Elizabeth Gaines, the first woman CEO of Fortescue Metals Group (FMG) - one of the world's largest iron ore producers, and the third largest in Australia - is stepping down. In an announcement on Friday, Gaines said she would remain on FMG's board of directors, the capacity in which she originally joined the company before taking the role of CFO in 2013 and subsequently becoming CEO in 2018.

As no successor has been named, Gaines will remain at the helm for an as-yet-indefinite transitory period until a new CEO is found. Leadership advisory firm Egon Zehnder has been appointed for the search.

Gaines will also retain the role of the company's global green hydrogen ambassador, appropriate given that she has led FMG through its expansion into green energy and resources. Previously a pure-play iron ore producer, FMG has been investing heavily in green hydrogen, with billionaire owner Andrew Forrest slamming the use of fossil fuel hydrogen and pouring billions into renewable energy developments.

Forrest called Gaines a 'truly inspiring leader' during the announcement, and described her role as renewables ambassador as critical.

"We are grateful that she has accepted the critical role of ensuring the world understands that green hydrogen, green ammonia, green energy and all its products, are combined, the only practical implementable solution to global warming that can be delivered on a commercial, highly sustainable basis," he said. "Elizabeth's depth of character, leadership, global integrity and respect is appreciated by Fortescue's executives and fellow directors."