Abstract
The tectonic evolution of northeast China is closely related to the subduction of the Pacific plate. The dehydration of the slab subduction process produces metasomatic agents that have important effects on the physical and chemical properties of the mantle wedge, including the decrease of seismic wave velocity and the increase of Poisson’s ratio and electrical conductivity. In order to investigate the tectonic evolution and fluid action of northeast China, this paper compares the previous seismic and electromagnetic imaging results of northeast China and explores the relationship between the genesis of Cenozoic volcanoes and fluid action in northeast China through rheological analysis. The results show that the western Pacific plate subducted into the mantle transition zone beneath northeast China, and sustained dehydration occurred. The upward migration of these released water caused partial melting at the base of the upper mantle. Some of the upwelling streams pierced the weak tectonic boundary under the buoyancy effect, which finally formed the large-scale Cenozoic volcanic events in northeast China.
Highlights
In northeast China, the northern margin of the Songliao Basin and its eastern and western flanks have developed many volcanoes, such as Changbaishan volcano, Longgang volcano, Jingpohu volcano, Abaga volcano, Halaha volcano, Wudalianchi volcano, and Nuominhe volcano
This paper explores the relationship between volcano genesis and fluid action in northeast China by sorting out previous seismic and electromagnetic imaging results and extracting information on geological processes and fluid action reflected by geophysical imaging results through rheological analysis
Global and regional seismic tomography results (Fukao et al, 1992; Zhao, 2004; Zhao et al, 2011; Fukao and Obayashi, 2013; Chen et al, 2017; Zhao, 2021) generally show that the northwest Pacific plate starts to subduct from the Japan Trench, and the subducted plate is as deep as the mantle transition zone and stalled above the 660-km velocity discontinuity
Summary
In northeast China, the northern margin of the Songliao Basin and its eastern and western flanks have developed many volcanoes, such as Changbaishan volcano, Longgang volcano, Jingpohu volcano, Abaga volcano, Halaha volcano, Wudalianchi volcano, and Nuominhe volcano. To investigate the volcano genesis of northeast China, many researchers have done much work and put forward some hypotheses about the formation mechanism of these volcanoes. Turcotte and Schubert (1982) suggested that the volcanoes in northeast China are hotspot volcanism formed by magma in the tail of the mantle column. Proposed a “hot region” hypothesis, suggesting that the “hot region” transported beneath northeast China provided the source of volcanic activities. Tatsumi et al (1990) explained the volcano genesis of northeast China using large-scale material injection into the crust from the Asthenosphere. Iwamori (1992) suggested that the deep primitive mantle became a molten “wet region” due to the lowering of solidus temperature by adding fluids. Buoyancy transported the partially molten mantle upward, causing crustal melting and volcanic activity near the upwelling center. Buoyancy transported the partially molten mantle upward, causing crustal melting and volcanic activity near the upwelling center. Tatsumi and Eggins (1995) suggested that the thermal
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