【摘要】 伊昭井田为伊犁盆地一特大型隐伏煤田,井田东南部地表煤层自燃形成大面积火烧区。采用地面高精度磁测工作,探测并圈定深部隐伏火烧区范围。煤层自燃后,顶底板及夹矸受到高温作用形成的烧变岩具有热剩磁现象,能在地面引起一定强度的磁异常,是开展磁测工作的地球物理前提。该文从磁测的理论依据、数据采集、资料的处理与解释、解译精度等方面进行了详细论述。探测面积约5.7 km2,布置测线62条,按100 m线距、20 m点距进行数据采集,并对ΔT数据进行化极处理及向上延拓处理。通过ΔT值平面等值线图、ΔT值剖面平面图及化极ΔT值上延平面等值线图等对异常进行定性及定量解译,共解译3个磁异常,自西向东强度增大,烧变岩埋深变浅、厚度变大,反映东部较西部烧变剧烈。结合磁异常的平面特征和地面填图成果,推测异常主要由5号煤层自燃后形成的烧变岩引起,与二维地震成果基本一致。更多还原

【Abstract】 Yizhao coal well is an exceptional large concealed coalfield in Yili basin.There is a large burning area in the southeastern coalfield formed by the surface coal-seam spontaneous combustion,and the ground high-precision magnetic survey has been used to detect and delineate the deep concealed burning area.After the coal-seam spontaneous combustion,the roof and the floor of the strata and the dirt band will be formed to the burnt rocks due to thermal remanence phenomenon under high temperature,and the remanence will cause a certain intensity of magnetic anomaly on the ground.All the above mentioned elements are geophysical premises to carry out magnetic survey work in this area.In this paper,theoretical basis,data collection,data processing and interpretation,interpretation accuracy of magnetic survey have been discussed in detail.The survey area is about 5.7km~2,62 measuring lines have been set and data collection has been carried out by line distance of 100 m and dot pitch of 20 m,and theΔT data is dealt with geomagnetic pole processing and upward continuation.According to the qualitative and quantitative interpretation of anomalies by the ΔT plane isoline graph,ΔT section plan and ΔT upward continuation plane isoline graph,3 magnetic anomalies have been determined.The strength increases from west to east with the depth of the brunt rock becoming lighter and the thickness becoming larger,all the above shows that metamorphism in the west part is more severe.It is inferred that the anomalies are mainly caused by the burnt rock formed by 5 coal-seam spontaneous combustion.The results are basically consistent by using the method of two-dimensional seismic exploration.更多还原