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31.
YANG Baoliang QIU Longwei YANG Yongqiang Kouassi Louis KRA DONG Daotao Danish KHAN 《《地质学报》英文版》2023,97(2):526-547
Coarse-grained subaqueous fans are vital oil and gas exploration targets in the Bohai Bay basin, China. The insufficient understanding of their sedimentary processes, depositional patterns, and controlling factors restricts efficient exploration and development. Coarse-grained subaqueous fans in the Yong′an area, Dongying Depression, are investigated in this study. These fans include nearshore subaqueous fans, and sublacustrine fans, and their sedimentary processes, depositional patterns and distribution characteristics are mainly controlled by tectonic activity and paleogeomorphology. Nearshore subaqueous fans developed near the boundary fault during the early–middle deposition stage due to strong tectonic activity and large topographic subsidence. Early sublacustrine fans developed at the front of the nearshore subaqueous fans in the area where the topography changed from gentle to steep along the source direction. While the topography was gentle, sublacustrine fans did not develop. During the late weak tectonic activity stage, late sublacustrine fans developed with multiple stages superimposed. Frequent fault activity and related earthquakes steepened the basin margin, and the boundary fault slopes were 25.9°–34°. During the early–middle deposition stage, hyperpycnal flows triggered by outburst floods developed. During the late deposition stage, with weak tectonic activity, seasonal floods triggered hyperpycnal flows, and hybrid event beds developed distally. 相似文献
32.
In the surface sediment samples collected from 7 transects in the continental shelf region off Karaikkal, Parangipettai, Cuddalore-SIPCOT, Cheyyur, Chennai, Tammenapatanam and Singarayakonda in the s... 相似文献
33.
British, German, American and Kenyan seismologists undertook a preliminary crustal seismic programme in the Kenya Rift in the summer of 1985. Thirteen explosions, totalling 7 tonnes, were fired in lakes and boreholes, and were recorded by 42 three-component stations. Preliminary results show that the deep structure along the axis of the Rift is more complex than previous models have suggested. 相似文献
34.
Major part of the Holocene Ganges-Brahmaputra delta occupies the southern and southwestern part of Bangladesh with a smaller
part extending beyond the international boundary in the west. Five facies assemblages are documented in the lower deltaic
plain in five different depositional environments: levee or levee complex, bil or depression, abandoned meander belt, interdistributary
plain and estuarine plain. The thickness of the Holocene sediments ranges from 30 m to 70 m in the deltaic plain, usually
floored by the Pleistocene stiff clays, with the exception of the abandoned meander belt deposit where Holocene channel sand
deposited directly on the Pleistocene sand. Radiocarbon dates indicate that low-rate sedimentation has occurred in the northern
part, where 4-6 m thick sediments were deposited since the mid-Holocene, whereas 10-30 mthick sediments were deposited in
the southern part during the same span of time. In addition, significant coastal subsidence (3 mm/a on average), added by
sea-level rise (1.5 mm/a, conservative rate) occurs in the study area, which serves as a negative factor in degrading the
coastal plain of Bangladesh in the future, while taking into consideration the weaker sedimentation in the area. 相似文献
35.
MALIK AMIN ASLAM KHAN 《Climate Policy》2013,13(2):162-165
The climate change issue faces a big challenge, perhaps the biggest challenge of all—politics. Pakistan has taken many noticeable steps in relation to climate change: (1) it is the only country in which the Prime Minister is heading an inter-ministerial task force on climate change, (2) it is the first developing country to establish a specialized, self-financed scientific centre to research the impact of climate change, and (3) it is the lead country to earmark budgetary funds for a national carbon sequestration programme. Pakistan, together with many developing countries, has much to offer the climate change issues. The author proposes five approaches to build consensus among climate policy negotiators: (1) reinforcing the polluter pays principle and ‘common but differentiated responsibility’, (2) active partnership by developing countries, (3) recognizing the voluntary actions taken by developing countries, (4) reinforcing the issue of adaptation, and (5) considering the option of equal per capita entitlements. 相似文献
36.
Asghar ALI Khaista REHMAN Owais TAYYAB Tahir ZAMAN Mahad JAMEEL Azeem KHAN Rafique AHMAD Muhammad IRFAN 《《地质学报》英文版》2020,94(5):1440-1450
Analysis of the anomalous magnetic mineral intensities and geochemistry for placer gold deposits are presented for those of the Attock area at the confluence of the Indus and Kabul rivers in northwestern Pakistan. Two grids covering an area of 10x18 m2 and 8x10 m2 were analyzed using a G-858 Cesium Vapor Magnetometer. The anomalous zones obtained were plotted on contour maps, 2D and 3D magnetic intensity maps. Based on the magnetic anomalies, grid-1 of the study area was sampled at three different anomalous zones for geochemical analysis. These zones contain gold concentrations, ranging from 2.11 ppm to 6.109 ppm with an average of 4.01 ppm. Increase in gold concentration in the subsurface within the anomalous zones indicates that magnetometer survey followed by a geochemical analysis can potentially narrow down the gold-bearing anomalous zones. 相似文献
37.
Kaleem Ullah Jan KHAN WANG Chang-ming Muhammad Wasim Jan KHAN LIANG Zhu LI Shuo LI Bai-long 《山地科学学报》2021,(6):1696-1709
The slope instability is associated with increasing rate of rainfall infiltration which cause shear strength reduction and suction loss and the slope tend to fa... 相似文献