Early uplift and exhumation of the Tanggula granitoid pluton since the Late Cretaceous: Implications for the stepwise topographic growth model in the eastern Qiangtang terrane

• DOI: 10.1130/b37271.1
• Publication Date: 2024-01-22T21:21:35Z
• Authors: Lu Lu; Xin Jin; Lilong Yan; Wen Li; Tao Wei; Yulin Shen
• Keywords: Fission track dating

Abstract Reconstructing the uplift process of eastern Qiangtang terrane is crucial for understanding growth model central Tibetan Plateau. However, due to limited amount data available, it not well constrained. The Tanggula granitoid pluton an outstanding geological feature in terrane, and thus could provide constraints on its history. We applied multiple thermochronologic systems over a broad temperature range, including apatite U-Pb, biotite K-feldspar 40Ar/39Ar, zircon fission-track, (U-Th)/He, study samples from pluton. results exhibit expected relative age order these systems, with 242–238 Ma U-Pb ages, 218–204 40Ar/39Ar 197–191 94–81 fission-track 70–58 (U-Th)/He 61–39 ages. Using ages thermal history modeling results, we reconstructed comprehensive pluton, which three rapid cooling phases were revealed. earliest phase (220–180 Ma; ~5.25 °C/m.y.) closely followed emplacement primarily expression natural triggered by conduction surrounding rocks. In contrast, during 100–60 since 20 can be interpreted represent intense exhumation, corresponding exhumation 5.0–6.0 km 2.3–2.8 km, as average rate 0.125–0.150 mm/yr 0.115–0.140 mm/yr, respectively. According history, region have been initiated early Late Cretaceous. published data, determined that onset entire had northeastward, stepwise propagation process. within or around Anduo first experienced late Early Cretaceous (ca. 130 Ma), northeast 100 farther Tuotuohe Yushu–Nangqian Paleocene 60 Ma). northeastward was likely caused combined Lhasa–Qiangtang India–Asia continental collisions.