Econ. Environ. Geol. 2006; 39(2): 129-149

Published online April 30, 2006

© THE KOREAN SOCIETY OF ECONOMIC AND ENVIRONMENTAL GEOLOGY

An Inquiry into the Formation and Deformation of the Cretaceous Gyeongsang (Kyongsang) Basin, Southeastern Korea

In-Chang Ryu1*, Seon-Gyu Choi2 and Soo-Meen Wee3

1Department of Geology, Kyungpook National University, Daegu 702-701, Korea
2Department of Earth and Environmental Sciences, Seoul 136-701, Korea
3Department of Earth Science Education, Korea National University of Education, Cheongwongun, Chungbuk 363-791, Korea

Correspondence to :

In-Chang Ryu

inchang@mail.knu.ac.kr

Received: May 18, 2005; Accepted: April 24, 2006

Abstract

Previously published stratigraphic, sedimentologic, paleontologic, paleomagnetic and geophysical data are reviewed to make an understanding on the tectonic evolution of the Cretaceous Gyeongsang (Kyongsang) basin, southeast Korea. A stratigraphic framework and a tectonic model on the formation and deformation of the Gyeongsang Basin are newly proposed on the basis of integration these data with magmatism and mineralization ages in the basin. A newly proposed stratigraphic framework indicates that strata in the basin can be subdivided into five distinct stratigraphic units that represent pre-rifting, syn-rifting, inversion I, II, and III stages. The Gyeongsang Basin was formed initially as a pre-rifting stage due to north-south extension in the Late Jurassic prior to a syn-rifting
stage that resulted from east-west extension during the Early Cretaceous. In the Late Cretaceous, the basin was deformed by three-staged sequential deformation of north-south, northwest-southeast, and east-west compressions. The tectonic history of the basin has been largely controlled by the change of motion of the Izanagi Plate from north to northwest during the Cretaceous. In the early Cretaceous, the Izanagi Plate began to subduct northward beneath the Eurasian Plate and caused the left-lateral strike-slip fault systems in the southern part of the peninsula. The left-lateral wrenching of these fault systems was causally linked to development of pull-apart basins, such as the Gyeongsang Basin in the southeastern part of the peninsula. However, northwestward movement of the Izanagi
Plate during the Late Cretaceous probably led to the extensive volcanism as well as sequential deformations in the basin. The stratigraphic and tectonic model, which is newly proposed as a result of this study, may be expected to enhancing the efficiency for exploration and exploitation of useful mineral resources in the basin as well as establishing geologic history in the Cretaceous Gyeongsang Basin. Together with the spatial and temporal correlation of the Cretaceous basins in adjacent areas, this stratigraphic and tectonic model provides a new geologic paradigm to delineate the sophisticated tectonic history of East Asia during the Cretaceous.

Keywords Cretaceous, Geodynamics, Gyeongsang basin, Integrated geology

Article

Econ. Environ. Geol. 2006; 39(2): 129-149

Published online April 30, 2006

Copyright © THE KOREAN SOCIETY OF ECONOMIC AND ENVIRONMENTAL GEOLOGY.

An Inquiry into the Formation and Deformation of the Cretaceous Gyeongsang (Kyongsang) Basin, Southeastern Korea

In-Chang Ryu1*, Seon-Gyu Choi2 and Soo-Meen Wee3

1Department of Geology, Kyungpook National University, Daegu 702-701, Korea
2Department of Earth and Environmental Sciences, Seoul 136-701, Korea
3Department of Earth Science Education, Korea National University of Education, Cheongwongun, Chungbuk 363-791, Korea

Correspondence to:

In-Chang Ryu

inchang@mail.knu.ac.kr

Received: May 18, 2005; Accepted: April 24, 2006

Abstract

Previously published stratigraphic, sedimentologic, paleontologic, paleomagnetic and geophysical data are reviewed to make an understanding on the tectonic evolution of the Cretaceous Gyeongsang (Kyongsang) basin, southeast Korea. A stratigraphic framework and a tectonic model on the formation and deformation of the Gyeongsang Basin are newly proposed on the basis of integration these data with magmatism and mineralization ages in the basin. A newly proposed stratigraphic framework indicates that strata in the basin can be subdivided into five distinct stratigraphic units that represent pre-rifting, syn-rifting, inversion I, II, and III stages. The Gyeongsang Basin was formed initially as a pre-rifting stage due to north-south extension in the Late Jurassic prior to a syn-rifting
stage that resulted from east-west extension during the Early Cretaceous. In the Late Cretaceous, the basin was deformed by three-staged sequential deformation of north-south, northwest-southeast, and east-west compressions. The tectonic history of the basin has been largely controlled by the change of motion of the Izanagi Plate from north to northwest during the Cretaceous. In the early Cretaceous, the Izanagi Plate began to subduct northward beneath the Eurasian Plate and caused the left-lateral strike-slip fault systems in the southern part of the peninsula. The left-lateral wrenching of these fault systems was causally linked to development of pull-apart basins, such as the Gyeongsang Basin in the southeastern part of the peninsula. However, northwestward movement of the Izanagi
Plate during the Late Cretaceous probably led to the extensive volcanism as well as sequential deformations in the basin. The stratigraphic and tectonic model, which is newly proposed as a result of this study, may be expected to enhancing the efficiency for exploration and exploitation of useful mineral resources in the basin as well as establishing geologic history in the Cretaceous Gyeongsang Basin. Together with the spatial and temporal correlation of the Cretaceous basins in adjacent areas, this stratigraphic and tectonic model provides a new geologic paradigm to delineate the sophisticated tectonic history of East Asia during the Cretaceous.

Keywords Cretaceous, Geodynamics, Gyeongsang basin, Integrated geology

    KSEEG
    Jun 30, 2024 Vol.57 No.3, pp. 281~352

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