A revised age, structural model and origin for the North Pennine Orefield in the Alston Block, northern England: intrusion (Whin Sill)-related base metal (Cu–Pb–Zn–F) mineralization

Mineralization and associated fluid migration events in the c . 1500 km 2 North Pennine Orefield (NPO) are known to be with tectonic activity, but age of these origins base metal sulfide mineralization remain unresolved. New fieldwork Alston Block shows that post-dates a weakly developed phase north–south shortening consistent far-field Variscan basin inversion during late Carboniferous. observations field relationships, coupled microstructural stress analyses, together Re–Os geochronology show vein-hosted (apart from barium minerals) was synchronous extension east–west coeval emplacement Whin Sill ( 297–294 Ma). Thus development NPO related an early Permian regional transtensional deformation, mantle-sourced hydrothermal magmatism northern Britain. Previously proposed Mississippi Valley Type models, or alternatives relating influx Mesozoic brines, can no longer applied Block. Our findings also mean existing models for equivalent fields worldwide (e.g. Zn–Pb districts Silesia, Poland Tennessee, USA) may need reassessed.