This geological process happened in places like Venezuela and the United States, and particularly in Canada.

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That led them to try to determine what type of geological process would result in those rocks.

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Rathlin Energy have now completed further geological surveys and are in the process of finalising the location of their second exploration site.

BBC: Ballinlea

If the methane is produced by geological activity, it could either originate from active Martian volcanoes or from a process called serpentinisation.

BBC: Martian methane mystery deepens