The Miocene Chunbuk Formation, Southeastern Korea: Marine Gilbert-Type Fan-Delta System

  1. Albina Colella2 and
  2. David B. Prior3
  1. I. G. Hwang and
  2. S. K. Chough

Published Online: 2 APR 2009

DOI: 10.1002/9781444303858.ch13

Coarse-Grained Deltas

Coarse-Grained Deltas

How to Cite

Hwang, I. G. and Chough, S. K. (1990) The Miocene Chunbuk Formation, Southeastern Korea: Marine Gilbert-Type Fan-Delta System, in Coarse-Grained Deltas (eds A. Colella and D. B. Prior), Blackwell Publishing Ltd., Oxford, UK. doi: 10.1002/9781444303858.ch13

Editor Information

  1. 2

    Universita della Calabria, Italy

  2. 3

    Atlantic Geoscience Center, Nova Scotia, Canada

Author Information

  1. Department of Oceanography, Seoul National University, Seoul 151–742, Korea

Publication History

  1. Published Online: 2 APR 2009
  2. Published Print: 19 OCT 1990

ISBN Information

Print ISBN: 9780632028948

Online ISBN: 9781444303858

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Keywords:

  • Miocene Chunbuk Formation, representing part of Doumsan fan-delta system;
  • fan-delta system, comprising tripartite depositional elements;
  • waves and currents, dominating sedimentary processes;
  • small-scale Tertiary sedimentary basins, occurring in eastern coast of Korean Peninsula;
  • breccias, comprising angular rock fragments;
  • calcite-cemented sandstone blocks

Summary

The Miocene Chunbuk Formation represents part of the Doumsan fan-delta system and comprises various breccias and gravelstones deposited in the subaerial, transitional and subaqueous environments of a marine Gilbert-type fan-delta. Detailed facies analysis reveals that the system can be represented by 12 sedimentary facies, which are organized into five facies associations. Facies association I (interpreted as subaerial fan in origin) is characterized by massive/crudely stratified breccias (facies B1-a and B1-b) deposited by sheetfloods and debris flows. It grades laterally into facies association II (braided stream) in which massive/crudely stratified and cross-bedded gravelstones (facies G1-a and G4) show channel geometries. Facies association III (Gilbert-type topset) is represented by coarsening-upward sequences in which massive and laminated sandstones (facies S1 and S2) grade vertically into massive/ crudely stratified and cross-bedded gravelstones (facies G1-a and G4). Facies association IV (Gilbert-type foreset) is characterized by steeply inclined (initial slopes of more than 20°) massive/crudely stratified and stratified gravelstones (facies G1-b, G2-a and G2-b) that were deposited by gravity slides or cohesionless debris flows. Facies association V (Gilbert-type toeset) comprises massive/crudely stratified gravelstones (facies G1-b) and massive muddy sandstones (facies MS1-b), in which slope failure resulted in extensive syndepositional deformation.

The development of this Gilbert-type system is most likely due to syndepositional tectonic subsidence. The abnormally thick foreset units (> 150 m in foreset height) are suggestive of rapid tectonic movement.