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431.
The Mottled Zone(MZ) or Hatrurim Formation,which occurs near the Levantine Transform in the South Levant,has been studied during the last 150 years but its origin remains debatable.Mottled Zone Complex/Complexes(MZC/MZCs) consist of brecciated carbonate and low-temperature calcium-hydro-silicate rocks,which include unusual high- and ultra-high-temperature low-pressure(HT-LP) meta-morphic mineral assemblages.The MZ has been regarded as a product of combustion of bituminous chalks of the Ghareb Fm.of Cretaceous(Maastrichtian) age.In this paper we present detailed geographic, geomorphologic,structural and geological data from the MZCs of the South Levant,which show that the MZCs cannot be stratigraphically correlated with the Ghareb Fm.,because MZC late Oligocene-late Pleistocene deposits occur within or unconformable i.e.,with stratigraphic hiatus,overlap both the late Cretaceous and,in places,Neogene stratigraphic units.We propose an alternative model for the formation of MZCs by tectonically induced mud volcanism during late Oligocene-late Pleistocene time. This model explains(i) the presence of dikes and tube-like bodies,which consist of brecciated exotic clastic material derived from stratigraphically and hypsometrically lower horizons;(ii) mineral assemblages of sanidinite facies metamorphism;(iii) multi-stage character of HT-LP pyrometamorphism;and (iv) multi-stage low-temperature hydrothermal alteration.High temperatures(up to 1500℃) mineral assemblages resulted from combustion of hydrocarbon gases of mud volcanoes.Mud volcanism was spatially and structurally related to neotectonic folds and deformation zones formed in response to opening of the Red Sea rift and propagation of the Levantine Transform Fault.Our model may significantly change the prospects for oil-and-gas deposits in the region.  相似文献   
432.
Unmanned aerial systems (UASs) are widely used for remote sensing, including the production of high‐resolution digital elevation models (DEMs). We study the possibilities of UAS‐based aerial surveys to produce photogrammetrically sound, high‐resolution DEMs intended for geomorphometric modeling. The study was conducted at the Zaoksky testing ground (Russia). To carry out an aerial survey, we used a UAS Geoscan‐101 equipped with a Sony DSC‐RX1 camera and a Topcon GNSS receiver. Aerial photographs were processed using Agisoft PhotoScan Professional software. Applying dense point cloud generation and classification, we produced DEMs with resolutions of 6 cm, 20 cm, and 1 m. Using a universal spectral analytical method, we derived models of several morphometric variables (i.e., slope gradient, horizontal, vertical, minimal, and maximal curvatures) from DEMs with resolutions of 20 cm and 1 m. We found that it is possible to produce noiseless models and well‐readable maps of morphometric variables for grassy areas with separately standing groups of trees and shrubs. However, UAS‐based DEMs cannot be applied for modeling of forested areas: there occur pronounced unrecoverable artifacts due to errors of automated classification of the dense point cloud. Finally, we present recommendations for the production of UAS‐derived, photogrammetrically sound, high‐resolution DEMs intended for geomorphometry.  相似文献   
433.
Mineralogy and Petrology - A new mineral hermannjahnite, ideally CuZn(SO4)2, was found in the sublimates of Saranchinaitovaya fumarole, Naboko scoria cone, where the recent Fissure Tolbachik...  相似文献   
434.
The island of Korčula, which has an area of 271.47 km2 is located along the north-eastern coast of the Adriatic Sea. Due to the Mediterranean climate, size and karst geology its water resources are very scarce. This paper describes the natural features of the island (air temperature, precipitation, geology, hydrogeology and groundwater) which are important for the water appearance and its distribution in time and space. The water supply of the island has been managed in the following ways: through a pipeline from the mainland, by drawing groundwater and by rain harvesting. Tourism causes high seasonal water needs which are barely met by the existing water supply system. Therefore, present water resource management on the island must be improved. The paper also presents mathematical programming scheme to get optimal costs and benefits of water exploitation on the island. Besides economic aspect, linear programming is applied to social and ecological objectives, as well. This study suggests that island’s water management should be primarily based on wisely using its proper water resources.  相似文献   
435.
Differentiation between benthic habitats, particularly seagrass and macroalgae, using satellite data is complicated because of water column effects plus the presence of chlorophyll-a in both seagrass and algae that result in similar spectral patterns. Hyperspectral imager for the coastal ocean data over the Indian River Lagoon, Florida, USA, was used to develop two benthic classification models, SlopeRED and SlopeNIR. Their performance was compared with iterative self-organizing data analysis technique and spectral angle mapping classification methods. The slope models provided greater overall accuracies (63–64%) and were able to distinguish between seagrass and macroalgae substrates more accurately compared to the results obtained using the other classifications methods.  相似文献   
436.
The negative effective magnetic-pressure instability operates on scales encompassing many turbulent eddies, which correspond to convection cells in the Sun. This instability is discussed here in connection with the formation of active regions near the surface layers of the Sun. This instability is related to the negative contribution of turbulence to the mean magnetic pressure that causes the formation of large-scale magnetic structures. For an isothermal layer, direct numerical simulations and mean-field simulations of this phenomenon are shown to agree in many details, for example the onset of the instability occurs at the same depth. This depth increases with increasing field strength, such that the growth rate of this instability is independent of the field strength, provided the magnetic structures are fully contained within the domain. A linear stability analysis is shown to support this finding. The instability also leads to a redistribution of turbulent intensity and gas pressure that could provide direct observational signatures.  相似文献   
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