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41.
James F Ni 《Journal of Earth System Science》1989,98(1):71-89
The Himalayan mountains are a product of the collision between India and Eurasia which began in the Eocene. In the early stage
of continental collision the development of a suture zone between two colliding plates took place. The continued convergence
is accommodated along the suture zone and in the back-arc region. Further convergence results in intracrustal megathrust within
the leading edge of the advancing Indian plate. In the Himalaya this stage is characterized by the intense uplift of the High
Himalaya, the development of the Tibetan Plateau and the breaking-up of the central and eastern Asian continent. Although
numerous models for the evolution of the Himalaya have been proposed, the available geological and geophysical data are consistent
with an underthrusting model in which the Indian continental lithosphere underthrusts beneath the Himalaya and southern Tibet.
Reflection profiles across the entire Himalaya and Tibet are needed to prove the existence of such underthrusting. Geodetic
surveys across the High Himalaya are needed to determine the present state of the MCT as well as the rate of uplift and shortening
within the Himalaya. Paleoseismicity studies are necessary to resolve the temporal and spatial patterns of major earthquake
faulting along the segmented Himalayan mountains. 相似文献
42.
根据对恒河盆地西部的多振型宽频带面波频散资料的分析推断,该区的地壳结构不具有大陆地盾的特征,相反,却非常象某些海洋高地。这一异常的海洋型地壳与恒河盆地东部地盾地壳的分界线可能在阿拉瓦利山脉(Aravalli Ridge)。该处地壳的地质特征具有异常高的电导率,其走向垂直于喜马拉雅山脉。目前广为接受的假定认为是构造均匀的印度大陆岩石圈向喜马拉雅山下俯冲。本文的研究结果对此观点提出了置疑:在北部印度大陆内的地壳运动可能存在着差异。我们追溯印度-欧亚大陆的碰撞历史,这个因素恐怕是不容忽视的。 相似文献
43.
The sedimentary cycles of the Cenomanian to Maastrichtian were investigated in the Basco-Cantabrian Basin (BCB) in northern Spain (Provinces of Alava, Vizcaya and Burgos). The depositional area was a distally steepened carbonate ramp which extended from Catalonia northwestwards to the Basque country. The investigated sediments range from calciturbidites and pelagic marls to marl-limestone alternations deposited on a distal carbonate ramp. Shallow marine limestones, marls and intertidal clastics and carbonates were deposited on the proximal part of the carbonate ramp. The establishment of a regional sequence analysis is based on the investigation of seismic profiles, well logs and outcrop sections. Examples of outcrop sections are interpreted in terms of sequence stratigraphy (unconformities of third- and second-order cycles, depositional geometries, systems tracts). The sequence stratigraphic interpretation of outcrop sections is based on facies analysis, interpretation of observed depositional geometries and correlation of unconformities and marine flooding surfaces through the basin. A biostratigraphic framework is established based on ammonites, inoceramids, planktonic and benthic foraminifera. As a result, a regional sequence stratigraphic cycle chart is presented and compared with published global cycle charts. The correlation of the regional cycle chart with published cycle charts is good. In the Cenomanian and Turonian, several sequence boundaries in the BCB are shifted by up to one biozone compared with the global chart. Some type 1 boundaries of the standard chart are only type 2 in the BCB. Important type 1 boundaries in the BCB are: top Geslinianum Zone with a 100 m lowstand wedge at the basis of the sequence (sequence boundary 92.2) ; base Petrocoriense Zone with a 250 m shallowing-upwards lowstand wedge at the basis (sequence boundary 89.2); and within the Syrtale Zone (sequence boundary 85.0).The Campanian-Maastrichtian sequence record is strongly disturbed by local compressive tectonics. Several sequences are recognizable and can be correlated with the global cycle chart. Correlation is hampered by the low biostratigraphic resolution in the western basin part. Subsidence analysis of several sections of the Upper Cretaceous of the BCB and its interpretation in the regional tectonic context leads to a discussion of the causes of the observed cyclicity. A regional eustatic curve is presented for the Upper Cretaceous of the BCB. Stage and substage names were used according Code-Committee (1977).
Correspondence to: K.-U. Gräfe 相似文献
44.
侏罗纪时东南亚大陆上形成两个大盆地,西为海相盆地,东为陆相红盆。白垩纪时大盆地闭合或解体。第三纪出现裂谷盆地,其发育受燕山期构造格局控制;拉张应力自南向北变弱,裂谷发育自南向北变晚。第四纪为上叠盆地阶段。滇西与泰国各时期盆地的对比研究有助于更好地认识其演化特征,恢复东南亚大陆侏罗纪以来不断碎裂、局部解体的历史。 相似文献
45.
内陆表海聚煤盆地的曾想到处分析 总被引:14,自引:0,他引:14
在华北石炭二叠纪内陆表海聚煤盆地,海侵的突发性和事件性,泥炭沼泽化的广泛性和等时性,是划分其层序内部构成单元的良好界面。研究表明,华北石炭二叠纪内陆表海聚煤盆地的层序结构为“二元结构型”,即“海侵-高位”,缺少低位体系域。海侵体系域由1~2个小层序构成,而高位体系域由小层序构成。体系域恰与小层序组对应,海侵小层序组表现为弱退积-加积型,而高位体系域则表现为弱进积-加积型。小层序为高精度的岩相古地理编图单位,它为解析层序格架和煤聚积规律提供了最可靠的依据。 相似文献
46.
Ammonite biostratigraphy plays a central role in the definition of Jurassic stratigraphy. Nevertheless, the strong provincialism
of European ammonite species during the Kimmeridgian is a long-standing problem in correlation attempts between the boreal
and Tethyan faunal realms. Moreover, the sequence-stratigraphic interpretations for northern and southern Europe given in
the Jurassic chronostratigraphic chart of Hardenbol et al. in SEPM Publ. 60 (chart) (1998) are different. The present study
aims to resolve this correlation problem in order to better understand the connections between the boreal and the Tethyan
realms during the Kimmeridgian. A sedimentological and high-resolution sequence-stratigraphic interpretation is presented
for two unpublished sections (Cras d’Hermont and Roche de Mars) in the northern Swiss Jura, where recently discovered ammonites
display both boreal and Tethyan influences. Then, these sections are correlated with the same time interval in the central
Swiss Jura and Vocontian Basin, which belong to the Tethyan realm. Lastly, a long-distance transect is constructed between
the Vocontian Basin, Swiss Jura, northern France, and southern England, the last two areas being part of the sub-boreal realm.
The main results of this work are that: (1) third-order depositional sequences, and also higher-frequency sequences, can be
correlated from the Tethyan to the boreal realm; (2) the sequence-stratigraphic interpretation given by Hardenbol et al. in
SEPM Publ 60 (chart) (1998) for northern Europe seems to be accurate and agrees with the sequence-stratigraphic framework established in the Swiss Jura;
(3) the Late Kimmeridgian of the Swiss Jura displays boreal influences; (4) integrated high-resolution sequence-stratigraphic
and cyclostratigraphic studies are a valuable approach for bridging the correlation gap between northern and southern Europe. 相似文献
47.
48.
49.
根据该地褶皱形态、断裂特征、应力场分布等资料研究,指出马边~永善及其两侧的构造形迹自西而东有一个相应强~弱变化过程。推测其力源主要来自西部喜马拉雅构造域的侧向推挤,所形成的马边-永善地震带是处于马边-昭通-曲靖断裂构造带的一部分,从而成为川西经向构造带的东部边界,也是青藏高原东南边缘与四川盆地西南边缘的浅部界线 相似文献
50.
刘宝珺 余光明 徐强 G. Einsele W. Frisch 刘光华 J. Wendt A. Wetzel L. Ratschbacher H. P. Luterbacher 《沉积与特提斯地质》1993,(1):32-49
通过对喜马拉雅三叠纪到第三纪区域沉积特征分析,阐明了雅鲁藏布喜马拉雅特提斯造山带从裂谷—被动大陆边缘—前陆盆地的沉积盆地演化史。随着以雅鲁藏布带为代表的喜马拉雅特提斯打开,三叠纪到早侏罗世为特提斯早期裂开的大陆边缘裂谷盆地。早期裂谷中心部位不是现在大陆缝合线的雅鲁藏布一带,而在低分水岭带。晚侏罗世到早白垩世,雅鲁藏布江南测为典型被动大陆边缘,其沉积盆地沉降、海平面变化与沉积作用相吻合。晚白垩世到第三纪为前陆盆地演化阶段,从沉积作用可以识别出晚白垩世晚期为造山第一暮,第三纪初为第二幕。 相似文献