FATES-HYPERS 宿命 Sediment sinks at depositional terrace in upper reach of the Gaoping Canyon Cheng-Shing Chiang a,* and Ho-Shing Yu b* a Hsiuping Institute of Technology, Taichung, Taiwan, ROC b Institute of Oceanography, National Taiwan University, Taipei, Taiwan, ROC

FATES-HYPERS 宿命 Introduction  The capability of canyons:  Sediment transfer  Erosion  Deposition  sediments are trapped in terraces  temporary or perennial sediment traps  types of terrace morphology  terrace formation and evolution

FATES-HYPERS 宿命 Introduction Sediments are traped within particular morphologies called terraces, with reference to fluvial environment. (Cirac et al.,2001; Gaudin et a.,2006)

FATES-HYPERS 宿命 What do we need to know about terrace? morphology features sink processes In terms of source to sink

FATES-HYPERS 宿命 Four types of terrace in Capbreton Canyon (Gaudin et al., 2006) Horseshoe terraces (T1) that is characterized by a flat, arcuate outer pattern surrounding an elongated and rounded topographic high. Hemispherical terraces (T2) with a flat top and have an arcuate pattern Rounded elongated terraces (T3) that is located inside meander loops and with a rounded top Flat elongated terraces (T4) that is flat and elongated parallel to the thalweg axis.

FATES-HYPERS 宿命 Evolution of Capbreton Canyon morphology (Gaudin et al., 2006) T1 : Horseshoe terraces T3 : Rounded elongated terraces T4 : Flat elongated terraces

FATES-HYPERS 宿命 Types of terrace in the world

FATES-HYPERS 宿命 Cross-section morphology

FATES-HYPERS 宿命 Cross-section terrace

FATES-HYPERS 宿命 Point bar terrace? Slide- or slump-related terraces ? Seismic profile terrace

FATES-HYPERS 宿命 Cross-section Steep wall

FATES-HYPERS 宿命 Slide- or slump-related terraces

FATES-HYPERS 宿命 Depositional terraces occurred in meander bend

FATES-HYPERS 宿命 Horseshoe terraces T1

FATES-HYPERS 宿命 Chirp sonar profile C3 T1

FATES-HYPERS 宿命 Elongated terrace T3 No cut-off presently

FATES-HYPERS 宿命 Compare with the Capbreton canyon arcuate pattern

FATES-HYPERS 宿命 Conclusion Terraces are well observed in the meandering segment of the canyon and mainly in inner parts of the meander bends, showing distinct depositional features of spill-over sediments to form levees. Four major types of terrace morphology have been established in the study area: Slide- or slump-related terraces, point bar terraces, horseshoe terraces (T1) and elongated terraces (T3).

FATES-HYPERS 宿命 We reveal the temporary sink of terrace of the Gaoping Canyon under the highstand of sea level as characterized by a direct sediment source from a small mountainous river with high sediment load.

FATES-HYPERS 宿命 Thanks, and your comments are welcomed