Formation of the Korean Cordilleran arc in the Jurassic

Study Summary

This study used new and published U-Pb geochronological, chemical, and Sr-Nd-Hf-O isotopic data (n > 2500) from Jurassic granite-granodiorite-diorite-monzonite-gabbro plutons in the southern part of the Korean Peninsula to assess the spatiotemporal evolution of a flare-up magmatism, its tectonic connection, and specific contributions of mantle and crustal reservoirs to the magmas generated.

The geochronological and geochemical data compiled in this study suggest a tectonomagmatic model consisting sequentially of (1) an extension-dominated arc system in the margin of the Yeongnam Massif (ca. 200–190 Ma); (2) low-angle subduction and the development of an advancing arc system (ca. 190–180 Ma); (3) continued low-angle subduction, extensive underthrusting of fertile crustal materials to the arc root, and consequent magmatic flare-up (ca. 180–170 Ma); and (4) flat subduction and the development of the Honam Shear Zone (ca. 170–160 Ma).

The subsequent magmatic lull and previous dating results for synkinematic rocks and minerals indicate that the compressional arc system was maintained until the Early Cretaceous.

[Figure 1] Representative electron microscope images of zircons analyzed in this study indicating U-Pb dating results and O-Hf isotopic measurements

This paper provides a fundamental basis for the tectonic research in the Korean Peninsula and east Asia

This paper adds data into the database for the geologic provinces of the southern Korean Peninsula

[Figure 2] Sensitive High-Resolution Ion Microprobe installed at the KBSI Ochang Center