Lo-En

Lo-En or Hess is an Albian–Campanian guyot in the Marshall Islands. One among a number of seamounts in the Pacific Ocean, it was probably formed by a hotspot in what is present-day French Polynesia. Lo-En lies southeast of Eniwetok which rises above sea level, and Lo-En is almost connected to it through a ridge.

The seamount is formed by basaltic rocks that probably formed a shield volcano first. It is believed that a number of hotspots such as the Macdonald hotspot, the Rarotonga hotspot and the Rurutu hotspot may have been involved in the formation of Lo-En. After volcanic activity, by the Turonian the seamount was submerged although it is possible that a carbonate platform formed during the Albian. After a hiatus, sedimentation commenced on the seamount in Oligocene time and led to the deposition of manganese crusts and pelagic sediments including limestone, some of which were later modified by phosphate.