The constructional and deformational history of the igneous basement penetrated at Site 786

Abstract

The results of a petrographic analysis of clastic facies recovered from Hole 786B are presented along with a summary of the structural data obtained from Holes 786A and 786B. These data are used to reconstruct the general lithostratigraphy and structure of the boninite and related rock suite which constitutes the Eocene-Oligocene basement of the forearc basement high of the Bonin arc area. Evidence has been sought that can provide insight into the depositional environments of most of the volcaniclastic intervals drilled at Site 786. The main Eocene volcanic and plutonic constructional stage of the present forearc basement high was followed by a period of active subsidence. -from Authors