Application Of BEMD For Extraction Of Gravity And Magnetic Anomaly Information In Luziyuan Area With Lead And Zinc Polymetallic Mineralization In Yunnan Province

The complexity of the factors of geological mineralized process's multi-stages and multi-phases and preserve after mineralization and etc,Leading to record this complex process data usually exhibit the characteristics of non-linearity and non-stationarity.At present mineralized target zone delineation and the mineral resources evaluation used by the traditional data processing method,whose limitations would result in extracting the useful ore-generating geological anomalies inaccurately.Today's geological field has accumulate a lot of two-dimensional geophysical,geochemical and remote sensing measurement geological data,but if we want to extract the hidden useful prospecting information from the two-dimensional data,we must use of non-linear method to deal with the non-linear and non-stationary data.In this thesis,BEMD is effectively used to extract anomalies from 1:50000 gravity and aeromagnetic data,and obtain the gravity and magnetic anomalies under different scales,combining with the geological and mineral resources map,thus the anomaly information can clearly reflect the geological structure and the relation of spatial distribution of lead and zinc polymetallic mineralization as well as the geological body,providing a scientific basis for lead and zinc polymetallic mineralized prognosis and assessment in the region.Getting the following research achievements:First.The distribution of the gravity is corresponding to the type of rock.The regional gravity anomaly map decomposed by BEMD that maybe can clearly reflect the distribution of the concealed intermediate-acidic rock body in Luziyuan area.The lead-zinc-iron polymetallic ore deposits are mainly located in the transitional zone between the positive and negative gravity anomaly that also the contact zone between the concealed intermediate-acidic rock body and its wall rocks.The shallow gravity anomaly map reflects structure,rock body,wall rock alteration and etc in Luziyuan area,the beaded and banded NE trending of positive and negative gravity anomalies can reflect the pattern of structure,which is the primary NE trending supplemented with the NW trending,when the concealed intermediate-acidic rock body intrude into carbonate rock along the favorable mineralized intersection of the Luziyuan NE trending multi-anticline,fault,and the surrounding secondary fault and fissure,always generate skarnization,which is close to mineralization,the NW trending faults are latter than the NE trending faults,however,destroy the ore body.Second.The distribution of the magnetic anomaly is corresponding to the type of rock.The positive magnetic anomaly is induced by basic volcanic rock that are belongs to the T3nh and C2w layer;the skarn type magnetite surrounding the contact zone of wall rocks that result in the local positive magnetic anomaly in Luziyuan area,the negative magnetic anomaly may be cause by the rise of high temperature magmatic hydrothermal liquid,making demagnetization effect of on the magnetic body,and the negative magnetic anomaly probable cause by the concealed intermediate-acidic rock body outside.Third.According to the geochemical anomaly map of copper-lead-zinc,we can figure out that this area has a good copper-lead-zinc polymetallic mineralization,and Luziyuan mining area's lead-zinc-iron polymetallic ore deposits are mainly skarn-type,so we speculate that exist the concealed intermediate-acidic rock body in the deep of Luziyuan,and this rock body have a certain range in the deep space.