How fluid-mediated rock transformations can mimic hydro-fracturing patterns in hydrothermal dolomite

Numerous studies of hydrothermal dolomite bodies describe brecciated rocks characterized by dark angular fragments dolomicrite bounded together saddle crystals forming veins. Often associated with ore deposits, these breccia (HDB) patterns are usually interpreted as related to hydro-fracturing and so considered univocal markers fluid overpressure. In this contribution we report an occurrence typical HDB pattern in a dolomitized sedimentary Mesozoic hyper-extension located the Northern Pyrenees (France). We propose model that accounts for textural crystallographic HDB, without any The following observations lead us results from texturally controlled, fluid-initiated recrystallization initial grain boundary migration: (1) rough contacts between structure; (2) dolomite; (3) different size distribution texture (4) spatial oxide particles. Our alternate interpretation was further tested 2D numerical simulations replacement process using ‘ELLE’ modelling toolbox. Simulations confirm advection hot fluids along porous zones can locally trigger migration, preservation larger, less permeable cold fragments. key features evidence assess whether is pinpointing towards episodes overpressure fracturing carbonates, or if it rather fluid-mediated rock recrystallization.