| The Late Permian Emeishan basalt is widely distributed in the Yunguichuan area of southwest China.It is the only Large Igneous Province recognized by the international academic community and has received extensive attention.After many domestic and foreign researchers have invested a lot of research,the research on Emeishan basalt has been fruitful.In recent years,research on the mantle plume model has also made important breakthroughs.However,previous studies on volcanic passages and volcanic structures in the Emeishan basalt distribution area were almost blank.This paper chooses to carry out rock magnetic fabric measurements on the widely distributed Emeishan basalt in the Xundian area of Yunnan,and attempts to restore the ancient volcanic mechanism of the Emeishan basalt in the Xundian area.At present,the following research results have been obtained:1.The average magnetic susceptibility(Km)of Emeishan basalt in Xundian area is mainly distributed between 0.1×10-2SI-0.3×10-2SI;the K-T curve and hysteresis loop characteristics indicate magnetite in Emeishan basalt.And pyrrhotite is the main ferromagnetic mineral;the magnetic susceptibility ellipsoid value of most samples is greater than zero,indicating that the Emeishan basalt magnetic susceptibility ellipsoid is flat;in addition,according to the analysis sample hc value and m The distribution ofrs/ms values is 0.07-0.3,and the particle size distribution of Emeishan basalt is mainly md(multi-domain).2.The magnetic anisotropy(pj)of Emeishan basalt in Xundian area is 70% distributed between 1.01-1.04,accounting for the vast majority of samples,and there is no linear correlation between pj and km.This indicates that the basalt of Emeishan in the study area has not been reconstructed by later geological processes and retains the original magnetic structure of the rock.The magnetic fabric structure of the Emeishan basalt in the Xundian area can effectively reflect the flow direction of the magma.3.The distribution of Emeishan basalt in the study area can be divided into six whistle to Jinyuan and its boundaries.The northwest direction is more widely distributed,the magnetic structure is more densely sampled,and the data is more detailed.The southeast direction distribution area is slightly smaller,but the magnetic fabric structure is more obvious.The basalt magnetic line K1 from the Yangjiawan to Dongchuan line indicates that the magma in the area is SW-SWW,and it is concluded that there is a crater in the NNE direction of Yangjiawan and a subvolcano in the NE direction of Yangjiawan.The magnetic fabric characteristics of the sampling point in the northeast direction of the Dangshui Cave indicate that the magma is NW flow direction information.We conclude that there should be a crater in the NW direction of Yangjiawan;the magnetic structure of the southwestern road of Zhuolong is a magma with SE flow.Inferred from the direction,it is concluded that there is a crater in the southwest of the higher-level Yanwei Street;the magnetic fabric features sampled in the Kowloon area indicate the flow of the magma flowing toward the SW,and it is inferred that there is a crater at about 10 Km in the southeast of Dajianshan.From the characteristics of the annular magnetic fabric of the Jiulongshan to Liushao line,we infer that the magma flows in a circular direction to the four sides,and there is a crater at the intersection.The same ring-shaped magnetic fabric features are also the 4Km southwest of Majie,the area of the barley field,and the mining points of the Huashi and Daheishan.According to the intersection of the annular magma flow direction,we infer the phase Corresponding to the three craters. |
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