40Ar/39Ar geochronology was carried out on the non-deformed synorogenic granitoid plutons from the Qinling–Dabie Orogen. The new model cooling history (MCH) method is applied to K-feldspar to obtain information about its cooling history. MCH is a quicker and easier method of calculating cooling histories compared with the multi-domain diffusion (MDD) model. Cooling histories indicate that Qinling–Dabie suffered differential uplift and denudation processes since the collision in the Late Triassic. East Qinling uplifted and denuded rapidly from c. 181–187 to c. 150 Ma at a rate of c. 20 °C Ma−1, three times as fast as west Qinling which was exhumed at a rate of c. 6.6 °C Ma−1 from c. 195–190 to c. 100 Ma. Although west and east Qinling started uplift and denudation at the same time, east Qinling reached the 150 °C geothermal line (c. 7.5 km deep) at c. 150 Ma, earlier than west Qinling by c. 50 myr, suggesting that earliest collision and strongest compression occurred in east Qinling. Dabie is characterized with a polyphased process of uplift and denudation, implying that the subduction of south China block in this region was multi-staged. The emplacement of the granitoids and uplift pattern along Qinling–Dabie may be due to delamination of the root of the mountains or the slab break-off. Cooling histories suggest that more mass had been removed from the root of east Qinling than west Qinling and Dabie; the final delamination occurred in Dabie at c. 100 Ma but affected the whole Qinling–Dabie orogen.
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Advances in 40Ar/39Ar Dating: From Archaeology to Planetary Sciences
Decoding the complete history of Earth and our solar system requires the placing of the scattered pages of Earth history in a precise chronological order, and the 40Ar/39Ar dating technique is one of the most trusted dating techniques to do that. The 40Ar/39Ar method has been in use for more than 40 years, and has constantly evolved since then. The steady improvement of the technique is largely due to a better understanding of the K/Ar system, an appreciation of the subtleties of geological material and a continuous refinement of the analytical tools used for isotope extraction and counting. The 40Ar/39Ar method is also one of the most versatile techniques with countless applications in archaeology, tectonics, structural geology, orogenic processes and provenance studies, ore and petroleum genesis, volcanology, weathering processes and climate, and planetary geology. This volume is the first of its kind and covers methodological developments, modelling, data handling, and direct applications of the 40Ar/39Ar technique.