Chapter 2.5 The Oldest Terrestrial Mineral Record: A Review of 4400 to 4000 Ma Detrital Zircons from Jack Hills, Western Australia

Abstract

Publisher Summary This chapter presents a review of 4400 to 4000 Ma detrital zircons from Jack Hills, Western Australia. The only identified materials on the Earth potentially old enough to record the Hadean–Archean transition are ancient, ≥4000 Ma zircons found in Archean metasedimentary rocks in Australia, China, and the United States. The Jack Hills, located in the Narryer Terrane of the Yilgarn Craton in Western Australia, comprise a ∼90 km long northeast-trending belt of folded and weakly metamorphosed supracrustal rocks that are composed primarily of siliciclastic and chemical metasedimentary rocks, along with minor metamafic/ultramafic rocks. Independent studies have demonstrated that the youngest metasedimentary rocks in the Jack Hills are Proterozoic in age. The minimum age of the Archean sediments in the Jack Hills is constrained by granitoid rocks that intruded the belt at ca. 2654 ± 7Ma. One of the most significant discoveries in U-Pb studies of Jack Hills zircons is a grain fragment that yielded a single concordant spot age of 4404 ± 8 Ma. Five additional >95% concordant spot analyses yielded a weighted mean age of 4352± 10, confirming the great antiquity of the crystal.