A group of geologists, oceanographers, and Earth scientists from many US and German universities have studied rocks taken from the ocean floor in 2013 in conjunction with seismic data to get additional insight into the past of the Melanesian Border Plateau. The journal Earth and Planetary Science Letters has published their research.

Seamounts, ridges, and volcanic guyots make comprise the vast (85,000 square mile) Melanesian Border Plateau on the Pacific Ocean floor, close to the Solomon Islands. The study team examined the gathered rock samples in this latest endeavour. More information regarding the history of the area dating back 120 million years was discovered by the researchers. They also discovered four separate volcanism stages in the area, each with a unique history that contributed to the characteristics seen today.

In 2013, the scientists conducted a five-week journey to the area in order to gather rock samples from 600 metres below the sea surface. The researchers were able to discover more about the history of the seafloor in the lab when they discovered that a large number of the rocks had been forced from beneath it by volcanic activity.

According to the rocks, a basaltic lava flood caused the plateau to begin some 120 million years ago, resulting in the creation of the Robbie Ridge. They also demonstrated how the Rurutu-Arago hotspot began to rise through the ocean floor around 45 million years ago, forming a seamount.

It’s possible that the old seamount was tall enough to break the surface. Over time, however, it eroded and became impenetrable; however, about 13 million years ago, the seamount shifted over a separate hotspot, which caused the seamount to re-erupt. On this occasion, it resulted in the creation of the modern-day Samoan Islands. Subsequently, some 3 million years ago, tectonic activity caused volcanic eruptions that altered the seafloor’s topography once more.

The researchers intend to carry out more research in order to increase our understanding of the world’s seas and map out the past of other underwater regions.