https://hdl.handle.net/2072/353045 Sat, 04 Apr 2026 02:21:22 GMT 2026-04-04T02:21:22Z https://hdl.handle.net/2072/481464 Petrogenesis of the alkaline lamprophyre cluster between Molí d’en Ponç and Collet de la Cidereda (eastern Catalonian Coastal Ranges, NE Iberia) Culí, Laura; Campeny, Marc; Solé, Jesús 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. DyN/YbN 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 (Fo74 to Fo88). 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.; Este trabajo se centra en el estudio del grupo de camptonitas de edad cretácica localizadas entre el Molí d'en Ponç y el Collet de la Cidereda, localizado en el macizo oriental del Montseny de las Cordilleras Costero-Catalanas (NE de la Península Ibérica). Estos lamprófidos post-orogénicos (~ 79 Ma) intruyen granitoides paleozoicos y variscos tardíos. Su intrusión está relacionada con la apertura del Golfo de Vizcaya. Por lo tanto, pertenecen a la Provincia Ígnea Alcalina Ibérica del Cretácico superior. El grupo estudiado comprende dos filones de dirección N110-N140 y diques subverticales que intruyen a los filones de camptonita o a la roca granodiorítica encajante. Las relaciones DyN/YbN ≥ 2.4 muestran que los fundidos primarios de las camptonitas estudiadas se generaron a presiones superiores a ~ 2.5 GPa (~ 80 km) en el campo de estabilidad del granate, cerca de la transición al campo de estabilidad de la espinela. Los fundidos más evolucionados, correspondientes a basaltos alcalinos sódicos, fueron sometidos a procesos de enriquecimiento intraplaca y cristalización fraccionada. Los antecristales y microlitos de olivino corresponden a forsterita (Fo74 a Fo88). Estos no muestran una composición procedente del manto peridotítico y algunos están en equilibrio con sulfuros. Los antecristales de clinopiroxeno corresponden a diópsido (Mg# 75–80) y no muestran una composición procedente del manto peridotítico. Los antecristales de forsterita, diópsido y kaersutita muestran variaciones composicionales oscilatorias que se relacionan con procesos de mezcla asociados al ascenso de sucesivos pulsos magmáticos. Las mayores concentraciones de Mn en los microlitos de forsterita y diópsido de la matriz, si se comparan con las de los antecristales, son coherentes con una composición más evolucionada del magma ascendente. La estimación de la presión obtenida a partir de los núcleos de los antecristales de diópsido (~ 1 GPa) es coherente con un estancamiento del magma ascendente en la corteza inferior o en el límite de la transición entre la corteza inferior y el manto superior. La presión obtenida en los bordes de los antecristales de clinopiroxeno es de ~ 0.28 GPa. Thu, 16 Jan 2025 00:00:00 GMT https://hdl.handle.net/2072/481464 2025-01-16T00:00:00Z https://hdl.handle.net/2072/537865 PGE-Ni-Cu sulphide segregation by interaction of basaltic melt and peridotite xenoliths of the Catalan Volcanic Zone (Spain) [accepted version] Roquet Peña, Miguel; Campeny, Marc; Llovet, Xavier Spinel lherzolite xenoliths from the Sant Corneli volcano (Catalan Volcanic Zone, NE Spain) carry the geochemical imprint of melt/rock reaction events that have affected the subcontinental lithospheric mantle (SCLM) beneath the northeastern Iberian margin. Trace element signatures of clinopyroxene indicate that this volume of the SCLM initially experienced low degrees (F = 8 %) of partial melting, followed by extensive refertilization by alkaline silicate melts undergoing chromatographic fractionation while percolating through the mantle peridotites. Furthermore, the presence of interstitial sulphide-bearing silicate glass, as well as secondary coronitic rims around mantle minerals, records the melt/rock reaction product associated with the infiltration of the host alkaline basalts while erupting to the surface. Abundant irregular/blocky sulphides located within the interstitial glass patches are comprised of myrmekitic intergrowths of pentlandite ± bornite ± chalcopyrite, suggesting their derivation from immiscible droplets of Fe-Ni-Cu sulphide melt transported by the host alkaline basalts. The variable chondrite-normalized platinum-group element (PGE) systematics and chalcogenes (Se, Te, As, Bi and Sb) abundances of these sulphides track two distinct transport mechanisms for their parental sulphide melts: 1) by unmixing of Ni-Cu-rich sulphide liquid in alkaline basalts attaining sulphide-saturation while interacting with the peridotite xenoliths, and 2) by mechanical transport of immiscible droplets of Ni-Cu-rich sulphide liquid originally extracted by residual monosulphide solid solution undergoing incongruent melting in their mantle source. In addition, many sulphides have PGE abundances that cannot be explained solely by solid-melt chemical partition coefficients but that were likely influenced by the mechanical entrapment, or earlymagmatic segregation, of pre-existing PGE-rich nanoparticles or nanomelts. The geochemical signal of these mineral nanoparticles may significantly influence sulphides PGE distribution, sometimes resulting in pronounced positive anomalies in Ir–Rh, Au, or Ru–Rh, along with negative anomalies in Pt. Sat, 28 Sep 2024 00:00:00 GMT https://hdl.handle.net/2072/537865 2024-09-28T00:00:00Z https://hdl.handle.net/2072/537658 Rare earth element distribution on the Fuerteventura basal complex (Canary islands, Spain): a geochemical and mineralogical approach Campeny, Marc; Menéndez, Inmaculada; Mangas, José The Fuerteventura Basal Complex comprises Oligocene and Miocene ultra-alkaline-carbonatitic magmatic pulses with outcrops that extend across kilometer-scale areas in some specific sectors of this oceanic island. Additionally, there is evidence of associated weathering materials that affect these magmatic lithologies. These alkaline magmatic rocks (including trachytes, phonolites, syenites, melteigites, and ijolites), carbonatites, and their associated weathering products underwent a preliminary evaluation of rare Earth element (REE) contents based on mineralogical and geochemical studies. REE concentrations in carbonatites of about 10 300 ppm REY (REEs plus yttrium) have been detected in volumes comparable to other locations hosting significant deposits of these critical elements worldwide. Conversely, alkaline magmatic rocks and the resulting weathering products display limited REE contents. Notably, REEs in carbonatites are associated with primary accessory phases such as REEbearing pyrochlore and britholite and secondary monazite. The results obtained in the carbonatites of Fuerteventura underscore the interest in studying the concentrations of critical elements, such as REEs, within a non-conventional geological setting like oceanic islands. However, due to intricate structural attributes, the irregular distribution of these mineralizations, and possible land use and environmental constraints, additional future detailed investigations are imperative to ascertain the real potential of these REE concentrations. Fri, 14 Jun 2024 00:00:00 GMT https://hdl.handle.net/2072/537658 2024-06-14T00:00:00Z https://hdl.handle.net/2072/537559 Com trobar elements rars de la taula periòdica a Catalunya? Melgarejo, Joan Carles; Campeny, Marc; Pujol-Solà, Núria Hi ha molts mecanismes de concentració d’elements químics a partir de la seva dispersió ge oquímica per tal de formar dipòsits minerals d’interès econòmic. La diversitat de processos geològics que han configurat el subsòl de Catalunya permet esperar una gran diversitat de recursos, molts d’ells explotats ja de fa segles. En aquest treball es discuteixen les possibilitats que alguns recursos d’elements rars, mai investigats en detall, es puguin trobar a Catalunya, i es conclou que hi ha recursos potencials en aquests elements formats per processos de fraccionament magmàtic, hidrotermal i supergènic.; There are many mechanisms for the concentration of chemical elements from their geochemical dispersion to the formation of mineral deposits of economic value. The diversity of geological processes that were active during the geological history of Catalonia led to the creation of a wide range of mineral resources, many of which have been exploited for centuries. This paper discusses the possibility that some rare element resources that have never been thoroughly investigated could be found in Catalonia, and concludes that potential resources of these elements have been formed by magmatic, hydrothermal, and supergene fractionation processes. Wed, 01 Jan 2020 00:00:00 GMT https://hdl.handle.net/2072/537559 2020-01-01T00:00:00Z