Fossil and present-day stromatolite ooids contain a meteoritic polymer of glycine and iron

TL;DR

This study reveals that fossil and modern stromatolite ooids contain hemoglycin, a meteoritic polymer of glycine and iron, suggesting extraterrestrial material has influenced Earth's sedimentary structures for billions of years.

Contribution

It demonstrates the presence of meteoritic hemoglycin in ancient and recent stromatolites, linking extraterrestrial organic polymers to Earth's sedimentary processes.

Findings

Hemoglycin identified in 2.1 Gya fossil stromatolite ooids.

Modern ooids show fluorescence matching meteoritic hemoglycin.

Lattice spacing in ooids matches that of meteoritic crystals.

Abstract

Hemoglycin, a space polymer of glycine and iron, has been identified in the carbonaceous chondritic meteorites Allende, Acfer 086, Kaba, Sutters Mill and Orgueil. Its core form has a mass of 1494Da and is basically an antiparallel pair of polyglycine strands linked at each end by an iron atom. The polymer forms two- and three- dimensional lattices with an inter-vertex distance of 4.9nm. Here the extraction technique for meteorites is applied to a 2.1Gya fossil stromatolite to reveal the presence of hemoglycin by mass spectrometry. Intact ooids from a recent (3,000Ya) stromatolite exhibited the same visible hemoglycin fluorescence in response to x-rays as an intact crystal from the Orgueil meteorite. X-ray analysis confirmed the existence in ooids of an internal 3-dimensional lattice of 4.9nm inter-vertex spacing, matching the spacing of lattices in meteoritic crystals. FTIR measurements of acid-treated ooid and a Sutters Mill meteoritic crystal both show the presence, via the splitting of the Amide I band, of an extended anti-parallel beta sheet structure. It seems probable that the copious in-fall of carbonaceous meteoritic material, from Archaean times onward, has left traces of hemoglycin in sedimentary carbonates and potentially has influenced ooid formation.