Abstract: The Yitong basin is a Cenozoic fault basin in the northern part of the Tan-Lu fault zone. The development and evolution of the Yitong basin is accompanied by strong volcanic activity. The distribution of buried volcanic edifices is of great significance to the study of volcanic evolution, geothermal exploration, and development in Yitong basin. In this study, we took the Hengtoushan volcano in the Yitong volcanic group as the research object, and used aeromagnetic measurements to determine the plane range of the buried volcanic edifice. The magnetic anomaly of the Hengtoushan volcanic area ranges of 2.6 km². Using an electromagnetic sounding (MT) section through the Hengtoushan volcanic area, we obtained the deep electrical structure, and analyzed the cause of the Hengtoushan volcano. The study shows that the volcanic strata formed in the first part of the Quaternary in Early Pleistocene, and under the action of torsional stress the basaltic magma crushed out of the surface along the Maanshan fault or stuck in the fault. Now, the magma channel is closed. Using the controllable source audio magneto telluric sounding method, the fine electrical structure near the Hengtoushan volcano was obtained to determine the shape and distribution range of the concealed magma capsule. Based on the above results, we obtained a clear understanding of the formation time, deep dynamic process, the spatial morphology, and the tectonic environment of the Hengtoushan volcano. We established a geophysical imaging mechanism for a buried volcanic edifice, which provides a reference for the development of volcanic geothermal systems in the Yitong basin.

Key words: Yitong volcanoes, Hengtoushan volcano, volcanic edifice, geophysical prospecting