Refined crustal thermal structure constrained by thermal infrared remote sensing reveals ancient continental relicts in the south China block

The South China Block, recognized as a pivotal geological domain for investigating continental tectonic evolution, hosts abundant geothermal and mineral resources. Accurate characterization of its crustal thermal structure is critical for deciphering geothermal anomalies and advancing understanding of regional tectonic dynamics. This study establishes an innovative inversion framework constrained by satellite thermal infrared remote sensing data to enhance spatial resolution and precision in thermal structure analysis. Through application of the split-window algorithm to Moderate Resolution Imaging Spectroradiometer (MODIS)-derived surface temperature datasets, we develop a surface heat flow inversion model that integrates the Curie depth and surface thermal parameters. Integration of remote sensing-derived ground temperature results with inverted surface heat flow data facilitates a more nuanced understanding of the thermal structure within the South China Block. Results indicate more consistency between the upper crustal thermal structure resolved by our method and empirical geothermal well measurements, confirming the validity of our approach. Notably, the deep crust thermal structure exhibits marked lateral and vertical heterogeneity, with low-temperature zones delineating several ancient continental relicts. These relicts manifest as distinct low-temperature anomalies corresponding to crustal thickening zones and lithospheric tectonic stabilization. Meanwhile, we suggest the possible existence of ancient continental relicts in the Jiangnan orogenic belt. This finding resolves previous limitations in interpreting ancient continental relicts that were attributed to insufficient thermal structure resolution, thereby providing novel crustal thermal structure evidence supporting an external position for the South China Block in the Rodinia supercontinent.