引言墨西哥湾北部陆架中段的地形在第四纪期受到海平面波动的强烈影响(Beard 等,1982)。海退建造作用,包括陆缘三角洲层序的沉积,主要起因于海岸平原穿越陆缘的向外扩展(suter 和 Berrjttr.,1985)。密西西比—亚拉巴马陆架是墨西哥湾的一个亚区,它构成密西西比河三角洲以东的宽广大陆台地(图一)。与密西西比河三角洲以西的得克萨斯——路易斯安那陆架相比,密西西比 INTRODUCTION The topography of the central shelf in the northern Gulf of Mexico is strongly influenced by sea level fluctuations during the Quaternary period (Beard et al., 1982). The role of retrogressive constructions, including the deposition of continental deltaic sequences, is mainly due to the outward expansion of the coastal plain across the margin (Suter and Berrjttr., 1985). Mississippi - The Alabama Shelf is a subregion of the Gulf of Mexico that forms the vast land to the east of the Mississippi Delta (Figure 1). Compared to the Texas-Louisiana shelf west of the Mississippi Delta, the Mississippi