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1.
中国1∶100万景观生态制图设计 总被引:5,自引:0,他引:5
中国1∶100万景观生态图系借鉴国内外传统景观制图方法和制图规范,在遥感、地理信息系统先进技术的支持下,设计研制其制图方法、制图内容、样图和技术流程,同时提出初步的景观分类系统,为今后编制中国1∶100万景观生态图奠定基础。 相似文献
2.
In the Northern Serre (S. Italy), a continuous section through a former lower continental crust is exposed (Schenk 1984, 1985). These granulite facies rocks have not been penetratively deformed during their uplift to higher crustal levels. Therefore, they allow to study the structural state of the lower continental crust. Most rockforming minerals, among them ortho- and clinopyroxene and cordierite, show recrystallization structures. Quarz basal subgrain boundaries are developed in lower levels of the lower crust and disappear toward higher levels. In addition to dimensional orientations of the rockforming minerals, the preferred crystallographic orientations of plagioclases, cordierite, amphibole, pyroxenes and, rarely, quartz reflect the strain orientation of the prograde high-T deformation. During this deformation, the stretching direction was constant NNE-SSW throughout the exposed lower crustal section. Shear indicators are rare. This points to the fact that deformation has been homogeneous and coaxial flattening. There is only a small variation in orientation and strength of textures throughout the exposed lower crust. Therefore, neighbouring layers of different composition rather than different deformation might serve as seismic reflectors in the former lower crust.
Zusammenfassung In der nördlichen Serre (Süditalien) ist ein zusammenhängender Bereich einer ehemaligen kontinentalen Unterkruste aufgeschlossen (Schenk 1984, 1985). Diese granulitfaziellen Gesteine sind bei ihrem Aufstieg in höhere Krustenbereiche nicht durchgreifend überprägt worden. Deshalb läßt sich an ihnen noch der strukturelle Zustand der ehemaligen Unterkruste studieren. Außer in Feldspäten, Quarz und Amphibol tritt auch in Ortho- und Klinopyroxen und in Cordierit Rekristallisation auf. In tieferen Krustenniveaus sind im Quarz basisparallele Subkorngrenzen entwickelt, die in höheren Krustenbereichen nicht auftreten. Sowohl die Gestaltregelungen der gesteinsbildenden Minerale als auch die kristallographischen Plagioklas-, Cordierit-, Amphibol-, Pyroxen- und (seltener) Quarzregelungen spiegeln die Strain-orientierung der prograden hochtemperierten Deformation wider. Während dieser Deformation blieb die Streckung im gesamten Unterkrustenbereich konstant NNE-SSW orientiert. Scherindikatoren sind selten. Beides deutet darauf hin, daß die Deformation homogen und als koachsiale Plättung abgelaufen ist. Im gesamten aufgeschlossenen Unterkrustenbereich variieren weder Intensität noch Orientierung der kristallographischen und gestaltlichen Regelungen der gesteinsbildenden Minerale wesentlich. Deshalb sollten in der ehemaligen Unterkruste Lagen unterschiedlicher Deformation weniger als seismische Reflektoren in Frage kommen als Lagen unterschiedlicher Zusammensetzung.
Résumé Le Massif de la Serre Septentrionale en Calabre (Sud de l'Italie) représente un tronçon d'une ancienne croûte continentale profonde (Schenk 1984, 1985). Les roches du faciès granulite qui le constituent n'ont pas subi de déformation penetrative lors de leur ascension dans les niveaux plus superficiels de la croûte. Leur étude permet donc de reconstruire les caractéristiques structurales de l'ancienne croûte profonde. Non seulement les feldspaths, le quartz et l'amphibole, mais encore l'orthopyroxène, le clinopyroxène et la cordiérite ont recristallisé. Dans les niveaux les plus profonds de la croûte on observe dans les cristaux de quartz des bordures de sous-grains parallèles à la base. Celles-ci n'apparaissent plus dans les niveaux plus superficiels. L'orientation des cristaux des minéraux constitutifs des roches, de même que l'orientation des réseaux cristallins du plagioclase, de la cordiérite, de l'amphibole, du pyroxène et (mais plus rarement) du quartz réflètent la direction de contrainte de la phase de déformation prograde de haute température. Pendant cette phase de déformation, la direction d'extension est demeurée NNE-SSW. Les témoins de cisaillement sont rares, ce qui montre que la déformation s'est effectuée de façon homogène, en relation avec un aplatissement coaxial. Les textures varient très peu en orientation comme en intensité dans toute la coupe de croûte profonde exposée. En conséquence, l'existence de réflecteurs sismiques devrait refléter des différences dans les compositions minéralogiques des roches plutôt que dans leurs caractéristiques structurales.
Serre (Schenk, 1984, 1985). . . , , . , , . , , , , () . NNE-SSW. . , . , , . , , .相似文献
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4.
The underwater acoustic image transmission system based on the high-speed DSP device TMS320C549 has been studied.We use Goertzel algorithm for source decoding and MFSK for modulation.Turbo code is used for channel coding and decoding.The purpose is to implement underwater video image data transmission. 相似文献
5.
重力异常垂向一阶导数的一种简便算法 总被引:1,自引:0,他引:1
利用拉格朗日插值导出了重力异常垂向一阶导数的计算公式,给出了地面以及地面之上不同高度的求导系数。该公式可以计算地面上的重力垂向一阶导数,还可以直接计算地面之上任意高度上的垂向一阶导数。鉴于该公式除系数不同外,与上延公式完全相同,因此,程序设计尤为简单。使用本公式对模型数据和实际资料进行了处理,证明了本算法的实用性。 相似文献
6.
Origin of ore fluids in the Muruntau gold system: Constraints from noble gas, carbon isotope and halogen data 总被引:6,自引:0,他引:6
Torsten Graupner Samuel Niedermann Reiner Klemd Achim Bechtel 《Geochimica et cosmochimica acta》2006,70(21):5356-5370
Hydrothermal vein minerals directly associated with native gold mineralization in the Muruntau vein system (Uzbekistan) have been studied for noble gas, carbon isotope and halogen chemistry of the trapped ore-related fluids. Helium trapped in early arsenopyrite 1, which has preserved the original fluid signature better than associated scheelite and quartz, indicates a small input from a mantle source (?5% of total He). However, the overwhelming majority of the He in the fluid (∼95%) is from crustal sources. The noble gases Ne, Kr and Xe in the sample fluids are dominated by gases of atmospheric origin. The carbon isotope (δ13C: −2.1‰ to −5.3‰) and halogen characteristics of the fluids (log Br/Cl: −2.64 to −3.23) lend further support for the activity of juvenile fluids during the main ore stage. The high proportion of crustal components in the ore-forming fluids may be explained by intense fluid-rock interaction and is also supported by previous Nd and Sr isotope studies. The involvement of a juvenile fluid component during the main stage of hydrothermal activity at Muruntau (∼275 Ma) can be linked to the emplacement of lamprophyric dikes at Muruntau, due to apparently overlapping ages for high-temperature alteration, related ore vein formation and intrusion of the dikes. The input of mantle-derived fluids, possibly related to the Hercynian collisional event in the western Tien Shan, stimulated intense fluid-rock interaction in the crust. In this context, the mantle-derived fluid should be considered as one possible carrier of metals. Significant amounts of external meteoric fluids circulating in fracture systems are interpreted to have modified the noble gas signature of fluid in quartz, mostly during late, low temperature fluid circulation. 相似文献
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8.
GIS与土壤溶质运移模型结合研究进展 总被引:4,自引:2,他引:4
地理信息系统对土壤溶质模型研究而言,使用者的要求与GIS所能提供的功能之间,还存在巨大的差距。出于对环境问题的关注,土壤中水分及溶质运移的规律及其对环境的影响,成为当前研究的热点。随着对土壤溶质运移模型研究的深入,一方面由于田间土壤特性具有很大的空间变异;另一方面,在实际应用中,往往溶质运移的宏观特征而非微观特征,具有更重要的意义。将溶质运移模型与GIS技术结合,定量研究空间尺度的溶质运移,成为溶质运移研究的必然发展趋势。由于计算机软硬件技术的发展,GIS正处于一个高速发展的时期。将GIS与溶质运移模型相结合,或者进一步,以GIS理论和技术为基础,建立基于GIS的溶质运移模型,将对溶质运移的规律及其对环境的影响,做出更深入和准确的描述。 相似文献
9.
Wolfgang H. Berger Memorie K. Yasuda Torsten Bickert Gerold Wefer 《International Journal of Earth Sciences》1996,85(3):466-495
We provide a reconstruction of atmospheric CO2 from deep-sea sediments, for the past 625000 years (Milankovitch chron). Our database consists of a Milankovitch template
of sea-level variation in combination with a unique data set for the deep-sea record for Ontong Java plateau in the western
equatorial Pacific. We redate the Vostok ice-core data of Barnola et al. (1987). To make the reconstructions we employ multiple
regression between deep-sea data, on one hand, and ice-core CO2 data in Antarctica, on the other. The patterns of correlation suggest that the main factors controlling atmospheric CO2 can be described as a combination of sea-level state and sea-level change. For best results squared values of state and change
are used. The square-of-sea-level rule agrees with the concept that shelf processes are important modulators of atmospheric
CO2 (e.g., budgets of shelf organic carbon and shelf carbonate, nitrate reduction). The square-of-change rule implies that, on
short timescales, any major disturbance of the system results in a temporary rise in atmospheric CO2. 相似文献
10.
Juergen Neumeyer Jan Hagedoorn Jens Leitloff Torsten Schmidt 《Journal of Geodynamics》2004,38(3-5):437
The redistribution of air masses induces gravity variations (atmospheric pressure effect) up to about 20 μgal. These variations are disturbing signals in gravity records and they must be removed very carefully for detecting weak gravity signals. In the past, different methods have been developed for modelling of the atmospheric pressure effect. These methods use local or two-dimensional (2D) surface atmospheric pressure data and a standard height-dependent air density distribution. The atmospheric pressure effect is consisting of the elastic deformation and attraction term. The deformation term can be well modelled with 2D surface atmospheric pressure data, for instance with the Green's function method. For modelling of the attraction term, three-dimensional (3D) data are required. Results with 2D data are insufficient.From European Centre for Medium-Range Weather Forecasts (ECMWF) 3D atmospheric pressure data are now available. The ECMWF data used here are characterised by a spacing of Δ and Δλ = 0.5°, 60 pressure levels up to a height of 60 km and an interval of 6 h. These data are used for modelling of the atmospheric attraction term. Two attraction models have been developed based on the point mass attraction of air segments and the gravity potential of the air masses. The modelling shows a surface pressure-independent part of gravity variations induced by mass redistribution of the atmosphere in the order of some μgal. This part can only be determined by using 3D atmospheric pressure data. It has been calculated for the Vienna Superconducting Gravimeter site.From this follows that the gravity reduction can be improved by applying the 3D atmospheric attraction model for analysing long-periodic tidal waves including the polar tide. The same improvement is expected for reduction of long-term absolute gravity measurements or comparison of gravity measurements at different seasonal times. By using 3D atmospheric pressure data, the gravity correction can be improved up to some μgal. 相似文献