Geology of the sea floor east of Guadalupe Island

Abstract

A gently rolling surface of very soft folded sediment lies at the anomalously shallow deep-sea depth of 1900 fathoms east of Guadalupe Island. Sub-bottom echoes occur at a uniform depth of 6–8 metres over most of the area and photographs reveal organisms vigorously reworking much of the upper ten centimetres of sediment. At present, the region is surrounded by a deeper sea floor and cannot receive bottom-transported sediment. The origin of this anticlinorium is indeterminate. Geomagnetic profiles reveal north-south anomalies which are typical of the oceanic crust of the northeastern Pacific Ocean basin and which parallel the folds though are not necessarily related to them. Large tectonic features surround the area such as volcanoes, ridges, basins and deeps. Compared to these features, it is relatively deformed and appears to have a normal oceanic crust because it has (1) a long depositional history, (2) north-south magnetic anomalies and (3) a normal thickness.