Estructura geològica

L'illa de Cabrera, situada al sud de Mallorca, és la continuació de les Serres de Llevant i hi té grans similituds geològiques. La sèrie estratigràfica s'inicia amb les fàcies keuper del Triàsic. El Juràssic inferior és representat per fàcies de plataforma marina i la resta del Juràssic i Cretaci inferior són enregistrats per una sedimentació marina corresponent a ambients de talús, amb olistòlits i olistostromes, i conca. Després d'una llacuna estratigràfica important, la sedimentació es reprèn amb fàcies litorals de l'Eocè mitjà i superior. Novament hi ha interrupcions importants del registre sedimentari i només es troben uns pocs sediments del Miocè superior i del Quaternari. L'estructura de Cabrera ve determinada per l'existència de falles normals, encavalcaments i uns pocs plecs. Algunes falles normals són juràssiques i s'han desenvolupat sincrònicament amb la sedimentació de les fàcies de talús; només es descriuen les existents entre el Cap des Morobutí i la Cova Blava, però de ben segur que algunes falles normals d'altres llocs de Cabrera tenen el mateix origen. D'altres falles normals tallen les roques eocenes i per tant hi són posteriors; se suggereix que aquestes podrien ser tardimiocenes o pliocenes. Si bé les falles normals són les estructures més evidents de Cabrera, considerem que els encavalcaments juguen un paper determinant. L'existència dels encavalcaments d'Es Penyal Blanc, d'Es Burrí i del Clot del Guix suggereixen dividir Cabrera en dues unitats estructurals diferents. La unitat inferior és la més gran i està constituïda per la sèrie estratigràfica sencera. La unitat superior ocupa les parts altes de l'illa i només està constituïda per roques de la fàcies de plataforma del Juràssic inferior.The Cabrera Island is located South of Mallorca and has many geologic similarities with the Serres de Llevant. The older rocks in Cabrera belongs to Triassic (Keuper facies). They are folowed by Early Jurassic marine shelf rocks, Middle and Late Jurassic marly limestones of submarine talus facies, and Lower Cretaceous basin marls. Big stratigraphic gaps exist and Cenozoic sedimentary record is discontinous; it includes Eocene litoral calcarenites, and Upper Miocene and Quaternary sediments. Normal faults are the more conspicous structures of Cabrera Island. A conjugated normal fault system Middle and Late Jurassic in age has been described between the Cap des Morobutí and the Cova Blava. Syngenetic faults other then those probably exist in other localities in Cabrera. Another set of normal faults cut Eocene rocks, thus they are post-Eocene in age. It is suggested they could be Latemost Miocene and Pliocene in age. Thrust faults play a major role in the structure of Cabrera Island. Es Penyal Blanc, Es B urrí and the Clot des Guix thrusts are clearly exposed, they suggest the existence of two different structural units. The lower one is the biggest and consists of the complete stratigraphic sequence. The upper one outcrops in the higher parts of the island and only consists of Early Jurassic shelf rocks

Variscan and Alpine structure of the hills of Barcelona: geology in an urban area

Line 9 of the underground railway is currently being constructed in Barcelona. This undertaking necessitates tunnelling through a number of hills that are mainly made up of Paleozoic rocks, which exhibit a complex structure due to the superposition of Variscan, Mesozoic, Paleogene, and Neogene structures. We present a geological map of the hills of Barcelona originally compiled at 1:5000 scale. Unpublished field notes from surveys carried out in the 1940s and in the early 1970s were crucial for drawing up this detailed map, which together with subsurface data from public works and our study of the few remaining outcrops, enabled us to provide fresh insights into the structure of this area. We also discuss the age of the structures on the basis of cross-cutting relationships and regional considerations. Our conclusions highlight the ongoing need for a geological survey of cities given that our understanding of their geology depends on impermanent outcrops and on the recovery of lost subsurface data. These considerations call for a suitable management of the geological information in urban areas with a complex geology for planning and developing safe infrastructures

Correlación de las series neoproterozoicas del Pirineo oriental a partir de datos U-Pb (SHRIMP) en zircones

New geochronological data from pre-Variscan igneous rocks of the Eastern Pyrenees (Canigó, Roc de Frausa and Cap de Creus massifs) confirm the presence of Neoproterozoic series in the Pyrenees, as the Balaig micaschists in the Canigó massif and the Lower Series in the Roc de Frausa and Cap de Creus massifs. That is, most of the pre-Upper Ordovician sequence in these massifs has to be Late Neoproteozoic in age. These geochronological data allow the correlation of the series along the Eastern Pyrenean massifs. The data also show two different ages (Late Neoproterozoic and Early Ordovician) and significance for the large bodies of granitic orthogneisses intruded at different levels in the series.Se han obtenido nuevos datos geocronológicos en rocas ígneas pre-variscas del Pirineo oriental (macizos del Canigó, Roc de Frausa y Cap de Creus). Se han datado metavulcanitas ácidas interestratificadas en la serie y gneises que derivan de granitos prevariscos. Las rocas metavolcánicas confirman la edad neoproterozoica de los esquistos de Balaig en el macizo del Canigó y de las series inferiores de los macizos del Roc de Frausa y del Cap de Creus. Estos datos implican que la mayor parte de la serie pre-ordoviciana superior tiene edad neoproterozoica y permiten correlacionar las series de los tres macizos. Las dataciones en los gneises evidencian dos edades distintas (neoproterozoica y ordovícica inferior) para los protolitos intruidos en niveles distintos de la serie.Depto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasTRUEMinisterio de Ciencia e Innovación (MICINN)Consolider-Ingenio 2010pu

Comparative geochemical study on Furongian-earliest Ordovician (Toledanian) and Ordovician (Sardic) felsic magmatic events in south-western Europe: underplating of hot mafic magmas linked to the opening of the Rheic Ocean

A geochemical comparison of early Palaeozoic felsic magmatic episodes throughout the south-western European margin of Gondwana is made and includes (i) Furongian-Early Ordovician (Toledanian) activities recorded in the Central Iberian and Galicia-Trás-os-Montes zones of the Iberian Massif, and (ii) Early-Late Ordovician (Sardic) activities in the Eastern Pyrenees, Occitan Domain (Albigeois, Montagne Noire and Mouthoumet massifs) and Sardinia. Both phases are related to uplift and denudation of an inherited palaeorelief, and stratigraphically preserved as distinct angular discordances and paraconformities involving gaps of up to 22 million years. The geochemical features of the predominantly felsic Toledanian and Sardic activities point to a predominance of magmatic byproducts derived from the melting of metasedimentary rocks, rich in SiO2 and K2O and with a peraluminous character. Zr ∕ TiO2, Zr ∕ Nb, Nb ∕ Y and Zr vs. Ga ∕ Al ratios, and rare-earth element (REE) and εNd(t) values suggest the contemporaneity, for both phases, of two geochemical scenarios characterized by arc and extensional features evolving to distinct extensional and rifting conditions associated with the final outpouring of mafic tholeiite-dominant lava flows. The Toledanian and Sardic magmatic phases are linked to neither metamorphism nor penetrative deformation; on the contrary, their unconformities are associated with foliation-free open folds subsequently affected by the Variscan deformation. The geochemical and structural framework precludes subduction-generated melts reaching the crust in a magmatic arc-to-back-arc setting and favours partial melting of sediments and/or granitoids in the lower continental crust triggered by the underplating of hot mafic magmas related to the opening of the Rheic Ocean

Detrital zircons from the pre-Silurian rocks of the Pyrenees: Geochronological constraints and provenance

The first LA-ICP-MS U-Pb detrital zircon ages from quartzites located below (three samples) and above (one sample) the Upper Ordovician unconformity in the Central Pyrenees (the Rabassa Dome, Andorra) were investigated. The maximum depositional age for the Jújols Group, below the unconformity, based on the youngest detrital zircon population, is around 475 Ma (Early Ordovician), whereas for the Bar Quartzite Fm., above the unconformity, the presence of only two zircons of 442 and 443 Ma precludes obtaining a precise maximum sedimentation age. A time gap of ~ 20 million years for the Upper Ordovician unconformity in the Pyrenees can be proposed, similar to that of the Sardic unconformity in Sardinia. The similar age patterns obtained on both sides of the Upper Ordovician unconformity suggest that there was no change in the source area of these series, while the absence of a Middle Ordovician age population may be due to a lack of sedimentation at that time. The four study samples present very similar U-Pb age patterns: the main age populations correspond to Neoproterozoic (Ediacarian-Cryogenian, ca. 550-750 Ma); Grenvillian (Tonian-Stenian, ca. 850-1100 Ma); Paleoproterozoic (Orosirian, ca.1900-2100 Ma) and Neoarchean (ca. 2500-2650 Ma). The similarity with the Sardinian age distribution suggests that these two terranes could share the same source area and that they were paleogeographically close in Ordovician times in front of the Arabian-Nubian Shield

Cadomian metabasites of the Eastern Pyrenees revisited

This study presents a new geochemical, petrological, and geochronological U-Pb dataset from Ediacaran metabasites of the Canigó and Cap de Creus massifs, Eastern Pyrenees. The rocks are composed of calcic amphibole + plagioclase + chlorite + epidote ± quartz plus titanite + apatite + ilmenite ± biotite ± rutile as accessory phases and show relict igneous textures. Peak pressure-temperature determinations share common conditions, ranging 452-482ºC and 5.2-7.7kbar. These intermediate P-T conditions suggest Barrovian-type metamorphism, most likely related to a collisional setting. The metabasites correspond to evolved basaltic rocks (Mg#<0.55) with moderate TiO2 content (up to 2.08wt.%) and relatively low Cr (43-416ppm). The rocks are moderately enriched in light rare earth elements (LREE) relative to heavy rare earth elements (HREE) (average (La/Lu)n of 2.7) and the N-MORB normalized multi-element patterns show negative slopes, with prominent negative Nb anomalies ((Nb/La)NMORB=0.33-0.78). These variations are akin to island arc tholeiites generated in back-arc basins and to other metabasites described in the Eastern Pyrenees with a putative Ediacaran age, and they differ from the Ordovician tholeiitic metabasites from the Canigó massif, which derived from a contaminated E-MORB source. The positive ƐNd(T) values (0.82-3.05) of the studied metabasites preclude a notable contribution from an older continental crust. U-Pb dating (LA-ICP-MS) of one chlorite-rich schist sample in contact with the metabasites from the Canigó massif yielded a main peak at ca. 632Ma. We argue that the Cadomian metabasites from the Pyrenees formed during back-arc extension in the continental margin of Gondwana and were later affected by (probably early Variscan) medium-P metamorphism before the HT-LP metamorphism classically described in the Pyrenees

Do ART and chemsex drugs get along? Potential drug-drug Interactions in a cohort of people living with HIV who engaged in chemsex: a retrospective observational study.

Introduction: People living with HIV (PLWH) who engaged in chemsex are at risk of potential drug-drug interactions (pDDIs) with recreational drugs. This study aimed to characterize pDDIs between antiretroviral treatment (ART) and chemsex drugs and evaluate their association with unscheduled relevant hospital consultations. Methods: We conducted a single-center, retrospective, observational study in a series of gay, bisexual, and other men who have sex with men (gbMSM) living with HIV who engaged in chemsex and who attended a tertiary hospital in Barcelona, Spain, from February 2018 through August 2019. Associations between all recorded pDDIs and relevant unscheduled consultations were estimated using the incidence rate (IR) per 100 person-years of those events compared between patients with no pDDI (green flag) or moderate severity pDDI (orange flag) with patients with high severity pDDI (red flag) using the incidence rate ratio (IRR). Results: Among 172 PLWH engaged in chemsex, 249 ART regimens were prescribed: 44% based on integrase inhibitors, 30% on boosted ART, and 26% based on non-nucleoside reverse transcriptase inhibitors. The substances and recreational drugs most frequently used were erectile dysfunction agents (83%), methamphetamine (79%), GHB (77%), and alkyl nitrites (71%). Polydrug use was reported in 52%. We observed 2048 pDDIs. Of these, 23% were orange flag pDDIs; 88% related to boosted ARTs. The IR of the 285 unscheduled relevant episodes in patients with orange flag pDDIs was 64.67 (95% CI 40.07-89.28). The IRR of green flag pDDIs was 1.05 (95% CI 0.60-1.8; p = 0.876). Conclusion: One in four pDDIs were of moderate severity but no significant increase in the incidence of unscheduled relevant consultations was observed. A high number of unscheduled consultations, predominantly for psychiatric events and intoxication, were observed. Beyond using non-boosted ART to minimize pDDIs, other factors related to the practice of chemsex must be addressed, in order to offer a better approach

Structured Treatment Interruptions and Low Doses of IL-2 in Patients with Primary HIV Infection. Inflammatory, Virological and Immunological Outcomes

BACKGROUND: Interventions during primary HIV infection (PHI) can modify the clinical course during the chronic phase. The long-term effect of structured treatment interruptions (STI) followed by low doses of interleukin-2 (IL-2) in treated PHI patients is unknown. METHODS: Twelve PHI patients with viral load (VL) 500 cells/mm3, and CD4/CD8 ratio >1, on antiretroviral therapy (ART) initiated within the first 90 days of infection and continued for at least 12 months were included. They underwent four STI and were then allocated (week 0 of the study) to ART alone or ART plus low doses of IL-2. ART was stopped once VL 500 cells/mm3 at 48 weeks; secondary endpoints were immune activation, inflammatory markers until 48 weeks and the time before resuming ART (CD4 500 cells/mm3 without ART at 48 weeks. All other virological and immunological parameters were comparable between groups at week 0, 'final stop' and week 48. However, the proportion of CD8-CD38+ cells, tumor necrosis factor and srIL-2 were higher in the IL-2 group at 'final stop' and week 24. All these differences vanished during follow-up. At 5 years after the final stop 3 out of 6 patients in the IL-2 group and 6 out of 6 patients in the STI group have resumed ART (P = 0.19). CONCLUSIONS: STI and IL-2 failed to achieve virological control after ART interruption. STI were not deleterious in long-term follow-up, an important issue for eradication and functional cure trials

Detrital zircons from the Ordovician rocks of the Pyrenees: Geochronological constraints and provenance

The first LA-ICP-MS U–Pb detrital zircon ages from quartzites located below (three samples) and above (one sample) the Upper Ordovician unconformity in the Central Pyrenees (the Rabassa Dome, Andorra) were investigated. The maximum depositional age for the Jújols Group, below the unconformity, based on the youngest detrital zircon population, is around 475 Ma (Early Ordovician), whereas for the Bar Quartzite Fm., above the unconformity, the presence of only two zircons of 442 and 443 Ma precludes obtaining a precise maximum sedimentation age. A time gap of ~20 million years for the Upper Ordovician unconformity in the Pyrenees can be proposed, similar to that of the Sardic unconformity in Sardinia. The similar age patterns obtained on both sides of the Upper Ordovician unconformity suggest that there was no change in the source area of these series, while the absence of aMiddle Ordovician age population may be due to a lack of sedimentation at that time. The four study samples present very similar U–Pb age patterns: the main age populations correspond to Neoproterozoic (Ediacarian–Cryogenian, ca. 550–750 Ma); Grenvillian (Tonian–Stenian, ca. 850–1100 Ma); Paleoproterozoic (Orosirian, ca.1900–2100 Ma) and Neoarchean (ca. 2500–2650 Ma). The similarity with the Sardinian age distribution suggests that these two terranes could share the same source area and that they were paleogeographically close in Ordovician times in front of the Arabian–Nubian Shield