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秦岭被商丹缝合带分为北秦岭和南秦岭两个部分，在北秦岭南缘残留着与俯冲作用相关的岛弧火山岩以及弧前沉积体。对沿海丹带两个地区（黑河地区和黑山地区）弧前沉积体岩相组合和相序的研究显示，它们主要由深水浊积岩系。火山碎屑岩，扇三角洲沉积以及局限性台地碳酸盐岩和陆棚碎屑岩组成。总的沉积序列显示向上变浅趋势，但在弧前内侧边缘则表现为向上变深趋势。两个不同地区岩相和相序的差异明显受物源、海平面变化以及特别是构造作用的挫制。深水浊积岩系所反映的线状物源供给形式、扇三角洲体系的发育和其内部不同沉积段反复重叠的特征指示一种活动构造环境。弧前区构造发展一方面与其前部加积或下部垫底作用有关，另一方面则在很大程度上受由斜向俯冲而导致的伸展作用的影响。
The Qinling Mountains were divided into two parts, the North Qinling and the South Qinling by the Shangdan suture zone. Island arc volcanic rocks associated with subduction and the pre-arc sediments remained in the southern margin of the North Qinling Mountains. Studies on lithofacies assemblages and facies sequences of the pre-arc sediments in two areas along the coast of Dandenong (Heihe and Montenegro) show that they are mainly composed of deep-water turbidite series. Volcaniclastic rocks, fan delta deposits, and limited platform carbonate and continental clastic rocks. The total sedimentary sequence shows an upward trend toward shallowing, but the inward edge of the arc shows a trend of upward deepening. The differences in lithofacies and facies sequences in the two different regions are clearly dominated by provenance, sea-level changes and, in particular, tectonic decay. The characteristics of the linear source distribution, the development of the fan delta system and the repeated overlapping of different sedimentary units in the deep turbidite series indicate a tectonic setting. The development of the pre-arc zone is related to the frontal infill or the lower basement, on the one hand, and the extensional effect caused by oblique subduction on the other.