关键词: 裂变径迹年龄；中&mdash, 新生代隆升；构造热历史；珠江口盆地；盆地基底

Abstract: As a representative of the epicontinental rift basin in the northern South China Sea, the Pearl River Mouth Basin is an ideal study area for a better understanding of the tectonic evolution of the South China Block and time limit of the opening of the South China Sea. This paper presents the apatite and zircon fission track dating results from basins Paleozoic gneissic and Cretaceous granitic drill samples. The zircon fission track apparent age ranges from 131.7 to 97.9 Ma, younger than their formation time; the apatite track apparent age falls between 79.7 and 61.9 Ma; at 11.3713.16 μm, the apatites fission track lengths show a cooling or mixing pattern. The geothermal simulation show that distinctive uplifting and cooling processes were present in different sites, cooling event took place earlier, and the uplifting rate was slower in the south than in the north in the Cenozoic. It is inferred that the basins basement uplifted about 6 km since the late Cretaceous when it experienced several episodes of rapid uplift in the late Cretaceous, the Shenhu tectonic event at Paleocene, the second scene of the Zhuqiong tectonic event, and the Nanhai tectonic event at Oligocene (before 26 Ma). During the Nanhai tectonic event, the uplift began earlier in the east than in the west. The timing of the rapid uplift is consistent with the timing of slipstrike of the Red River Fault, and the uplift shows good correlation with the basin formation. Our data provide important constraints on the extension of the South China Sea. It is confirmed that the basement uplift of the Pearl River Mouth Basin was a result of a conjuncture of the subduction of the Pacific Plate, collision of the IndianEurasian Plate and extension of the South China Sea.

Key words:  fission track, MesoCenozoic uplifting, tectonothermal evolution, the Pearl River Mouth Basin, basement uplift