南沙海域晚中新世火山侵入伸展幕  

Volcano intrusive stretching episode in Late Miocene Nansha basins of South China Sea

作　　者：关成尧[1,2] 张厚和 漆家福[2] 邱楠生[2] 吴景富 杨桥[2] 高剑波 

机构地区：[1]防灾科技学院地震科学系,河北三河065201 [2]中国石油大学油气资源与探测国家重点实验室,北京102249 [3]中海油研究总院,北京100027

出　　处：《石油学报》2013年第S02期129-136,共8页Acta Petrolei Sinica

基　　金：国家重大科技专项(2011ZX05025-005)资助

摘　　要：南海在17Ma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10.4Ma和5.5Ma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。10.4Ma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。The spreading of the South China Sea had stopped and fault activity weakened, but it started nurturing volcanic intrusion in 17 Ma. In the Late Miocene ＂basin-range＂ period, there occurred two volcanic eruptions at 10.4 Ma and 5.5 Ma. The volcano cutting the original volcanic basin structure and lead to and complexed the deformation of those basins. The basement subsidence in Nansha is four times the Xisha after 10.4 Ma. To anysis the huge difference of the post-rift subsidence between Nansha and Xisha, the 2D and 3D volcano balanced geological section model were established, and the paper calculated that the volcanic intrusion volume in Nansha basins was much larger than the volume of stratum deformation. The volcanic intrusion had made those basins extending and fast stretching, 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 Miocene.

关 键 词：南沙盆地区 盆岭构造 火山侵入 伸展幕 晚中新世 火山平衡地质剖面 

分 类 号：TG121.2[金属学及工艺—金属学]