- 長崎大学教育学部自然科学研究報告 (ISSN:0386443X)
- no.32, pp.p99-114, 1981-03
The continental shelf of Hyuga-nada, off Miyazaki Prefecture has an average width of about 20 km. The depth at the shelf break are 130-140 m in the northern area and 160-170 m in the southern area. The bottom sediments of the shelf are classified into three sediment types according to the grain size distribution, namely Sand (II), Transition sand (IIIa) and Mud (III). The distribution of these sedimenttypes are shown in Figure 5.The average content of organic carbon, total hydrogen and total nitrogen in the 42 bottom sediment samples of the Hyuga-nada shelf are 0.34, 0.25 and 0.052%,respectovely. The average of total content of C, H and N is 0.625%. The bottom sediment of the inner shelf of the northern area has less than 0.3% of carbon and 0.05% of nitrogen contents. On the other side, the inner shelf sediments of the southern area have more than 0.5% of carbon and 0.07% of nitrogencontents. The C/N ratio ranges from 3.33 to 8.20 with an average of 6.12. This value is slightly less than 7.0 which is taken from the Atlantic continental margin of the United States.