Cretaceous exhumation history of the southwestern South China Block: Constraints from fission‐track thermochronology

Abstract

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.

Burial and Exhumation History of the Lujing Uranium Ore Field, Zhuguangshan Complex, South China: Evidence from Low-Temperature Thermochronology

“…This is interpreted as recording pronounced regional uplift and denudation that led to the development of the unconformity between Cambrian and Upper Cretaceous strata (Figure 2). This regional-scale exhumation episode is thought to have resulted from NW-SE-directed compression related to the northwestward subduction of the paleo-Pacific plate [30] and the ESE-directed retreat and subsequent WNW-oriented subduction of the Pacific slab [42,79].…”

Low‐Temperature Thermochronological Perspective on Geodynamic Evolution of the Cathaysia Block Since Early Mesozoic

“…As exhumation of intrusive rocks is commonly a crustal‐scale response to plate tectonics, low‐temperature thermochronology allows placing temporal constraints on the interplay between shallow and deep geological processes. However, low‐temperature thermal history of the CB, particularly in the intracontinental regions, is not well documented and/or variably interpreted, making it difficult to assess the existing geodynamic models (Chen et al., 2020; Li, Shi, et al., 2016, 2017; Su et al., 2017; Sun et al., 2021; Y. J. Wang et al., 2020a). In addition, the tectonism and magmatism in the intracontinental CB are primarily Jurassic–Early Cretaceous in age whereas the epicontinental CB are more characterized by Late Cretaceous ages.…”

Artificial intelligent identification of apatite fission tracks based on machine learning

“…The fission track method (Silk and Barnes 1959, Price and Walker 1962, Fleischer et al 1965 has been applied to resolve many geological problems such as determining the thermal history of sedimentary basins (Gleadow et al 1986, Emmel et al 2014, the timing of fault activities (Roden-Tice and Wintsch 2002, Abbey and Niemi 2018), source-sink coupling during mountain building processes (Ruiz et al 2004, Chen et al 2020, uplift histories of orogenic belts (He et al 2018, Bonilla et al 2020, Wang et al 2023, regional tectonic evolution (Grist and Zentilli 2003), and mineralization (Chakurian et al 2003). In the 1980s and 1990s, the apatite fission track dating method has been greatly improved after the introduction of ζ age parameter reference, the performance of annealing experiments, the development of annealing models, and the quantification of apatite multivariate kinetic annealing processes (Hurford and Green 1983, Laslett et al 1987, Green et al 1989, Vrolijk et al 1992.…”