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Progress in Natural Science:Materials International 2006年第2期16卷 192-200页

作者： ZHOU Ling and CHEN Bin (Key Laboratory of Orogenic Belts and Crustal Evolution, MOE, school of earth and space sciences, peking university, beijing 100871, china) Key Laboratory of Orogenic Belts and Crustal Evolution MOE School of Earth and Space Sciences Peking University Beijing 100871 China

The Hongshan syenitic pluton (South Taihang) is mainly made up of hornblende syenite and minor granite. SHRIMP zircon dating yields a U-Pb age of 135±2.7 Ma for the emplacement of the pluton, while biotite Rb-Sr isotopic data give an isochron of 120. 3±2.4 Ma. Hongshan syenites show low silica, high alkalis and LILE such as Sr, and exhibit negligible Eu anomalies or slightly positive anomalies in the REE patterns. The syenites show quite enriched isotopic compositions with Isr from 0.7052 to 0. 7102 and εNd(t) from -7.5 to - 11.1. Petrogenesis of the pluton can be that partial melting of an enriched lithospheric mantle gave birth to an alkali basaltic magma, which subsequently underplated in the lower crust and experienced a coupled fractionation of ferromagnesian phases like pyroxene and hornblende and minor ( china Plateau" in the Mesozoic.

关键词： syenite zircon SHRIMP Nd-Sr isotopes Taihang North china craton.

On Riemann-Finsler geometry

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Chinese Science Bulletin 1998年第6期43卷 447-450页

作者： MO Xiaohuan school of Mathematical sciences, peking university, beijing 100871, china school of Mathematical sciences Peking University Beijing China

The history of Finsler geometry is reviewed and briefly recent development in Finsler geometry and its application is completed systematically. Furthermore, an interesting open problem has been proposed in this field.

关键词： Finsler space Chern connection Hilbert form Minkowski potential projective sphere bundle.

Structures,kinematics,thermochronology and tectonic evolution of the Ramba gneiss dome in the northern Himalaya

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Progress in Natural Science:Materials International 2008年第7期18卷 851-860页

作者： Lei Guo,Jinjiang Zhang,Bo Zhang The Key Laboratory of Orogenic Belts and Crustal Evolution,Ministry of Education,china school of earth and space sciences,peking university,beijing 100871,china The Key Laboratory of Orogenic Belts and Crustal Evolution Ministry of Education China school of earth and space sciences Peking University Beijing 100871 China

The Ramba gneiss dome,one of the north Himalayan gneiss domes,is composed of three tectono-lithologic units separated by an upper and a lower detachment ***-grade metamorphic Tethyan Himalayan sedimentary sequence formed the upper unit above the brittle upper detachment *** gneiss and a leucogranite pluton made up the lower unit beneath the ductile lower detach- ment *** middle-grade garnet-,staurolite-and andalusite-schist constituted the middle unit between the two faults,which may be that the basal part of the upper unit experienced detachment *** Ramba dome underwent three episodes of deformation in its tectonic *** first episode was a top-down-to-north-northwest sliding possibly related to the activity of the south Tibetan detachment system(STDS).The second episode was the dominant deformation related to a east–west extension,which resulted in a unique top-down-to-east kinematics and the major tectonic features of the *** third episode was a collapse sliding toward the outsides of the *** Ramba gneiss dome is possibly a result of the east–west extension and magmatic *** lower detachment fault is probably the main detachment fault separating the sedimentary sequence from the crystalline basement during the east–west extension in the dominant deformation *** diapir of the leucogranite pluton formed the doming shape of the Ramba gneiss *** pluton intruded in the core of the dome in a late stage of the dominant deformation,and its Ar–Ar cooling ages are about 6 *** indicates that the dominant deformation of the dome happened at the same time of the east–west extension represented by the north–south trending rifts throughout the northern Himalaya and southern ***,the formation of the Ramba gneiss dome should be related to this east–west extension.

关键词： Ramba gneiss dome North Himalayan gneiss domes East–west extension

C-isotope composition and correlation of the Upper Neoproterozoic in Keping area, Xinjiang

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Chinese Science Bulletin 2007年第4期52卷 504-511页

作者： HE XiuBin, XU Bei & YUAN ZhiYun The Key Laboratory of Orogenic Belts and Crustal Evolution, peking university Ministry of Education of china school of earth and space sciences, peking university, beijing 100871, china The Key Laboratory of Orogenic Belts and Crustal Evolution Peking University Ministry of Education of china school of earth and space sciences Peking University Beijing China

C-isotope analysis of the carbonates in the Upper Neoproterozoic in Keping, Xinjiang indicates that the Qigebrak Formation and the Upper Sugaitbrak Formation mainly record positive C-isotope values, and a distinct positive excursion occurs in the lower part of the Qigebrak Formation. There are three negative excursions in the boundary between the Qigebrak Formation and the Cambrian, the uppermost and lowermost Upper Sugaitbrak Formation. These characters resemble those of the Upper Neoproterozoic in the Three-Gorge area, which suggests that the Upper Sugaitbrak Formation and Qigebrak Formation can be correlated with the middle and upper parts of the Doushantuo Formation and Dengying Formation, respectively. The negative excursion at the top of the Upper Sugaitbrak Formation corresponds to that at the top of the Doushantuo Formation, while the negative excursion at the bottom of the Sugaitbrak Formation can be correlated with that at the middle part of the Doushantuo Formation in the Three-Gorge area and that at the top of the Hangelchaok diamictites in the Quruqtagh area.

关键词：新疆柯坪地区晚震旦世 C同位素成分冰川作用

Geochemical characteristics and tectonic implications of HP-UHP eclogites and blueschists in southwestern Tianshan, china

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Progress in Natural Science:Materials International 2006年第6期16卷 624-632页

作者： AI Yongliang, ZHANG Lifei, LI Xuping and QU Junfeng (MOE Key Laboratory of Orogenic Belt and Crust Evolution, school of earth and space sciences, peking university, beijing 100871, china school of Geosciences and Resources, china university of Geosciences, beijing 100083, china) MOE Key Laboratory of Orogenic Belt and Crust Evolution School of Earth and Space Sciences Peking University Beijing 100871 China school of Geosciences and Resources China University of Geosciences Beijing 100083 China

Four rock assemblages in correspondence with two different tectonic settings have been recognized in the NEE-SWW extending HP-UHP metamorphic belt in southwestern Tianshan, northwest china. Eclogite assemblage EC1 is geochemically akin to alkaline within-plate oceanic island basalt (OIB). EC2 shows affinity to enriched mid-oceanic ridge basalt (EMORB). Rare earth element (REE) and other immobile trace element characteristics of blueschist assemblage BS1 resemble those of normal mid-oceanic ridge basalt (NMORB). These three assemblages are likely formed on a seamount setting, and the prevalent presence of carbonate minerals and om-phacite quartzite stripes/gobbets suggests ancient pelagic sediments including marls are probably developed upon the basaltic seamount. Whereas the geochemical characteristics of BS2 assemblage are of volcanic arc basalt-type. The seamount with the pelagic sediments on it is brought into the subduction zone, and volcanic arc basalts formed on the active continental margin and trench sediments are eroded and enwrapped in the subducting mass, they are altogether subjected to high to ultrahigh pressure metamorphism and subsequent exhumation towards surface. The HP-UHP metamorphic belt is thus interpreted as a subduct ion-accretionary complex formed by tectonic juxtaposition and imbrication of seamount, seafloor, trench and volcanic arc sequences during oceanic crust subduction.

关键词： southwestern Tianshan HP-UHP metamorphic belt snbduction-accretion complex trace element geochemistry.

BRILL-NOETHER MATRIX FOR RANK TWO VECTOR BUNDLES

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Chinese Annals of Mathematics,Series B 2002年第4期23卷 531-538页

作者： TAN XIAOJIANGschool of Mathematical sciences, peking university, beijing 100871, china school of Mathematical sciences Peking University Beijing 100871 China

Let X be an arbitrary smooth irreducible complex projective curve, E (?)X a rank two vector bundle generated by its sections. The author first represents ?as a triple {D1,D2,f}, where D1 , D2 are two effective divisors with d = deg(D1) + deg(D2), and f ∈ H?X, [D1] |D2) is a. collection of polynomials. E is the extension of [D2] by [D1] which is determined by f. By using / and the Brill-Noether matrix of D1+D2, the author constructs a 2g × d matrix WE whose zero space gives Im{H0(X,[D1]) (?) H0(X, [D1] |D1)}(?) Im{H?X, E) (?) H0(X,[D2]) (?) H0(X, [D2]|D2)} From this and H0(X,E) = H0(X,[D1]) (?)Im{H0(X,E) (?) H0(X, [D2])}, it is got in particular that dimH0(X, E) = deg(E) - rank(WE) + 2.

关键词： Brill-Noether matrix Vector bundle Effective divisor

Affinities and functional morphology of the Middle Cambrian ornamented tubules from West Hunan,china

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Progress in Natural Science:Materials International 2004年第10期14卷 67-71页

作者： ZHU Caifa 1,2 and DONG Xiping 1 (1.school of earth and space sciences,peking university,beijing100871,china 2.university of Petroleum,beijing102249,china) Sch. of earth and space Sci. Peking Univ. Beijing 100871 China Univ. of Petroleum Beijing 102249 China

Problematic phosphatic tubular microfossils with ornamented sculptures are documented to exist in limestones of the up-per Middle Cambrian Huaqiao Formation at the Paibi section and the Wangcun section in West Hunan,*** morphological pat-terns,including Ornamented Tube Form I and Ornamented Tube Form II are *** on the analysis of the preservation,wall structure and composition of the fossils,it is deduced that these ornamented tubes may represent carapace spines of some Cambrian arthro-pods with phosphatic carapaces,such as bradoriid *** of functional morphology indicates that the sclerites may rather be considered of a defensive than grasping function on the original organism body.

关键词： Middle Cambrian ornamented tubes affinities functional morphology West Hunan

The late Paleoproterozoic extension event:aulacogens and dyke Swarms in the North china craton

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Progress in Natural Science:Materials International 2006年第2期16卷 201-208页

作者： HOU Guiting, LI Jianghai, LIU Yulin and QIAN Xianglin (Key Laboratory of Orogenic Belts and Crustal Evolution, school of earth and space sciences, peking university, beijing 100871, china) Key Laboratory of Orogenic Belts and Crustal Evolution School of Earth and Space Sciences Peking University Beijing 100871 China

The extension structures and tectonic implication in the North china Craton ( NCC) are discussed in this paper based on the mafic dyke swarms and geochronology, combining with the geochronology of aulacogens. The late Paleoproterozoic time is the important turning point in the Precambrian evolution of the NCC. The extension system (e.g. aulacogens and dyke swarms) is widespread in the NCC, which marks the carbonization of the NCC with the rigid characteristic similar to the modern plate. The paleostress field modeling suggests that the dyke swarms and aulacogens are arogenic extension marking the start of the supercontinent, not synorogenic and post-orogenic extension. The mafic dyke swarms in the NCC mainly ranged from 1.83 to 1.77 Ga. The extension of the NCC is very limited brittle extension, the average extension ratio is only 0.35% given by mafic dyke swarms extension calculation, so most of extension in the NCC is contributed by the aulacogens. The mafic dyke swarms are related with the aulacogens in the origin.

关键词： North china craton late Paleoproterozoic aulacogens mafic dyke swarms extension.

Global well-posedness for the 2D critical dissipative quasi-geostrophic equation

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Science china Mathematics 2007年第4期50卷 485-494页

作者： Zhi-fei ZHANG school of Mathematical sciences, peking university, beijing 100871, china school of Mathematical sciences Peking University Beijing China

We study the initial value problem for the 2D critical dissipative quasi-geostrophic equation. We prove the global existence for small data in the scale invariant Besov spaces ? p,1 2/p , 1 ? p ? ∞. In particular, for p = ∞, our result does not impose any regularity on the initial data. Our proofs are based on an exponential decay estimate of the semigroup $e^{{ - t\kappa ( - \Delta )}^{\alpha}} $ and the use of space-time Besov spaces.

关键词： quasi-geostrophic equation Besov space Littlewood-Paley decomposition well-posedness 35Q35

Developmental sequence of Cambrian embryo Markuelia

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Chinese Science Bulletin 2007年第7期52卷 929-935页

作者： DONG XiPing1,2 1 school of earth and space sciences, peking university, beijing 100871, china 2 Laboratory of Palaeobiology & Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of sciences, Nan-jing 210008, china (email: dongxp@***) school of earth and space sciences Peking University Beijing China Laboratory of Palaeobiology & Stratigraphy Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences Nanjing China

Based on more exquisitely preserved specimens of Markuelia hunanensis recently recovered from Middle and Upper Cambrian in western Hunan and in the light of Synchrotron radiation X-ray tomo-graphic microscopy, the developmental sequence from cleavage through organogenesis to the pre-hatching of Cambrian embryo Markuelia, especially the developmental sequence during the pre-hatching stage, i.e. from the earliest period when the scalids and tail spines only took shape to the latest period (just about hatching), is established. This developmental sequence provides a pattern of embryonic development during the pre-hatching stage, which has not been established in the living scalidophorans (priapulids, loriciferans and kinorhynchs). Thus, it not only enriches our knowledge on the embryonic development of the extant descendants of Markuelia, but also opens a new window to the evolution and development of the animal.

关键词：寒武纪蠕虫化石胚胎发育序列两侧对称动物胚胎