Origin of inner-shelf mud deposit in the southeastern Yellow Sea: Huksan Mud Belt

A variety of previous sedinentological results, together with newly obtaine d hydrodynamic data, are summarized and reinterpreted with respect to the m ost likely origin of the Huksan Mud Belt (HMB) in the southeastern Yellow S ea. The HMB consists of two mud units that have similar grain texture and c lay mineralogy but can be differentiated on seismic profiles because the lo wer unit is generally harder than the watery upper unit. The hydrographic m easurements together with satellite imagery clearly indicate that the suspe nded plume covering the HMB originates from the west coast of Korea. The su spended plume becomes enhanced by winter monsoon winds beginning in late fa ll. Most of the studies of clay mineralogy, geochemistry, and isotherm dist ribution also suggest that the HMB has been derived from the west coast of Korea, particularly from the Keum River. An approximate evaluation of the d epositional time for the HMB, based on its dimensions and the discharge rat e of the Keum River, suggests a time duration of the order of 14,000 years. Hydrodynamic measurements across two transects over the northernmost HMB re veal that suspended matter travels southwest toward the main body of the HM B in a well-constrained corridor ultimately connected with the Keum River. Time-series (12.5 h) hydrodynamic measurements at a site over the HMB sugge st that the winter-season suspended plume carries concentrations of suspend ed matter one to two orders of magnitude higher than those of the summer. S ilt grains of 5-6 phi well sorted through numerous resuspension events, set tle out onto the HMB, forming distinctive silt laminae alternating with cla y-rich laminae,