Scientists say they've found evidence of plastic rock on a Big Island beach. The rocks are formed when melted plastic mixes with beach sediment, basalt fragments and other types of debris.
A report in the journal GSA Today says the result is a new type of rock called plastiglomerate.
The Hawaii Tribune-Herald reports the scientists focused their research on Kamilo Beach because it receives large deposits of ocean debris, including plastic.
Partial lid containers contributed to 22 percent of the fragments. Fishing equipment was found in 20 percent of the samples.
Three researchers from the University of Western Ontario in Canada and Algalita Marine Research Institute in California authored the report.
GSA Today is the journal of the Geologic Society of America.