ENTANGLEMENT FLUCTUATION DURING PHASE-SEPARATION IN POLYMER BLENDS

For perhaps the first time, the dynamics of liquid-liquid phase separation was studied by time-resolved mechanical spectrometry in order to establish the relationship between blends' properties and the phase structures during spinodal decomposition (SD). The selected system was chlorinated polyethylene (CPE)/ethylene-vinyl acetate copolymer (EVA). It was found that in the early and intermediate stage of SD, the storage modulus (G') and the loss modulus (G'') increase with time after the initiation of the isothermal phase separation; in the later stage, G' and G'' decrease as phase separation proceeds. An entanglement fluctuation model was presented to manifest this phenomenon; it was found that the rheological behavior agrees well with the expections of the model in the early stage. For the later stage, the reduction of G' and G'' can be attributed to the increment of phase-domain size. (C) 1993 John Wiley & Sons, Inc.

WATER-SOLUBLE AND AMPHIPHILIC POLYMERS .11. GRAFT-POLYMERIZATION OF ACRYLIC-ACID ON POLY(VINYL ALCOHOL)

The graft polymerization of acrylic acid(AA) on poly(vinyl alcohol) (PVAL) has been investigated by using either potassium persulfate (KPS) or ceric ammonium nitrate(CAN) as an initiator. In the case of KPS initiation, the formation of the graft polymer always lags behind the homopolymer formation. The graft polymer is separated by acetone, and the increase of reaction temperature favors the homopolymer formation at the early stage. In the case of CAN initiation, graft polymers with a high PAA content can hardly be obtained when the polymerization is performed under nitrogen and at < 0.06 mol/L HNO3 concentration. It has been found that incorporation of a small amount of oxygen in a protective nitrogen gas accelerates markedly the graft polymerization, and that the resulting graft polymers can not be separated by acetone precipitation technique in most cases. The Dalian nitrogen(containing 0.7% oxygen) is a good protective gas for CAN-initiated PVAL-AA graft polymerization.

Ulva diversity in the Yellow Sea during the large-scale green algal blooms in 2008-2009

P>In the Yellow Sea of China, large-scale green tides have broken out for three consecutive years from 2007 to 2009. As part of the efforts to localize the algal source, two cruises were conducted in the early stage and the outbreak stage of the bloom in 2009. We analyzed the morphological and genetic diversity of drifting Ulva specimens and culture-derived isolates from seawater sampled in different localities. For phylogenetic analyses, the nuclear encoded ribosomal DNA internal transcribed spacer region (ITS nrDNA) and the plastid encoded large subunit of ribulose-1, 5-bisphosphate carboxylase/oxgenase gene (rbcL) were used. Our molecular and morphological data indicate that the dominant free-floating Ulva species in 2008 and 2009 possibly belonged to a single strain of the U. linza-procera-prolifera (LPP) clade. The ITS sequences from bloom-forming algal samples with dense branches were identical to those from U. linza-like specimens without branches derived from the Yellow Sea. Microscopic individuals of the dominant Ulva strain were detected in eight stations, revealing that spore dispersal in the water helped to enlarge biomass in the water during the outbreak stage of green tide in the Yellow Sea.

Molecular structure and expression patterns of flounder (Paralichthys olivaceus) Myf-5, a myogenic regulatory factor

Myf-5, a member of the myogenic regulatory factors (MRF), has been shown to be expressed in muscle precursors in early stage zebrafish embryos. The MRFs, including MyoD, Myf-5, Myogenin and MR-F4, belong to the basic Helix-Loop-Helix transcription factors that contain a conserved basic Helix-Loop-Helix (bHLH) domain. To better understand the role of Myf-5 in the development of fish muscles, we have isolated the Myf-5 genomic sequence and cDNA from Flounder (Paralichthys olivaceus), and analyzed its structures and patterns of expression. Promoter analysis identified several putative transcription factor binding sites such as an E-box, NF-Y sites that might confer muscle-specific expression. Myf-5 transcripts were first detected in the paraxial mesoderm that gives rise to slow muscles. During somitogenesis, Myf-5 expression was found in developing somites. Myf-5 expression decreased gradually in somites in the anterior region, but remained strong in the newly formed somites. In the hatching stage, the expression was also detected in other muscle cells such as head muscle and fin muscle. In the growing fish, RT-PCR results showed that Myf-5 was expressed in the skeletal muscle and intestine. (c) 2006 Elsevier Inc. All rights reserved.

Long-Wave Dynamics of Sea Level Variations during Indian Ocean Dipole Events

Long-wave dynamics of the interannual variations of the equatorial Indian Ocean circulation are studied using an ocean general circulation model forced by the assimilated surface winds and heat flux of the European Centre for Medium-Range Weather Forecasts. The simulation has reproduced the sea level anomalies of the Ocean Topography Experiment (TOPEX)/Poseidon altimeter observations well. The equatorial Kelvin and Rossby waves decomposed from the model simulation show that western boundary reflections provide important negative feedbacks to the evolution of the upwelling currents off the Java coast during Indian Ocean dipole (IOD) events. Two downwelling Kelvin wave pulses are generated at the western boundary during IOD events: the first is reflected from the equatorial Rossby waves and the second from the off-equatorial Rossby waves in the southern Indian Ocean. The upwelling in the eastern basin during the 1997-98 IOD event is weakened by the first Kelvin wave pulse and terminated by the second. In comparison, the upwelling during the 1994 IOD event is terminated by the first Kelvin wave pulse because the southeasterly winds off the Java coast are weak at the end of 1994. The atmospheric intraseasonal forcing, which plays an important role in inducing Java upwelling during the early stage of an IOD event, is found to play a minor role in terminating the upwelling off the Java coast because the intraseasonal winds are either weak or absent during the IOD mature phase. The equatorial wave analyses suggest that the upwelling off the Java coast during IOD events is terminated primarily by western boundary reflections.

大气季节内振荡对东亚夏季风活动的影响研究

利用ERA40逐日再分析资料、NCEP/NCAR2逐日再分析资料、中国740个测站日降水资料、上海台风研究所提供的西太平洋热带气旋资料、Kaplan等重建的月平均SSTA资料、NOAA逐日长波辐射（OLR）等资料，应用离散功率谱分析、带通滤波、EOF分析等统计方法，研究了东亚夏季风(EASM）的移动特征、东亚地区季节内振荡(ISO)的基本特征、季节内振荡对东亚夏季风活动的影响、季节内振荡对东亚夏季风异常活动的影响机理。主要结论如下： （1）综合动力和热力因素定义了可动态描述东亚夏季风移动和强度的指数，并利用该指数研究了东亚夏季风的爆发和移动的季节内变化及其年际和年代际变化特征。研究发现，气候平均东亚夏季风前沿分别在28候、33候、36候、38候、40候、44候出现了明显的跳跃。东亚夏季风活动具有显著的年际变率，主要由于季风前沿在某些区域异常停滞和突然跨越北跳或南撤引起，造成中国东部旱涝灾害频繁发生。东亚夏季风的活动具有明显的年代际变化，在1965年、1980年、1994年发生了突变，造成中国东部降水由“南旱北涝”向“南涝北旱”的转变。 （2）东亚季风区季节内变化具有10~25d和30~60d两个波段的季节内振荡周期，以30-60d为主。存在三个主要低频模态，第一模态主要表征了EASM在长江中下游和华北地区活动期间的低频形势；第二模态印度洋-菲律宾由低频气旋式环流控制，主要表现了ISO在EASM爆发期间的低频形势；第三模态主要出现在EASM在华南和淮河活动期间的低频形势。第一模态和第三模态是代表东亚夏季风活动异常的主要低频形势。 （3）热带和副热带地区ISO总是沿垂直切变风的垂直方向传播。因此，在南海-菲律宾东北风垂直切变和副热带西太平洋北风垂直切变下，大气热源激发菲律宾附近交替出现的低频气旋和低频反气旋不断向西北传播，副热带西太平洋ISO以向西传播为主。中高纬度地区，乌拉尔山附近ISO以向东、向南移动或局地振荡为主；北太平洋中部ISO在某些情况下向南、向西传播。 （4）季风爆发期，伴随着热带东印度洋到菲律宾一系列低频气旋和低频反气旋， 冷空气向南输送，10~25天和30~60天季节内振荡低频气旋同时传入南海加快了南海夏季风的爆发。在气候态下，ISO活动表现的欧亚- 太平洋（EAP）以及太平洋-北美（PNA）低频波列分布特征(本文提出的EAP和PNA低频波列与传统意义上的二维定点相关得到的波列不同)。这种低频分布形式使得欧亚和太平洋中高纬度的槽、脊及太平洋副热带高压稳定、加强，东亚地区的低频波列则成为热带和中高纬度ISO相互作用影响东亚夏季风活动的纽带。不同的阶段表现不同的低频模态，30~60d低频模态的转变加快了EASM推进过程中跳跃性；30-60d低频模态的维持使得EASM前沿相对停滞。 （5）30-60d滤波场，菲律宾海域交替出现的低频气旋和低频反气旋不断向西北传播到南海-西太平洋一带。当南海-西太平洋地区低频气旋活跃时，季风槽加强、东伸，季风槽内热带气旋（TC）频数增加；当南海-西太平洋低频反气旋活跃时，季风槽减弱、西退，TC处于间歇期，生成位置不集中。 （6）在El Nino态下，大气季节内振荡偏弱，北传特征不明显，但ISO由中高纬度北太平洋中部向南和副热带西太平洋向西的传播特征显著，东亚地区ISO活动以第三模态为主，EASM集中停滞在华南和淮河流域，常伴随着持续性区域暴雨的出现，易造成华南和江淮流域洪涝灾害，长江和华北持续干旱。在La Nina态下，大气季节内振荡活跃，且具有明显的向北传播特征，PNA低频波列显著，东亚地区ISO活动以第一模态单峰为主；EASM主要停滞在长江中下游和华北地区，这些地区出现异常持续强降水，华南和淮河流域多干旱；在El Nino态向La Nina态转换期，ISO活动以第一模态双峰为主，长江中下游常常出现二度梅。

Temporal and spatial variability in nitrogen uptake kinetics during harmful dinoflagellate blooms in the East China Sea

Temporal and spatial variability in the kinetic parameters of uptake of nitrate (NO3-), ammonium (NH4+), urea, and glycine was measured during dinoflagellate blooms in Changjiang River estuary and East China Sea coast, 2005. Karenia mikimotoi was the dominant species in the early stage of the blooms and was succeeded by Prorocentrum donghaiense. The uptake of nitrogen (N) was determined using N-15 tracer techniques. The results of comparison kinetic parameters with ambient nutrients confirmed that different N forms were preferentially taken up during different stages of the bloom. NO3- (V-max 0.044 h(-1); K-s 60.8 mu M-N) was an important N source before it was depleted. NH4+ (V-max 0.049 h(-1); K-s 2.15 mu M-N) was generally the preferred N. Between the 2 organic N sources, urea was more preferred when K. mikimotoi dominated the bloom (V-max 0.020 h(-1); K-s 1.35 mu M-N) and glycine, considered as a dominant amino acid, was more preferred when P. donghaiense dominated the bloom (V-max 0.025 h(-1); K-s 1.76 mu M-N). The change of N uptake preference by the bloom-forming algae was also related to the variation in ambient N concentrations. Published by Elsevier B.V.

Effect of annual weeds on the growth of perennial grass mixtures in the alpine region of the Qinghai-Tibetan Plateau

In the alpine region of the Tibetan Plateau, five perennial grass cultivars, Bromus inermis (B), Elymus nutans (E), Clinelymus nutans (C), Agropyron cristatum (A), and Poa crymophila (P) were combined into nine communities with different compositions and ratios, B+C, E+A, B+E+A, E+B+C,C+E+A,B+E+C+A,B+C+A+P,B+E+A+P and E+C+A+P. Each combination was sown in six 10 X 10 m plots with three hand-weeded plots and three natural-growing plots in a completely randomised design in 1998. A field experiment studied the performance of these perennial grass combinations under the competitive interference of annual weeds in 3 consecutive years from 1998 to 2000. The results showed that annual weeds occupied more space and suppressed the growth of the grasses due to earlier germination and quicker growth in the establishment year, but this pattern changed in the second and third years. Leaf area indexes (LAIs) of grasses were greatly decreased by the competitive interference of weeds, and the negative effect of weeds on LAIs of grasses declined and stabilised in the second and third years. E+B+C, B+E+C+A, and B+E+A+P possessed relatively higher LAIs (P < 0.05) among all grass combinations and their LAIs were close to five when the competitive interference of weeds was removed. Grasses were competitively inferior to weeds in the establishment year, although their competitive ability (aggressivities) increased throughout the growing season. In the second and third years, grasses were competitively superior to weeds, and their competitive ability decreased from May until August and increased in September. Dry matter (DM) yields of grasses were reduced by 29.8-74.1% in the establishment year, 11.0-64.9% in the second year, and 16.0-55.8% in the third year by the competitive interference of weeds. B+E+C+A and B+E+A+P can produce around 14 t/ha of DM yields, significantly higher (P < 0.05) than the production of the other grass combinations in the second and third years after the competitive interference of weeds was removed. It was preliminarily concluded that removal of competitive interference of weeds increased the LAIs of all grass swards and improved the light interception of grasses, thus promoting the production of perennial grass pastures. The germination stage of the grasses in the establishment year was the critical period for weeding and suppression of weeds should occur at an early stage of plant growth. The grass combinations of B+E+C+A and B+E+A+P were productive and can be extensively established in the alpine regions of the Tibetan Plateau. Two or three growing seasons will be needed before determining success of establishment of grass mixtures under the alpine conditions of the Tibetan Plateau.

塔克拉玛干沙漠地球化学研究

The Taklamakan Desert, lying in the center Tarim Basin of sourthern Xinjiang, is the largest sand sea in China and well known in the world as its inclemency. For understanding the formation and evolution of the Taklamakan Desert, it is very important to identify the provenance of aeolian sediments in the extensive dune fields, but the opinions from earlier studies are quite different. In this study, we examined the major- and trace-element compositions, mineral compositions and grain-size distributions of some Quaternary aeolian and nonaeolian sediments collected from the Taklamakan Desert, together with the variation of chemical and mineralogical compositions of different grain-size fraction. At the same time, we also studied the chemistries of some natural water samples (river water and groundwater) with the items of TDS, pH, Alkalinity, conductivity and major cation and anion compositions. Our results of analysis show some significant opinions as follow: Most of the frequency-distribution curves of grain size of dune sand samples are simgle peak, but that of the river and lacustrine sediment are most double peak or multi-peak. The grain-size distribution of dunefield sand changed gradually from north to south with the major wind direction in large scale, but there are many differences in regional scale. The major, REE, trace element compositions and mineral compositions are very different among the coarse, fine fraction and bulk samples due to the influence of grain-size. Most of the fine fractions are geochemically homogenous, but the coarse fractions and bulk samples are heterogenous. All the surface and ground waters are limnetic or sub-salty, their chemical compositions are mainly controlled by rock-weathering and crystallization- evaporation processes, and mainly come from the evaporate, while the contributions of the carbonate and silicate are little, excluding the influence on oasis water by carbonate. The mineral compositions of selected samples are stable, mainly composed of the strongly resistant mineral types. The mineral maturity of them are more immature at whole compared with other sandy sediments in the world, and they have experienced less degree of chemical weathering and recycling, being lying in the early stage of continental weathering. Among these sediments, the river sediments are relatively primitive. The sources of these sediments are maybe mainly terrigenous, silicic and subaluminous/ metalunious rocks, such as the granodiorite and its metamorphic rock. The geochemical compositions of dunefield sand are similar with those of the river sediments and dune sands near the river way; There are not only the resemblances but also the differences on geochemistry and granularity between north and south dunesands; The sediments from same section have different age but same trace-element compositions; The sediments from the south edge of Tarim Basin are all somewhat geochemically similar with the palaeo-river-sediment on the south edge of studying area. The REE data support the idea that the south dunesands are a little older than the north dunesands, and the tectonic settings of source area are mainly active continental margin based on the major-element compositions, so they indicate that the sediment of Taklamakan Desert maybe come mainly from the rock-weathering production of north part of the Kunlun Mountains. Compared with the sands of other dune field in north of China, the sands of the Taklamakan Desert are distinct by REE composition, but similar with the Luochuan loess, center China, and the two sandy dusts of Beijing, eastern China.

西天山造山带古生代构造演化与地壳增生—来自花岗岩和蛇绿岩的证据

The Central Asian Orogen Belt (CAOB), which is different from the subductional orogen and the collisional orogen, is known as the most important site of crustal growth in the Phanerozoic, and it has been a ‘hot spot’ for studying the orogenic belts. The Chinese West Tianshan Orogen is occupying the west-southern part of the CAOB and is of great importances to understand the orogenic processes and the continental growth in the Central Asia. The West Tianshan Orogen had undergone complex tectonic evolutional processes in Paleozoic times and large volumes granitic rocks have recorded important information about these processes. Litter is known about Phanerozoic continental growth in the Western Tianshan area so far, compared with the other areas of the CAOB, such as eastern Junggar, western Junggar, Altai and Alakol. The aim of this dissertation is to set up the chronology frame of granitoids in western Tianshan, provide new evidence for the tectonic evolution and discuss the Paleozoic continental growth in this area, on the basis of the studies on the isotopic chronology, major element, trace element and Nd-Sr isotopic geochemistry of granitoids and the isotopic chronology and geochemistry of the ophiolites in this area, especially the Kule Lake ophiolites. 25 precise SHRIMP U-Pb zircon and LA-ICPMS U-Pb zircon ages have been obtained in this dissertation. The granitic rocks in western Tianshan had been formed during two periods: the granitic gneiss with an age of 896Ma, possibly representing the forming age of the Precambrian basement; the granitic rocks with ages varying from 479Ma to 247Ma, recording the Paleozoic orogenic process of western Tianshan. The granitoids in western Tianshan are composed of intermediate-basic rocks, intermediate rocks, intermediate-acid rocks and acid rocks, mainly intermediate-acid rocks and acid rocks. They are mostly granite, granodiorite, quartz syenite and monzodiorite. Different types of granitic rocks are exposed in different tectonic units. The granitoids on the northern margin of the Yili Plate mainly formed in late Paleozoic (413Ma ~ 281Ma), those with ages varying from 413Ma to 297Ma show continental arc affinities and the magnesian calc-alkalic metaluminous diorite of 281Ma display the geochemical characteristics similar to those of granites formed during the post-orogenic period. The granitiods on the southern margin of the Yili Plate include the adakite diorite of 470Ma which was formd by partial melting of thickened lower crust, the post-collisional alkali-feldspar granite of 430Ma, the volcanic arc granite of 348Ma and the Triassic post-collisional granite. The granitoids in the Central Tianshan Plate formed in 479Ma ~ 247Ma, mainly in 433Ma ~ 321Ma. The granitic rocks with ages of 479Ma ~ 321Ma are magnesian calc-alkalic to alkalic rocks with continental arc affinities. A few post-collisional granitoids of 276Ma ~ 247Ma may have inherited the geochemical characteristics of pre-existing arc magma. The granitic rocks in Southern Tianshan (northern margin of the Tarim plate) formed two stages, 420Ma ~ 411Ma and ca. 285Ma. The magnesian calcic to alkalic granites of 420Ma ~ 411Ma may formed during the extension process of the continental margin. The granite of 285Ma includes mostly ferroan calc-alkalic to alkali-calcic rocks with high SiO2 and high alkaline contents, and obviously negative anomaly of Eu, Ba, Sr, P, Ti, similar to the geochemical characteristics of the A-type granite which is formed during post-collisional extension. The Kule Lake ophiolite in southern Tianshan shows the affinity of N-MORB. A SHRIMP zircon U-Pb age of 425±8Ma has obtained for gabbros. Some zircons have given another group of 206Pb/238U age 918Ma, which may indicate the information of the pre-exist old basement rock. The small oceanic basin represented by Kule Lake ophiolite probably developed on the split northern margin of Tarim block. A model for Paleozoic tectonic evolution of the West Tianshan Orogen has been proposed here on the basis of the new results obtained in this dissertation and the previous published data. In Early Cambrian, the Terskey Ocean occurred along the North Nalati fault (NNF), and it separated the Yili plate from the Central Tianshan plate which was probably connected with the Tarim plate. The Terskey Ocean probably subducted towards south under the Central Tianshan plate and towards north under the Yili plate simultaneously. In the early stage of Late Ordovician, the Terskey Ocean had been closed, and the Yili and Central Tianshan plates collided. Meanwhile, extension happened within the joint Central Tianshan and Tarim plates gradually and the Paleo-South Tianshan Ocean had been formed. In Early Silurian, the Paleo-South Tianshan Ocean began to subduct beneath the composite Yili-Central Tianshan plate, which was intruded by volcanic arc granitoids. In Middle Silurian, the Paleo-South Tianshan Ocean, which had reached a certain width, was subducting strongly. And this subduction may have produced voluminous granitoids in the Central Tianshan plate. In the latest stage of Carboniferous, the Paleo-South Tianshan ocean closed, and the Yili-Central Tianshan plate and Tarim plate collided. In Late Cambrian, Paleo-Junggar Ocean occurred to north of the Yili plate; and started to subduct towards south under the Yili plate in Ordovician. This subduction may have produced a magma arc on the northern margin of the Yili plate. In Late Carboniferous, the Paleo-Junggar Ocean had been closed. The Yili-Central and Junggar plates amalgamated together. The West Tianhan Orogen may undergo a post-collisional collapse since Permian. And the magmatic activities may continue to early Triassic. The initial 87Sr/86Sr ration of the granitic rocks in the western Tianshan Mountains varies from 0.703226 to 0.716343, and Nd（t）from -6.50 to 2.03. The characteristics of Sr-Nd isotope indicate that the source of granitic material is not a sole source, which may be produced by mantle-crust magma mixing. In Paleozoic time, lateral growth of the continental crust along active continental margins was dominant, whereas the vertical growth of continental crust resulted from post- collisional mantle derived magmas was not obvious.

松辽盆地南部腰英台区块低渗透储层整体压裂改造技术研究

The Yaoyingtai Block is located within the northeastern Changling Depression of southern Songliao Basin, where the reservoir sandstones are petrophysically characterized by very low permeability, which results in the low success probability of artificial fracturing, and the low oil yield by water injection in the course of oil production. In order to improve the situations as stated above, this research aims to work out an integral fracturing technology and strategy applicable to the low permeable reservoirs in Yaoyingtai Block. Under the guidance of geological theory, reservoir engineering and technology, the subsurface occurrences of natural and hydraulic fractures in the reservoirs are expected to be delineated, and appropriate fracturing fluids and proppants are to be optimized, based on the data of drilling, well logging, laboratory and field experiments, and geological data. These approaches lay the basis of the integral fracturing technology suitable for the low permeable reservoir in the study area. Based on core sample test, in-situ stress analysis of well logging, and forward and inversion stress field modeling, as well as fluid dynamic analysis, the maximum in-situ stress field is unraveled to be extended nearly along the E-W direction (clustering along N85-135°E) as is demonstrated by the E-W trending tensional fractures. Hydraulic fractures are distributed approximately along the E-W direction as well. Faulting activities could have exerted obvious influences on the distribution of fractures, which were preferentially developed along fault zones. Based on reservoir sensitivity analysis, integrated with studies on rock mechanics, in-situ stress, natural fracture distribution and production in injection-production pilot area, the influences of primary fractures on fracturing operation are analyzed, and a diagnostic technology for primary fractures during depressurization is accordingly developed. An appropriate fracturing fluid (hydroxypropyl guar gum) and a proppant (Yixing ceramsite, with a moderate-density, 0.45-0.9mm in size) applicable to Qingshankou Formation reservoir are worked out through extensive optimization analysis. The fracturing fluid can decrease the damage to the oil reservoir, and the friction in fracturing operation, improving the effect of fracturing operation. Some problems, such as sand-out at early stage and low success rate of fracturing operations, have been effectively solved, through pre-fracturing formation evaluation, “suspension plug” fracturing, real-time monitoring and limited-flow fracturing. Through analysis of fracture-bearing tight reservoir with variable densities and dynamic analysis of influences of well patterns on fracturing by using numerical simulation, a fracturing operation scheme for the Qingshankou Formation reservoir is proposed here as being better to compress the short factures, rather than to compress the long fractures during hydraulic fracturing. It is suggested to adopt the 450m×150m inverted 9-spot well pattern in a diamond shape with wells placed parallel to fractures and a half fracture length of 60-75m.

中国黄土高原洛川剖面 630 kyr 以来的孢粉记录

It is known that global climate changed from the early Tertiary “Green House” to the Quaternary “Ice House” of cyclic glacial-interglacial climatic changes. Since the middle Pleistocene, the climate cycles changed from 40 kyr to 100 kyr, and the amplitudes of climatic fluctuations increased significantly. Therefore, it is important to study the climate changes since the middle Pleistocene. The loess-paleosol sequence in China is considered as one of the most continuous continental records of the last 2.58 Ma. Paleoclimatic and environmental changes have been widely extracted through various climatic parameters. However, the history of paleovegetation on the Loess Plateau still remains unclear. Did an extensive broadleaf forest ever exist on the Loess Plateau? Pollen preserved in the loess and paleosol provides a direct record for vegetation and paleoenvironmental change on the Plateau. However, because it is difficult to extract sufficient pollen grains from loess, the pollen record since the middle Pleistocene especially in the central part of the Chinese Loess Plateau has not been well studied. So we preliminarily focus on the palynological records of the loess-paleosol sequence spanning the last 630 kyr at Luochuan and aim to understand the evolution of vegetation and climate change on the Chinese Loess Plateau. The main results and conclusions are as follows: 1. The palynological results show that the grassland has been a dominant vegetation in the Luochuan area since 630 kyr, even during the intervals of relatively warm and wet climatic conditions. 2. The pollen concentration of Luochuan section sharply decreases from the bottom of S1 to downward depth. This decrease can be attributed to depositional environment rather than climate change. In loess, not only oxidation, but also the PH of deposits and bacteria or fungi have been able to degrade sporopollenin. 3. The paleoclimatic condition during S4 stage, characterized with warmer condition during the early stage, was warmer and wetter than that during S5 in Luochuan area. Paleoclimate was warmer and wetter during the early stage of S5 and became colder and drier later. The special pedogenic features of S5-I can be attributed to a prolonged pedogenic duration rather than a warm-wet climate. 4. Evidence from pollen assemblage suggests that the Holocene vegetation has been affected by human impacts, especially after the Yangshao Culture. 5. The present steppe environment on the loess plateau is mainly due to natural conditions. Temperature, seasonal precipitation and soil structure are three important factors which control the vegetation type. 6. The vegetation on the loess plateau is characterized with zonal or azonal distribution. So local conditions should be taken into account when recover natural vegetation. Finally, the restoration and reconstruction of ecosystem on the loess plateau area should be focused on planting grassland rather than forests.

急倾斜金属矿体开采岩体移动规律与变形趋势预测研究

Rockmass movement due to mining steep metallic ore body is a considerable question in the surface movement and deformation issue caused by underground mining. Research on coal mining induced rockmass movement and its prediction problem have been performed for a long-term, and have achieved great progress at home and abroad. However, the rockmass movement caused by mining steep metal mine is distinctivly different from coal seam mining.. Existing surface movement laws and deformation prediction methods are not applicable to the rockmass movement caused by mining steep metal mine. So far the home and abroad research to this theory is presently at an early stage, and there isn’t mature theory or practical prediction method, which made a great impact on production. In this paper, the research object—Jinchuan nickel mine, which is typical steep metal mine, characterized by complex geological conditions, developed faults, cracked rockmass, high geostress, and prominent engineering stability problems. In addition, backfill mining method is used in the mine, the features of rockmass movement caused by this mining method are also different from other mining methods. In this paper, the laws of rock mass movement, deformation and destroy mechanism, and its prediction were analyzed based on the collection of data, detailed in-sit engineering geology survey, ground movement monitoring by GPS, theoretical analysis and numerical simulation. According to the GPS monitoring of ground surface movement, ground subsidence basin with apparent asymmetry is developing, the influence scope is larger in the upper faulted block than in the lower faulted block, and the center of ground movement is moving along the upper faulted block direction with increasing depth of mining. During the past half and seven years, the largest settlement has amounted to 1287.5mm, and corresponding horizontal displacement has amounted to 664.6mm. On the ground surface, two fissure belts show a fast-growing trend of closure. To sum up, mining steep metal mine with backfill method also exist the same serious problem of rockmass movement hazards. Fault, as a low intensity zone in rockmass, when it located within the region of mining influence, the change of potential energy mainly consumed in fault deformation associated with rockmass structure surface friction, which is the essence of displacement and stress barrier effects characterized by fault rupture zone. when steep fault located in the tensile deformation region incurred by underground excavation, no matter excavation in hangingwall or in footwall of the fault, there will be additional tensile stress on the vertical fault plane and decrease in the shear strength, and always showing characteristics of normal fault slip, which is the main reason of fault escarpment appeared on the ground surface. The No.14 shaft deformation and failure is triggered by fault activation, which showed with sidewall move, rupture, and break down features as the main form of a concentrated expression of fault effects. The size and orientation of principal stress in surrounding rock changed regularly with mining; therefore, roadway deformation and damage at different stages have different characteristics and distribution models. During the process of mining, low-intensity weak structures surface always showed the most obvious reaction, accompany with surface normal stress decrease and shear strength bring down, to some extent, occurred with relative slide and deformation. Meanwhile, the impact of mining is a relatively long process, making the structure surface effect of roadway deformation and damage more prominent than others under the influence of mining. Roadway surrounding rockmass deformation caused by the change of strain energy density field after excavation mainly belongs to elastic deformation, and the correspondented damage mainly belongs to brittle rupture, in this circumstance, surrounding rockmass will not appear large deformation. The large deformation of surrounding rockmass can only be the deformation associated with structure surface friction or the plastic deformation of itself, which mainly caused by the permanent self-weigh volume force，and long-term effect of mining led to the durability of this deformation Good pitting fill effect and supporting effect of backfill, as well as the friction of rockmass structure surface lead to obvious macro-rockmass movement with long-lag characteristics. In addition, the loss of original intensity and new structure surface arisen increased flexibility in rockmass and fill deformation in structure surface, which made the time required for rockmass potential energy translate into deformation work associated with plastic deformation and structure surface friction consumed much, and to a large extent, eliminated the time needed to do those plastic work during repeated mining, all of which are the fundamental reason of rockmass movement aftereffect more significant than before. Mining steep deposits in high tectonic stress area and in gravity stress area have different movement laws and deformation mechanism. The steep deposit, when the vertical size of the mining areas is smaller than the horizontal size of the orebody, no matter mining in gravity stress area or in high tectonic stress area, they have similar features of ground movement with mining horizontal orebody; contrarily, there will appear double settlement centers on the ground surface under the condition of mining in high tectonic stress area, while there will always be a single center under the other condition. Meanwhile the ground movement lever, scale of mining influence area and macro features of ground movement, deformation and fracture are also different from mining in gravity stress area, and the fundamental reason lies in the impact of orientation of the maximum principal stress on rock movement features in in-site rock stress field. When mining thick and steep deposit, the ground surface movement and deformation characteristic curves are significantly different from excavating the horizontal ore bed and thin steep deposit. According to the features of rockmass movement rate, the development process of mining-induced rockmass movement is divided into three stages: raising stage, steadily stage and gradually decay stage. Considering the actual exploitation situation, GPS monitoring results and macro-characteristics of surface movement, the current subsidence pattern of Jinchuan No.2 mine is in the early stage of development. Based on analysis of surface movement rate, surface subsidence rate increase rapidly when mining in double lever at the same time, and reach its peak until the exploitation model ended. When double lever mining translate into single, production decreased, surface subsidence rate suddenly start to reduce and maintain a relatively low value, and the largest subsidence center will slowly move along with the hangingwall ore body direction with increasing depth of mining, at the same time, the scope and extent of subsidence in footwall ore body will begin magnify, and a sub-settlement center will appear on ground surface, accompanied with the development and closure trend of ground fissure, the surrounding rockmass of shaft and roadway will be confronted to more frequent and severe deformation and failure, and which will have a negative impact on the overall stability of No.2 mine mining. On the premise of continuity of rockmass movement, gray system model can be used in ground rockmass movement prediction for good results. Under the condition of backfill mining step by step, the loose effect of compact status of the hard, broken rockmass led to lower energy release rate, although surrounding rockmass has high elastic energy, loose and damage occurred in the horizontal ore body, which made the mining process safety without any large geological hazards. During the period of mining the horizontal ore body to end, in view of its special “residual support role”, there will be no large scale rockmass movement hazards. Since ground surface movement mainly related to the intensity of mining speed and backfill effect, on the premise of constant mining speed, during the period of mining the horizontal ore body to end, the rate of ground surface rockmass movement and deformation won’t have sudden change.

内蒙古赤峰红花沟地区早中生代构造－岩浆活动特征及金成矿作用

Honghuagou gold field, Inner Mongolia, is selected as the study area for the dissertation. The geological background for gold mineralization, geology of gold deposits, ore-controlling factors, physical and chemical conditions, material sources, genesis and ore-forming epoch for gold mineralization are studied in the dissertation. Especially, the Early Mesozoic tectonic and magmatic activities and their relationship with gold mineralization are studied with special efforts. Based on the study, the criteria for ore-prospecting are systemically summarized, target areas for ore-prospecting are circled and their gold reserves is estimated. Based on the first discovery of Early Mesozoic ductile zone which show the detachment features and the study on the emplacement of Early Mesozoic maficintermediate dyke swarms, the author present that the studied area was mainly in extensional uplift state during Early Mesozoic. The tectonic evolution can be divided into two stages. The extension was dominated by ductile metamorphose at early stage, whose geodynamics was related with the post orogenic extension after the collision between the Northern China Plate with Siberia Plate. The extension at late stage was featured by the intrusion of diorite and the emplacement of dyke swarms, whose geodynamics was related with mantle uplift. The gold deposits in the area are just the products of the tectonic and magmatic activities resulted from Early Mesozoic extension. The plagio-amphibolite from Archean metamorphic rocks is partially melted under the influence of underplating caused by mantle uplift, result in the formation of diorite magma. The gold in metamorphic rocks will also be melted into magma pond, and ascend into the upper parts of crust along with the intrusion of magma. The gold-bearing hydrothermal fluids is formed during magma differentiation, and caused the precipitation and concentration of gold in favorable geological conditions, result in the formation of gold deposits. The fracture caused by the emplacement of dyke swarms break a path for the ascending and movement of hydrothermal fluids, some of them become parts of ore-controlling and host structure. The gold is thought to be formed in Early Mesozoic, not in Yanshanian epoch.

新第三纪红河盆地特征及红河断裂活动对其形成与发育的控制

Based on geodynamic analysis of sedimentary basins, combined sedimentology with structural geology and other methods, the author studied the Honghe basin located in Yunnan province of Southwestern China. Sandstone slice grain size analysis, combined with field geology and indoors study indicate that a set of inland alluvial fan diposits, fluvial deposites, delta deposits and some lacustrine sediments are in Honghe basin. Studying on shape of the Honghe basin, sedimentary and structural characteristic and distribution of different kinds of conglomerate and its structural significance, we hold the idea that the formation and evolution of Honghe basin are controlled by the activity of Red River faut. Correlation of lithostratic cross section in Honghe basin and studying on activity of Red River fault indicate that Honghe basin was formed in two stages. It is a complex basin constitutes of the first-stage trans-releasing basin and the second-stage trans-downfaulted basin. Due to the uplift of Qinghai-Xizang plateau and deformation of orogeny, the western Yunnan and adjacent area move to SE direction as a result of Tectonic Escape. Right lateral strike slip occurred along Red River fault, trans-releasing basin formed at the bend part of the fault due to stress relexation. As the block escaping, it moves away from the other block of the Red River fault, the upper block move down obliquely and trans-downfaulted basin formed. Combined the age of phytolite and regional structural events, we think the first-stage transreleasing basin was formed in late Miocene, on the other words, the dextral strike slip of Red River fault may began in late Miocene (10-7Ma). The second-stage trans-downfaulted basin may be formed in early stage of Pliocene (about 4.7Ma). Subsequently, the bilateral faults dipping to the inside of the plateau and thrusting outwards occurred in the marginal region of Qinghai-Xizang plateau during its uplifting as a fan-shaped mountain body, this results in the uplift of the strata to the east of Red River fault and supply large quantity of provenance for the Honghe basin. In last Pliocene (about 3Ma), strong uplift of Qinghai-Xizang plateau leads to massive clastic sediment entered Honghe basin and causes its closure. As a kind of trans-tentional basin, trans-releasing basin is different to pull-apart basin. The author compared the Mosha trans-releasing basin with Jinggu pull-apart basin in SW Yunan, China, and described their character correspondingly. Otherwise, the author combined the predecessors' studding with conclusion of own study, discussed the kinematics of Ailaoshan-Red River belt in Cenozoic, and the relationship between the formation of Honghe basin and uplifting of Qinghai-Xizang plateau.