The Electrical And Deep Structure Features Of Faults Around Akebasitao Area In Western Jungga

Audio Magnetotelluric sounding (AMT) is a frequency domain sounding method developed from Magnetotelluric sounding method. Its theory foundation is exactly the same to Magnetotelluric method using the natural Magnetotelluric field. However, the sampling frequency range is 0.1-10000Hz which is different from Magnetotelluric sounding method. Due to audio frequency magnetotelluric with low cost, high efficiency, less affected by terrain, can penetrate the high resistivity, the advantages of horizontal and vertical resolution is better, it has been widely used in metal mineral exploration, coal, groundwater, karst, oil and gas fields and other fields. Audio frequency magnetotelluric sounding method is an important method of geophysical exploration.As a part of the Central Asian Orogenic Belt, West Junggar receives massive scholar’s attention. The Ophiolitic melange belt, granite, mafic dykes are widely appeared in West Junggar which indicating the evolution of the late Paleozoic tectonic is very complex. North East regional faults and nearly East-West secondary fault as the most important fault system in West junggar, controlling the tectonic evolution of the region, providing transport, storage space for rock magma. The current research on these faults are from a geological perspective, analyzing the trends, tendencies and other characteristics of fracture, but there is no deep electrical structure and fracture characteristics of deep structures. We can provide geophysical basis for the study of the deep geological structure of the whole area by the study of the electrical and deep structure features of the faults around Akebasitao area in Western Junggar.The study area is located in the middle of Tacheng in Zaire mountain area and the whole area is located in northwest plate of Darbut fault. Because the trend of Darbut and Anqi fault is north-east direction, so the survey lines are arranged perpendicular to the fault strike. The line direction is NW-SE and there are sixteen lines and each line contains thirty one points which pitch is lkm, line spacing of 2km. Audio magnetotelluric exploration used Canada MTU-NET equipment company based in Phoenix and a Germany GMS-07e magnetotelluric instrument. The field construction generally use "cross" shaped symmetrically. In the gathering process, we carries on the gathering work strictly according to the standard.Data processing phase is mainly through Fourier transform, such as numerical calculation method for impedance information, and then get the apparent resistivity and phase curves, Then the frequency point, eliminating the distortion of the smooth curve, data denoising, polarization mode discrimination, static correction and other steps, and then the inversion. Judging from the comparison model and inversion of OCCAM, OCCAM inversion is suitable for the region. Final this article has selected the OCCAM two-dimensional inversion method and has obtained the satisfactory result.Judging from the inversion slices, the Darbut fault is across the the whole region and is located in the south of Akebasitao rock mass. The properties of the fault are similar in every slices which are tend to the North West and high angle steep. Although the specific depth of the fault in each slices is different but most of the depth is more than 5 kilometers deep, some slices even reached 8 km deep. In most of measuring lines, the bottom of the fault is connected to the low resistivity materials which is probably the primitive stratum before Magma intrusion below the Akebasitao rock mass. The Anqi fault is high angle dip to the north west fault, even close to the vertical angle, and the depth is about 4 km. The secondary fault which is in to shape with Darbut and Anqi fault is tend to the north with large inclination and depth between 3-kilometer to 5-kilometer.Darbut fault cuts southern ascending magma from Akebasitao rock, which means Darbut fault does not provide the magma ascending channel。 The deep magma below Anqi fault and Secondary fault is connected with the surface rock, which means Anqi and Secondary fault are very likely provide the magma ascending channel.