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为了深入了解南沙中部海域的沉积特征及构造演化过程,选取了该区具代表性的02N02测线对其进行详细的构造和地层解释.发现研究区南部存在一整套厚度较大的中生代甚至更老的地层,该地层普遍发生了强烈的褶皱作用,褶皱翼部存在一系列NE-NEE向断裂,控制沉积明显,背斜顶部多被剥蚀,翼部为充填沉积.新生代地层Tg(中始新世)到T40(中中新世)界面之间,为裂谷充填和披覆沉积,层内控制沉积的断裂普遍发育,而T40界面之上为平整的盖层沉积,断裂作用极少,地层厚度变化不大.结合以上特征对比区内与02N02测线相交的87N4测线、临近的90N9等测线,以及横穿该区的94N2测线,分析了南沙中部海域中、新生代地层的构造成因,并进一步探讨了其中、新生代地层的演化过程.
In order to deeply understand the sedimentary characteristics and tectonic evolution of the central Nansha sea area, we selected the representative 02N02 survey line to conduct a detailed structure and stratigraphic interpretation of the area, and found that there is a whole set of thick Mesozoic ancestors in the southern part of the study area Of the strata, the strata generally have strong folds, and there are a series of NE-NEE faults in the fold wing, controlled deposition, most of the anticline is denuded, and the wing is filled with sediments. The Cenozoic formation Tg Between the T40 (Middle Miocene) and the T40 (Middle Miocene) interfaces, rift filling and drafting sediments generally developed within the stratigraphic controlled sediments, while the T40 interface formed a flat caprock with little faulting. The change of thickness has little effect.According to the above characteristics, the 87N4 line intersecting the 02N02 survey line, the adjacent 90N9 survey line and the 94N2 survey line across the area are analyzed, and the structures of Mesozoic and Cenozoic strata in the middle Nansha sea area are analyzed Causes and further explored the evolution process of the Mesozoic and Cenozoic strata.