclusion is consistent with the observation that the 2.35-2.0 Ga magmatism shows a typical bimodal distribution where the mafic rocks mostly have arc affinities and the acidic rocks mainly comprise highly-fractioned calc-alkaline to alkaline（or A-type）granites,and that this magmatism was coeval with development of extensional basins characteristic of transgressive sequences with volcanic interlayers such as in the Hutuo *** the final amalgamation of the NCC was believed to occur at ～1.85 Ga,recent zircon U-Pb age dating for mica schist in the Wutai Group suggests a collisional event may have occurred at ～1.95 *** metamorphic ages of ～1.85 Ga,obtained mostly from the high-grade rocks using the zircon U-Pb approach,most probably indicate uplifting and cooling of these high-grade *** is because（i）phase modeling suggests that newly-grown zircon grains in highgrade rocks with a melt phase cannot date the age of peak pressure and temperature stages,but the age of melt crystallization in cooling stages;（ii）the metamorphic P-T paths with isobaric cooling under 6-7 kb for the Hengshan and Fuping granulites suggest their prolonged stay in the middle-lower crust;and（iii）the obtained metamorphic age data show a continuous distribution from 1.95 to 1.80 ***,an alternative tectonic scenario for the Hengshan-Wutai-Fuping region involves：（i）formation of a proto-NCC at ～2.5 Ga;（ii）back-arc extension during 2.35-2.0 Ga resulting in bimodal magmatism and sedimentation in rifting basins on an Archean basem

关键词： Bimodal magmatismMetamorphic P-T pathPaleoproterozoic tectonic evolutionHengshan-Wutai-Fuping regionNorth China Craton

Metamorphism of the East Sector of the Southern Qinling Orogenic Belt and Its Geological Significance

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Acta Geologica Sinica(English Edition) 1999年第1期73卷 65-77页

作者： wei chunjing YANG Chonghui ZHANG Shouguang Department of Geology Peking University Beijing 100871 Institute of Geology Chinese Academy of Geological Sciences Beijing 100037

The east sector of the southern Qinling belt is, lithologically, composed mainly of metapelites, ***qüartzites, marbles and small amount of metabasites and gneisses, whose protoliths are the Silurian, Devonian and less commonly the Sinian and Upper Palaeozoic. They have been subjected at least to two epochs of metamorphism. The early epoch belongs to progressive metamorphism which is centered on high amphibolite-granulite fades in the Fuping area and changed outwards into low amphibolite facies (staurolite-kyanite zone), epidote amphibolite facies (garnet zone) and greenschist facies (chlorite and biotite zones), the metamorphic age of which is about 220–260 Ma. This early-epoch metamorphism belongs to different pressure types: the rocks from greenschist to low amphibolite facies belong to the typical medium-pressure type which shows geothermal gradients of about 17–20 ***C/km and was probably produced by a crustal thickening process related to continental collision, and the high amphibolite-granulite facies belongs to the low-pressure type which shows geothermal gradients of about 25–38 ***C/km and was probably affected by some magmatic heats. Based on the basic characteristics of the P-T paths of the different facies calculated from the garnet zonations, it can be deduced that the metamorphism of medium-pressure facies series took place during an imbricated thickening process, rather than during the uplifting process after thickening. The late-epoch metamorphism belongs to dynamic metamorphism of greenschist facies which is overprinted on the early-epoch metamorphic rocks and is Yanshanian or Himalayan in age, probably related to intracontinental orogeny.

关键词： metamorphism metamorphic minerals P-T conditions and paths east sector of the southern Qinling orogenic belt

Metamorphism, fluid behavior and magmatism in oceanic subduction zones

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Science China Earth Sciences 2020年第1期63卷 52-77页

作者： Chimjing wei Yongfei ZHENG Key Laboratory of Orogenic Belts and Crustal Evolution School of Earth and Space SciencesPeking UniversityBeijing 100871China School of Earth and Space Sciences University of Science and Technology of ChinaHefei 230026China

Based on the updated results of experimental petrology and phase equilibria modelling and combined with the available thermal structure models of subduction zones, this paper presents an overview on the dehydration and melting of basic,sedimentary and ultrabasic rocks that occur in the different stages during oceanic subduction processes and their influences on magmatism above subduction zones. During the subduction at the forearc depth of <90–100 km, the basic and ultrabasic rocks from most oceanic slabs can release very small amounts of water, and significant dehydration may occur in the slab superficial sediments. Strong dehydration occurs in both basic and ultrabasic rocks during subduction at the subarc depth of 90–200 km. For example, more than 90% water in basic rocks is released by the successive dehydration of chlorite, glaucophane, talc and lawsonite in the subarc depths. This is diversely in contrast to the previous results from synthetic experiments. Ultrabasic rocks may undergo strong dehydration through antigorite, chlorite and phase 10 ? at the subarc depth of 120–220 km. However,sediments can contribute minor fluids at the subarc depth, one main hydrous mineral in which is phengite(muscovite). It can stabilize to ~300 km depth and transform into K-hollandite. After phengite breaks down, there will be no significant fluid release from oceanic slab until it is subducted to the mantle transition zone. In a few hot subduction zones, partial melting(especially flux melting) can occur in both sediments and basic rocks, generating hydrous granitic melts or supercritical fluids, and in carbonates-bearing sediments potassic carbonatite melts can be generated. In a few cold subduction zones, phase A occurs in ultrabasic rocks, which can bring water deep into the transition zone. The subducted rocks, especially the sediments, contain large quantities of incompatible minor and trace elements carried through fluids to greatly influence the geochemical composition

关键词： Oceanic subduction Metamorphism Phase equilibria Fluid activity Subduction zone magmatism Carbon cycle