Cretaceous mantle exhumation in the central Pyrenees: New constraints from the peridotites in eastern Ariège (North Pyrenean zone, France)

摘要: We provide new constraints on the modes of mantle exhumation and denudation in pre-orogenic Pyrenees by investigating poorly known peridotites located east Lherz body, eastern Arie ge (Vicdessos, Urs, Bestiac, Caussou Prades main peridotitic bodies). show that: (1) numerous peridotite bodies, not described so far, are constituted decametric to sub-metric outcrops scattered between around identified Monchoux (1970); (2) most form blocks lenses various sizes, from millimetric monocrystalline grains hectometric olistoliths, embedded debris flows involving mainly Mesozoic metasediments; these can therefore be linked S-type Lagabrielle et al. (2010), share similarities with region (Clerc al., 2012). All originated tectono-sedimentary processes associated relation extreme thinning breakoff continental basement; (3) petrographic characters their heterogeneity serpentinisation degree imply a peculiar mode exhumation, which merges fragments inherited different structural levels; (4) lack tectonic structures such as faults shear planes ultramafic-rich breccia formation presence neoformation metamorphic minerals within matrix preclude origin cataclasites related Latest Cretaceous Tertiary Pyrenean contractional deformation. The indisputable witnesses an inverted hyper-extended passive margin forming current North zone. geometry extensional system was complex probably strike-slip transcurrent motion. s 2016 Authors. Published Elsevier Masson SAS behalf Acade mie des sciences. This is open access article under CC BY-NC-ND license (http://creativecommons. org/licenses/by-nc-nd/4.0/).