Gravity Anomaly Derivative Identification Configuration Application In Qiong Dongnan Basin

Geological tectonic boundary is mainly refers to the boundary and fracture of rock mass structure and stratigraphic unconformity contact zone and linear structure, the both sides of the linear structure generally density difference or magnetic differences, magnetic anomaly near the border with geological structure form the cascade with obvious. Magnetic anomalies of tectonic boundary recognition is often used to construct the identification and interpretation. In the tectonic boundary identification method, gravity anomaly derivative method is the highest degree in research, application range of the most widely method. The main research content of this article is to carry out the gravity anomaly derivative method, and applied to actual data processing and interpretation.This paper through the establishment of the forward model and theory of trial, verify the feasibility of the interpolating cut method; Using the interpolating cut method to the gravity anomaly and anomaly separation, the interpolating cut method for system analysis and research. Second, through the establishment of trial, the forward modeling comparing various methods in the process of identification, the actual effect, summarized the merits of the different methods of identification, identification results and the impact in the process of identifying, selecting the optimum method of gravity anomaly derivative. Forward modeling shows that vertical first derivative of the extreme value point can enhance the boundary of the anomalous field position, highlight the shallow abnormality and suppressing deep abnormal, but because of the influence of superimposed anomaly, vertical second derivative of the zero point to the location of abnormal body is delineated and boundary, prominent local field, pressing area, affected by superposition of abnormal small; Total level derivative method through its enormous value to determine abnormal body boundary, the major fault recognition effect is good, but not outstanding small anomaly; Gravity gradient anomalies can be through the six components linear characteristics, the comprehensive analysis of abnormal distribution situation, extreme value, the information such as dividing line to divide the location of the fracture, and the distribution of abnormal body position; Edge detection is to detect the location of the image characteristics change, express different series anomaly intensity information, especially in small anomalies and regional information, can be more intuitive to see the spatial variation of the intensity of data.In this paper, the measured gravity data in the qiongdongnan basin, the interpolating cut method to isolate local anomalies and regional anomaly. Applying normalized total level, canny operator edge detection, conversion of gravity gradient in the basin in the southeast of fracture, which can identify the qiongdongnan basin mainly develop NE and nearly EW and NW to three sets of faults, the NE to and nearly EW to fracture is the main of basin-controlling fault, such as: F2 fault show NE- NNW direction, is located in the qiongdongnan basin of the north and adjacent hainan island, the fault north east sag, south to cliff north sag, north and west sag of east sag come loose. F3 fault in NE- NEE, cliff south sag of the fault in the west, by the lingshui low bulge to the song tao raised the south rim, the fault is small basin EW fracture to stagger, F1 fracture in NNW direction, in the yinggehai basin in the southeast of the dividing line. The results of the study for regional linear structural analysis and division of tectonic units provide effective help.