BATHYMETRY AND SEDIMENTATION
IN COMRA’S CONTRACT AREA
Huaiyang Zhou
School of Ocean and Earth Science
Tongji University, Shanghai, PR China
Bathymetry of CCZ is mostly controlled by Pacific Mid-Ocean Ridge Tectonics
CCZ
Bathymetry of CCZ- 1minute grid
COMRA’s
Bathymetric Map of COMRA
s East Area
Bathymetric Map of COMRA’s West Area
Cumulative Frequency Curve of Bathymetry
COMRA’s East Area
COMRA’s West Area
Fr equency ( %)
Fr equency ( %)
10
20
30
40
50
60
70
80
90
100
3000
3000
3500
3500
4000
4500
5000
Wat er d
dept h ( m)
Wat er d
dept h ( m)
0
0
4000
4500
5000
5500
5500
6000
6000
10
20
30
40
50
60
70
80
90
100
40
Fr equency ( %)
F
35
30
25
COMRA’s East Area
20
15
10
5
0
3900- 4000- 4500- 4800- 5000- 5100- 5200- 5300- 5400- 55004000 4500 4800 5000 5100 5200 5300 5400 5500 5600
Wat er dept h ( m)
Histogram of
Bathymetry
35
Fr equenccy ( %)
30
25
20
15
COMRA’s West Area
10
5
0
2900- 4000- 4500- 4800- 5000- 5100- 5200- 5300- 5400- 55004000 4500 4800 5000 5100 5200 5300 5400 5500 6000
Wat er dept h ( m)
Characteristics of
COMRA’s Contract Area
three types of topography: abyssal hills,
seamount chains and abyssal basins
basins,
EW strike of seamount chains and NS
strike
t ik off sedimentary
di
t
graben
b
Seamount chains are more obvious in
the West Area than in the East Area
Data of Sediments from COMRA’s Area
1,606 stations by free fall grab samplers;
849 stations from the East Area;
757 stations from the West Area.
Types of Sediment
There are generally four types of surface
sediment in the COMRA area:
siliceous clay;
siliceous ooze;
siliceous-calcareous ooze;;
calcareous ooze.
Distribution map of sediment in
COMRA’ East
COMRA’s
E tA
Area
Distribution map of sediment in COMRA’s
West Area
RELATIONSHIPS BETWEEN SEDIMENT
TYPES AND BATHYMETRY
the calcareous ooze is only located on the top of seamounts
RELATIONSHIPS BETWEEN SEDIMENT TYPES
AND BATHYMETRY
the calcareous ooze is only located on the top of seamounts, siliceous-calcareous ooze
occurs clearly as transitional zone from calcareous to siliceous oozes.
East Block of COMRA Area
E
Relationship among topography, reflection and coverage
(blue line is reflection(dB); data in red is coverage of nodule)
East Block of COMRA Area
E
Relationship among topography, reflection and coverage
(blue line is reflection(dB); data in red is coverage of nodule)
¾Patchy distribution of nodules
¾A patch of nodules could be from several square meters to
dozens of square kilometers