(Table 2) Color, epoch, nannofossil zone, and clay mineralogy at DSDP Site 90-591@en

Pale green laminae < 2 mm thick are common features of the Neogene and Quaternary sediment of Lord Howe Rise. We believe these laminae represent diagenetically altered volcanic ash layers from regional volcanic events. Although no consistent high abundances of volcanic glass are found within the laminae, the volcanic origin of the laminae is suggested by (1) similar temporal distribution of the laminae and the distribution of volcanic ash layers elsewhere in the southwest Pacific; (2) the high abundances of authigenic smectite in the laminae; and (3) the common occurrence of iron sulfides in proximity to most of the laminae. The resulting tephrostratigraphy is considerably more complex and detailed than was previously known.