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361.
在华北盆地中西部的临城一巨鹿深地震反射剖面上,CDP叠加剖面在双程走时2.5-4.5s部分显示出一系列连续性好、能量强的低角度反射事件,在剖面上显示的延伸距离达40km.这些反射事件解释为滑脱断层,它自西向东倾角变缓,发育在深度为skin(剖面西端)至10km(东端)的结晶基岩中.在剖面的浅部显示出两个相似的单边断陷盆地,其主断裂以铲形归并到这一滑脱构造.上盘在伸展过程中向东滑移,拉张和重力滑动作用可能是形成这些断裂的主要原因.剖面东部的中下地壳内众多的反射事件具有叠层状的特征,并遭受强烈的变形,可能表示地幔物质上涌侵入至地壳内.岩浆侵入在地壳上部形成附加的伸展应力场,同时使下地壳增热,粘度下降,某些矿物发生脱水作用,脱出的水上移并储存于中地壳内.伸展应力场及热和水的作用促进滑脱构造的形成.邢台地震的震源深度分布表明,这一地区脆韧过渡带的深度为10-25km,滑脱面为过渡带的上界面. 相似文献
362.
设计合成一种尚未见文献报道的酚醚型双臂开链冠醚化合物L(L=2,6-二(8’-喹啉氧甲基)-4-甲基-苯甲醚),经元素分析、IR、1HNMR、MS等方法确定了其组成和结构。其Ag(Ⅰ)、Cu(Ⅱ)、Ni(Ⅱ)固体配合物的元素分析结果表明金属离子不同,则其配合物的配位比(M∶L)不同,Ag(Ⅰ)配合物为1∶1,Cu(Ⅱ)、Ni(Ⅱ)配合物为2∶3。并运用热重-差热分析对其热稳定性进行初步研究。 相似文献
363.
364.
Recent deep-towed, high resolution sidescan sonar records and seismic profiles have been collected on the lower Valencia Fan (Northwestern Mediterranean). Three morphological zones, channelled, transition and unchannelled, have been recognized in the Valencia Channel mouth. Sonographs from the transition zone show a progresive transversal gradation from depositional to erosional bedforms. This asymmetry may be due to the lateral inputs of sediment flows from the rhone deep-sea fan and to the effect of the Coriolis force, which could have diverted the flows to the southwest. Bedforms recorded in the study area include trains of starved ripples and dunes, sand ribbons, and fields of elongated scours. Most morphological features, bedforms and seismic characteristics of the Valencia Channel mouth are typical of channel-lobe transition zones. 相似文献
365.
This paper studies the magnetic hysteresis and refrigeration capacity of Ni--Mn--Ga alloys in detail during heating and cooling isothermal magnetisation processes. The Ni--Mn--Ga alloys show larger magnetic hysteresis when they transform from austenite to martensite, but smaller magnetic hysteresis when they transform from martensite to austenite. This behaviour is independent of either the pure Ni--Mn--Ga alloys or the alloys doped with other elements. Because of the existence of the magnetic hysteresis, the relation between the magnetic entropy change and refrigeration capacity is not simply linear. For practical consideration, magnetocaloric effect of Ni--Mn--Ga alloys should be investigated both on cooling and heating processes. 相似文献
366.
367.
论东海陆架盆地玉泉运动 总被引:1,自引:0,他引:1
据地质及地球物理勘探资料,并结合周围邻近盆地的对比研究后提出:(1)目前确定的新玉泉运动,其影响比前人描述的轻微得多;(2)以前所确定的原(老)玉泉运动的活动强度比新玉泉运动强烈得多,不应将原(老)玉泉运动取消,而应将新、老玉泉运动的间隔期视为构造变革过渡期。 相似文献
368.
Andreas Goldschmidt-Rokita Knut J. F. Hansch Hans B. Hirschleber Takaya Iwasaki Toshihiko Kanazawa Hideki Shimamura Markvard A. Sellevoll 《Marine Geophysical Researches》1994,16(3):201-224
The Cenozoic margins of the Norwegian-Greenland Sea offer ideal conditions for passive margin studies. A series of structural elements, first observed on these margins, led to the concept of volcanic passive margins. Questions still remain about the development of such features and the location of the boundary between oceanic and continental crust. Despite the thin sediment cover of the margins, seismic reflection data are not able to image the deeper structures due to the occurrence of igneous rocks at shallow depth.This paper presents a 320-km long profile perpendicular to the strike of the main structural units of the Lofoten Margin in Northern Norway. A geological model is proposed, based on observations made with ocean bottom seismographs, which recorded seismic refraction data and wide angle reflections, along with a seismic reflection profile covering the same area. Ray-tracing was used to calculate a geophysical model from the shelf area into the Lofoten basin. The structures typical of a volcanic passive margin were found, showing that the Lofoten Margin was influenced by increased volcanic activity during its evolution. The ocean/continent transition is located in a 30-km wide zone landwards of the Vøring Plateau escarpment.The whole margin is underlain by a possibly underplated, high velocity layer. Evidence for a pre-rift sediment basin landwards of the escarpment, overlain by basalt flows, was seen. These structural features, related to extensive volcanism on the Lofoten Margin, are not as distinct as further south along the Norwegian Margin. Viewed in the light of the hot-spot theory of White and McKenzie (1989) the Lofoten Margin can be interpreted as a transitional type between volcanic and non-volcanic passive margin. 相似文献
369.
Kevin R. Harris 《The Australian geographer》1995,26(2):189-199
Significant real estate activity by Vietnamese households in Adelaide did not occur until 1979, and since then the groups buying activity has been heavily concentrated in the northwest region of the metropolitan area. Therefore, the median housing price paid by Vietnamese buyers has not kept pace with the median price paid by all buyers. Concentration also causes Vietnamese buyers to be disproportionately active in the middle‐to‐lower end of the market, within which there has been a strong preference for rural properties and for houses rather than home units and maisonettes. Amongst Vietnamese buyers who subsequently sell their properties, the majority have not re‐entered the market and their capital gain from ownership has been marginal. 相似文献
370.
Journal of Geographical Sciences - Energy development has a significant impact on urbanization. This study employs the entropy method to evaluate the level of urbanization in Central Asia and... 相似文献