Séminaire Site Buffon - Lundi 10 mars 2014 à 11 h

IMPMC - Site Buffon - 61, rue Buffon, Paris 5e

Salle des élèves - 2e étage

The biomimetic effect of silica on calcium carbonate crystallization   

 

Juan Manuel Garcia-Ruiz - University Granada, Spain

 

 

Abstract

Life was able to create (bio)chemical pathways to mineral structures of great complexity, breaking the symmetry of single crystals into complex textures exhibiting morphologies with continuous curvature forbidden in crystalline point symmetry. The formation of architectures such as shells and other exoskeletons of living organisms is governed by organic molecules or matrices, which modify the crystallization of calcium carbonate. Their influence provokes the breaking of the single crystal character of the mineral precipitation and often leads to sinuous shapes, which have been thought to be a sign of life, and distinguish these minerals from their inanimate, mostly euhedral counterparts. In this lecture I will review how the chemical coupling of silica -an ubiquitous mineral in the Earth crust- with CO₃ ⁼ and OH^- creates abiotic, purely inorganic, self-assembled structures made of millions of nanocrystals building textures of high complexity and showing morphologies with continuous non-crystalographic curvature. I will also discuss the geochemical plausibility of these self-organized mineral processes in terms of their implication in the origin of life and primitive life detection.

J.M. García-Ruiz, et. al., Science 2003, 302, 1194. DOI: 10.1126/science.1090163.

J.M. Garcia-Ruiz, E. Melero, S. Hyde, Science 2009, 323, 362. DOI: 10.1126/science.1165349.

M. Kellermeier, H Cölfen, and J.M. García-Ruiz. European Journal of Inorganic Chemistry (2012) 5123–5144. DOI: 10.1002/ejic.20121029.

Contact : Jennifer Miot (jmiot @ mnhn.fr)