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Potassic, high-silica Hadean crust.

ABSTRACT: Understanding Hadean (>4 Ga) Earth requires knowledge of its crust. The composition of the crust and volatiles migrating through it directly influence the makeup of the atmosphere, the composition of seawater, and nutrient availability. Despite its importance, there is little known and less agreed upon regarding the nature of the Hadean crust. By analyzing the ⁸⁷Sr/⁸⁶Sr ratio of apatite inclusions in Archean zircons from Nuvvuagittuq, Canada, we show that its protolith had formed a high (>1) Rb/Sr ratio reservoir by at least 4.2 Ga. This result implies that the early crust had a broad range of igneous rocks, extending from mafic to highly silicic compositions.

SUBMITTER: Boehnke P

PROVIDER: S-EPMC6016771 | biostudies-literature | 2018 Jun

REPOSITORIES: biostudies-literature

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Potassic, high-silica Hadean crust.

Boehnke Patrick P Bell Elizabeth A EA Stephan Thomas T Trappitsch Reto R Keller C Brenhin CB Pardo Olivia S OS Davis Andrew M AM Harrison T Mark TM Pellin Michael J MJ

Proceedings of the National Academy of Sciences of the United States of America 20180604 25

Understanding Hadean (>4 Ga) Earth requires knowledge of its crust. The composition of the crust and volatiles migrating through it directly influence the makeup of the atmosphere, the composition of seawater, and nutrient availability. Despite its importance, there is little known and less agreed upon regarding the nature of the Hadean crust. By analyzing the 87Sr/86Sr ratio of apatite inclusions in Archean zircons from Nuvvuagittuq, Canada, we show that its protolith had ...[more]

PMID: 29866820

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