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Interpretation of the Gravity and Magnetic Anomalies of the Cappadocia Region,Central Turkey 总被引：3，自引：0，他引：3
A.?Büyüksara?Email author D.?Jordanova A.?Ate? V.?Karloukovski 《Pure and Applied Geophysics》2005,162(11):2197-2213
The Cappadocia region, located in Central Turkey, is characterized by widespread lava flows and volcanoclastic deposits dating from Miocene to Quaternary. Gravity and aeromagnetic anomalies of the region appear to present similar high and low amplitude regions, although the aeromagnetic anomalies exhibit a rather complex pattern which is thought to be caused by remanent magnetization. The low-pass filtered aeromagnetic map shows a deep-seated magnetic anomaly which may be linked to the widespread volcanic activity at the surface. The pseudogravity transformation of the upward continued anomaly has been constructed. The pseudogravity anomaly demonstrates some form of clockwise rotation. This anomaly was modelled by means of a three-dimensional method. The top and bottom of the body are at 6.3km and 11km (including the flight height) from the ground surface, respectively. This deep body is ellipsoidal and extends along an E-W direction, which is in line with the regional stress direction deduced from GPS measurements. A new mobilistic dynamo-tectonic system appears to explain the body’s E-W elongation. The modelled body may be the source for the inferred geothermal energy of the region. Magnetic measurements were carried out on oriented rock samples collected from outcrops of ignimbrites and basalts, providing directions and intensities of remanent magnetization, susceptibilities and Koeningsberger (Q) ratios. Standard deviations of remanent directions of the Natural Remanent Magnetization (NRM) display a wide scatter implying unreliability of the surface data. Reduction to pole (RTP) transformation of magnetic anomalies was successful with the induced magnetization angle despite the complex pattern of magnetic anomalies. 相似文献
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M. Knab V. Hoffmann E. Petrovský A. Kapička N. Jordanova E. Appel 《Environmental Geology》2006,49(4):527-535
Measuring magnetic susceptibility is a method which is used to estimate the amount of magnetic particles in soils, sediments
or dusts. Changes in magnetic susceptibility can be due to various reasons: input from different sources of sediments, e.g.
from different soils or rocks, atmospheric fallout of anthropogenic dusts containing magnetic particles produced by fossil
fuel combustion, steel production or road traffic. In the case of river sediments, input from the catchment is of primary
significance. The main aim of this investigation was to test the potential of magnetic susceptibility screening in identifying
the effect and significance of anthropogenic activities in an area with complex geological conditions. We investigated the
magnetic susceptibility of riverbed sediments of the largest river of the Czech Republic, the Moldau river. Besides that,
the magnetic signal of nearby topsoils as well as of outcropping bedrocks in the vicinity of the river was examined. In the
upper 300 km of the river, the magnetic enhancement of the river sediments can be linked to anthropogenic activities. Positive
correlations were found in the river sediments between the contents of Cu and Zn and magnetic susceptibility, while Fe, Mn
and Ni did not show a correlation with magnetic susceptibility. However, the major geogenic magnetic anomaly in the area around
the Slapy dam has made it impossible to unambiguously interpret the magnetic signal in terms of anthropogenic impact in the
last 80 km downstream. 相似文献
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J. M. Quinn G. Paschmann N. Sckopke V. K. Jordanova H. Vaith O. H. Bauer W. Baumjohann W. Fillius G. Haerendel S. S. Kerr C. A. Kletzing K. Lynch C. E. McIlwain R. B. Torbert E. C. Whipple 《Annales Geophysicae》1999,17(12):1503-1512
We present the first triangulation measurements of electric fields with the electron drift instrument (EDI) on Equator-S. We show results from five high-data-rate passes of the satellite through the near-midnight equatorial region, at geocentric distances of approximately 5–6 RE, during geomagnetically quiet conditions. In a co-rotating frame of reference, the measured electric fields have magnitudes of a few tenths of mV/m, with the E × B drift generally directed sunward but with large variations. Temporal variations of the electric field on time scales of several seconds to minutes are large compared to the average magnitude. Comparisons of the “DC” baseline of the EDI-measured electric fields with the mapped Weimer ionospheric model and the Rowland and Wygant CRRES measurements yield reasonable agreement. 相似文献