关键词: 南方沙漠, 鄱阳湖, 多宝沙山, 高密度电阻率法, 瞬变电磁法, 成因机制

Abstract: The Poyang Lake area is located in a humid subtropical monsoon climate zone, but deserts are developed in many places along the lakeside. Duobao Desert is the largest desert among them, which has caused severe harm to the local environment. Previous researchers mostly believed that Duobao Desert was eolian, however, the stratigraphic stratification of many coastal outcrops is characterized by water formation. For further verifying the genesis of Duobao Desert, a combination of geophysical exploration (high-density resistivity method and transient electromagnetic method) and field geological outcrop investigation were applied in this study. It was found that the thickness distribution and sequence stratigraphy of the Quaternary of Duobao Desert are also  hydrogenic, besides the eolian features. This study indicated that Duobao Desert was the result of the combined action of both wind transport and underwater sedimentation, and its formation was related to the coupling of multiple factors in time and space, including the multiple fluctuations in the lake level, the southward expansion of the Penglize, a flat landform of the lake bottom, the rapid sedimentation of the delta, the differential movement of fault blocks, and the strong winter monsoon. Duobao Desert was developed in the Holocene， located in the subfacies of the front edge of the ancient Ganjiang River delta. After tectonic uplift, Duobao Desert was reconstructed by strong winds. The sand covered the paleotectonic highlands except for Xishan Mountain and Bijia Mountain, and finally made the current Duobao Desert.

Key words: southern desert, Poyang Lake, Duobao Desert, high-density resistivity method, transient electromagnetic method, genetic mechanism