Description du projet
Les défauts de réseau du quartz pourraient nous donner des indices sur les processus de formation des roches
L’analyse des provenances aide les géologues à identifier la région d’origine des échantillons d’un sédiment. Le quartz est l’un des minéraux les plus courants constituant les roches. Les cristaux de quartz contiennent un grand nombre de défauts ponctuels. Ces défauts sont parfois utilisés pour dater les sédiments du Quaternaire, mais notre compréhension de leur formation et de leur dynamique reste encore limitée. Le projet PROGRESS, financé par l’UE, a pour objectif de prouver que les défauts ponctuels dans le quartz peuvent nous donner des indices sur le métamorphisme des roches et mettre en évidence les processus d’altération, de transport ou de recyclage. Pour étudier les défauts ponctuels, les chercheurs combineront des analyses de luminescence avec des techniques de microscopie.
Objectif
Quantitative provenance analysis studies are instrumental in understanding the tectonic and climatic processes that are shaping Earth`s landscape. Although the most abundant mineral in the sedimentary system is quartz, almost all studies in provenance analysis investigate accessory minerals. Quartz crystals contain a vast number of point defects, intrinsic or due to impurities. Although our understanding on the formation and dynamics of these defects is far from complete, a few of these defects in quartz are used for dating Quaternary sediments by luminescence (thermoluminescence (TL) or optically stimulated luminescence (OSL)) or by electron spin resonance (ESR). PROGRESS aims at proving that point defects in quartz have also the capacity to carry genetic information and their modifications can provide evidence for antiquity, metamorphism (or lack thereof) as well as knowledge on weathering, transport, or recycling. This information can be unravelled by ESR and luminescence methods in combination with microscopic techniques such as scanning electron microscopy coupled with cathodoluminescence (CL) wavelength resolved spectroscopy. To understand changes that are occurring at atomic level in quartz in nature in geological time, PROGRESS will investigate quartz grains extracted from independently dated old to young quartz-bearing continental crustal sources, metamorphosed rocks versus their unmetamorphosed equivalents, fresh versus highly weathered samples, as well as intrusive versus volcanic rocks, besides conducting experiments in laboratory environments. To tackle nature`s complexity during sediment movement in space and time the effect of physical and chemical changes that occur during transport of quartz grains will be investigated by the study of river sediments that drain different lithologies. These investigations will allow a simple quartz based fingerprinting method to be developed, that will have a significant impact on quantitative provenance studies.
Champ scientifique
Programme(s)
- HORIZON.1.1 - European Research Council (ERC) Main Programme
Régime de financement
ERC - Support for frontier research (ERC)Institution d’accueil
400084 Cluj Napoca
Roumanie