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Volcanic successions, including their spatial, temporal, tectonic, and 22 geochemical attributes, were identified based on well data, 2D/3D seismic data, U-Pb 23 isotopic ages, and major and trace element data from the Changling fault depression 24 of the Songliao Basin in northeastern China. Three eruption cycles developed in the 25 Changling fault depression: K 1 h (Huoshiling Formation) (118-124 Ma), K 1 yc 1 (first 26 member of the Yingcheng Formation) (115-106 Ma), and K 1 yc 3 (third member of the 27 Yingcheng Formation) (106-102 Ma). These three eruption cycles comprised seven 28 eruption stages. The volcanic successions in every eruption cycle were bimodal and 29 evolved from basic to acidic. The magma of the basic and intermediate rocks in these 30 cycles was derived from partial melting of the asthenosphere. In K 1 yc 1 and K 1 yc 3 , 31 partial melting of the newly formed basic rocks in the lower crust formed the 32 high-SiO 2 acidic magma. In addition, fractional crystallization of basic magma 33 formed the small-scale intermediate-acidic magma. In K 1 h, the most likely origin of 34 the acidic magma was fractional crystallization of basic magma. During the early 35 stage of the fault depression, the volcanic rocks of K 1 h were controlled primarily by 36 the boundary fault activity. In K 1 yc 1 and K 1 yc 3 , basic-intermediate rocks were 37 distributed widely along syngenetic faults, and acidic rocks were concentrated in areas 38 Page 2 of 74 https://mc06.manuscriptcentral.com/cjes-pubs Canadian Journal of Earth Sciences 39 the volcanic successions were controlled by magmatic evolution, and the spatial 40 distribution was controlled by basin tectonics.41

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