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Study On Airborne Gamma-ray Spectrometry Data Processing Method In Complex Terrain Area

Posted on:2013-02-26Degree:DoctorType:Dissertation
Country:ChinaCandidate:J H WanFull Text:PDF
GTID:1110330371482201Subject:Geophysics
Abstract/Summary:PDF Full Text Request
Airborne gamma-ray spectrometry survey, by installed the detector inthe aircraft, detects the gamma-ray spectrum released from the terreneand obtains the appear content. As one of the most important regionalgeophysics methods ,the technology has been used widely in geology mapping,mineral exploration and environmental monitoring and evaluation act.In order to relieve the pressure on the domestic demand for mineralresources, China's mineral exploration work are gradually advancing tothe areas of the deep crust or the areas of complex terrain. Airbornegamma- ray spectrometry technology is now mainly applicable to the goodterrain areas, and the data processing method for complex terrain areasare still relatively lacking. Focusing on the different about the dataprocessing in complex terrain areas, the following problems were studiedby theoretical analysis or field experiments, including noise reducingand eliminating, scattering background subtraction, height normal andterrain correction etc., and the combination of theoretical analysis andfield experiments, etc. Those methods were applied to the real dataprocessing to obtain appear contents in the ground. Through the study,some of the major conclusions were drawn as following:(1)Focusing on the prominent noise component in the airbornegamma-ray spectrum noise in the spectrum, the optimized NASVD method wasimproved to applicable to a large amount of data for airborne gamma-rayspectrometry. The results show that NASVD method can improve the accuracyof the measurement datae effectively. As well, the noise-reducedgamma-ray spectrum provides a necessary protection for the subsequentdata processing.(2) Using the wavelet analysis, the scattering spectrum produced bythe radioactive sources of cosmic rays and geological body were subtracted.This method is height-free and no using the ground stripping coefficient which is difficult to effectively stripped the Compton scattering in theair data.(3) Use the polynomial exponential fitting method instead of theconventional exponential fitting to approach the height normal, and thismethod is better than the exponential fitting one to meet the greatermeasure height range. The study preliminary show that quadraticpolynomial fitting can meet the height normal in the complex terrain area.(4) By comparing analysis and field data test, the terrain influencecoefficient method, which includes equivalent surface source method andcube source method, is a relative effective terrain correction method .Theequivalent surface source method is faster.(5)According to the distribution map of the radioactive elementcontent obtained through the new method, combined with the necessarygeological maps, remote sensing images and other information to explainthe tectonic characteristics of the test areas, including the fracture,magmatic rocks and stratigraphy.
Keywords/Search Tags:Airborne gamma-ray spectrometry, Noise reducing and eliminating, height normal, terrain correction, data processing
PDF Full Text Request
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