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Tracing the evolution of magma chemistry during the Archean using apatite

Clémentine Antoine1, Lili Loth1, Martin Guitreau2, Alexandra Tsay1, Nicolas Greber1,3, Luca Caricchi1

  • Affiliations: 1 Department of Earth Sciences, University of Geneva, Geneva, Switzerland, 2 Laboratoire Magmas et Volcans, University Clermont-Auvergne, Aubière, France 3 Museum of Natural history, Geneva, Switzerland

  • Presentation type: Poster

  • Presentation time: Thursday 16:30 - 18:30, Room Poster Hall

  • Poster Board Number: 252

  • Programme No: 1.1.38

  • Theme 1 > Session 1

Abstract

Many aspects of Earth's early evolution remain enigmatic, one of them being the nature of the creation of the first felsic crusts. Remnant lithologies from these ancient times are rare and usually not pristine, which hinders greatly the interpretation of their primary compositions.  We studied apatite inclusions in Archean (4.0-2.5 Ga) zircon crystals to better understand the petrogenesis of their parental magmas. Zircon crystals are well known for their resilience to metamorphic events, which, added to their capacity to be robustly and precisely dated, makes them the most robust host for primary inclusions. Apatite incorporates large quantities of rare-earth (RE) and volatile elements (F, Cl, OH) that allow to check for their chemical integrity and to trace the magmatic environments of their formation. We measured REE and major element concentrations in apatite inclusions from the Karelia Craton (Russia, Finland), the Wyoming Craton (USA) and the Slave craton (Canada) to cover more than 1.5 Gy. In this contribution, we will discuss the results of the chemical composition of the apatite grains coupled with U-Pb LA-ICP-MS dating of the host zircon crystals, in respect to the formation and volatile contents of these early felsic rocks at a local and global scale.