华北地区岩石圈有效弹性厚度及其地球动力学意义北大核心CSCD

以EIGEN-6C4模型布格重力异常数据、V19.1地形数据和CRUST1.0模型地壳数据为基础,采用导纳法和相关函数法联合反演,计算华北地区岩石圈有效弹性厚度(T_(e))。结果表明,华北地区T_(e)值的分布存在明显的横向不均匀性,西部鄂尔多斯地块为高值区,T_(e)厚度约为30~60 km;中部华北平原为低值区,T_(e)厚度约为5~25 km;鲁东黄海地块为中、高值区,T_(e)厚度约为20~50 km。华北克拉通高T_(e)值区与稳定的鄂尔多斯地块相对应,中、低T_(e)值区则对应构造相对活跃的太行山构造带和郯庐断裂带。从T_(e)值与地表热流的关系来看,高T_(e)值区一般对应低热流值区,而低T_(e)值区一般热流值也较高,这与岩石圈厚度和地表热流的一般分布规律一致。从T_(e)与地震的空间分布来看,华北地区的地震活动主要集中在中、低T_(e)值区,表明T_(e)较低的地区稳定性较差,可能更有利于地震的孕育和发生。     

Temperature trends and elevation dependent warming during 1965 – 2014 in headwaters of Yangtze River,Qinghai Tibetan Plateau

The understanding of temperature trends in high elevation mountain areas is an integral part of climate change research and it is critical for assessing the impacts of climate change on water resources including glacier melt, degradation of soils, and active layer thickness. In this study, climate changes were analyzed based on trends in air temperature variables(T_(max), T_(min), T_(mean)), and Diurnal Temperature Range(DTR) as well as elevation-dependent warming at annual and seasonal scales in the Headwaters of Yangtze River(HWYZ), Qinghai Tibetan Plateau. The Base Period(1965-2014) was split into two subperiods; Period-Ⅰ(1965-1989) and Period-Ⅱ(1990-2014) and the analysis was constrained over two subbasins; Zhimenda and Tuotuohe. Increasing trends were found in absolute changes in temperature variables during Period-Ⅱ as compared to Period-Ⅰ.T_(max), T_(min), and T_(mean) had significant increasing trends for both sub-basins. The highest significant trends in annual time scale were observed in T_(min)(1.15℃ decade~(-1)) in Tuotuohe and 0.98℃ decade~(-1) in Zhimenda sub-basins. In Period-Ⅱ, only the winter season had the highest magnitudes of T_(max) and T_(min)0.58℃ decade~(-1) and 1.26℃ decade~(-1) in Tuotuohe subbasin, respectively. Elevation dependent warming analysis revealed that T_(max), T_(min) and T_(mean) trend magnitudes increase with the increase of elevations in the middle reaches(4000 m to 4400 m) of the HWYZ during Period-Ⅱ annually. The increasing trend magnitude during Period-Ⅱ, for T_(max), is 1.77, 0.92, and 1.31℃ decade~(-1), for T_(min) 1.20, 1.32 and 1.59℃ decade~(-1),for T_(mean) 1.51, 1.10 and 1.51℃ decade~(-1) at elevations of4066 m, 4175 m and 4415 m respectively in the winter season. T_(mean) increases during the spring season for 3681 m elevations during Period-Ⅱ, with no particular relation with elevation dependency for other variables. During the summer season in Period Ⅱ, T_(max), T_(min), T_(mean) increases with the increase of elevations(3681 m to 4415 m) in the middle reaches of HWYZ. Elevation dependent warming(EDW), the study concluded that magnitudes of T_(min) are increasing significantly after the 1990s as compared to T_(max) in the HWYZ. It is concluded that the climate of the HWYZ is getting warmer in both sub-basins and the rate of warming was more evident after the 1990s. The outcomes of the study provide an essential insight into climate change in the region and would be a primary index to select and design research scenarios to explore the impacts of climate change on water resources.     

川西、藏东晚三叠世诺利期牙形刺

本文描述了采自藏东贡觉—江达地区上三叠统波里拉组(T_3b)和川西白玉地区上三叠统下逆松多组碳酸盐岩段(T_3~x~2)的牙形刺 Epigondolella postera 组合,成员包括 Epigondolella postera,E.sp.,Neogondolellanavicula。含上述牙形刺化石的地层时代为中诺利期。     

长江三峡链子崖危岩体形变特征和监测系统之我见

本文在系统研究长江三峡链子崖危岩体区域地质、岩体结构基础上,根据目前危岩体各段的变形特征,对现有监测手段及点位布设提出了若干看法。认为,链子崖危岩体的产生和发展,主要受控于特殊的地质构造环境和临空的高陡边坡条件,因此,有效监测手段布设必须完成两个转化,即由相对位移观测为主转向绝对位移观测为主;从普遍布点转向敏感段落设防,把监测重点摆到变形最明显、危险性最大的T_(5-1)与T_6裂缝、T_(11)与T_(12)裂缝围限的基岩块体和7000m~3堆积体上。在没有充分报警尺度依据的情况下,建议暂不使用限位报警系统,以免造成人为的混乱局面。     

一种基于Emardson-H的GPT3改进模型构建方法北大核心CSCD

针对GPT3模型各气象参数存在明显周期性误差的问题,以2015~2019年长三角地区7个探空站资料作为参考,分析GPT3模型残差的季节性周期变化,并利用Emardson-H模型构建一种新的GPT3改进模型。实验结果表明:1)与探空资料相比,GPT3模型气压、温度、水汽压和加权平均温度(T_(m))的均方根(RMS)均值分别为5.09 hPa、3.90 K、4.01 hPa和4.54 K;2)基于Emardson-H的GPT3改进模型气压、温度、水汽压和T_(m)的RMS均值分别为4.64 hPa、3.53 K、3.73 hPa和3.27 K,比GPT3模型分别提升0.45 hPa、0.37 K、0.28 hPa和1.27 K。综上分析,基于Emardson-H的GPT3改进模型精度相比GPT3模型有所改进。     

青海省沱沱河南九十二道班地区铅锌多金属矿地质特征及找矿前景浅析

九十二道班地区位于羌北地块(弧后前陆盆地T_3-J)三级构造单元,在1∶5万化探和铜多金属矿调查评价工作基础上,通过对该地区化探异常特征、地质背景及已知矿化点深入分析研究,强化对化探高含量点的地质追索,物化探先行、地质跟进的思路,最终取得了突破,并确定九十二道班铅锌多金属矿床为与火山(次火山)活动有关的受断裂构造控制的中低温热液型矿床。     

胶北地区古元古代基性-超基性岩锆石U-Pb定年Hf同位素组成及其构造岩浆演化意义

胶北地区位于古元古代胶-辽-吉构造岩浆岩带的南段,前人对该区的早前寒武纪地质事件进行了较多研究,然而,对古元古代基性—超基性岩研究较少。通过对该区基性—超基性岩岩石地球化学、锆石U-Pb定年及Hf同位素分析,讨论了其成因、形成时代及其对构造岩浆演化意义。基性—超基性岩为偏铝质岩石,具有低硅贫钾的特征,无明显Eu异常,轻重稀土分馏不明显。获得岩浆锆石年龄~2.1 Ga,形成时代为古元古代,与区域上古元古代构造热事件一致。同时获得变辉长岩~2.4 Ga,~2.7 Ga的2组继承锆石年龄和1.8~1.9 Ga的变质年龄。一个变辉长岩样品的岩浆锆石的ε_(Hf)(t)值和T_(DM2)分别为-11.1~-2.1和2 859~3 408 Ma(10个数据点),一个超基性岩样品的外来锆石ε_(Hf)(t)值和T_(DM2)分别为4.6~5.3和2 355~2 398 Ma(2个数据点)。研究表明,基性岩来自于地幔但受到陆壳物质的强烈影响,变质超基性主要为古元古代亏损地幔或其新生地壳组分,岩浆熔融程度较高。总体反映该地区由早期的挤压机制转为古元古代的伸展机制。     

广西晚元古代本洞和三防花岗岩类岩体Nd、Sr同位素特征

广西晚元古代本洞和三防花岗岩类岩体的εNd(T)平均值分别是-5.0±0.38(7)和-6.7±0.68(8)。εSr(T)变化很大。本洞岩体Nd模式年龄T_(DM)~(Nd)平均值为2120Ma。根据两个岩体在εSr(T)—εNd(T)和εNd(T)—T两个图上的分布特征,推断它们的成因类型基本相同,来源于同一岩浆库。该岩浆库是10亿年前由下地壳物质完全重熔产生,但是在演化过程中,本洞岩体中有少量亏损性地慢物质加入,三防岩体同化混染了大量沉积岩。以四堡群为代表的下地壳形成年龄大于2120Ma。岩浆期后自交代和气成热液作用导致岩石的Rb/Sr比增高,εSr(T)降低和Sm—Nd系统再次分异。     

苗儿山花岗岩复式岩基锶、氧、钕、铅同位素研究

苗儿山花岗岩复式岩基位于湘桂两省交界处,是华南地区规模较大的多期多阶段花岗岩复式岩基。其岩浆活动可分为四期:加里东期,海西期,印支期和燕山期。加里东期花岗岩是该岩体的主体岩石。作者对该复式岩基进行了Sr、O、Nd、Pb多元同位素体系的示踪研究,有关参数如下:各期花岗岩的(~(87)Sr/~(86)Sr)Ⅰ值范围为0.7168—0.7265,δ~(18)O为9.39—10.73,∈xd=-7.1,∈Sr=177-209,长石的铅同位素组成为~(206)Pb/~(204)Pb=18.759—18.833,~(207)Pb/~(204)Pb=15.669—15.747,全岩的铅同位素比值为:~(206)Pb/~(204)Pb=18.512—19.269,~(207)Pb/~(204)Pb=15.559—15.729。锆石的u—Pb不一致线与一致性曲线的上交点年龄为1126Ma,T_(DM)=1553Ma。上述各项同位素参数表明苗儿山岩体的成岩物质源自上部地壳,可能为中晚元古代的基底物质重熔而成。     

随机变量导出的广义概率赋范空间及拓扑

本文给出了广义概率赋范空间(简称GN空间)的定义,由随机变量及分市函数族构造出一个在T_m下的GN空间,在一般情形证明了此空间是T_1 型的拓扑线性空间,基于PN空间的收敛性质,证明了Bernoulli大数定律,并指出了在随机变量分布合成方面的应用。 在传统的PN空间理论中,分布函数F_(pq)(x)示E中p点与q点之间的距离小于xΞR的概率,在PN空间中,概率范数f,(x)作为表示B空间中p点的范数小于XΞR的慨率,如果将普通随机变量p小于XΞR的概率F,(x)作为p点的广义概率范数,由此导出的空间,正是本文讨论的GN空间。     

右江盆地火山岩的地球化学特点及其构造环境

右江盆地的火山活动比较频繁,从泥盆纪到中三叠世,除中、晚石炭世外,都有发育。按其活动特点可以东吴运动为界分为两个阶段:早阶段(D_1—P_1)以基性岩为主,强度低,范围小,主要分布于盆地南缘,受NW向构造控制:晚阶段(P_2—T_2)包括基性岩与中、酸性岩,强度大,分布广,主要分布于盆地南、北缘,受NE向及NW向构造控制。不同时代的火山岩的岩石化学成分、稀土元素和微量元素组成均有明显差异,与多种参数的构造环境判别结果基本一致。即三叠纪玄武岩属拉斑玄武岩系列,具岛弧特点:石炭纪、二叠纪玄武岩属拉斑玄武岩系列,盆地北缘的二叠纪玄武岩属碱性系列,虽然仍属大陆裂谷型,但它具有许多大洋玄武岩的特点。     

Microanalysis and preliminary pharmacokinetic studies of a sulfated polysaccharide from Laminaria japonica

A rapid,sensitive and reproducible high performance liquid chromatography(HPLC) method with post-column fluorescence derivatization has been developed to determine the amount of low-molecularweight sulfated polysaccharide(GFS) in vivo. The metabolism of GFS has been shown to fit a two component model following its administration by intravenous injection,and its pharmacokinetic parameters were determined to be as follows: half-time of distribution phase(t_(1/2α))=11.24±2.93 min,half-time of elimination phase(t_(1/2β))=98.20±25.78 min,maximum concentration(C_(max))=110.53 μg/mL and peak time(T_(max))=5 min. The pharmacokinetic behavior of GFS was also investigated following intragastric administration. However,the concentration of GFS found in serum was too low for detection,and GFS could only be detected for up to 2 h after intragastric administration(200 mg/kg body weight). Thus,the bioavailability of GFS was low following intragastric administration because of the metabolism of GFS. In conclusion,HPLC with postcolumn derivatization could be used for quantitative microanalysis and pharmacokinetic studies to determine the presence of polysaccharides in the serum following intravenous injection.     

西安地区的硅热流

本文参照C.A.Swanberg和P.Morgan等人计算区域硅热流的方法,对西安地区的硅地温和硅热流进行了计算。计算是在西安地区500米深以内地下水中二氧化硅含量资料并考虑到本区具体的地质、水文地质和地球化学条件的基础上进行的。计算结果为:西安地区的硅地温T_(sio2)=55.52±18.96°C;硅热流q_s=1.48±0.27HFU。     

Petrogenesis of Early Cretaceous hornblende gabbro in Khanka Massif: evidence from geochronology and geochemistry

The authors report zircon U-Pb geochronological,whole-rock geochemical and zircon Lu-Hf isotope data for the hornblende gabbro within the Khanka Massif,with the aim of constraining its formation time and petrogenesis. The zircon U-Pb dating shows that ~(206)Pb/~(238)Pb ages of zircons from the hornblende gabbro range from 120 to 129 Ma,yielding a weighted mean age of 123 ± 2 Ma,i. e.,the Early Cretaceous. The hornblende gabbro has SiO_2 of 44. 77%--46. 58% and belongs to the tholeiitic series on FeO~t/MgO-SiO_2 diagram. It displays a right-inclined REE pattern with( La/Yb)_N ratios of 3. 44 to 4. 42. The trace element spidergram shows that they are enriched in large ion lithophile elements( LILE) such as Rb,Th,U,K and Pb,and depleted in high field strength elements( HFSE) such as Nb,Ta,Ti and P,indicating an affinity to arc igneous rocks.The ε_(Hf)( t) values of zircons vary from -2. 6 to + 3. 9 and Hf model ages( T_(DM1)) range from 622 to 883 Ma.These geochemical characteristics indicate that primary magma of the hornblende gabbro could be derived from partial melting of young mantle material accreted during the Neoproterozoic. Combined with the Early Cretaceous igneous rock assemblages in NE Asia. It is concluded that the hornblende gabbro formed in an active continental margin related to the westward subduction of the Paleo-Pacific Plate beneath the Khanka Massif.     

架状硅酸盐矿物晶胞参数与硅氧四面体几何要素的关系

架状硅酸盐矿物晶体结构为氧离子作开层堆积,阳离子充填空隙而形成.矿物晶胞参数与硅氧四面体的排列方式有关,和硅氧四面体的棱长l、对棱间距T_(?)、四面体的高T_h等几何要素有确定的函数关系.     

U-Pb-Hf isotopes and petrogenesis of Late Jurassic akakitic quartz monzodiorite in Xingcheng area,western Liaoning Province

The petrogenesis and geodynamic setting of the Late Jurassic Baita porphyry quartz monzodiorite in Xingcheng--Liaoxi area provide information for understanding the Mesozoic tectonic evolution of the northeastern North China Craton. In this paper, geochronological, whole-rock geochemical, and in-situ zircon Hf isotopic analyses of Baita porphyry quartz monzodiorite were investigated to constrain the crystallization age and petrogenesis. Zircons exhibit typical oscillatory zoning in cathodoluminescence images and show relatively high Th/U ratios(0.78--1.62), and U-Pb analyses indicate that these rocks were crystallized during the Late Jurassic(159±1 Ma). Geochemically, they are characterized by high contents of SiO_2(65.21 wt%--65.31 wt%), Al_2O_3(16.29 wt%--16.31 wt%), Sr(521×10~(-6)-539×10~(-6)), and Sr/Y ratio(45.1--47.8) but low Y(10.9×10~(-6)-12.0×10~(-6)), with obvious adakitic geochemical affinities. These above-mentioned findings, combined with their negative ε_(Hf)(t) values(-21.7 to-20.2), corresponding two-stage model age(T_(DM2)) of 2 579--2 484 Ma, as well as low MgO(1.38 wt%--1.39 wt%), Cr(18.5×10~(-6)-19.5×10~(-6)) and Ni(9.45×10~(-6)-9.46×10~(-6)) values, indicate that Baita porphyry quartz monzodiorite may be generated by partial melting of the Neoarchean-Paleoproterozoic thickened basaltic lower crust. Based on the results from this study and pre-vious regional studies, it is concluded that Baita porphyry quartz monzodiorite was spatially related to the westward subduction of the Paleo-Pacific plate.     

鄂尔多斯盆地富县地区长7油层组致密砂岩成岩作用及孔隙演化

致密砂岩油是非常规油气勘探的热点领域。以鄂尔多斯盆地东南部富县地区长7油层组为研究对象,利用铸体薄片、扫描电镜、常规物性、X线衍射和稳定同位素等方法,分析致密砂岩的成岩作用,并对孔隙度演化进行半定量恢复。结果表明:长7油层组致密砂岩储层处于中成岩阶段A期,经历机械压实、绿泥石包膜、泥微晶方解石和亮晶方解石胶结、有机酸溶蚀、高岭石及蒙皂石向伊/蒙混层转化、少量微晶石英和石英次生加大等成岩作用。物性演化主要受机械压实、亮晶方解石胶结和有机酸溶蚀等成岩作用影响,但不同成岩作用在不同成岩时期所起作用存在差异。砂岩储层大致经历早成岩阶段A期(T_3—J_1末)、早成岩阶段B期(J_1末—K_1早)、中成岩阶段A期快速埋藏(K_1早—K_2早期)和中成岩阶段A期缓慢抬升等4个孔隙演化阶段,孔隙度从35.0%的原始孔隙度一直演化至现今6.6%。该研究结果对鄂尔多斯盆地东南部富县地区油气勘探有指导意义。     

Geochemistry,U-Pb,Hf isotopic characteristics and geological significance of Zhalaxiageyong trachydacite in Tuotuohe area,Qinghai

The Zhalaxiageyong lead-zinc-copper polymetallic deposit is a typical porphyry deposit of the Tuotuohe area. Whole-rock geochemical analyses,Zircon U-Pb dating and Hf isotope analysis are undertaken for the ore host trachydacite with the aim of constraining its petrogenesis,magma source and regional tectonic setting.LA-ICP-MS zircon U-Pb dating indicates that the trachydacite was formed in 32. 68 ± 0. 50 Ma( MSWD =1. 6),i. e.,Oligocene. The trachydacite is rich in potassium and poor in Mg#( 5. 10-9. 70),belonging to the peraluminous shoshonite series. The rocks are enriched in LILE( large ion lithophile elements) Rb,Ba,K and LREE,depleted in HFSE( high field strength elements) Nb,Ta,P,Ti,with high Sr and low Y and Yb,having the characteristics of the C type adakite. It is calculated that the initial εHf( t) of the zircons range from-0. 92 to 2. 07 and their two-stage Hf model ages T_(DM2) range from 978 Ma to 1 169 Ma. The magma source should be mainly the partially melt mafic rocks of the thickened Middle Neoproterozoic lower crust of the Northern Qiangtang massif with the addition of ancient aluminosilica material in the melting process. The rocks formed in the tectonic setting of delamination of lithosphere and extension of the thickened crust. During the period of 40-32 Ma,large-scale potassium rich alkaline magmatism occurred in this area. The porphyry metallogenesis is related to the magmatic activities in this period.     

Late Pleistocene-Holocene slip history of the Langshan-Seertengshan piedmont fault(Inner Mongolia,northern China) from cosmogenic ~(10)Be dating on a bedrock fault scarp

Offset geomorphic features and deformed late Quaternary strata indicate active deformation along the Langshan-Seertengshan piedmont fault(LSPF),one of the most active faults in the Hetao fault zone in Inner Mongolia,North China.The widespread occurrence of bedrock fault scarps along the LSPF offers excellent opportunity to examine the faulting history.Using cosmogenic (10)~Be exposure dating,we measured the exposure ages of the western Langshankou scarp,located in the middle segment of the LSPF.Our data revealed at least two earthquakes that occurred at 22.2±3.3 ka and 7.2±2.4 ka,respectively.These events are consistent with previous paleoseismic trench studies.The regression of the relationship between the age and sampling height along the scarp yield a fault slip rate of 0.10 +0.05/-0.06 mm/yr,which issignificantly lower than the average post-late Pleistocene fault slip rate of ~1 mm/yr,as estimated from the offset of the T_2 terraces by previous studies.This indicates that the slip of the LSPF may have been accommodated by other fault branches.     

Geochronology,geochemistry and geodynamics implications of Middle Triassic garnet-bearing muscovite monzogranite in central Jilin Province

Zircon LA-ICP-MS U-Pb geochronology and geochemical analyses are undertaken for the garnet-bearing muscovite monzogranite in Yitong area,central Jilin Province. The formation age and petrogenesis of the granite are determined,and the regional tectonic background is discussed. Zircons from the granite are euhedral-subhedral in shape,and display fine-scale oscillatory growth zoning,indicating a magmatic origin. LAICP-MS zircon U-Pb dating result indicates that the garnet-bearing muscovite monzogranites formed in the middle Triassic( 243 Ma). The garnet-bearing muscovite monzogranites have high SiO_2( Si O2= 74. 1%--76. 49%),rich aluminum( Al_2O_3= 14. 47%--14. 68%) and alkali( Na_2O + K_2O = 4. 31%--7. 9%),low Fe_2O_3 T and MgO( MgO = 0. 1%--0. 13%,Fe_2O_3 T = 0. 46%--1. 02%). The ratio of CaO/Na_2O is between 0. 17--0. 21. The garnet-bearing muscovite monzogranites in Yitong region are relatively enriched in light rare earth elements( LREEs) and large ion lithophile elements( LILEs),and depleted of heavy rare earth elements( HREEs) and high field strength elements( HFSEs). They are characterized by high Sr and Ba,poor Rb and Y,and negative Eu abnormally( δEu = 0. 48--0. 62),with Rb/Sr 1. The ε_(Hf)( t) values and T_(DM2) of zircons range from + 6. 10 to + 8. 00 and from 725 Ma to 814 Ma,respectively. The above features indicate that garnet-bearing muscovite monzogranites in Yitong area were derived from partial melting of metasedimentary rock.These granites have high Sr/Y ratios,which suggest they formed in a thickened continental crust. Combined with the coeval granitic rocks in central Jilin Province,we suggested that a significant collisional and thickening event took place during the Middle Triassic.