Stradbroke is the name of two islands in Moreton Bay, near Brisbane in southeastern Queensland, Australia. Giant sandhills up to 600 feet (183 meters) high have been built up by southeasterly winds over thousands of years. Both North and South Stradbroke islands have mineral sands containing rutile, ilmenite, and zircon. Ilmenite and rutile contain the important metal titanium. The islands started to form 500,000 years ago, and large masses of sand are still moving. North Stradbroke, the larger island, formed in four major stages corresponding to glaciation and recessions of the sea level.
