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Absolute age dating of a brittle deformation using radiometric techniques is often problematic. Unlike ductile deformation, suitable minerals with high parent/daughter and low common Pb are rare. Nevertheless, U-Pb dating of carbonate minerals has become one of the most conceivable geochronometers despite low U and high initial Pb in carbonates. Carbonates can be formed in wide range of environments and are a typical fracture-filling minerals in rocks affected by brittle deformation. U-Pb dating technique using Laser Ablation Inductively Coupled Plasma Mass Spectrometer (LA-ICP-MS) has been utilized with some success for near a decade. However, challenges remained, and a new method (LA-ICP-MS imaging U-Pb dating) is developed recently which enables surface scan of larger analytical area to increase the possibil-ity of getting sufficient spread in U-Pb ratios. The main aim of this research project was to test the LA-ICP-MS imaging technique on fracture filling calcite minerals. Samples were collected at the Dalby and Skrylle quarries which are located along the Sorgenfrei Tornquist Zone (STZ) of Scania in southernmost Sweden. Linear surface scans were conducted on selected rectangular areas (analytical areas) of chosen samples across relatively less altered and homogeneous zones based on petrographic characterization. Age dating calculations were done based on selection and pooling of data points using certain criteria. Age dating results of calcite in the Skrylle quarry are 222 ± 46 and 213 ± 29 Ma. Dated calcite from the Dalby quarry yielded 495 ± 29, 553 ± 10, and 505 ± 9 Ma. The results show that combining petrography and LA-ICP-MS imaging U-Pb analyses is a promising approach to acquire plausible absolute ages of car-bonates and hence brittle deformation. On the assumption that the ages are accurate, and that calcite is formed at the instant of fracturing, these U-Pb ages are the first that directly dates brittle deformation along the STZ. Given that, age dating, Absolut åldersdatering av spröd deformation med radiometriska tekniker är ofta problematiskt. Till skillnad från duktil deformation är lämpliga mineral med högt förälder/dotter isotopförhållande och lågt innehåll av initialt Pb sällsynta. Ändå har U-Pb-datering av karbonatmineral blivit en av de mest tänkbara geokronometrarna trots lågt U och högt initialt Pb i karbonater. Karbonater kan bildas i många olika miljöer och kalcit är ett typiskt sprickfyllande mineral i bergarter som påverkats av spröd deformation. U-Pb-dateringsteknik med laserablation induktivt kopplad plasmamasspektrometer (LA-ICP-MS) har använts med viss framgång i nästan ett decennium. Utmaningar kvarstod dock och en ny metod (LA-ICP-MS imaging U-Pb-datering) har nyligen utvecklats, vilket möjliggör ytskanning av större analytisk yta och ökar möjligheten att få tillräcklig spridning i U-Pb-förhållanden. Huvudsyftet med detta forskningsprojekt var att testa LA-ICP-MS avbildningstekniken på sprickfyllande kalcitmineral. Prover togs vid Dalby och Skrylle stenbrott som ligger längs Sorgenfrei Tornquist Zonen (STZ) i Skåne i sydligaste Sverige. Linjära ytavsökningar utfördes på utvalda rektangulära områden (analytiska områden) av valda prover över relativt mindre förändrade och homogena zoner baserat på petrografisk och 2-D element- och isotopkarakterisering. Åldersdateringsberäkningar gjordes baserat på urval och sammanslagning av datapunkter med hjälp av vissa kriterier. Åldersdateringsresultat av kalcit i Skryllebrottet är 222 ± 46 och 213 ± 29 Ma. Daterad kalcit från Dalbytäkten gav 495 ± 29, 553 ± 10 och 505 ± 9 Ma. Resultaten visar att kombinationen av petrografi och LA-ICP-MS avbildning U-Pb-analyser är ett lovande tillvägagångssätt för att få rimliga absoluta åldrar av karbonater och därmed spröd deformation. Under antagandet att åldrarna är korrekta och att kalcit bildas i ögonblicket för sprickbildning, är dessa U-Pb åldrar de första som direkt daterar spröd deformation längs STZ. Med tanke på, U-Pb dating of carbonates can be applied to a variety of geological themes including constraining the time of a brittle deformation/faulting (i.e., tectonic processes of the upper, rigid part of the crust). However, absolute age dating of brittle deformation is challenging mainly due to a lack of robust chronometers that meet isotopic prerequisites. To tackle these challenges, the combined use of U-Pb geochronology and Laser Inductively Coupled Plasma Mass Spectrometer (LA-ICP-MS) of carbonate minerals have been utilized since a near decade. Carbonates, and especially calcite, are prime targets because they are typical fracture-filling minerals, and they can incorporate sufficient amounts of U during formation. Nonetheless, the challenges remained as the U incorporated to carbonates is low (typically below ca. 10 ppm) while the amount of initial Pb is significant. Additionally, carbonates are susceptible to a secondary alteration process that involves mobility of U and Pb. The LA-ICP-MS imaging U-Pb method circumvent many challenges via increasing surface scan of analytical areas, thereby allowing usage of 2-D elemental and isotope map characterization as well as petrographic interpretations of analyzed areas. The goal of this thesis project was to test and apply the LA-ICP-MS imaging U-Pb method on tectonic carbonate/fracture-filling calcites using the Bruker Aurora Elite single collector ICP-MS at the Department of Geology, Lund University. Samples were collected in the Skrylle and Dalby quarries along the Sorgenfrei Tornquist Zone (STZ) of Scania region, southernmost Sweden. STZ represents a 20-50 km wide, NW-SE trending major tectonic system of fault zones within the gneissic basement, which also affects overlaying Phanerozoic sediments in southern Sweden. In situ sampling was done on thin section surfaces via successive linear scans of rectangular areas aimed to obtain the largest possible spread in U-Pb to constrain a lower intercept age in the Tera-Wasserburg

Dating fold-related structures is critical to understand the timing, duration, and rate of fold growth as well as the sequential evolution of fold-and-thrust belts. In this contribution, we combine structural analysis of fractures with U-Pb dating of calcite veins related to the evolution of the Bóixols-Sant Corneli anticline (Southern Pyrenees) aiming to constrain the age and evolution of deformation and the duration of folding. Twenty-three U-Pb ages were obtained in the different sets of fracture-filling calcite veins, which span from Late Cretaceous to late Miocene (79.8 ± 1.2 Ma to 9 ± 4.6 Ma). These ages have been attributed to growth (71.2 to 56.9 Ma), fold tightening (55.5 to 27.4 Ma) and collapse (20.8 to 9.0 Ma) of the Bóixols-Sant Corneli anticline. This reveals a duration of 14 Myr for the folding stage and 28 Myr for the fold tightening, which translates in 42 Myr of the entire folding process and thus encompassing most of the Pyrenean compression.

U-Pb dating and geochemical analyzes ( 818 O, 813 C, A47 , 87 Sr/ 86 Sr and elemental composition) have been applied to fracture-filling calcite veins and host carbonates from the Boixols-Sant Corneli anticline, which developed along the front of the Boixols thrust sheet in the Southern Pyrenees. This robust dataset is used to determine: (i) the absolute timing of fracturing and mineralization from fluid flow; (ii) the age and duration of fold evolution; and (iii) the variations and implications of fluid behavior across the anticline, as has been described in the article "Spatio-temporal variation of fluid flow behavior along a fold: The Boixols-Sant Corneli anticline (Southern Pyrenees) from U-Pb dating and struc-tural, petrographic, and geochemical constraints - Marine and Petroleum Geology (2022) (Munoz-Lopez et al., 2022). In this new contribution, we present the raw data that have been analyzed and discussed in the related research article and, also, the whole elemental and REE composition of cal-cite veins and host carbonates that has not been published yet. These data may be used to unravel the age and origin of veins, to understand their sequential evolution in orogenic belts and to compare our results with those obtained in sim-ilar settings worldwide.

Calcite veins precipitated in the Estamariu thrust during two tectonic events have been investigated in order to decipher the relationships between deformation and fluid migration in Paleozoic basement rocks. Structural observations constrain the timing of vein formation and fluid migration, whilst geochemical analyses (¿13C, ¿18O, 87Sr/86Sr and elemental composition) of the related calcite cements indicate the fluid origin, pathways and extent of fluid-rock interaction. The first tectonic event, related to the Alpine reactivation of the Estamariu Variscan thrust, is characterized by the upward migration of fluids derived from the crystalline basement, giving rise to the precipitation of calcite cements Cc1 and Cc2. The second tectonic event, developed during the Neogene extension, was responsible of the reactivation of the Estamariu thrust and the development of normal faults and shear fractures in which calcite cements Cc3, Cc4 and Cc5 precipitated. Cc3 and Cc4 precipitated from meteoric fluids that interacted at depth with basement rocks before upflowing through fault zones and related structures. Cc5 precipitated from meteoric fluids percolating from the surface through small fractures.

Detailed geochemical investigations of calcite veins, genetically related to intrusions and vein-hosting bedrock, have been used to indicate fluid evolution during intrusion-related hydrothermal mineralization, involving fluid mixing and water rock interaction. The area of investigation is located in the southeast of Sweden. The 1.85 Ga granitoid country rocks and the 0.9 Ga dolerite vein-related intrusions differ in chemical, geochemical, and stable isotope composition. The variation in rare earth and stable isotope composition across calcite veins and the presence of two groups of fluid inclusions suggests mixing of two types of fluids. Light rare earth enrichment and increasing Sr-87/Sr-86-ratios suggest water rock interaction of one/both fluids. (C) 2013 The Authors. Published by Elsevier B.V.