CAJ | 학술논문

南海北部陆架海底沙波是否为残留沙波长期存在争议.为配合陆丰油田的开发,在LF13-2和LF13-1站位之间进行了详细的地形、地貌和海底底流测量.观测数据显示,本研究区发育两组海底沙波.两组沙波的分布和当今的海底地形密切相关,沙波的波宽、波高,沙脊的长度及延伸的方向也都和现今的水深密切相关.此外,沙波区的底质、沉积物颜色等也随现今水深的变化而变化.跨年度的测量结果显示,从2003年夏季到2005年冬季,海底沙波发生了明显的变化,除有明显的沙波迁移,并有新的沙波生成外,沙波区的水深也整体变深,研究区东南端平均加深了0.29 m.由于东沙海底高原的存在,东沙区底流有了复杂的变化.实际的观测结果显示,在9MKII站位,向南的退潮流明显大于向北的涨潮流,但在AEM-HR站位,WNW向的涨潮流则稍稍大于ESE向的退潮流.9MKII站位测得的最大底流速为48 cm/s,有22%的底流速大于20 cm/s,这是启动海底沉积物并能形成海底沙波的最小底流速.本文指出,东沙隆起后,由于强烈的底流侵蚀,在东沙区的中陆架和外陆架区几乎没有现代沉积.构成海底沙波的沉积物主要来自海底地层的剥蚀.测深结果显示的海底加深可能和海底剥蚀有关.很明显,海底沙波和现今的海底底流体系有很好的吻合关系,从而是在现今底流体系条件下形成的,而非晚更新世末次冰期的残留沙波.
남해북부륙가해저사파시부위잔류사파장기존재쟁의.위배합륙봉유전적개발,재LF13-2화LF13-1참위지간진행료상세적지형、지모화해저저류측량.관측수거현시,본연구구발육량조해저사파.량조사파적분포화당금적해저지형밀절상관,사파적파관、파고,사척적장도급연신적방향야도화현금적수심밀절상관.차외,사파구적저질、침적물안색등야수현금수심적변화이변화.과년도적측량결과현시,종2003년하계도2005년동계,해저사파발생료명현적변화,제유명현적사파천이,병유신적사파생성외,사파구적수심야정체변심,연구구동남단평균가심료0.29 m.유우동사해저고원적존재,동사구저류유료복잡적변화.실제적관측결과현시,재9MKII참위,향남적퇴조류명현대우향북적창조류,단재AEM-HR참위,WNW향적창조류칙초초대우ESE향적퇴조류.9MKII참위측득적최대저류속위48 cm/s,유22%적저류속대우20 cm/s,저시계동해저침적물병능형성해저사파적최소저류속.본문지출,동사륭기후,유우강렬적저류침식,재동사구적중륙가화외륙가구궤호몰유현대침적.구성해저사파적침적물주요래자해저지층적박식.측심결과현시적해저가심가능화해저박식유관.흔명현,해저사파화현금적해저저류체계유흔호적문합관계,종이시재현금저류체계조건하형성적,이비만경신세말차빙기적잔류사파.
Sand waves on the northern South China Sea Shelf had been considered as stable relict bed form. For the industry use of sea bed between LF13-2 and LF13-1, a new round exploration was carried out. The newly obtained data show that both spacings and amplitudes of sand waves are all systematically changing with water depth. Repeated observations since 2003 to 2004 showed that the sea bed is currently active. Due to strong erosion of surface sediment since Dongsha uplifting, there are almost no modern sediments on the shelf of Dongsha area. Sand materials in the study area mainly originate from the erosion of the bed sediment formation. Water depth increment revealed by repeated echo sounder data is mainly due to erosion. Bottom currents are quite complex in the area of Dongsha under water plateaus. At site 9MKII, the south ward ebb current is stronger than the north ward flood current, while at site AEM-HR, the WNW ward flood current is slightly stronger than the ESE ward ebb current. At site 9MKII, the maximum bottom current speed is 48 cm/s, and 22% of the observed bottom current speeds are larger than 20 cm/s, that meet the minimum bottom current speed required for the creation of sand wave. This paper points out that present-day oceanographic condition couples well with the sand wave morphologies, and the sand waves are to a great extent in equilibrium with the ongoing present-day oceanographic bottom current condition, and active.