古珠江河口湾岸线与水下地形重建

Reconstruction of Coastline and Bathymetry of the Pearl River Paleoestuary

根据现代地形图的等高线与大量测年钻孔资料,考虑珠江三角洲的地貌格局、海平面变化、沉积压实、构造沉降等影响因素,对6 000 aBP海侵盛期古珠江河口湾的岸线进行了重建;同时,利用修订的古水深计算公式和kriging插值方法,恢复这一时期的古珠江河口湾水下地形。论文讨论了影响岸线与水深重建的局部地形变化、山麓入水坡度、上游河床坡降等诸多误差因素。结果表明,珠江三角洲特殊的地形结构是古珠江河口湾岸线与水下地形合理重建的基础,重建后的地形分为内、外河口湾两部分,内湾岛丘众多,周缘水深相对较浅,分布有数条古西、北江切割深槽;外湾等深线大致与岸线平行。

Considering the impacts caused by the landform patterns,sea level changes,sedimentary compaction and tectonic subsidence,the coastline of the Pearl River paleoestuary at 6 000 a BP is rebuilt based on the elevation contours in recent time and borehole data.The bathymetry of the Pearl River paleoestuary is reconstructed by using the water-depth formula and Kring interpolation.Several error factors influencing the coastline and bathymetry,including local terrain changes,slope of piedmonts,and slope of upper reaches are discussed.The results show that special topographic structures of the Pearl River Delta make it possible to rebuild the coastline and bathymetry of the Pearl River paleoestuary.The Pearl River paleoestuary can be divided into inner and outer parts.There are lots of islands and several ancient channels of the West and North Rivers in the inner estuary.The contours of the outer estuary are parallel to those of the coastline.