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南海的形成演化一直是国内外关注的热点之一.为了揭示南海的构造演化过程,分析对比了3组物理模拟实验.实验结果表明,断裂样式和裂谷带的走向与岩石圈的初始热流变结构密切相关.对比模拟结果与陆缘的断层样式,推测在张裂初期,陆坡区比陆架区具有相对热减薄的岩石圈,从而导致不同构造位置上发育不同的裂陷特征.受下地壳和软流圈韧性流动的影响,断层越是靠近扩张区,倾角变得越平缓.实验揭示,破裂首先以点状出现,这些点不断扩大并互相连接形成连续的扩张区.共轭边缘常具有对称的形状,向海盆方向对凹或者对凸.当离散边界附近有刚性块体时,扩张区域的边界会明显受到地块边缘形态的影响.通过模拟实验,推测破裂过程可能以较粘性的方式进行.西北次海盆的发育可能是沿着中-西沙地块北缘深裂陷槽破裂的结果.
The formation and evolution of the South China Sea has been one of the hot spots at home and abroad.In order to reveal the tectonic evolution of the South China Sea, three sets of physical simulation experiments are analyzed and compared.The experimental results show that the fracture pattern and the trend of rift zone are similar to the initial heat flux Which is closely related to the structure of the continental margin.Comparing the simulation results with those of the continental margin, it is speculated that at the initial stage of the cracking, the slope area has a relatively thinner lithosphere than the shelf region, resulting in different rift features in different tectonic positions. And the influence of the ductile flow in the asthenosphere, the closer the fault is to the expansion zone, the more gentle the dip angle.Experiments have shown that the rupture first appears in a point shape, and these points are continuously expanded and connected to form a continuous expansion zone.The conjugate edge often has Symmetrical shape and concave or convex to the basin direction.When there are rigid blocks near the discrete boundary, the boundary of the expansion area will be significantly affected by the shape of the edge of the block.It is presumed by the simulation experiment that the fracture process may be more viscous . The development of the Northwest sub-basin may be the result of the rupture of deep rifts along the northern margin of the Central-Xisha block.