Paleoceanographic records in the sedimentary cores from the middle Okinawa Trough

Two gravity piston cores (Cores 155 and 18) involved in this study were collected from the middle Okinawa Trough. Stratigraphy of the two cores was divided and classified based on the features of planktonic foraminifera oxygen isotope changes together with depositional sequence, millennium-scale climatic event comparison, carbonate cycles and AMS(14)C dating. Some paleoclimatic information contained in sediments of these cores was extracted to discuss the paleoclimatic change rules and the short-time scale events presented in interglacial period. Analysis on the variation of oxygen isotope values in stage two shows that the middle part of the Okinawa Trough may have been affected by fresh water from the Yellow River and the Yangtze River during the Last Glacial Maximum (LGM). The oxygen isotope value oscillating ranges of the cores have verified that the marginal sea has an amplifying effect on climate changes. The delta(13)C of benthic foraminifera Uvigerina was lighter in the glacial period than that in the interglacial period, which indicates that the Paleo-Kuroshio's main stream moved eastward and its influence area decreased. According to the temperature difference during the "YD" period existing in Core 180 and other data, we can reach the conclusion that the climatic changes in the middle Okinawa Trough area were controlled by global climatic changes, but some regional factors had also considerable influence on the climate changes. Some results in this paper support Fairbanks's point that the "YD" event was a brief stagnation of sea level rising during the global warming up procession. Moreover, the falling of sea level in the glacial period weakened the exchange between the bottom water of the Okinawa Trough and the deep water of the northwestern Pacific Ocean and resulted in low oxygen state of bottom water in this area. These procedures are the reasons for carbonate cycle in the Okinawa Trough area being consistent with the "Atlantic type" carbonate cycle.

Millennial-scale paleoceanography in Okinawa Trough during Late Quaternary period

Based on the analyses of foraminifer and accelerator mass spectrometer radiocarbon dating in DGKS9603 core from mid-Okinawa Trough close to bottom, oscillation curve, which expressed the relation between the surface water temperature and the depth, has been obtained by using foraminifer analysis and calculation of FP-12E transfer function. The whole core indicated seven cold phases and eight warm phases. Obvious expression of low temperature event during Middle and Late Holocene, YD,H1,H2,H3 and H4 events, as well as the short cold phase during the middle last glacial period, implied that short shifts since 50 kaBP would have been global significance. Sedimentation rate during cold phases is usually faster than that in warm stages, with the lowest rate in Holocene, which may be connected with rising sea level and principal axial of Kuroshio Current moving to west. Volcanic activities highly developed in Okinawa Trough during the Quaternary period, thus abundant volcanic glass and pumice were well preserved.

ISOTOPIC CHARACTERISTICS AND AGE DATING OF THE PUMICE IN OKINAWA TROUGH

The data on the isotope compositions of rubidium, strontium and oxygen in the pumice of Okinawa Trough are reported for the first time. The ages of the pumice were successfully dated with the method of U-series disequilibrium. Then, the material source, crystallization evolution of magma and activity cycles of volcanos are explored. Isotopic data show that pumice magma was originally from the mantle, but had undergone a full crystallization differentiation and had been contaminated to a fair extent by crust-derived materials before the magma was erupted out of the sea floor. According to the dating results available so far, the earliest volcanic eruption in Okinawa Trough occurred about 70,000 a ago and the latest eruption was about 10,000 a B.P. During this period, there were three volcanic eruption cycles which were respectively corresponding to the middle Late Pleistocene, the late Late Pleistocene and the Early Holocene.

Seismic profiles across the middle Tan-Lu fault zone in Laizhou Bay, Bohai Sea, eastern China

The stratigraphic architecture, structure and Cenozoic tectonic evolution of the Tan-Lu fault zone in Laizhou Bay, eastern China, are analyzed based on interpretations of 31 new 2D seismic lines across Laizhou Bay. Cenozoic strata in the study area are divided into two layers separated by a prominent and widespread unconformity. The upper sedimentary layer is made up of Neogene and Quaternary fluvial and marine sediments, while the lower layer consists of Paleogene lacustrine and fluvial facies. In terms of tectonics, the sediments beneath the unconformity can be divided into four main structural units: the west depression, central uplift, east depression and Ludong uplift. The two branches of the middle Tan-Lu fault zone differ in their geometry and offset: the east branch fault is a steeply dipping S-shaped strike-slip fault that cuts acoustic basement at depths greater than 8 km, whereas the west branch fault is a relatively shallow normal fault. The Tan-Lu fault zone is the key fault in the study area, having controlled its Cenozoic evolution. Based on balanced cross-sections constructed along transverse seismic line 99.8 and longitudinal seismic line 699.0, the Cenozoic evolution of the middle Tan-Lu fault zone is divided into three stages: Paleocene-Eocene transtension, Oligocene-Early Miocene transpression and Middle Miocene to present-day stable subsidence. The reasons for the contrasting tectonic features of the two branch faults and the timing of the change from transtension to transpression are discussed. Crown Copyright (C) 2008 Published by Elsevier Ltd. All rights reserved.

渤海湾盆地济阳坳陷东部走滑构造特征及其对油气成藏的影响研究

研究区位于郯庐断裂中段与济阳坳陷的构造结合部，区内走滑构造广泛发育，主要的走滑断裂有7条，分别是郯庐断裂带的东西两支、垦东断层、孤东断层、长堤断层、埕东断层和发育于垦东凸起中部的浅层走滑构造带。走滑构造带与油气富集带有着明显的对应关系。 通过对研究区内二维、三维地震测线和平面构造图的精细解释和分析，分别揭示了各走滑断裂在平面、剖面和三维空间上的构造形态。根据走滑断裂及其伴生构造的平面和剖面上的几何学特征，将研究区内的走滑断裂划分为三种类型：成熟型走滑断裂、隐伏型走滑断裂、不连续型的走滑断裂。 从理论模式研究入手，推导了拉分盆地中盆地的走滑速率与沉降速率之间的关系，证实了走滑速率同盆地的几何形状参数、最大沉降深度和盆地的沉降速率存在着稳定的数值关系。通过对莱州湾地区潍北凹陷基底沉降历史的分析，建立了潍北凹陷沉降速率与郯庐断裂中段走滑速率之间的经验关系式，进而求出郯庐断裂中段新生代右行走滑位移量的大小为40km。 运用2DMove软件，对研究区内四条典型剖面进行构造复原，计算出了各条剖面每个时期的伸展参数，对研究区构造活动强度进行了定量分析，揭示了研究区的构造演化规律。通过运用Ansys软件进行有限元模拟，恢复了晚白垩世晚期-古近纪早期研究区内的构造应力场和应变场，揭示了扭张作用是研究区内走滑断层开始走滑的主要原因。 通过上述分析，结合对究区内近几年勘探开发成功和失败的实例分析，全面探讨了走滑活动对于油气成藏“生”、“储”、“盖”、“圈”、“运”、“保”各因素的影响。

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。

高原鼠兔的季节性繁殖

A nnual changes of the rep roduct ive act ivity in adult male p lateau p ika (Ochotona curzoniae) , a small endemic mammal in Q inghai2T ibet P lateau, w ere invest igated from J anuary to December, 1991. A ll of the animals w ere k illed and decap itated during the nigh t (23:00～ 24:00) and the p lasma, p ineal glands, testes ep ididym is, sem inal vesicles, deferent ducts were co llected and used for biochemical, and histo logical studies. Significant changes associated with seasonal cycles were found. (1) In February～ early April, the restoration phase, the weights of testes, epididym ides and deferent ducts were increased; the process of sperm atogenesis was strengthened and testo sterone level in plasma was increased, but the pineal weight and its melatonin content were decreased. (2) During the middle of April～ late May, the sexually active phase, a significant elevation of gonadal activity was observed. In this period, gonadalw eights were increased, spermatogenesis was completed, pineal weights were decreased and melatonin contents were fluctuated at alow level. These results suggested the increasing in sexual activity as well as in the ability of testo sterone secretion. (3) A striking reduction of test icular activity appears in June～A ugust. In this inhibition phase, gonada lweight, process of sperm atogenesis, plasma testo sterone level were decreased while the pineal weight and pineal melatonin content were increased. (4) During Sep tember～ J anuary, the sexually quiescent phase, declining in weights of testes and epididymides, arrest of spermatogenesis, decreasing of plasma testo sterone concent ration, fluctuating in pineal weights and increasing in pinealmelatonin level were observed. Our findings indicated that the male pikas under natural conditions exhibited an annual rep roductive cycle. A possible relationship between pineal activity and reproductive function was also suggested.

渤海湾盆地前第三系构造演化与煤成气成藏研究

The disequilibrium between supply and demand the east part of North China accelerated natural gas exploration in Bohai bay basin. Exploration practice showed that coal-derived gas is important resource. In searching of big to middle scaled coal derived gas field, and realize successive gas supply, the paper carried out integrated study on structural evolution of Pre-Tertiary and evaluation of reservoir forming condition of coal-derived gas. Study work of the paper was based on the following condition: available achievement in this field at present, good understanding of multiphase of tectonic movement. Study work was focused on geological evolution, source rock evaluation and dissection key factors controlling reservoir forming. Based on analysis of seismic data, drilling data, tectonic style of Pre-Tertiary was subdivided, with different tectonic style representing different tectonic process. By means of state of the art, such as analysis of balanced cross section, and erosion restoration, the paper reestablished tectonic history and analyzed basin property during different tectonic phase. Dynamic mechanism for tectonic movement and influence of tectonic evolution on tectonic style were discussed. Study made it clear that tectonic movement is intensive since Mesozoic including 2 phase of compressional movement (at the end of Indo-China movement, and Yanshan movement), 2 phase of extensional movement (middle Yanshan movement, and Himalayan movement), 2 phase of strike slip movement, as well as 2 phase of reversal movement (early Yanshan movement, and early Himalayan movement). As a result, three tectonic provinces with different remnant of strata and different tectonic style took shape. Based on afore mentioned study, the paper pointed out that evolution of Bohai bay basin experienced the following steps: basin of rift valley type (Pt2+3)-craton basin at passive continental margin (∈1－2)-craton basin at active continental margin (∈3- O)-convergent craton basin (C-T1+2)-intracontinental basin (J＋K). Superposition of basins in different stage was discussed. Aimed at tectonic feature of multiple phases, the paper put forward concept model of superposition of tectonic unit, and analyzed its significance on reservoir forming. On basis of the difference among 3 tectonic movements in Mesozoic and Cenozoic, superposition of tectonic unit was classified into the following 3 categories and 6 types: continuous subsidence type (I), subsidence in Mesozoic and uplift for erosion in Cenozoic (II1), repeated subsidence and uplift in Mesozoic and subsidence in Cenozoic (II2), repeated subsidence and uplift in Mesozoic and uplift for erosion in Cenozoic (II3), uplift for erosion in Mesozoic and subsidence in Cenozoic (II4), and continuous uplift (III). Take the organic facies analysis as link, the paper established relationship between sedimentary environment and organic facies, as well as organic facies and organic matter abundance. Combined information of sedimentary environment and logging data, the paper estimated distribution of organic matter abundance. Combined with simulation of secondary hydrocarbon generation, dynamic mechanism of hydrocarbon generation, and thermal history, the paper made static and dynamic evaluation of effective source rock, i.e. Taiyuan formation and Shanxi formation. It is also pointed out that superposition of tectonic unit of type II2, type II4, and type I were the most favorable hydrocarbon generation units. Based on dissection of typical primary coal-derived gas reservoir, including reservoir forming condition and reservoir forming process, the paper pointed out key factors controlling reservoir forming for Carboniferous and Permian System: a. remnant thickness and source rock property were precondition; b. secondary hydrocarbon generation during Himalayan period was key factor; c. tectonic evolution history controlling thermal evolution of source rock was main factor that determine reservoir forming; d. inherited positive structural unit was favorable accumulation direction; e. fault activity and regional caprock determined hydrocarbon accumulation horizon. In the end, the paper established reservoir forming model for different superposition of tectonic units, and pointed out promising exploration belts with 11 of the first class, 5 of the second class and 6 of the third class.

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.

中低纬电离层暴的统计分析与经验建模

As a key issue of ionospheric weather study, systemic studies on ionospheric storms can not only further improve our understanding of the response of the ionosphere to solar and geomagnetic disturbances, but also help us to reveal the chemical, dynamic and electro-dynamic mechanisms during storms. Empirical modelling for regional ionospheric storm is also very useful, because it can provide us with tools and references for the forecasting and further practical application of ionospheric activity. In this thesis, we focus on describing and forecasting of ionospheric storms at middle and low latitudes. The main points of my investigations are listed as follows. (1) By using magnetic storms during the period over 50 years, the dependence of the type, onset time and time delay of the ionospheric storms on magnetic latitude, season and local time at middle and low latitudes in the East-Asian sector are studied. The results show that the occurrences of the types of ionospheric disturbances differ in latitude and season. The onset of the ionospheric storms depends on local time. At middle latitudes, most negative phase onsets are within the local time interval from night to early morning, and they rarely occurred in the local noon and afternoon sectors. At low latitudes, positive phases commence most frequently in the daytime sector as well as pre-midnight sector. The average time delays for both the positive and negative ionospheric storms increase with descending latitudes. The time delay has significant dependence on the local time of main phase onset (MPO). The time delay of positive response is shorter for daytime MPO and longer for night-time MPO, whereas the opposite applies for negative response. (2) Based on some previous researches, a primary empirical model for mid-latitude ionospheric disturbance is set up. By fitting to the observed data, we get a high accuracy with a mean RMSE of only 12-14% in summer and equinox. The model output has been compared with the output of STORM model, and the results show that, our model is much better than STORM in summer and a little better for some mid-latitude stations at equinox. Especially, for the type of two-step geomagnetic storm, our model can present twice descending of foF2 very well. In addition, our model can forecast positive ionospheric storms.

柴达木盆地北缘地区油气成藏过程模拟与含油气系统评价

As an important part of petroleum exploration areas in the west of China, the north part of Qaidam basin is very promising in making great progress for petroleum discovery. But there are still many obstacles to overcome in understanding the process of petroleum formation and evaluation of oil & gas potential because of the complexity of geological evolution in the study area. Based upon the petroleum system theory, the process of petroleum formation is analyzed and the potential of oil & gas is evaluated in different petroleum systems by means of the modeling approach. The geological background for the formation of petroleum systems and the consisting elements of petroleum systems are described in detail. The thickness of strata eroded is estimated by means of vitrinite reflectance modeling, compaction parameter calculating and thickness extrapolating. The buried histories are reconstructed using the transient compaction model, which combines of forward and reverse modeling. The geo-history evolution consists of four stages - sedimentation in different rates with different areas and slow subsidence during Jurassic, uplifting and erosion during Cretaceous, fast subsidence during the early and middle periods of Tertiary, subsidence and uplifting in alternation during the late period of Tertiary and Quaternary. The thermal gradients in the study area are from 2.0 ℃/100m to 2.6 ℃/100m, and the average of heat flow is 50.6 mW/m~2. From the vitrinite reflectance and apatite fission track data, a new approach based up Adaptive Genetic Algorithms for thermal history reconstruction is presented and used to estimate the plaeo-heat flow. The results of modeling show that the heat flow decreased and the basin got cooler from Jurassic to now. Oil generation from kerogens, gas generation from kerogens and gas cracked from oil are modeled by kinetic models. The kinetic parameters are calculated from the data obtained from laboratory experiments. The evolution of source rock maturation is modeled by means of Easy %Ro method. With the reconstruction of geo-histories and thermal histories and hydrocarbon generation, the oil and gas generation intensities for lower and middle Jurassic source rocks in different time are calculated. The results suggest that the source rocks got into maturation during the time of Xiaganchaigou sedimentation. The oil & gas generation centers for lower Jurassic source rocks locate in Yikeyawuru sag, Kunteyi sag and Eboliang area. The centers of generation for middle Jurassic source rocks locate in Saishenteng faulted sag and Yuka faulted sag. With the evidence of bio-markers and isotopes of carbonates, the oil or gas in Lenghusihao, Lenghuwuhao, Nanbaxian and Mahai oilfields is from lower Jurassic source rocks, and the oil or gas in Yuka is from middle Jurassic source rocks. Based up the results of the modeling, the distribution of source rocks and occurrence of oil and gas, there should be two petroleum systems in the study area. The key moments for these two petroleum, J_1-R(!) and J_2-J_3, are at the stages of Xiaganchaigou-Shangyoushashan sedimentation and Xiayoushashan-Shizigou sedimentation. With the kinetic midels for oil generated from kerogen, gas generated from kerogen and oil cracked to gas, the amount of oil and gas generated at different time in the two petroleum systems is calculated. The cumulative amount of oil generated from kerogen, gas generated from kerogen and gas cracked from oil is 409.78 * 10~8t, 360518.40 * 10~8m~3, and 186.50 * 10~8t in J_1-R(!). The amount of oil and gas generated for accumulation is 223.28 * 10~8t and 606692.99 * 10~8m~3 in J_1-R(!). The cumulative amount of oil generated from kerogen, gas generated from kerogen and gas cracked from oil is 29.05 * 10~8t, 23025.29 * 10~8m~3 and 14.42 * 10~8t in J_2-J_3 (!). The amount of oil and gas generated for accumulation is 14.63 * 10~8t and 42055.44 * 10~8m~3 in J_2-J_3 (!). The total oil and gas potential is 9.52 * 10~8t and 1946.25 * 10~8m~3.

扬子板块西部大陆地幔地球化学特征及壳幔演化－有关基性岩超基性岩的地球化学研究

The continental mantle geochemical characteristics and crust-mantle evolution in the west of Yangtze Plate was discussed through the study of some within-plate basic-ultrabasic rocks from Lower Proterozoic to Later Paleozoic in this paper. In the Lower Proterozoic, the plate subduction between the pre-Tethys Proterozoic Ocean Plate and paleo-Yangtze Plate induced some basic volcanic formed in the island arc-back arc surrounding, which were represented by Ailaoshan Group-Dibadu Formation-Dahongshan Group, and there existed EM I component in the mantle source. The Middle Proterozoic Caiziyuan peridotite was formed in the epicontinental basin at the ocean-land boundary or within-continent rift basin. Its mantle source could be metasomatized by the dehydration fluid of subducted plate, and much initial radioactive ~(143)Nd was added to the source. In the Later Proterozoic, some rifts at the epicontinent or within-continent was formed due to the pre-Tethys oceanic plate subduction, and within-plate hot-spot Dahongshan diabase came into being. The whole-rock isochronal age of diabase is 1066±110Ma, and its mantle source was enriched Nd isotope and trace element which was related to the primary volatile component from asthenosphere and mantle plume. Its mantle source was included "FOZO" component representing mantle plume. The layer ultramafic rocks located at the Panxi Rift in the Middle-Later Paleozoic were resulted from different period and source. The early ultramafic indicated the incipient action of Panxi Rift, which is residue of continental lithospheric partial melting. Its mantle source involved subducted material and had distinct EM II component. The Emeishan basalt in the Later Paleozoic was typical continental flood basalt and its source also contained EM II component. The subduction of paleo-Tethys Ocean Plate provided essential dynamic condition for the large-scale opening of Panxi Rift, while the mantle plume supplied much material for Emeishan basalt. However, the plume was contaminated by the metasomatized continental mantle lithosphere in its upwelling process, which resulted in the Sr isotopic and incompatible elemental enrichment, and the Nd isotope kept down the weak-depleted character of mantle plume. The magmatic history in the west of Yangtze Plate is the tectonic process between pre-Tethys, paleo-Tethys Oceanic Plate and Yangtze Plate in a long history. Due to the subduction of oceanic plate, the crustal source material took part in the crust-mantle evolution widely. the continental mantle lithosphere in the west of Yangtze Plate was metasomatized by the fluid released by the subducted plate and the primary volatile from deeper mantle, and the mantle source include obvious enriched component.

鄂尔多斯盆地西缘中生代构造与地层分析及盆地演化研究

Through the detailed analyses of Mesozoic tectono-stratigraphy and basin formation dynamic mechanism and the styles of different units in the western margin of Ordos Basin(Abbreviated to "the western margin"), while some issues of the pre-Mesozoic in the western margin and central part of Ordos Basin also be discussed, the main views and conclusion as follows: 1. There are three types of depositional systems which are related with syndepositional tectonic actions and different tectonic prototype basins, including: alluvial fan systems, river system (braided river system and sinuosity river system), lacustrine-river delta system and fan delta system. They have complex constitutions of genetic facies. For the tectonic sequence VI, the fan sediments finning upper in the north-western margin and coarse upper in the south-western margin respectively. 2. In order to light the relationship between basin basement subsidence rate and sediment supply and the superposed styles, five categories of depositional systems tracts in different prototype basins were defined: aggrading and transgressive systems tracts during early subsidence stage, regressive and aggrading systems tracts during rapid subsidence, upper transgessive systems tracts during later subsidence stage. Different filling characteristics and related tectonic actions in different stages in Mesozoic period were discussed. 3. In order to determined the tectonic events of the provenance zones and provenance strata corresponding to basins sediments, according the clastics dispersal style and chemical analyses results of sediments in different areas, the provenance characteristics have been described. The collision stage between the "Mongolia block" and the north-China block may be the late permian; The sediments of Mesozoic strata in the north-western margin is mainly from the Alex blocks and north-Qilian Paleozoic orogeny, while the south-western margin from Qinling orogeny. The volcanic debris in the Yan'an Formation may be from the arc of the north margin of north-China block, although more study needed for the origin of the debris. The provenance of the Cretaceous may be from the early orogeny and the metamorphic basement of Longshan group. 4. The subsidence curve and subsidence rate and sedimentary rate in different units have been analyzed. For different prototype basin, the form of the subsidence curves are different. The subsidence of the basins are related with the orogeny of the basins.The beginning age of the foreland basin may be the middle Triassic. The change of basement subsidence show the migration of the foredeep and forebulge into the basin. The present appearance of the Ordos basin may be formed at the late stage of Cretaceous, not formed at the late Jurassic. 5. The structure mode of the west margin is very complex. Structure transfer in different fold-thrust units has been divided into three types: transfer faults, transition structures and intersected form. The theoretic explanations also have been given for the origin and the forming mechanism. The unique structure form of Hengshanpu is vergent west different from the east vergence of most thrust faults, the mechanism of which has been explained. 6. In Triassic period, the He1anshan basin is extensional basin while the Hengshanbu is "forland", and the possible mechanism of the seemingly incompatible structures has been explained. First time, the thesis integrate the Jurassic—early Cretaceous basins of west margin with the Hexi corridor basins and explain the unitive forming mechanism. The model thinks the lateral extrusion is the main mechanism of the Hexi corridor and west margin basins, meanwhile, the deep elements and basement characters of the basins. Also, for the first time, we determine the age of the basalt in Helanshan area as the Cretaceous period, the age matching with the forming of the Cretaceous basins and as the main factor of the coal metamorphism in the Helanshan area. 7. The Neoprotterozoic aulacogen is not the continuation of the Mesozoic aulacogen, while it is another new rift stage. In the Paleozoic, the Liupanshan—southern Helanshan area is part of the back-arc basins of north Qilian ocean. 8. The Helanshan "alacogen" is connected with the north margin of north China block, not end at the north of Zhouzishan area like "appendices". Also, I think the upper Devonian basin as the beginning stage of the extensional early Carboniferous basins, not as a part of the foreland basins of Silurian period, not the collision rift. 9. The controlling factor of the difference of the deformation styles of the north-west margin and the south-west margin is the difference of the basements and adjacent tectonic units of the two parts.

东天山地区金矿床成矿流体地球化学及其成矿机制

The mechanism of gold ore formation in the eastern Tianshan Mountains, Xinjiang Uygur Autonomous Region, that has been dealt with from various aspects, remains unclear. On the basis of investigations of regional geology, ore deposit geology, and microscopic observations of ores and related rocks of the Jinwozi, the 210, and the Mazhuangshan gold ore deposits, this thesis made a systematic research on the microthermometry of gangue quartz-hosted fluid inclusions, gas, liquid ion and rare earth element compositions and hydrogen, oxygen isotope compositions of sulfide- and quartz-hosted fluid inclusions, and sulfur and lead isotope compositions of sulfide ore minerals from the major ores in the three deposits. On the basis of the above synthetic studies, sources of ore-forming fluids and metals, and mechanism of gold ore formation in the region were discussed. Gas compositions of pyrite- and sphalerite-hosted fluid inclusions were first analyzed in this thesis. Compared with gangue quartz-hosted fluid inclusions, the sulfide-hosted ones are richer in gaseous species CO2, CO, and CH4 etc. Both gas and liquid CO2 are commonly observed in fluid inclusions, whereas halite daughter minerals rarely occur. Ore-forming fluids for the three gold ore deposits are characteristically of medium to low temperatures, medium to low salinities, are rich in CO2 and Na+, K+, Cl" ions. Gas covariation diagrams exhibit linear trends that are interpreted as reflecting mixing between the magamtic fluid and meteoric-derived groundwater. Regarding rare earth element compositions, the Jinwozi and the 210 deposits show moderate to strong LREE/HREE fractionations with negative Eu anomalies. However, the Mazhuangshan deposit shows little LREE/HREE fractionation with positive Eu anomalies. Hydrogen and oxygen isotope compositions of pyrite-hosted fluid inclusions that were first analyzed in this thesis indicate the presence of magmatic water. Hydrogen and oxygen isotope compositions of pyrite- and quartz-hosted fluid inclusions suggest mixing between magmatic water and meteoric-derived groundwater. Sulfur and lead isotope compositions of sulfide ore minerals indicate multi-sources for the metallogenetic materials that range from the crust to the mantle. On the basis of the above synthetic studies, genesis of the gold ore deposits in the eastern Tianshan Mountains was approached. From the Middle-Late Hercynian to Early Indosinian, geodynamic regime of the region was changing from the collisional compression to the post-collisional extension. During the period, magmas were derived from the crust and the mantle and carried metallogenetic materials. Magma intrusion in the upper crust released the magmatic fluids, and drove circulation of groundwater. Mixing of magmatic fluid with groundwater, and extraction of metallogenetic materials from the country rocks are the mechanism for the gold ore formation in the eastern Tianshan Mountains.

西秦岭晚古生代弧前盆地沉积与成矿作用

The Western Qinling Orogenie belt in the Taibai-Fengxian and Xihe-Lixian areas can be subdivided into three units structurally from north to south, which are the island-arc, forearc basin and accretionary wedge, respectively. The forearc basin developed in the Late Paleozoic mainly controls sedimentation and some larger lead-zinc and gold deposits in the western Qinling. Stratigraphically, the island arc is dissected into the Liziyuan Group, the Danfeng Group and the Luohansi Group. The metavolcanic rocks include basic, intermediate and acidic rocks, and their geochemistry demonstrates that these igneous rocks generated in an island arc. Where, the basalts are subalkaline series charactered by low-medium potassium, with enriched LREE, negative Eu anomaly, and positive Nd anomaly. Cr-content of volcanic rocks is 2-3 times higher than that of island arc tholeiite all over the world. In addition, the lightly metamorphosed accretionary wedge in the areas of Huixian, Chengxian, Liuba and Shiqun is dominated by terrigenous sediments with carbonatite, chert, mafic and volcanic rocks. The age of the wedge is the Late Palaeozoic to the Trassic, while previous work suggested that it is the Silurian. The Upper Paleozoic between the island arc belt and accretionary wedge are mainly the sediments filled in the fore arc basin. The fillings in the forearc basin were subdivided into the Dacaiotan Group, the Tieshan Group, the Shujiaba Group and the Xihanshui Group, previously. They outcropped along the southern margins of the Liziyuan Group. The Dacaotan Group, the Upper Devonian, is close to the island arc complex, and composed of a suite of red and gray-green thick and coarse terrestrial elastics. The Shujiaba Group, the Mid-Upper Devonian, is located in the middle of the basin, is mainly fine-grained elastics with a few intercalations of limestone. The Xihanshui Group, which distributes in the southern of the basin, is mainly slates, phyllites and sandstones with carbonatite and reef blocks. The Tieshan Group, the Upper Devonian, just outcrops in the southwest of the basin, is carbonatite and clastic rocks, and deposited in the shallow -sea environment. The faults in the basin are mainly NW trend. The sedimentary characteristics, slump folds, biological assemblages in both sides of and within those faults demonstrate that they were syn-sedimentary faults with multi-period activities. They separated the forearc basin into several sub-basins, which imbricate in the background of a forearc basin with sedimentary characteristics of the piggyback basin. The deep hydrothermal fluid erupted along the syn-sedimentary faults, supported nutrition and energy for the reef, and resulted in hydrothermal-sedimentary rocks, reef and lead-zinc deposits along these faults. The sedimentary facies in the basin varies from the continental slope alluvial fan, to shallow-sea reef facies, and then to deep-water from north to south, which implies that there was a continental slope in the Devonian in the west Qinling. The strata overlap to north and to east respectively. Additionally, the coeval sedimentary facies in north and south are significantly different. The elastics become more and more coarser to north in the basin as well as upward coarsing. These features indicate prograding fillings followed by overlaps of the different fans underwater. The paleocurrent analyses show that the forearc basin is composed of thrust-ramp-basins and deep-water basins. The provenance of the fillings in the basin is the island arc in the north. The lead-zinc deposits were synchronous with the Xihanshui Group in the early stage of development of the forearc basin. They were strongly constrained by syn-sedimentary faults and then modified by the hydrothermal fluids. The gold deposits distributed in the north of the basin resulted from the tectonic activities and magmatism in the later stage of the basin evolution, and occurred at the top of the lead-zinc deposits spatially. The scales of lead-zinc deposits in the south of the basin are larger than that of the gold-deposits. The Pb-Zn deposits in the west of the basin are larger than those in the east, while the Gold deposits in the west of the basin are smaller than those in the east. Mineralizing ages of these deposits become younger and younger to west.