首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:从到   被引次数:从到   他引次数:从到 提示：输入*表示无穷大
全文获取类型
  收费全文   14篇
  免费   0篇
专业分类
地球物理   1篇
地质学   9篇
海洋学   4篇
出版年
  2022年   1篇
  2021年   1篇
  2016年   1篇
  2013年   1篇
  2011年   1篇
  2010年   2篇
  2009年   1篇
  2008年   1篇
  2006年   1篇
  2002年   3篇
  2001年   1篇
排序方式： 共有14条查询结果，搜索用时 109 毫秒
1.
Interpretation of deep 2-D multi-channel seismic data sheds insights into the geological evolution of the West Luzon Basin, Philippines. This basin is a sediment-filled trough that is located between the island of Luzon and the outer arc high of the west Luzon subduction zone. High-amplitude, low-frequency reflection bands mark the acoustic basement. The basement, at about 6 s (TWT), is dissected by normal faults with some of them being inverted in a later phase of deformation. The sedimentary successions, overlying the basement are stratified with partly chaotic structures and discontinuous reflectors. Five regional unconformities separate major stratigraphic units. Grid calculations of our seismic data reveal variations in the sedimentation pattern of the basin with a shift of the deposition centre from east to west and backwards during formation. A distinct bottom-simulating reflector is commonly observed. Because the northern boundary of the continental fragments to the South of the West Luzon Basin is unclear we speculate that the basin may be (partly) underlain by continental crust. The continental crust was affected by rifting prior to and during the opening of the South China Sea and the basin was overprinted at a later stage by a forearc structural setting when subduction was initiated.  相似文献   
2.
The nature and origin of the sediments and crust of the Murray Ridge System and northern Indus Fan are discussed. The uppermost unit consists of Middle Miocene to recent channel–levee complexes typical of submarine fans. This unit is underlain by a second unit composed of hemipelagic to pelagic sediments deposited during the drift phase after the break-up of India–Seychelles–Africa. A predrift sequence of assumed Mesozoic age occurring only as observed above basement ridges is composed of highly consolidated rocks. Different types of the acoustic basement were detected, which reflection seismic pattern, magnetic anomalies and gravity field modeling indicate to be of continental character. The continental crust is extremely thinned in the northern Indus Fan, lacking a typical block-faulted structure. The Indian continent–ocean transition is marked on single MCS profiles by sequences of seaward-dipping reflectors (SDR). In the northwestern Arabian Sea, the Indian plate margin is characterized by several phases of volcanism and deformation revealed from interpretation of multichannel seismic profiles and magnetic anomalies. From this study, thinned continental crust spreads between the northern Murray Ridge System and India underneath the northern Indus Fan.  相似文献   
3.
The tectonic position of the Kamchatka Cape Peninsula at the junction of the active Kuril–Kamchatka and Aleutian arcs exposes the coastline of the peninsula to strong neotectonic activities. Fracture zones have variable influence on uplift of the Kamchatka Cape Peninsula. Relevant morphologic indicators of neotectonic activity are multilevel, highly uplifted marine terraces and terraces displaced along active faults. Recent uplift rates of coastal sediments are determined by remote sensing via ASTER and SRTM DEM combined with optically stimulated luminescence dating (OSL). On the Kamchatka Cape Peninsula, terraces from the same generation are mapped at different elevations by remote sensing methods. After defining different areas of uplifted terraces, four neotectonic blocks are identified. According to apatite fission track data, the mean differential exhumation rates range from 0.2 to 1.2 mm year?1 across the blocks since Late Miocene. The OSL data presented point to significant higher uplift rates of up to 3 ± 0.5 and 4.3 ± 1 mm year?1, which indicates an acceleration of the vertical movement along the coast of Kamchatka Cape Peninsula in Upper Pleistocene and Holocene times.  相似文献   
4.
Based on new multi-channel seismic data, swath bathymetry, and sediment echosounder data we present a model for the interaction between strike-slip faulting and forearc basin evolution off north-western Sumatra between 2°N and 7°N. We examined seismic sequences and sea floor morphology of the Simeulue- and Aceh forearc basins and the adjacent outer arc high. We found that strike-slip faulting has controlled the forearc basin evolution since the Late Miocene. The Mentawai Fault Zone extends up to the north of Simeulue Island and was most probably connected farther northwards to the Sumatran Fault Zone until the end of the Miocene. Since then, this northern branch jumped westwards, initiating the West Andaman Fault in the Aceh area. The connection to the Mentawai Fault Zone is a left-hand step-over. In this transpressional setting the Tuba Ridge developed. We found a right-lateral strike-slip fault running from the conjunction of the West Andaman Fault and the Tuba Ridge in SSW-direction crossing the outer arc high. As a result, extrusion formed a marginal basin north of Simeulue Island which is tilted eastwards by uplift along a thrust fault in the west. The shift of strike-slip movement in the Aceh segment is accompanied by a relocation of the depocenter of the Aceh Basin to the northwest, forming one major Neogene unconformity. The Simeulue Basin bears two major Neogene unconformities, documenting that differences in subsidence evolution along the northern Sumatran margin are linked to both forearc-evolution related to subduction processes and to deformation along major strike-slip faults.  相似文献   
5.
The Nankai Trough located southeast of Shikoku Island, Japan, exhibits a zone of exceptionally high heat flow. In the central part of the Nankai Trough the fossil spreading centre of the Shikoku Basin is subducted beneath the southwest Japan arc. We have modelled the temperature and maturation history along the Muroto Transect reaching from the tip of the thrust zone out into nearly undeformed Quaternary and Tertiary sediments seawards of Nankai Trough. We used two balanced cross-sections defining the sections before and after overthrusting as input for 2D-basin modelling. We can show that rapid burial and overthrusting during the Quaternary in combination with a heat flow history following the cooling curve of a 15 Ma old oceanic plate is not sufficient to explain the measured maturity of organic material in the sediments. Several heat flow scenarios derived from theoretical concepts [Yamano, M., Kinoshita, M., Goto, S., Matsubayashi, O., 2003. Extremely high heat flow anomaly in the middle part of the Nankai Trough. Physics and Chemistry of the Earth, Parts A/B/C 28, 487–497.] and previous modelling approaches [e.g. Brown, K.M., Saffer, D.M., Bekins, B.A., 2001. Smectite diagenesis, pore water freshening, and fluid flow at the toe of the Nankai wedge. Earth and Planetary Science Letters 194, 97–109; Spinelli, G.A., Underwood, M.B., 2005. Modeling thermal history of subducting crust in Nankai Trough: constraints from in situ sediment temperature and diagenetic reaction progress. Geophysical Research Letters 32(L09301): doi:10.1029/2005GL022793; Steurer, J., Underwood, M.B., 2003. Clay mineralogy of mudstones from the Nankai Trough reference sites 1173 and 1177 and frontal accretionary prism site 1174. In: H. Mikada et al. (Eds.), pp. 1–37. Available from: <http://www-odp.tamu.edu/publications/190196SR/VOLUME/CHAPTERS/211.PDF>] were tested. The best match between observed maturity levels, temperature and heat flow measurements is reached for a heat flow history which initially assumes the cooling of a 15 Ma old oceanic lithosphere but is reheated to 170–180 mW/m2 during the phase of rapid burial in the Quaternary. This can be achieved either by assuming the onset of hydrothermal circulation in the cooling crust or by reheating caused by off-axis volcanism at about 6 Ma [Yamano, M., Kinoshita, M., Goto, S., Matsubayashi, O., 2003. Extremely high heat flow anomaly in the middle part of the Nankai Trough. Physics and Chemistry of the Earth, Parts A/B/C 28, 487–497.].  相似文献   
6.
The Indus Fan records the erosion of the western Himalayas and Karakoram since India began to collide with Asia during the Eocene, 50 Ma. Multi-channel seismic reflection data from the northern Arabian Sea correlated to industrial well Indus Marine A-1 on the Pakistan Shelf show that sedimentation patterns are variable through time, reflecting preferential sedimentation in deep water during periods of lower sea-level (e.g., middle Miocene, Pleistocene), the diversion of sediment toward the east following uplift of the Murray Ridge, and the autocyclic switching of fan lobes. Individual channel-levee systems are estimated to have been constructed over periods of 105–106 yr during the Late Miocene. Sediment velocities derived from sonobuoys and multi-channel stacking velocities allow sections to be time-depth converted and then backstripped to calculate sediment budgets through time. The middle Miocene is the period of most rapid accumulation, probably reflecting surface uplift in the source regions and strengthening of the monsoon at that time. Increasing sedimentation during the Pleistocene, after a late Miocene-Pliocene minimum, is apparently caused by faster erosion during intense glaciation. The sediment-unloaded geometry of the basement under the Pakistan Shelf shows a steep gradient, similar to the continent-ocean transition seen at other rifted volcanic margins, with basement depths on the oceanward side indistinguishable from oceanic crust. Consequently we suggest that the continent-ocean transition is located close to the present shelf break, rather than >350 km to the south, as previously proposed.  相似文献   
7.
The Aleutian island arc collides with the Kuril–Kamchatka arc in the area of the Cape Kamchatka peninsula. Field studies of neotectonic structures and apatite fission track analysis provide evidence for crustal plate shortening onshore the Cape Kamchatka peninsula. Tectonic blocks show differential mean exhumation rates varying from 0.18 ± 0.04 mm yr−1 in the north up to 1.2 ± 0.18 mm yr−1 in the south of the peninsula. A few of the fission track length data point to an unsteady exhumation rate. The blocks are separated by major dextral fault zones splaying off from Aleutian island arc fault zones. Across the western segment of the North American–Pacific Plate boundary the strain is partitioned along the fault zones and increases from north to south. Results from this study suggest that indentation and accretion of island arc fragments has recently occurred in the southeastern part of the Cape Kamchatka peninsula.  相似文献   
8.
Submarine landslides can generate local tsunamis with high run-ups, posing a hazard to human lives and coastal facilities. Both ancient (giant Storegga slide off Norwegian coast, 8200 B. P.) and recent (Papua New Guinea, 1998) events show high potential danger of tsunamigenic landslides and the importance of mitigation efforts. This contribution presents newly discovered landslides 70 km off Padang (Western Sumatra, Indonesia) based on recent bathymetry measurements. This highly populated city with over 750,000 inhabitants exhibits high tsunami vulnerability due to its very low elevation. We model tsunamis that might have been induced by the detected landslide events. Estimations of run-up heights extrapolated from offshore tsunami amplitudes for Padang and other locations in the northern Mentawai fore-arc basin yield maximum values of about 3 m. We also provide a systematic parametric study of landslide-induced tsunamis, which allows us to distinguish potentially dangerous scenarios for Padang. Inside the fore-arc basin, scenarios involving volumes of 0.5–25 km³ could endanger Padang. Apart from slide volume, the hazard distribution mainly depends on three landslide parameters: distance to Padang, water depth in the generation region, and slide direction.  相似文献   
9.
Tsukanov  N. V.  Freitag  R.  Gaedicke  C. 《Doklady Earth Sciences》2021,500(1):709-714
Doklady Earth Sciences - New data on the fission track ages of apatite detrital grains from Eocene–Miocene deposits of different ages in the Kronotskii Peninsula and the Tyushevka...  相似文献   
10.
Structural evolution of the Kamchatka–Aleutian junction area in late Mesozoic and Tertiary was generally controlled by (1) the processes of subduction in Kronotskiy and Proto-Kamchatka subduction zones and (2) collision of the Kronotskiy arc against NE Eurasia margin. Two structural zones of the pre-Pliocene age and six structural assemblages are recognized in studied region. 1: Eastern ranges zone comprises SE-vergent thrust folded belt, which evolved in accretionary and collisional setting. Two structural assemblages (ER1 and ER2), developed there, document shortening in the NW–SE direction and in the N–S direction, respectively. 2: Eastern Peninsulas zone generally corresponds to Kronotskiy arc terrane. Four structural assemblages are recognized in this zone. They characterize (1) precollisional deformations in the accretionary wedge (EP1) and in the fore-arc basin and volcanic belt (EP2), and (2) syn-collisional deformation of the entire Kronotskiy terrane in plunging folds (EP3) and deformations in the foreland basin (EP4). Analysis of paleomagnetic declinations versus present day structural strike in the Kronotskiy arc terrane shows that originally the arc was trending from west to east. Relative position of the accretionary wedge, fore-arc basin and volcanic belt, as well as northward dipping thrusts in accretionary wedge indicate, that a northward dipping subduction zone was located south of the arc. The accretionary wedge developed from the Late Cretaceous through the Eocene, and it implies that the subduction zone maintained its direction and position during this time. It implies that Kronotskiy arc was neither a part of the Pacific nor Kula plates and was located on an individual smaller plate, which included the arc and Vetlovka back-arc basin. Motion of the Kronotskiy arc towards Eurasia was connected only with NW-directed subduction at Kamchatka margin since Middle Eocene (42–44 Ma). Emplacement of the Kronotskiy arc at the Kamchatka margin occurred between Late Eocene and Early Miocene. This is based on the age of syn-collisional plunging folds in Kronotskiy terrane, and provenance data for the Upper Eocene to Middle Miocene Tyushevka basin, which indicate in situ evolution of the basin with respect to Kamchatka. Collision was controlled by the common motion of the Kronotskiy arc with Pacific plate towards the northwest, and by the motion of the Eurasian margin towards the south. The latter motion was responsible for the southward deflection of the western part of the Kronotskiy arc (EP3 structures), and for oblique transpressional structures in the collisional belt (ER2 structures).  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号