To detect the exhumation history of the southwestern South China Block (SCB), we performed fission track (FT) analysis on zircon and apatite grains in granitoid and sedimentary samples. From east to west, the study area includes the Yunkai Massif, Lingshan granitic belt, Shiwandashan Basin, and eastern margin of the Youjiang Basin. The granite sample of the Yunkai Massif has two peaks of 75 and 92 Ma for zircon FT dating. The Lingshan granitic belt samples yield zircon FT central ages from 135 to 132 Ma. The Permian bauxite samples of the Youjiang Basin yield zircon FT central ages from 109 to 93 Ma and display age peaks at ~97–93 Ma. The Yunkai Massif granite sample has two peaks at 74 and 104 Ma for apatite FT dating, while the Lingshan granitic belt sample has two peaks at 81 and 111 Ma. The cooling paths of the Yunkai Massif sample started with an Early Cretaceous (~120–100 Ma) cooling event that brought the granitoids into the apatite partial annealing zone (PAZ). Through comparative studies, we suggest that the southwestern SCB underwent three periods of crustal uplift during ~135–132, ~111–92, and ~ 81–74 Ma, respectively, which is consistent with the regional stratigraphic unconformity and crustal extension. Only the Yunkai Massif and Lingshan granitic belt were uplifted during ~135–132 Ma. During ~111–92 Ma, the southwestern SCB experienced crustal uplift, and the basal conglomerate began to deposit in the Shiwandashan Basin. Late Cretaceous uplifted occurred during ~81–74 Ma, and the Yunkai Massif was uplifted throughout the Cretaceous. From 97 to 92 Ma, the Permian bauxite deposits in the Youjiang Basin were uplifted, which provided the basis of the later transformation to Quaternary bauxite.

中文翻译：

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华南西南地块的白垩纪发掘史：裂变径迹热年代学的限制

为了检测西南华南地块（SCB）的发掘历史，我们对花岗岩和沉积样品中的锆石和磷灰石晶粒进行了裂变径迹（FT）分析。从东到西，研究区域包括云开地块，灵山花岗岩带，十万大山盆地和右江盆地的东缘。云凯地块的花岗岩样品在锆石FT测年有两个峰75和92 Ma。灵山花岗岩带样品的锆石FT中心年龄为135至132 Ma。右江盆地的二叠纪铝土矿样品产生的锆石FT中心年龄为109至93 Ma，且显示的年龄峰值在〜97–93 Ma。云凯地块花岗岩样品在磷灰石FT测年有74和104 Ma的两个峰，而灵山花岗岩带样品在81 Ma和111 Ma的两个峰。云凯地块样品的冷却路径始于早白垩世（〜120–100 Ma）冷却事件，使花岗岩进入磷灰石部分退火区（PAZ）。通过比较研究，我们认为西南SCB分别在〜135–132，〜111–92和〜81–74 Ma期间经历了三个地壳隆升期，这与区域地层不整合面和地壳扩展一致。在约135-132 Ma期间，只有云开地块和灵山花岗岩带才抬升。在〜111–92 Ma期间，西南SCB经历了地壳隆升，并且基底砾岩开始沉积在十万大山盆地。晚白垩世隆起发生在〜81-74 Ma，云凯地块隆起于整个白垩纪。从97 Ma到92 Ma，右江盆地的二叠纪铝土矿床隆升，