新疆及邻区大地构造编图研究

新疆及邻区大地构造1150万的编图范围为北纬34°～50°，东经72°～98°，面积约370×10     

Geochemistry and magnetostratigraphy of deccan flows at Anjar, Kutch

Chemical analysis of nine Deccan flow basalts at Anjar, Kutch, western India, indicates that all, except the uppermost flow F-9, are alkaline. In their major and trace element composition, the alkali basalts resemble Ocean island basalts (OIB). Similarities of many diagnostic trace element ratios (e.g. Sm/Nd, Ba/Nb,Y/Nb and Zr/Nb) are similar to those found in the Réunion Island basalts. The uppermost basalt is tholeiitic and chemically resembles the least contaminated Deccan basalt (Ambenali type). The Anjar basalts have iridium concentration ranging between 2 and 178 pg/g. Some of these values are higher by about an order of magnitude compared to the Ir concentration in other basalts of the Deccan. A synthesis of chemical, palaeomagnetic and geochronologic data enables us to construct a chemical and magnetic stratigraphy for these flows. The three flows below the iridium enriched intertrappean bed (IT III) show normal magnetic polarity whereas all except one of the upper basalts show reversed magnetic polarity. The sequence seems to have started in polarity zones 31N and probably continued up to 28R or 27R. The results presented here support the view that Deccan volcanism in Kutch occurred on a time span of a few million years.     

Onset of seafloor spreading in the Iapetus Ocean at 608 Ma: precise age of the Sarek Dyke Swarm, northern Swedish Caledonides

The Sarek Dyke Swarm (SDS) crops out in the Sarektjåkkå Nappe (SN) of the Seve-Kalak Superterrane in the northern Swedish Caledonides. The SN has two main components: (1) a 4–5 km thick succession of rift-related sedimentary rocks, which is intruded by (2) a suite of tholeiitic dykes (the SDS) constituting 70–80% of the nappe. The nappe was deformed during Caledonian thrusting, but dykes and sedimentary rocks in the interior of the eastern parts of the SN are preserved in a pristine state. The tholeiitic dykes of the SDS commonly occur in sheeted dyke complexes, and up to 11 successive generations can be identified from crosscutting relations. The SN represents the fossil continent–ocean transition between the Baltic craton and the Iapetus Ocean, marking the initiation of seafloor spreading. Bubble-shaped pods and veinlets of diorite are present in the SDS sheeted dyke complexes. The pods are absent in the oldest dykes, but the younger a dyke, the more frequent the pods. The diorite pods are the equivalent of gabbro pegmatites, and both cogenetic and coeval with the dykes. The rapid successive emplacement of tholeiitic magma raised the ambient temperature in the dyke complex, so that crystallization in the youngest dykes mimicked similar processes in gabbro plutons. Six zircon fractions, from the diorite pods including two single grains, were analysed geochronologically by the U–Pb thermal ionization mass spectrometry method. The data yield a linear array of points that are 0.4–0.8% normally discordant, indicating a crystallization age of 608±1 Ma (²⁰⁷Pb/²⁰⁶Pb=607.9±0.7 Ma, MSWD=0.33). This age is inferred to date the onset of seafloor spreading in the Iapetus Ocean along the Baltoscandian margin.     

IDA和CDSN资料的长周期面波研究

１９８０年和１９９２年分别在昆明和北京白家疃台架设了ＩＤＡ观测仪器，１９８５年开始又陆续在北京，兰州，海拉尔等地布设和完善了ＣＤＳＮ数字化地震观测台网，为开展长周期面波研究提供了方便。本文结合国内外研究现状，论述了超长周期地震观测在地球自由振荡，震源物理面波理论地震图合成及非均匀地球介质结构研究中的应用。同时结合１９８９年５月６日发生在秘鲁的Ｍｓ７．０地震，介绍了利用简正振型资料开发地震矩张量反演     

星载合成孔径雷达海洋遥感与大数据

星载合成孔径雷达以其全天候、全天时、不受云雨影响的工作特性在空间对海观测中起到了重要作用，又以其高空间分辨率、多极化、多成像模式的特点展示了其在海洋动力要素反演和海洋多尺度动力过程研究中独特的魅力.起步于20世纪70年代末的星载合成孔径雷达技术，迎来了发展的"黄金时期"，大数据和机器学习又赋予了星载合成孔径雷达海洋遥感更强大的生命力.本文首先阐述了星载合成孔径雷达大数据的5"V"特性，进而以高分辨率海面风场反演、海洋内波中尺度动力过程观测两类典型案例，阐述了大数据、机器学习等现代信息科学技术与卫星海洋遥感结合，实现海洋环境参数高精度反演和海洋动力过程科学深层次认知的研究.最后，展望了星载合成孔径雷达海洋遥感与大数据的发展前景.     

科学大洋钻探中的新技术

大洋钻探诸多科学目标的实现与包括钻探、取芯、测试和海底观测技术在内的各种新技术的开发和革新密不可分。即将开展的IODP计划,将对各种技术提出新的要求。在钻探技术上,将联合使用多平台,以实现区域更广深度更大的钻探作业;在取芯技术上,取样范围更广,从各种岩石取样到地下流体的取样,并要求样品保持原始状态,同时确保获得更高的岩芯采收率;在测试上,要求采用随钻测试技术,以适时地获得地下真实信息;在观测技术上,要求开发各种工具,去除由于钻探造成的扰动,使得各种观测仪器能够进行长期的跟踪观测。     

Using unmanned underwater vehicles as research platforms in coastal ocean studies

The advantages of using unmanned underwater vehicles in coastal ocean studies are emphasized. Two types of representative vehicles, remotely operated vehicle (ROV) and autonomous underwater vehicle (AUV) from University of South Florida, are discussed. Two individual modular sensor packages designed and tested for these platforms and field measurement results are also presented. The bottom classification and albedo package, BCAP, provides fast and accurate estimates of bottom albedos, along with other parameters such as in-water remote sensing reflectance. The real-time ocean bottom optical topographer, ROBOT, reveals high-resolution 3-dimentional bottom topography for target identification. Field data and results from recent Coastal Benthic Optical Properties field campaign, 1999 and 2000, are presented. Advantages and limitations of these vehicles and applications of modular sensor packages are compared and discussed.     

La prévision du climat : de l'échelle saisonnière à l'échelle décennale

The atmosphere and the ocean are subject to many dynamical instabilities, which limit the time during which their behaviour can be deterministically forecasted. At longer timescales, the atmosphere can be predicted at best using statistical methods, as a response to external forcing linked to sea- and land-surface anomalies. Climate being defined as the mean of atmospheric states, it appears that it can be predicted up to a few months in advance, which is the characteristic time of the so-called slow components of the climate system. Forecasting can sometimes be extended to longer time ranges, especially when the coupled ocean–atmosphere system exhibits internal variability modes, with characteristic times of a few years. Seasonal climate forecasting is most often based upon Monte-Carlo simulations, where the various realisations correspond to slightly different initial conditions. The present sate-of-the-art in Europe (ECMWF) and/or in the USA (IRI) allows to forecast such major phenomena, as El Niño, up to six months in advance. Finally, some parameters may exhibit predictability at still longer time-ranges (inter-annual to decadal), but only for certain regions. The example of electricity production is used to underline the potentially large economical benefit of seasonal climate forecasting. To cite this article: J.-C. André et al., C. R. Geoscience 334 (2002) 1115–1127.

Résumé

L'atmosphère et l'océan sont le siège d'instabilités dynamiques, qui limitent la durée pendant laquelle il est possible d'en prévoir l'évolution de façon déterministe. Au-delà, l'atmosphère n'est plus prévisible, au mieux, que de façon statistique, en fonction du forçage externe qu'exerce(nt) sur elle l'océan et/ou la surface des continents. Le climat (au sens d'une moyenne des états atmosphériques) se révèle ainsi prévisible jusqu'à des échéances temporelles de quelques mois, échelle de temps caractéristique des composantes dites « lentes » du système climatique. La prévision peut s'étendre à des échéances parfois plus longues, dans le cas où le système couplé océan–atmosphère posséderait des modes de variabilité temporelle de périodes caractéristiques de quelques années. La prévision climatique saisonnière est très souvent construite à partir de simulations de type Monte-Carlo, avec des ensembles de réalisations utilisant des conditions initiales légèrement différentes. Dans l'état actuel de ces prévisions, qu'elles soient réalisées en Europe (CEPMMT) ou aux États-Unis (IRI), il est possible de prévoir environ six mois à l'avance un certain nombre de phénomènes climatiques, en particulier ceux liés aux épisodes dits « El Niño », pour lesquels l'amplitude des variations est suffisamment importante. Il existe, par ailleurs, une prévisibilité à encore plus longue échéance (inter-annuelle à décennale), mais seulement pour certains paramètres et certaines régions. L'exemple de la production d'électricité montre l'importance économique potentielle très grande de la prévision climatique saisonnière. Pour citer cet article : J.-C. André et al., C. R. Geoscience 334 (2002) 1115–1127.     

A study on the nonlinear stability of fronts in the ocean on a sloping continental shelf

1.IntroductionArnol'd(1965,1969)variationalprincipleandapriorestimatemethodisessentiallyageneralizationofLyapunovstabilitymethodforfinite--dimensionaldynamicalsystemsininfinite--dimensionalones,andhestudiedthenonlinearstabilityof2--dimensionalincompressibleidealfluidmotionbyuseofthismethod,andestablishedtwotheoremswhichareArnol,d'sfirsttheoremandArnol'd'ssecondtheorem.Eversincethe1980's,manyscientistshavebeenworkingonthissubject,Holmetal.(1985);MclntyreandShepherd(1987);Zeng(1989);Muetal.(1…