关于峨眉山溢流玄武岩省资源勘查的几个问题   总被引：10，自引：1，他引：10       下载免费PDF全文

朱炳泉 《中国地质》2003,30(4):406-412

通过全球资料对比表明峨眉山溢流玄武岩省具有较完整的岩浆—热液成矿系列。峨眉山玄武岩裂隙式喷发的溢流通道受地球化学边界所揭示的岩石圈不连续界面所控制。这些地段存在完整的古火山口相岩石组合，为找矿提供了重要线索。溢流通道岩浆房存在贫硫低氧逸度、贫硫高逸度和富硫3个岩浆分异趋向，构成3个岩浆成矿系列(Cu—Ni—PGE，Cu—Ag—Pd与Fe—Ti—V)。同生火山热液活动形成了从低绿片岩相、葡萄石相到沸石相(400℃至100℃)的铜成矿系列。热液组成的不同控制自然铜、氧化铜和铜硫化物的形成。反射率资料对比表明对自然铜形成起重要制约作用的沥青来自P2—T1界面地层有机质的热液裂解，并处于生油成熟期。因此和Keweenaw大陆裂谷一样，应开展铜、镍、铂钯、油气一体化的勘查。  相似文献   

Intra-Seasonal Oscillation (ISO) of south Kerala rainfall during the summer monsoons of 1901–1995     

P. V. Joseph  Anu Simon  Venu G. Nair  Aype Thomas 《Journal of Earth System Science》2004,113(2):139-150

Time series of daily averaged rainfall of about 40 rain gauge stations of south Kerala, situated at the southern-most part of peninsular India between latitudes about 8‡N and 10‡N were subjected to Wavelet Analysis to study the Intra Seasonal Oscillation (ISO) in the rainfall and its inter-annual variability. Of the 128 days, 29th May to 3rd October of each of the 95 years 1901-1995 were analysed. We find that the period of ISO does not vary during a monsoon season in most of the years, but it has large inter-annual variability in the range 23 to 64 days. Period-wise, the years cluster into two groups of ISO, the SHORT consisting of periods 23, 27 and 32 days and the LONG with a single period of 64 days, both the sets at a significance level of 99%. During the 95 years at this level of significance there are 44 years with SHORT and 20 years with LONG periods. 11 years have no ISO even at the 90% level of significance. We composited NCEP SST anomalies of the summer monsoon season June to September for two groups of years during the period 1965–1993. The first group is of 5 years with a LONG ISO period of 64 days for south Kerala rainfall at significance level of 99% and the second group is of 12 years with SHORT ISO periods of 23, 27 and 32 days at the same level of significance. The SST anomaly for the LONG (SHORT) ISO resembles that for an El Nino (La Nina).  相似文献   

INFLUENCE OF TIBETAN PLATEAU ON AIR-SEA INTERACTION OVER TROPICAL PACIFIC IN OCEAN-ATMOSPHERIC COUPLED SYSTEM     

吴爱明  倪允琪 《Acta Meteorologica Sinica》1998,(3)

A hybrid coupled ocean-atmosphere model is designed,which consists of a global atmosphericgeneral circulation model(L9R15 AGCM)and a simple ocean model(ZC ocean model over tropicalPacific).Using the model,experimental predictions are performed for the 1986/87 El Nino eventand the 1988/89 La Nina event with and without the Tibetan Plateau respectively(called TPFORC and NTP FORC hereinafter).It is found as follows:(1)The coupled system cansuccessfully predict the El Nino or La Nina event even if the Tibetan Plateau orography is notincluded in the model.The patterns of SSTA and wind anomalies in the model without the TibetanPlateau are similar to those with the Tibetan Plateau,which further verifies the fact that ENSOprocess is mainly caused by the air-sea interaction in tropical Pacific.(2)However.the existenceof the Tibetan Plateau exerts its influences on the intensity and duration of El Nino(or La Nina).It is unfavorable to the development and maintenance of westerly anomalies,so to some extent,restrains the development of El Nino,but favors the development of La Nina.(3)Effects of theTibetan Plateau orography on the wind anomalies in the coupled system are different from those inuncoupled AGCM simulation.  相似文献   

Late Palaeozoic NE–SW ductile–brittle extension in the La Serre horst,eastern France     

Guilhem Coromina  Olivier Fabbri 《Comptes Rendus Geoscience》2004,336(1):75-84

In the La Serre horst of the Alpine foreland, the pre-Triassic La Serre median fault zone separates a Late Devonian–Early Carboniferous granite from an ignimbrite of unknown age and from Permian deposits. Motion along this fault zone took place first in ductile conditions and then evolved in brittle conditions. Both ductile and brittle shear criteria indicate a top-NE normal-dextral displacement. Similar motions are reported along faults bounding Late Palaeozoic intramontane coal basins located in the Massif Central and correspond to a widespread NE–SW Late to Post-Orogenic extension that affected the Variscan basement during Late Carboniferous to Early Permian times. To cite this article: G. Coromina, O. Fabbri, C. R. Geoscience 336 (2004).  相似文献   

DIAGNOSTIC PREDICTIONS OF SST IN THE EQUATORIAL EASTERN PACIFIC OCEAN BASED ON FUZZY INFERRING AND WAVELET DECOMPOSITION     

张韧  周林  董兆俊  李训强 《热带气象学报(英文版)》2002,8(2):168-179

Methods and approaches are discussed that identify and filter off affecting factors (noise) above primary signals,based on the Adaptive-Nework-Based Fuzzy Inference System. Influences of the zonal winds in equatorial eastern and middle/western Pacific on the SSTA in the equatorial region and their contribution to the latter are diagnosed and verified with observations of a number of significant El Nino and La Nina episodes. New viewpoints are propsed. The methods of wavelet decomposition and reconstruction are used to build a predictive model based on independent domains of frequency,which shows some advantages in composite prediction and prediction validity.The methods presented above are of non-linearity, error-allowing and auto-adaptive/learning, in addition to rapid and easy access,illustrative and quantitative presentation,and analyzed results that agree generally with facts. They are useful in diagnosing and predicting the El Nino and La Nina problems that are just roughly described in dynamics.  相似文献   

厄尔尼诺现象和拉尼娜现象与中高纬地区气候的关系     

赵玉洁 《黑龙江气象》2002,(4):16-18

利用概率统计学方法,分析厄尔尼诺现象和拉尼娜现象与中高纬地区四季气温、≥10℃活动积温、初霜、终霜及降水等的关系,对短期气候预测具有较好的参考价值。  相似文献   

热带西太平洋对风应力的斜压响应   总被引：4，自引：0，他引：4       下载免费PDF全文

巢纪平  陈鲜艳  何金海 《地球物理学报》2002,45(2):176-187

发展了一个线性热带西太平洋两层模式,分别为混合层和温跃层,其密度、温度各不相同.利用这一模式分析了热带西太平洋对纬圈风应力的响应,求出西边界的解,以及解析地求得热带西太平洋温跃层厚度、洋流及海温分布.结果表明,热带西太平洋物理量的变异在El Nino/La Nina事件中起着重要作用,在温跃层中海温变化的振幅明显大于混合层,这从理论上支持了近年来的观测事实.  相似文献   

西藏尼木南北向活动构造带的初步研究   总被引：2，自引：0，他引：2  

龚宇  张文甫 《四川地震》1993,(1):13-19

西藏尼木南北向活动构造带是西藏高原上著名的当雄—羊八井—多庆错活动构造带的组成部份,具有强烈的第四纪活动性。它由活动断裂和裂陷型断陷盆地两大部份构成。盆地内的地貌特征显示它在第四纪持续沉降的特点。该带中的活动断裂主要有两组,即南北向和北北东向。第四记的强烈活动在带内留下了众多的断错地貌现象,南北向活动断裂的主要活动时期较早,在更新世。北北东向活动断裂的主要活动时期较晚,在全新世。  相似文献   

云南镍矿地质特征及找镍方向   总被引：1，自引：0，他引：1  

薛步高 《云南地质》2008,27(1):1-11

云南硫化镍矿以与铂钯矿的伴生镍为主（11．76万t）,其中：大理-弥渡（6．85万t）、金平（6．38万t）、元谋-永仁-牟定（5．12万t）。硅酸镍主要在墨江-元江（64．41万t）;蛇绿混杂岩型硫砷化物镍矿（1．73万t）,是云南-大特色。与成矿有关的岩体主要是华力西期,次为加里东期,产出与深大断裂有关。找矿方向应以富宁、金平及景东东山-红河底玛为主攻目标。  相似文献   

Synthesis and characteristics of Sr-dope LaNbO4 ultrafine powders     

TIAN Li-yu  YU De-li  LIU Shu-qin 《世界地质》2008,27(3)

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