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The Maesan fan delta, Miocene Pohang Basin, SE Korea: architecture and depositional processes of a high‐gradient fan‐delta‐fed slope system
Author(s) -
Hwang I. G.,
Chough S. K.
Publication year - 2000
Publication title -
sedimentology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.494
H-Index - 108
eISSN - 1365-3091
pISSN - 0037-0746
DOI - 10.1046/j.1365-3091.2000.00335.x
Subject(s) - geology , sedimentary depositional environment , delta , structural basin , geomorphology , paleontology , architecture , archaeology , geography , aerospace engineering , engineering
The Maesan fan‐delta‐fed slope system in the Miocene Pohang Basin occurs between two Gilbert‐type fan deltas. Detailed analysis of sedimentary facies and bed geometry reveals that the sequence is represented by 13 sedimentary facies. These facies can be organized into three facies associations, representing distinct depositional environments: alluvial fan (facies association I), steep‐faced slope (facies association II), and basin plain (facies association III). Subaerial debris flows and dense, inertia‐dominated currents were transformed into subaqueous sediment gravity flows in steep‐faced slope environments. Further downslope, these flows were channelized and formed lobate conglomerate and sandstone bodies at the terminal edge of the channels (or chutes). Interchannel and interlobe areas were dominated by homogeneous mudstone and muddy sandstone, deposited by suspension settling of fine‐grained materials. Part of the steep‐faced slope deposits experienced large‐scale slides and slumps. The chutes/channels, lobes and splays on the steep‐faced slope of the Maesan system are similar to those in modern subaqueous coarse‐grained fan‐delta systems.