Petrogenesis of the alkaline lamprophyre cluster between Molí d'en Ponç and Collet de la Cidereda (eastern Catalonian Coastal Ranges, NE Iberia)
Culí i Verdaguer, Laura (Universitat Autònoma de Barcelona. Departament de Geologia)
Campeny, Marc (Museu de Ciències Naturals de Barcelona)
Solé, Jesús (Laboratorio Nacional de Geoquímica y Mineralogía)

Date:	2025
Abstract:	This work focuses on the cretaceous camptonite cluster between Molí d'en Ponç and Collet de la Cidereda, eastern Montseny massif from the Catalan Coastal Ranges (NE Iberian Peninsula). These post-orogenic lamprophyres (~ 79 Ma) crosscut Palaeozoic and late Variscan granitoids. Their intrusion is related to the opening of the Bay of Biscay. Thus, they belong to the Late Cretaceous Iberian Alkaline Igneous Province. The studied cluster comprises two sills displaying a N110-N140-trending direction and subvertical dikes that intrude the camptonite sills or the granodioritic host rock. Dy/Yb ratios ≥ 2. 4 show that the primary melts of the studied camptonites were generated at pressures higher than ~ 2. 5 GPa (~ 80 km) on the garnet stability field close to the transition to the spinel stability field. The more evolved melts, corresponding to sodic alkaline basalts, were subjected to within-plate enrichment and fractional crystallization processes. The olivine antecrysts and microlites correspond to forsterite (Fo to Fo). They do not show peridotitic mantle source composition and some are in equilibrium with sulfides. The clinopyroxene antecrysts correspond to diopside (Mg# 75-80) and do not show peridotitic mantle source composition. The forsterite, diopside, and kaersutite antecrysts display compositional oscillatory variations related to mixing processes associated with ascending successive magma pulses. The higher concentrations of Mn in forsterite and diopside microlites from the groundmass, compared to the antecrysts, are consistent with a more evolved composition of the ascending magma. The pressure estimation obtained from diopside antecryst cores (~ 1 GPa) supports the stagnation of ascending magma in the lower crust or the transitional boundary between the lower crust and upper mantle. The pressure obtained from clinopyroxene antecryst rims is ~ 0. 28 GPa.
Note:	Altres ajuts: acords transformatius de la UAB
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Catalan Coastal Ranges ; Cretaceous Iberian Alkaline Province ; Lamprophyric magma
Published in:	Journal of Iberian Geology, (February 2025) , ISSN 1886-7995

DOI: 10.1007/s41513-025-00283-z

22 p, 5.0 MB

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