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The Makran accretionary wedge has a much larger number of mud volcanoes then those reported earlier. Using high-resolution satellite images, over 70 active mud volcanoes were identified. These mud volcanoes occur within a well-defined zone; we call it the Makran zone of active mud volcanoes (MZAMV), which is parallel to the regional trend of the accretionary wedge. Mud volcanoes within the zone occur as clusters, which form linear belts parallel to the regional thrusts associated with anticlines. The MZAMV zone also includes the offshore mud volcanoes occurring in the shallow shelf area, including the recurrently emerging mud islands. Several occurrences of thick deposits of old mud volcanoes (Pleistocene or even older) are also present within this zone, which also display recognizable features that are characteristic of the fossil mud volcanoes. We propose that the MZAMV developed and evolved in response to the continued compression within the Makran accretionary wedge, which in turn, is a response of the subduction process. Mud diapirism has been an ongoing phenomena since Pleistocene or even earlier. The events of enhanced mud extrusion in mud volcanoes and/or emergence of island(s) have relevance with seismic phenomena and, therefore, may be closely monitored.  相似文献   
2.
The use of natural coagulant protein in drinking water treatment has been discussed for a long time, though the method is still not in practice, probably due to limited knowledge and availability of material. In the present work, different Mustard varieties were tested for the presence of coagulant protein compared with Moringa seed extract and their potential application in water treatment. The coagulation activity of the protein extract was measured using synthetic clay solution as well as water from pond. The protein content was determined by Bradford method, molecular mass determined by Sodium dodecyl sulfate–polyacrylamide gel electrophoresis, and peptide sequence was analyzed by Mass spectrometry. Extract of Mustard (large) and Moringa seed showed coagulation activity of ?70 and ?85 % after 90 min, respectively. Interestingly, seed extracts from other Mustard varieties had coagulation activity after heat activation at 95 °C for 5 h. However, the coagulation activity of Mustard seed extract against turbid pond water was higher (?60 %) compared to Moringa seed extract (?50 %). The peptide sequence analysis of 6.5 and 9 kDa proteins was found to be homologous to Moringa coagulant protein and napin3, respectively. To our knowledge, this could be the first report on Mustard seed having coagulant protein. The coagulation activity of Mustard (large) against highly turbid pond water suggested that it could be a potential natural coagulant for water treatment.  相似文献   
3.
Chlorophyll-a (Chl-a) and Suspended Solid Concentration (SSC) shows the productivity of water and their surrounding environment. These parameters can be effectively estimated through several remote sensing techniques. From the recent reports on the Gulf of Thailand, it is found that Chl-a and SSC are increasing in coastal areas due to changing environment caused by variations in the global carbon cycle, climate change and water pollution linking to anthropogenic conditions such as high population density and rapid urbanization in neighbouring coastal areas deteriorating the coastal and marine environment. Various models are evaluated in this study for estimation of marine Chl-a and SSC by employing Ocean Colour Monitor-2 sensor of Oceansat-2 satellite for Northern Gulf of Thailand. The retrieval of Chl-a and SSC by the atmospheric correction of visible bands from 400 to 700 nm to attain normalized water-leaving radiances and then a suitable algorithm is applied. The In-situ reflectance values of sea waters are measured using the ASD spectroradiometer. The reflectance values of the spectroradiometer are correlated for the same day atmospherically corrected satellite reflectance and the analysis offers high correlation R2 0.73. Satellite derived, Chl-a and SSC are correlated with observed in situ Chl-a and SSC. This analysis offered better correlation of R2 0.86 and 0.85 respectively with the algorithms of Chl-a and SSC.  相似文献   
4.
Since 1960, many gravity studies have been carried out in the Yagoua region of northern Cameroon. Gravity data was collected over a wide area of approximately 11628 km2. These data are insufficient, irregular, scattered and do not efficiently permit gravity field downward and upward continuations, derivatives and other operations that might require regular gridded data. Some anomalies on the Collignon map (1968), may correlate with known geological structure but do not appear on maps by Louis (1970) and Poudjom et al. (1996). To produce regular gridded gravity data and better control anomalies due to geological structures, the kriging method was applied to a 188-data baseline. Several variogram models were tested for this purpose. It was found that a spherical variogram model is the best; it has produced a new kriging dataset of about 10,100 data and a new map of kriged Bouguer data. This map contains positive anomalies in the Maroua-Mindif and Maga areas on the Collignon (1968) map, which were not present on Louis (1970) and Poudjom et al. (1996) maps. The positive anomalies of Guibi-Doukoula and Yagoua, not separated on the Louis (1970) and Poudjom et al. (1996) maps, show up as clearly distinct as previewed by Collignon (1968). The new results can be used for subsequent gravimetric studies.  相似文献   
5.
The Maastrichtian Pab Formation in the southern part of Pakistan is composed of fine- to very coarse-grained texturally mature quartz arenite and subordinate sublitharenite varieties. The sandstones have undergone intense and complex diagenetic episodes due to burial and uplift. Diagenetic modifications were dependent mainly on the clastic composition of sandstone, burial depth and thrust tectonics. Diagenetic events identified include compaction, precipitation of calcite, quartz, clay minerals and iron oxide/hydroxide, dissolution and alteration of unstable clastic grains as feldspar and volcaniclithic fragments as well as tectonically induced grain fracturing. The unstable clastic grains like feldspar and lithic volcanic fragments suffered considerable alteration to kaolinite and chlorite. Dissolution and alteration of feldspar and volcanic lithic fragments and pressure solution were the main sources of quartz cements. Mechanical compaction and authigenic cements like calcite, quartz and iron oxide/hydroxide reduced the primary porosity, whereas dissolution of clastic grains and cements has produced secondary porosity. Chlorite coatings on clastic grains have prevented quartz cementation. Coarse-grained, thick bedded packages of fluviodeltaic, shelf delta lobe and submarine channels facies have higher average porosity than fine-grained, thin bedded and bioturbated sandstone of deeper shelf and abyssal plain environments and these facies are concluded to be possible future hydrocarbon prospects.  相似文献   
6.
Recurring emergences of mud islands on shelf of the Arabian Sea, along the Makran coast of Pakistan are now known to be submarine mud volcanoes. They are expressions of enhanced extrusions of fluidized mud and gases coupled with compressional tectonics in convergent margin settings. Since 1945 the Malan island has emerged four times, and some other mud islands have also been emerging repeatedly, at their own positions.The first known emergence, during November 1945, was concurrent with an earthquake of magnitude 8.0 (M8.0), the 2nd and 3rd emergences, in March 1999 and November 2010 respectively, were not related apparently with earthquakes. The 4th emergence concurred with the Awaran earthquake (M7.7) of 24th September 2013. Landsat images of March 1999 and November 2010 emergences indicate appearance of round-shaped island of 4.4 and 5.2 hectare area, followed by erosion and disappearance. The island was composed of mud breccias and circular vents spewing mud slurry and methane gas.The emergence of Malan island, in March 1999 and November 2010 was compared with earthquake data before and after the emergences. The earthquakes data, two years before March 1999 and November 2010 emergences and two years afterwards, shows correlation with both small and large earthquakes, prior to the emergence, in the radius of over 400 km. It is proposed that mud islands develop in response to the episodes of enhanced mud extrusion, which inturn are related with the enhanced compressional and/or seismic events. These events are followed by periods of relative quiescence characterized by normal activity of mud extrusion and marine erosion.  相似文献   
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