Tungsten isotope evidence from similar to 3.8-Gyr metamorphosed sediments for early meteorite bombardment of the Earth

The 'Late Heavy Bombardment' was a phase in the impact history of the Moon that occurred 3.8-4.0 Gyr ago, when the lunar basins with known dates were formed(1,2). But no record of this event has yet been reported from the few surviving rocks of this age on the Earth. Here we report tungsten isotope anomalies, based on the Hf-182-W-182 system (half-life of 9 Myr), in metamorphosed sedimentary rocks from the 3.7-3.8-Gyr-old Isua greenstone belt of West Greenland and closely related rocks from northern Labrador, Canada. As it is difficult to conceive of a mechanism by which tungsten isotope heterogeneities could have been preserved in the Earth's dynamic crust-mantle environment from a time when short-lived Hf-182 was still present, we conclude that the metamorphosed sediments contain a component derived from meteorites.

The Paragould meteorite / Sharat Kumar Roy -- and Robert Kriss Wyant --

v.10:no.23(1955)

Meteorite studies -- by Oliver Cummings Farrington, Ph.D., Curator, Dept. of Geology.

v.1:no.11(1902)

The Navajo meteorite, by Sharat Kumar Roy -- and Robert Kriss Wyant --.

v.7:no.8(1949)

Meteorite studies. by Oliver Cummings Farrington --

v.3:no.8(1910)

The Walters meteorite / Sharat Kumar Roy -- , Jewell J. Glass -- [and] Edward P. Henderson --.

v.10:no.37(1960)

The Smithonia meteorite / by Sharat Kumar Roy -- and Robert Kriss Wyant --.

v.7:no.9(1950)

The Mapleton meteorite / by Sharat Kumar Roy -- and Robert Kriss Wyant --.

v.7:no.7(1949)

The La Porte Meteorite / by Sharat Kumar Roy -- and Robert Kriss Wyant --.

v.7:no.10(1950)

The Rodeo meteorite / by Oliver Cummings Farrington --

v.3:no.1(1905)

Meteorite studies : Oliver Cummings Farrington --

v.3:no.6(1907)

The Benld meteorite / by Sharat Kumar Roy -- and Robert Kriss Wyant --.

v.7:no.11(1951)

Handbook and catalogue of the meteorite collection / by Oliver C. Farrington, Ph.D., Curator, Dept. of Geology.

v.1:no.1(1895)

The Chervettaz (L5) meteorite

The Chervettaz meteorite was an observed fall on 1901 November 30. Our study confirms the previous classification as an L5 chondrite. Weak deformations indicate stage S3 of shock deformations.