An unusual discovery in the Pacific Ocean is challenging how science has understood island formation and human environmental impact until now.
In Fiji, a team of researchers has identified a small island near Vanua Levu, which was not formed by natural processes like volcanic activity or sand deposition, but almost entirely from marine debris. According to research, about 90% of this island's surface consists of millions of mollusk shells accumulated over centuries.
Researchers describe this phenomenon as a "midden island," which translates to "trash island." According to a study published in the journal Geoarchaeology, the area has been used for about 1,200 years by ancient communities who went there to process seafood. They opened the mollusks to extract the meat and discarded the shells in the same place, gradually creating a large, compact mass.
Radiocarbon dating indicates that the island's origin dates back to around 760 AD, during the expansion of the Lapita culture, a seafaring people who colonized a large part of the Pacific islands.
Initially, scientists suspected that the accumulation might have been caused by a tsunami, but analyses of marine sediments ruled out this possibility. It turned out that the island was created simply by daily human activity, repeated for centuries on end.