Thursday, January 16, 2014

Large landmasses existed 2.7 billion years ago

Decoupled Hf-Nd isotopes in Neoarchean seawater reveal weathering of emerged continents Viehmann, et al., Geology, on-line early publication.

Kamandi by jack Kirby © DC Comics
Researchers have determined the isotope composition of the rare trace elements Hafnium and Neodymium in 2,700 million year-old seawater by using high purity chemical sediments from Temagami Banded Iron Formation in Canada.

The new findings show that 2,700 million years ago relatively large landmasses emerged from the oceans that were exposed to weathering and erosion by the sun, wind and rain.

Dr. Hoffmann: "The isotope Hafnium 176 in contrast to its counterpart Neodymium 143 was transported by means of weathering into the oceans and became part of iron-rich sediments on the sea floor 2,700 million years ago. link