Guocheng Pan  D. P. Harris 《Mathematical Geology》1991,23(6):861-886

A new multidimensional scaling (MS) technique, referred to as the Pijk model, is formulated on the basis of associations among triple objects (samples or variables), instead of pairs of objects as used in the usual MS methods, such as factor analysis. The computational scheme provided for this method is the reduction of an original problem to a standard eigenvalue-eigenvector problem. The major goal of the technique is simplification and reduction of data structures and the rescaling of original objects into a new and reduced space, so that patterns and relations of the original objects can be conventiently examined in two-dimensional factor plots. The Pïjk method is illustrated and tested by using a set of geochemical data related to the epithermal gold and silver vein deposits in the Walker Lake quadrangle of Nevada and California. The characteristics of element associations suggested in the Pijk analysis are consistent with field observations. A preliminary comparison between the new method and the ordinary factor analysis also is made on the basis of the same data set. Results are encouraging in that analysis by the Pijk model captures triple-object associations that might be missed by the ordinary factor analysis which considers only pair-variable correlations  相似文献   

Rigid unit modes in the molecular dynamics simulation of quartz and the incommensurate phase transition     

Frank Stefan Tautz  Volker Heine  Martin T. Dove  Xiaojie Chen 《Physics and Chemistry of Minerals》1991,18(5):326-336

A molecular dynamics simulation of quartz at different temperatures both in the a and in the phase has been conducted. The - phase transition could be observed. A phonon analysis of the -phase confirms and rounds out in a quantitative way the origin of the incommensurate (ic) modulated phase. In particular it traces the optic soft mode at becoming (to a good approximation) a so-called rigid unit mode (RUM) at q0, and elucidates its coupling to the transverse acoustic mode which precipitates the incommensurate transition. This success underpins and illuminates the concept of RUMs and their role in structural phase transitions.  相似文献   

Commission health and development     

M. Erdtmann-Vourliotis  M. Klein  K. Hohgardt 《GeoJournal》1991,25(1):125-126

IGU-Reports

Commission health and development  相似文献   

Littoral '92     

H. Flanquart  C. Meur-Férec  Ph. Deboudt  V. Morel  A.-P. Hellequin  et al. 《GeoJournal》1991,24(2):223-223

Reports

Littoral '92  相似文献   

造山带中富集型上地幔的成因——以萨尔托海蛇绿岩块为例   总被引：1，自引：0，他引：1  

郝梓国  王希斌  鲍佩声 《地球学报》1991,12(1):159-166

发育于造山带中的蛇绿岩,其剖面下部的地幔橄榄岩部分是造山带地区富集型上地幔的直接标本。其地球化学特点是:主要元素Al_2O_3、TiO_2、CaO、Na_2O、K_2O强烈亏损,而REE,痕量元素和87Sr/86Sr则强烈富集;同时,143Nd/144Nd<0.511836,亦表明它们属于一个富集型的源区。 形成富集型上地幔的主要机制是地幔交代作用,富含不相容元素的低熔岩浆和富Ca-LREE流体与已亏损的地幔橄榄岩发生脉状交代和渗透交代反应,从而造成上地幔中不相容元素的富集。造山带富集型上地幔形成的构造环境是:洋壳从扩张脊向两侧运移并最终拼入造山带这段时间内。富集型上地幔不但存在于大陆区,而且亦存在于造山带地区,它可能是一种全球性的地球内部的化学作用。  相似文献   

宁夏香山-天景山弧形断裂带新活动特征及1709年中卫南71/2级地震形变带   总被引：5，自引：1，他引：4       下载免费PDF全文

张维岐  焦德成  柴炽章  宋方敏  汪一鹏 《地震地质》1988,10(3):12

本文根据野外地质填图和水系位移测量结果,论述了香山-天景山弧形断裂带新生代有两个不同活动性质的阶段,即早期阶段的强烈挤压和晚期阶段的左旋走滑兼挤压。分析、讨论了不同活动阶段的时间界限和转变原因。指出了1709年中卫南71/_2级地震形变带的表现形式、延伸范围  相似文献   

鄂尔多斯地块构造演化的古地磁学研究   总被引：15，自引：0，他引：15       下载免费PDF全文

程国良  白云虹  孙宇航 《地震地质》1988,10(2):81

鄂尔多斯地块与中朝地台其它地区相同时代地层的古地磁结果基本一致表明:晚二叠世以来,中朝地台经历了从低纬度(19°左右)向中纬度的北移过程,并伴有50°左右的逆时针旋转;晚二叠世—中三叠世地台北移10°(1000km)左右,而方位基本未变;中三叠世—中侏罗世主要发生50°左右的逆时针旋转,而北向位移不明显,这一旋转可能与杨子地台和中朝地台碰撞拼合有关,或者说是印支运动在该地区的反应,中侏罗世—早白垩世地块已基本和现代位置一致  相似文献   

渭河盆地北缘断裂带活动特征的初步研究   总被引：8，自引：1，他引：7       下载免费PDF全文

徐煜坚  申屠炳明  汪一鹏 《地震地质》1988,10(4):77

本文从渭河盆地北缘断裂的形成和活动时代,活动特征等资料出发,结合北缘断裂带及整个盆地历史地震活动和新生界地层发育特征的综合分析,对北缘断裂带的活动期次,主要断层的运动幅度和滑动速率及其时空演变规律和机制等问题进行了探讨。文章指出,北缘断裂带的形成是一个由盆地中心向北逐渐扩展的过程,自上新世起,断层活动明显有东强西弱的变化特征,而且扩展方向也发生了偏转。这一转变及活动强度的东西差异与山西剪切带对渭河盆地的影响密切相关  相似文献   

A model of the galactic centre with magnetic monopoles     

Wang De-Yu  Peng Qiu-He  Chen Ting-Yang 《Astrophysics and Space Science》1986,118(1-2):379-382

A model of the galactic centre with magnetic monopole has been presented here. The positron can be produced continuously through magnetic monopoles to induce baryon decay (Rubakov catalytic reaction) and a lot of energy can be released as well. The calculation results show that even if the galactic center contains only a few magnetic monopoles (=N _M/N_B10^–24), this massive object can not collapse into a black hole. This model can explain the observed intensities of the annihilation line and higher energy photons ofE >511 keV from the galactic centre.Paper presented at the IAU Third Asian-Pacific Regional Meeting, held in Kyoto, Japan, between 30 September–6 October, 1984.  相似文献   

Age-metallicity relation for F-stars     

Hong Bae Ann  Yong Hee Kang 《Astrophysics and Space Science》1986,118(1-2):325-327

We derived the age-metallicity relation for the solar neighbourhood from theuvby, H photometry of F-stars using the evolutionary models of Hejlesen (1980). It is shown that disk formation is divided into two phases according to the fast and slow collapse which accompany the initial rapid enrichment and slow increase of the metallicity of the galactic disk, respectively.Paper presented at the IAU Third Asian-Pacific Regional Meeting, held in Kyoto, Japan, between 30 September–6 October, 1984.  相似文献