ABSTRACT
Tugidak basin, a fore-arc basin on the continental shelf southwest of Kodiak Island, Alaska, exhibits a developmental sequence that may be common to other basins on a convergent margin. The basin first formed on a continental slope, and then rose to shelf depths. An unconformity that forms the acoustic basement underlies a sequence of gently folded strata that may be of late Miocene and younger age. The seaward limit of the basin is formed by an uplift that blocked sediment flow across the shelf or down the slope. Uplift growth tilted the strata within the basin toward the land and moved the basin depocenter northwestward. During Pleistocene time, continued uplift resulted in erosion of the crest of the fold. Some of the eroded sediment was shed northwestward into the basin, forming a sequence of beds that prograde toward the land. Compressional deformation of the basin fill dies out landward from the anticline and normal faults are present near the volcanic arc.
