CAJ | 학술논문

南海在17 Ma已经停止扩张，其中南沙海域在晚中新世进入盆岭构造期，在10.4 Ma和5.5 Ma发生两期次火山喷发，形成南沙盆岭构造带，火山切割原有盆地结构，并导致盆地内复杂变形。10.4 Ma后南沙海域基底沉降是西沙海域基底沉降的4倍，为了分析西沙和南沙之间巨大沉降差异的原因，建立了火山的二维和三维平衡地质剖面模型，经计算发现南沙海域的火山侵入体积远大于地层变形体积，火山侵入约占地壳体积的1/4。火山侵入早期在深部形成的局部挤压伸展形成盆地浅部的拉张伸展环境，形成南沙海域晚中新世火山侵入伸展幕。
남해재17 Ma이경정지확장，기중남사해역재만중신세진입분령구조기，재10.4 Ma화5.5 Ma발생량기차화산분발，형성남사분령구조대，화산절할원유분지결구，병도치분지내복잡변형。10.4 Ma후남사해역기저침강시서사해역기저침강적4배，위료분석서사화남사지간거대침강차이적원인，건립료화산적이유화삼유평형지질부면모형，경계산발현남사해역적화산침입체적원대우지층변형체적，화산침입약점지각체적적1/4。화산침입조기재심부형성적국부제압신전형성분지천부적랍장신전배경，형성남사해역만중신세화산침입신전막。
The spreading of the South China Sea had stopped and fault activity weakened,but it started nurturing volcanic intrusion in17Ma.In the Late Miocene"basin-range"period,there occurred two volcanic eruptions at 10.4Ma and 5.5Ma.The volcano cuttingthe original volcanic basin structure and lead to and complexed the deformation of those basins.The basement subsidence in Nanshais four times the Xisha after 10.4Ma.To anysis the huge difference of the post-rift subsidence between Nansha and Xisha,the 2D and3D volcano balanced geological section model were established,and the paper calculated that the volcanic intrusion volume in Nanshabasins was much larger than the volume of stratum deformation.The volcanic intrusion had made those basins extending and faststretching,volcanic intrusive crustal volume was accounted for about 1/4 of the crust.Volcanic intrusion in"volcano intrusive stretc-hing episode"bring an extensional environment in the shallow formation of the basin and again bring a new fast stretching in late Mi-ocene.