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云南腾冲火山盆地深部存在岩浆囊是人们关注的问题,多方面进行了大量的研究且存在不同意见。作者此前依据低电阻异常推断出位于小空山、大空山、黑空山等火山口的下部,深13~30 km范围内东西向25 km,南北向30km的低电阻率的岩浆囊,其东侧为大盈江断裂。文章利用反射地震、重力、航空磁测资料进一步探讨了岩浆囊的其他地球物理特征。由于火山喷发,不仅在火山口附近形成了局部物质亏损,而且,岩浆囊本身也亏损了岩浆物质,在重力上延图中滤去了表层的火山局部负重力异常后,呈现出大空山北侧的与低阻体相对应的负重力异常,这与岩浆囊高温熔融状态含水低密度物质有密切关系。整体的重力负异常印证了低阻岩浆囊的存在。腾冲马站岩浆囊的温度为397~651°C,平均温度为524°C,其主体中心部位不可能存在磁性体。对航磁资料的处理,消除表层火山岩影响后,仍然发现有较强磁异常,其平面投影范围与低阻体相近,推断磁异常是岩浆囊顶层,在15 km深度以上范围内,随着岩浆囊体温度逐步下降,当低于480°C以后会形成新的铁磁性矿物,因此,在囊体上层出现了范围与囊体相近的较强的磁性体。反射地震仅仅在浅部较清楚地观测到较连续的反射波界面,是浅部火山岩、含水层、以及花岗岩顶界面的反映。向深部反射界面很不连续推测是由于多次岩浆上涌,其喷发时间有先后,成分有差异,故岩浆囊物质的不均匀性,虽然由于含水、矿化、熔融体构成了低电阻的共性,可温度的不均匀,却又显示了不同期次岩浆成分有变化,由岩浆囊向地表的通道上,东部花岗岩下为高速,相对于较低温度的物质,在小空山、大空山和黑空山深部沿大盈江断裂带有东西两个大的隐伏花岗岩体之间是最新的火山喷发通道,具有相对低速的通道。
The existence of magma pockets in the deep of Tengchong volcanic basin in Yunnan Province is a concern. Many studies have been made and different opinions exist. Based on the low resistivity anomalies, the authors deduced the low resistivity magma pockets located in the lower part of the crater such as Xiaogashan, Dadongshan and Heikongshan within 25 km from east to west and 30 km from north to south in the range of 13 ~ 30 km Dayingjiang break. In this paper, the other geophysical characteristics of magma potholes are further explored by using reflected seismic, gravity and aeromagnetic data. Due to the volcanic eruption, not only the local material loss was formed near the crater, but also the magma itself lost the magma material. After the local negative gravity anomaly of the surface volcano was filtered out in the gravity map, The negative gravity anomaly corresponding to the low resistivity body is closely related to the aqueous low-density material in the molten state of the magma at high temperature. Negative gravity anomaly of the whole confirms the existence of low-resistance magma pockets. Tengchuoma station magma capsule temperature of 397 ~ 651 ° C, the average temperature of 524 ° C, the central part of the main body can not exist magnetic body. After processing the aeromagnetic data and eliminating the influence of surface volcanics, strong magnetic anomalies are still found. The plane projection range is similar to that of the low resistivity body. It is deduced that the magnetic anomaly is the top of the magma chamber. Within the range of 15 km depth, The temperature of the capsule decreased gradually, and below 480 ° C, new ferromagnetic minerals were formed. Therefore, a stronger magnetic body appeared in the upper layer of the capsule with a similar area to that of the capsule. Reflective earthquakes clearly reflect the more continuous reflection wave interface only in the shallow part and are a reflection of shallow volcanic rocks, aquifers and granite top interfaces. The discontinuity of the deep reflection interface is presumed to be due to the multiple upwelling of magma. The eruption time varies from one component to another. Therefore, the inhomogeneity of magma inclusions in the magma is a common cause of low resistance due to water, mineralization and melt , But the temperature is not uniform, but also shows the different stages of magmatic composition changes, from the magma chamber to the surface of the channel, the eastern granite is high speed, relative to the lower temperature of the material, in the small mountain, big mountain and black There are two volcanic eruption channels between the two deep concealed granite bodies along the DaYingJiang fault and the east-west deep empty mountain, with a relatively low velocity channel.