Sm and Nd nucleosynthetic anomalies in EL and EH chondrites

International audienceEnstatite chondrites(EC)have been proposed to be genetically related to the main building blocks of the Earth[1,2]. ECare divided into two groups, EH and EL,according to theirmetallic Fe content. Thesetwo groups also differ in terms of petrological types, with EH being mostly primitive and unequilibrated (a few EH5), and EL being mostly highly metamorphosed witha veryfew EL3 meteorites. The origin of EL3 chondrites is still debated, whether it is primitive or melted [3, 4]. Trace elementabundances and the Nd isotopic composition of EC suggest that EL3 are from a different parent body than equilibrated EL and EHchondrites[5].An earlier study by [6]alsoreported the heterogeneous Nd nucleosynthetic compositionsof EH3 chondriteleachates.We will report Nd and Sm isotopecompositionsof leachates obtained by step-wise dissolutionand mineral separates on unequilibrated enstatitechondritesfrom EH and EL type. Preliminary results on EL3 chondrite leachatesindicate noresolvable Nd nucleosynthetic anomalies. In contrast, EH3 chondrites display very large anomalies in the different leached components, especially residues that have an isotopecomposition enriched in s-process. The homogeneous Nd composition of the EL3 leachates is at odds with its primitive characteristics identified by some authors. It appears that contrary to theisotope complementarity (Mo, W) between chondrules and matrix observed in carbonaceous chondrites[e.g. 7], EH3 chondriteseparates sorted to represent the main EH3 components share an homogeneousNd isotope composition.Therefore, metal-sulphide nodules, chondrules and matrix of EH3 seem to have been formed in asimilar region of the protoplanetary disk, homogeneous in Nd isotope composition.[1] Javoy et al., 2010, GCA.[2] Dauphas et al., 2017, Nature.[3] El Goresy et al., 2017, MAPS.[4] Van Niekerk and Keil, 2011, MAPS.[5] Boyet et al., 2018, EPSL. [6] Boyet and Gannoun, 2013, GCA.[7] Budde et al.,2016, EPS