EFFECT OF THE INDIAN PENINSULA ON THE COURSE OF THE ASIAN TROPICAL SUMMER MONSOON^*          下载免费PDF全文

XU Haiming  HE Jinhai  DONG Min 《Acta Meteorologica Sinica》2001,15(3):310-322

In terms of the NCAR Community Climate Model (CCM3),the effect of the Indian Peninsula on the course of the Asian tropical summer monsoon is simulated in this paper,and numerical experimental results show that the Indian Peninsula plays a critical role in the establishment process of the Asian tropical summer monsoon.When the CCM3 includes the Indian Peninsula,the model successfully simulates out the course of the Asian tropical summer monsoon,i.e.the South China Sea (SCS) summer monsoon at first bursts in middle May,while the Indian monsoon just establishes until middle June.However when the Indian Peninsula topography is deleted in the model,the Indian and SCS summer monsoons almost simultaneously establish in late May.Numerical results further indicate that in the former experiment the sensible heating of the Indian Peninsula warms the air above and produces evident temperature contrast between the peninsula and its adjacent SCS and Bay of Bengal (BOB).which results in the strengthening and maintenance of the BOB trough in the low-middle layer of the troposphere in the end of spring and early summer and thus the earliest establishment of the Asian tropical summer monsoon in the SCS in middle May.However,the Indian summer monsoon just establishes until middle June when the strong west wind over the Arabian Sea shifts northwards and cancels out the influence of the northwest flow behind the BOB trough.In the latter experiment the effect of Tibetan Plateau only produces a very weak BOB trough,and thus the SCS and Indian summer monsoons almost simultaneously establish.  相似文献   

Paleomagnetism of Cretaceous units of the Mametchinskiy Peninsula, Kuyul Region, Northeastern Russia: implications for development and evolution of the Northwest Pacific Basin     

William Harbert  Maxim Alexutin  Sergei Sokolov  Kirill Krylov  Vladimir Grigoriev  Alexander Heiphetz  Robert Graham 《Tectonophysics》2001,340(3-4):215-231

The northernmost part of the Kamchatka Peninsula of northeastern Russia, located along the northwestern margin of the Bering Sea, consists of zones of complexly deformed accreted terranes. Progressing from the northwestern Bering Sea inland are the Olyutorskiy, Ukelayat, and Koryak superterranes, which were accreted to the Okhotsk–Chukotsk volcanic–plutonic belt (OChVB) during the Campanian–Maastrichtian (Koryak) to Middle Eocene (Olyutorskiy), respectively. To constrain the accretion paleolatitude of the Koryak superterrane, we paleomagnetically sampled a sedimentary series on the Mametchinskiy Peninsula. At the Mametchinskiy Peninsula, in the northeastern Penzhinskaya Guba (61.45° N, 163.75° E), a gently deformed, well-bedded section of fine-grained Lower to lower Upper Cretaceous turbidites, the Mametchinskaya and Tylakrylskaya Formations are exposed. These strata, which represent the lower part of the sedimentary cover of the terranes in this region and the forearc of OChVB, were sampled at 39 sites (three to seven samples per site). Within the Ainyn terrane, more than 1000 m of section of Cenomanian–Turonian age was sampled at a basal locality (sample groups I and II, sites 1–18, 19–29) and at an upper locality of Valanginian–Barremian age (sample group III, sites 30–39) along the western shore of the Peninsula. Thermal demagnetization and principal component analysis of the demagnetization data show lower-temperature (A) and higher-temperature (B) magnetic components. Although group III samples did not display a coherent A component, the A component of group I and II samples was observed as a single-polarity lower-unblocking temperature component generally removed by 100–400 °C. This component failed the fold test at the 95% confidence level. With respect to direction, the A component is similar to both the present-day field and axial–geocentric dipole directions expected at this site. The B component was observed during thermal demagnetization steps up to 580 °C and was always of downward-directed inclination. Coherence of bedding corrections within each section do not allow statistically meaningful fold tests within groups I, II or III. Assuming the B component represents a Cretaceous magnetization, two overall models are proposed. In the first model (preferred), with the highest clustering of directions (k-value=36.7, N (sites)=36), indicates significant poleward motion of the Ainyn terrane (observed paleolatitude λ_M1=61.0±6.5°; expected North America plate reference site paleolatitude λ_E=74.0±3.5°). In the second model, no significant poleward displacement is implied (λ_M2=72.0±9.6).  相似文献   

胶东金矿床Au迁移富集的地球化学探讨          下载免费PDF全文

张言  杨凤筠 《地质科学》1992,(2):193-197

本文编制了系统 Fe²⁺—Fe³⁺—∑S—∑CO₂—[SO₁^2-]和 Fe²⁺—FeS—FeCO—Fe(OH)₂的相图,以及溶液中络合物 Au—s 和 Au—Cl 在不同温度下的 C_Au—PH 图。有证据表明,金可能是以 Au—S 络合物形式迁移的,控制金沉淀的主要因素是溶液的 Eh 和∑S 的活度。  相似文献   

Photogeological study of cenozoic landform evolution in the Cooktown area,North Queensland,Australia     

C. R. Nash 《地球表面变化过程与地形》1992,17(4):399-406

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Imaging of shear-wave velocity structure beneath Iberia   总被引：1，自引：0，他引：1  

Jose Badal    Victor Corchete    G. Payo    L. Pujades  J. A. Canas 《Geophysical Journal International》1996,124(2):591-611

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Late Miocene valley-confined subglacial volcanism in northern Alexander Island,Antarctic Peninsula     

J L Smellie  M J Hole  P A R Nell 《Bulletin of Volcanology》1993,55(4):273-288

Isolated, Late Miocene volcanogenic sequences in northern Alexander Island, Antarctic Peninsula, form an unusual, cogenetic association of volcaniclastic, sandy-gravelly lithofacies (including tillites) and volcanic (lava/hyalocalstite) lithofacies. Using simple lithofacies analysis and theoretical considerations of hydrodynamic effects of subglacial eruptions, valley-confined volcanic activity beneth thin, wet-based ice is suggested. The Alexander Island successions are complete enough to be regarded as model sequences for this uncommonly recorded type of eruptive/depositional activity. The sedimentary lithofacies represent resedimented tuffs and meltout or flow tills, which were probably deposited in subglacial ice tunnels eroded or enlarged by volcanically heated meltwater. The volcanic lithofacies formed by the interaction of hot magma with the ice tunnel walls (generating abundant meltwater) and water-saturatedsediments, resulting in the formation of heterogeneous masses of lava and hyaloclastite. There is no obvious sequence organisation in the sedimentary sections. This is probably due to a complex interplay of eruption-related and environmental hydrodynamic factors affecting the relative proportions of water and entrained sediment.  相似文献   

朝鲜中生代构造   总被引：1，自引：0，他引：1  

金贞焕 《地球学报》1994,15(Z1):32-44

朝鲜中生代构造作用以多旋回的克拉通内变形为特，其中包括：a)韧性或脆必剪切走滑作用；b)挤压期的褶皱、冲断和走滑压扭作用；c）引张期的正断层或多米诺断裂系统和张扭走滑作用形成的盆地。它们发生于3个构造事件期间：Sougnim、Daebo和Bulgugsa造山期。晚二叠世一早三叠世的 Songuim 造山可分为两个阶段。当Songnim造山作用减弱时，后构造花岗岩石发生侵位，在张性构造环境下形成 Daedong盆地。晚三叠世-早侏罗世 Daedong 群沉积之后，Daebo造山随之发生，形成NE走向的褶皱和  相似文献   

胶东金青顶和邓格庄金矿床的同位素组成及其地质意义     

应汉龙 《地质与资源》1994,3(3):201-207

本文主要研究了胶东金青顶和邓格庄金矿床蚀变体系的氧、硅同位素组成、硫化物矿物的硫同位素组成，方解石的碳、氧、锶、钐、钕同位素组成，结果表明金矿床早阶段成矿热液中水以非大气降水为主，晚阶段成矿热液中大气降水增加；成矿物质来源于地壳。推断金矿床由地壳物质在燕山期大规模低程度熔融出的富K、Na的流体交代改造岩石并汲取成矿元素形成的矿化热液和岩浆热液共同作用形成。  相似文献   

焦家式金矿中铬铝云母化学成分的标型性   总被引：1，自引：1，他引：1  

鲁安怀  陈光远 《岩石矿物学杂志》1994,13(4):353-361

本文系统研究了胶东地区金矿中产出的铬铝云母亚族中３个白云母、１６个绢云母和３２个含Ｃｒ云母种属的化学成分特征。提出了含Ｃｒ云母种属结构层内四面体、八面体及层间离子种类和数量在焦家式金矿成矿过程中的指示作用，阐明了白云母、绢云母及含Ｃｒ云母种属之间的演化特征在与焦家式金矿化有关的成岩成矿作用中的标型意义。  相似文献   

雷州半岛九斗洋干玛珥湖火山机构与第四系空间展布——基于高密度电阻率法勘测和钻孔研究     

曾砺锋  陈聪  郑卓  肖凡  黄康有  满美玲  田俐萍 《热带地理》2018,38(2):244-254

为查明雷琼火山群中九斗洋干玛珥湖的第四纪地层空间展布,以及埋藏古火山形态,为后续研究提供地质背景资料,采用高效、便捷的高密度电阻率法对九斗洋干玛珥湖湖盆区进行勘测,并结合钻孔岩芯的研究进行验证。得出的主要结论为：1）盆地深部地层最高电阻率可达到300 Ω?m以上,盆地中央基岩以下存在高阻地质体,推测为岩浆通道位置。岩浆经过通道溢出后横向展布,覆于沉积地层上,随后在火山口内形成湖泊,堆积第四纪湖相沉积,其火山机构与玛珥湖型火山一致;2）九斗洋干玛珥湖第四纪松散沉积地层的电阻率通常＜60 Ω?m,泥炭层电阻率最低;3）第四纪沉积总厚度为25~50 m,盆地松散沉积的岩浆岩基底总体平整,但尚有波状起伏。研究结果表明,高密度电阻率法结合钻孔验证是研究火山机构形态及火山口湖第四纪沉积空间展布的有效方法。  相似文献