408
DiZhou
110.(1)
,,, oa
,,2.00
Fig.S Geographic distributions of grain-size types of
sediments and grain-size regionalization
~Ty,..
2)(1)
CHI NA
22.(1)
1800
+ Typ.l-l
X Tp ~2
* -'"'
o ~''''
o _,>2
South China Sea
1'0.00
111.00
112.00
11$.00
Fig.6 Geographic distribution of geochemical classes
of sediments and geochemical regionalization
- ,
2)(1)
-
CH I NA
x a.Jlc1
+ Oltnd'
•
,,*,11;1;(.3
•
atone"
22.(1)
South China Sea
1800
The western most portion of this region is unique in having only Subtype 1-1
sediments, the finest sediments on the shelf with no grain coarser than fine
sand. The deposition of such sediments is controlled by the specific hydrodynamic condition: the southwestward-movingWGCC is bent and slowed down
near the Leizhou Peninsula, and a counterclockwise eddy is formed by the
meeting of this bent current and the eastward current from the Qiongzhou
Strait (Huang et al. 1994).
2. A modified relict littoral sedimentary region lies in the present middle and
outer shelf between the 50 m and 200 m isobaths (region B in Fig.S, also regions 113 , IIIl and part of III2 in Fig. 6). In this region, sediments are dominated by the Type II clayey fine sand with very poor sorting. The sandy fractions of these sediments deposited in a littoral condition during the Pleis-