New methods are presented for processing and interpretation of shallow marine differential magnetic data, including constructing maps of offshore total magnetic anomalies with an extremely high reso- lution of up to 1...New methods are presented for processing and interpretation of shallow marine differential magnetic data, including constructing maps of offshore total magnetic anomalies with an extremely high reso- lution of up to 1-2 nT, mapping weak anomalies of 5-10 nT caused by mineralization effects at the contacts of hydrocarbons with host rocks, estimating depths to upper and lower boundaries of anom- alous magnetic sources, and estimating thickness of magnetic layers and boundaries of tectonic blocks. Horizontal dimensions of tectonic blocks in the so-called ＂seismic gap＂ region in the central Kuril Arc vary from 10 to 100 km, with typical dimensions of 25-30 km. The area of the ＂seismic gap＂ is a zone of intense tectonic activity and recent volcanism. Deep sources causing magnetic anomalies in the area are similar to the ＂magnetic belt＂ near Hokkaido. In the southern and central parts of Barents Sea, tectonic blocks with widths of 30-100 kin, and upper and lower boundaries of magnetic layers ranging from depths of 10 to 5 km and 18 to 30 km are calculated. Models of the magnetic layer underlying the Mezen Basin in an inland part of the White Sea-Barents Sea paleorift indicate depths to the lower boundary of the layer of 12-30 km. Weak local magnetic anomalies of 2-5 nT in the northern and central Caspian Sea were identified using the new methods, and drilling confirms that the anomalies are related to concentrations of hydrocarbon. Two layers causing magnetic anomalies are identified in the northern Caspian Sea from magnetic anomaly spectra. The upper layer lies immediately beneath the sea bottom and the lower layer occurs at depths between 30-40 m and 150-200 m.展开更多
The size determination of dynamical structures from spectral images poses the question where to fix the shape’s boundary. Here, we propose a method, suitable for nearly elliptical shape, based on the fit of a 2D Gaus...The size determination of dynamical structures from spectral images poses the question where to fix the shape’s boundary. Here, we propose a method, suitable for nearly elliptical shape, based on the fit of a 2D Gaussian to the pixel intensities of the spectral image. This method has been tested on a vortex structure embedded in the wake of the 2010 Saturn’s giant storm. On January 4th 2012, the Visual and Infrared Mapping Spectrometer (VIMS), onboard Cassini, observed a giant vortex in the Saturn’s northern hemisphere. The structure was embedded in the wake storm system detected on December 2010 by Fletcher et al. [1]. Therefore, all the VIMS observations focused on the Saturn’s storm have been analyzed to investigate its morphology and development. VIMS detected the vortex from May 2011up to January 2012. The evolution of shape and size has been determined for the vortex cloud top, visible at 890 nm. The largest size resulted 4000 km about and seemed to shrinks continuously up to January 2012, while the shape varied in the second half of the year. The vortex oscillated in 2 degrees latitude around 37°N planetocentric latitude, and drifted in longitude by ~0.75 deg/day in westward direction.展开更多
基金supported by the Russian Fund of Fundamental Research(Grant No.11-05-00280)
文摘New methods are presented for processing and interpretation of shallow marine differential magnetic data, including constructing maps of offshore total magnetic anomalies with an extremely high reso- lution of up to 1-2 nT, mapping weak anomalies of 5-10 nT caused by mineralization effects at the contacts of hydrocarbons with host rocks, estimating depths to upper and lower boundaries of anom- alous magnetic sources, and estimating thickness of magnetic layers and boundaries of tectonic blocks. Horizontal dimensions of tectonic blocks in the so-called ＂seismic gap＂ region in the central Kuril Arc vary from 10 to 100 km, with typical dimensions of 25-30 km. The area of the ＂seismic gap＂ is a zone of intense tectonic activity and recent volcanism. Deep sources causing magnetic anomalies in the area are similar to the ＂magnetic belt＂ near Hokkaido. In the southern and central parts of Barents Sea, tectonic blocks with widths of 30-100 kin, and upper and lower boundaries of magnetic layers ranging from depths of 10 to 5 km and 18 to 30 km are calculated. Models of the magnetic layer underlying the Mezen Basin in an inland part of the White Sea-Barents Sea paleorift indicate depths to the lower boundary of the layer of 12-30 km. Weak local magnetic anomalies of 2-5 nT in the northern and central Caspian Sea were identified using the new methods, and drilling confirms that the anomalies are related to concentrations of hydrocarbon. Two layers causing magnetic anomalies are identified in the northern Caspian Sea from magnetic anomaly spectra. The upper layer lies immediately beneath the sea bottom and the lower layer occurs at depths between 30-40 m and 150-200 m.
文摘The size determination of dynamical structures from spectral images poses the question where to fix the shape’s boundary. Here, we propose a method, suitable for nearly elliptical shape, based on the fit of a 2D Gaussian to the pixel intensities of the spectral image. This method has been tested on a vortex structure embedded in the wake of the 2010 Saturn’s giant storm. On January 4th 2012, the Visual and Infrared Mapping Spectrometer (VIMS), onboard Cassini, observed a giant vortex in the Saturn’s northern hemisphere. The structure was embedded in the wake storm system detected on December 2010 by Fletcher et al. [1]. Therefore, all the VIMS observations focused on the Saturn’s storm have been analyzed to investigate its morphology and development. VIMS detected the vortex from May 2011up to January 2012. The evolution of shape and size has been determined for the vortex cloud top, visible at 890 nm. The largest size resulted 4000 km about and seemed to shrinks continuously up to January 2012, while the shape varied in the second half of the year. The vortex oscillated in 2 degrees latitude around 37°N planetocentric latitude, and drifted in longitude by ~0.75 deg/day in westward direction.
