Testing carbonate chemostratigraphy across differentiated ancient shallow-platform environments (Early Kimmeridgian, S Iberia)

Shallow-platform settings with marked differences in paleoplatform bottom physiography influence the degree of connection with oceanic waters and overall circulation patterns, even when sharing the same palaeoclimatic conditions. Two Kimmeridgian shallow-marine settings have been explored to test the sensitivity and reliability of carbonate chemostratigraphy to detect such differences. An integrated overview of the obtained elemental trends depicted four major facies, shared along specific stratigraphic intervals of both depositional records. Diagenesis obliterated original geochemical signals only throughout the siliciclastics-rich interval, corresponding to the most landward setting. For the remaining facies, elemental features could be attributed to the differential action of forcing mechanisms operating along the south-Iberian paleomargin during Kimmeridgian times. The highest degree of continental influence can be recognized by a strong relationship between Fe and Mn for the most proximal setting, which fades out along the mixed carbonate-fine siliciclastic rhythmic deposition in more open settings. A characteristic geochemical signature of progressively more positive d13C values and significantly higher Sr content is identified for the interval dominated by biogenic sponge buildups.This research was supported by Projects CGL2008-05251-E and CGL2012-39835 (MINECO) and the Research Group RNM-178, Junta de Andalucía, Spain. R. Coimbra is currently supported by the Post- Doctoral Fellowship SFRH/BPD/92376/2013 (Fundação para a Ciência e a Tecnologia, Portugal) and the research units GeoBiotec - UID/GEO/04035/2013 and MARE- UID/MAR/04292/2013

Customised display of large mineralogical (XRD) data: Geological advantages and applications

X-ray diffraction mineralogical analysis of geological sequences is a well-established procedure in both academia and industry, rendering a large volume of data in short-analytical time. Yet, standard data treatment and resulting interpretations present limitations related to the inherent complexities of natural geological materials (e.g. compositional variety, structural ordering), and are often time consuming and focussed on a very detailed inspection. Several alternatives were evaluated in terms of advantages and disadvantages to the main goal of generating a user-friendly, fast and intuitive way of processing a large volume of X-ray diffraction data. The potential of using raw X-ray diffraction data to interpret mineralogical diversity and relative phase abundances along sedimentary successions is explored here. A Python based program was tailored to assist in raw data organisation. After this automated step, a 3D surface computation renders the final result within minutes. This single-image representation can also be integrated with complementary information (sedimentary logs or other features of interest) for contrast and/or comparison in multi-proxy studies. The proposed approach was tested on a set of 81 bulk and clay-fraction diffractograms (intensity in counts per second—cps and respective angle—º2Ɵ) obtained from a Cenomanian mixed carbonate–siliciclastic stratigraphic succession, here explored by combining mineralogical (XY) and stratigraphic/geological information (Z). The main goal is to bypass preliminary data treatment, avoid time-consuming interpretation and unintended, but common, user-induced bias. Advantages of 3D modelling include fast processing and single-image solutions for large volumes of XRD data, combining mineralogical and stratigraphic information. This representation adds value by incorporating field (stratigraphic/sedimentological) information that complements and contextualises obtained mineralogical data. Limitations of using raw intensity data were evaluated by comparison with the results obtained via other standard data interpretation methods (e.g. semi-quantitative estimation). A visual and statistical contrast comparison confirmed a good equilibrium between computation speed and precision/utility of the final output. © 2022 The Authors. The Depositional Record published by John Wiley & Sons Ltd on behalf of International Association of Sedimentologists

Relatório de estágio

Este relatório surge como resultado do estágio curricular desenvolvido na área de Saúde Infantil e Pediatria, enquadrado no 7º curso de Mestrado em Enfermagem com Especialização em Saúde Infantil e Pediátrica, do Instituto de Ciências da Saúde do Porto da Universidade Católica Portuguesa. O estágio desenvolveu-se em três módulos: Módulo I – Saúde Infantil, com um total de 250 horas, que decorreu na Unidade de Saúde Familiar Terras da Feira e Unidade de Cuidados na Comunidade de Santa Maria da Feira; Módulo II – Serviços de Medicina e Cirurgia que foi desenvolvido no Serviço de Pediatria do Centro Hospitalar Entre Douro e Vouga num total de 250 horas; Módulo III – Serviços de Urgência Pediátrica e Serviços de Neonatologia, que decorreu no Serviço de Urgência Pediátrica do Centro Hospitalar Entre Douro e Vouga, com 125 horas, e na Unidade de Cuidados Intensivos Neonatais do Hospital de São João, igualmente com 125 horas. O percurso trilhado em cada módulo de estágio teve como principal objetivo a aquisição de competências, através da concretização dos objetivos, nos domínios da prestação de cuidados, formação, gestão e investigação. No sentido de demonstrar o processo de aquisição e desenvolvimento de competências nos domínios descritos, na área da Saúde Infantil e Pediatria, este documento, tem como principal objetivo a análise crítica e reflexiva das atividades que foram desenvolvidas ao longo dos diferentes módulos do estágio. As áreas da parentalidade, da dor e da parceria de cuidados foram aquelas que ao longo do estágio me permitiram adquirir e desenvolver capacidades e habilidades na sua abordagem.This report is produced as the result of the apprenticeship developed in the area of Child Health and Paediatrics, within the seventh degree of the Masters with Specialization in Child Health and Paediatrics Nursing by the Instituto de Ciências da Saúde of Oporto of Universidade Católica Portuguesa, being as a document for evaluation purposes in order to obtain the professional title of Nurse Specialist in the correspondent area. The apprenticeship consisted of three modules: Module I - Child Health, with a total of 250 hours, which were carried out at Unidade de Saúde Familiar Terras da Feira and Unidade de Cuidados na Comunidade de Santa Maria da Feira; Module II - Medical and Surgical Service, which as developed at the Pediatric Internment of Centro Hospitalar Entre Douro e Vouga, totaling 250 hours; Module III - Service of Pediatric Intensive Care and Pediatric Emergency, which were carried out at the Pediatric Urgency Service, of Centro Hospitalar Entre Douro e Vouga, with 125 hours and at the Neonatal Intensive Care Unit at the Hospital de São João, also with 125 hours. Throughout the learning path in every apprenticeship module had as principal goal the acquisition of skills, through the concretization of the goals in the domians of Care Providing, Management, Training and Investigation. In order to demonstrate the process of acquisitions a development of skills in the areas above described, in the field of Child Health and Paediatrics, this document, as the main aim a critic and reflexive analysis of the activities developed in the diferentes modules of the apprenticeship. The areas of parenting, pain and partnership care, were those that along the apprenticeship allowed to acquire and to develop capacites and skills in its approach

Evaluating and comparing geochemical sampling protocols in dinosaur eggshells: refining Cretaceous ecosystem research

The geochemical signatures of dinosaur eggshells represent well-established proxies in paleoenvironmental and paleobiological research. The variable sampling procedures reported in the literature, however, deserve attention. In order to evaluate the impact of different sampling methodologies on carbon and oxygen isotope and elemental concentrations, grinding was contrasted with drilling to extract powder samples from eggshell fragments collected at several locations. Eggshell data were further contrasted with surface materials, encasing matrix and compared with independent proxies using petrographic and elemental techniques. Iron and manganese elemental concentrations revealed an enrichment sequence depending on the sampling strategy for the same eggshell fragment. This pattern can be mistaken for a variable state of preservation. In contrast, carbon and oxygen isotope values exhibited only subtle differences and lacked clear trends. This suggests that isotope data are less susceptible to different methodological approaches. It is shown that drilling offers a wider range of possibilities compared to grinding (e.g., faster and less destructive). Additionally, drilled powder samples can confidently be used for elemental and isotope analysis, excluding contamination, thus providing a more accurate set of proxy data from eggshell archives

Spatial geochemistry and chemostratigraphy across a late Jurassic paleomargin - marine water masses in S- E Iberia

Tesis Univ. Granada. Departamento de Estratigrafía y Paleontología. Leída el 21 de octubre de 201

Disentangling shallow-water bulk carbonate carbon isotope archives with evidence for multi-stage diagenesis: An in-depth component specific petrographic and geochemical study from Oman (mid-Cretaceous)

Disentangling shallow-water bulk carbonate carbon isotope archives into primary and diagenetic components is a notoriously difficult task and even diagenetically screened records often provide chemostratigraphic patterns that significantly differ from global signals. This is mainly caused by the polygenetic nature of shallow-water carbonate substrates, local carbon cycle processes causing considerable neritic-pelagic isotope gradients and the presence of hiatal surfaces resulting in extremely low carbonate preservation rates. Provided here is an in-depth petrographic and geochemical evaluation of different carbonate phases of a mid-Cretaceous (Barremian-Aptian) shallow-water limestone succession (Jabal Madar section) deposited on the tropical Arabian carbonate platform in Oman. The superposition of stable isotope signatures of identified carbonate phases causes a complex and often noisy bulk carbon isotope pattern. Blocky sparite cements filling intergranular pores and bioclastic voids evidence intermediate to (arguably) deep burial diagenetic conditions during their formation, owing to different timing or differential faulting promoting the circulation of fluids from variable sources. In contrast, sparite cements filling sub-vertical veins reveal a rock-buffered diagenetic fluid composition with an intriguing moderate enrichment in C-13, probably due to fractionation during pressure release in the context of the Miocene exhumation of the carbonate platform under study. The presence of abundant, replacive dedolomite in mud-supported limestone samples forced negative carbon and oxygen isotope changes that are either associated with the thermal breakdown of organic matter in the deep burial realm or the expulsion of buried meteoric water in the intermediate burial realm. Notwithstanding the documented stratigraphically variable and often facies-related impact of different diagenetic fluids on the bulk-rock stable isotope signature, the identification of diagenetic end-members defined C-13 and O-18 threshold values that allowed the most reliable primary' bulk carbon isotope signatures to be extracted. Most importantly, this approach exemplifies how to place regional shallow-water stable isotope patterns with evidence for a complex multi-stage diagenetic history into a supraregional or even global context

Improving the detection of shell alteration: Implications for sclerochronology

Sclerochronology makes use of (fossil) shell-archives to establish records allowing for investigation of high-resolution environmental dynamics. Nevertheless, this potential can often not be fully exploited due to the interplay between paleoenvironmental variability, vital effects and the potential diagenetic modification of skeletal materials, which often results in highly complex records. A novel dynamic approach, aiming to separate pristine from altered shell material for paleoclimate and paleoenvironmental reconstructions is proposed. Seventeen fossil bivalve shells (requieniid rudists, pectinids and chondrodonts) from two neighbouring Lower Cretaceous (Albian) shallow-water sections (Lusitanian Basin, western Portugal) were analysed for their major and trace elemental compositions using high-resolution quantitative μXRF line scans. Their complex records were subject to a novel statistical analysis protocol, which tested mono- and multi-species datasets, as well as comparing shells from both locations. Characteristic elemental associations reveal the differential impact of early and late diagenetic alteration processes. The incorporation of elements associated with detrital contribution (Fe, Si, Al) is attributed to syn-depositional bioerosion (shell-boring). In clear contrast, shell-portions showing a strong correlation between Fe and Mn are indicative of later diagenetic alteration. The influence of each process is different at each site, revealing local differential alteration pathways. Mono-specific comparisons provides identical geochemical responses, suggesting that intra-specific differences do not control the observed elemental patterns. In contrast, inter-species tests rendered a clear separation in the way elements are incorporated in the shells of pectinids and requieniids (e.g., as evidenced by differences in Mg or Sr content). Such differences can be linked to differential biomineralization pathways, easily detected by the applied method. We present a new, dynamic method for distinguishing pristine from altered shell material, not relying on arbitrary diagenetic thresholds for trace element content. By clearly identifying shell-alteration pathways, syn- to post-depositional processes are recognized. A progressive cleaning of the elemental dataset allows paleoenvironmental studies to be based on the most pristine data, contributing to unravelling the complex interplay between climate, environmental dynamics and their impact on biomineralization processes and sclerochronological archives

Improving the detection of shell alteration: Implications for sclerochronology

Sclerochronology makes use of (fossil) shell-archives to establish records allowing for investigation of high-resolution environmental dynamics. Nevertheless, this potential can often not be fully exploited due to the interplay between paleoenvironmental variability, vital effects and the potential diagenetic modification of skeletal materials, which often results in highly complex records. A novel dynamic approach, aiming to separate pristine from altered shell material for paleoclimate and paleoenvironmental reconstructions is proposed. Seventeen fossil bivalve shells (requieniid rudists, pectinids and chondrodonts) from two neighbouring Lower Cretaceous (Albian) shallow-water sections (Lusitanian Basin, western Portugal) were analysed for their major and trace elemental compositions using high-resolution quantitative μXRF line scans. Their complex records were subject to a novel statistical analysis protocol, which tested mono- and multi-species datasets, as well as comparing shells from both locations. Characteristic elemental associations reveal the differential impact of early and late diagenetic alteration processes. The incorporation of elements associated with detrital contribution (Fe, Si, Al) is attributed to syn-depositional bioerosion (shell-boring). In clear contrast, shell-portions showing a strong correlation between Fe and Mn are indicative of later diagenetic alteration. The influence of each process is different at each site, revealing local differential alteration pathways. Mono-specific comparisons provides identical geochemical responses, suggesting that intra-specific differences do not control the observed elemental patterns. In contrast, inter-species tests rendered a clear separation in the way elements are incorporated in the shells of pectinids and requieniids (e.g., as evidenced by differences in Mg or Sr content). Such differences can be linked to differential biomineralization pathways, easily detected by the applied method. We present a new, dynamic method for distinguishing pristine from altered shell material, not relying on arbitrary diagenetic thresholds for trace element content. By clearly identifying shell-alteration pathways, syn- to post-depositional processes are recognized. A progressive cleaning of the elemental dataset allows paleoenvironmental studies to be based on the most pristine data, contributing to unravelling the complex interplay between climate, environmental dynamics and their impact on biomineralization processes and sclerochronological archives

Inter-species variability in palaeoseasonality records from fossil bivalve shells: Evidence from Late Albian rudist and pectinid shells from the Lusitanian Basin, Portugal

Palaeoclimate reconstructions are essential for improving our understanding of Earth’s climate. Complementaryto more commonly reported long term palaeoclimate reconstructions, much information can be obtained frompalaeoclimate and –environment reconstruction on a shorter, seasonal time scale. Calcite shells of bivalves canprovide the high resolution climate archives required for doing these reconstructions in deep-time. These organismsgrow by incrementally adding carbonate to their shell, and are shown to precipitate stable oxygen isotoperatios in equilibrium with the ambient sea water, hereby recording past sea water composition and temperature(Klein et al., 1996). However, additional proxies such as stable carbon isotope and trace element ratios are requiredto disentangle the impact of various environmental parameters on the shell geochemistry (e.g. de Winter et al.,2017). The incorporation of these proxies into bivalve shells is not fully understood and often complicated by bothspecies- or specimen-specific vital effects, diagenesis and variations in sea water concentrations (e.g. Gillikin etal., 2005; Freitas et al., 2008).The current study aims at combining multi-proxy sclerochronological records (stable isotopes and trace elements)of different Late Albian bivalve taxa (rudists and pectinids) derived from the same proto-North Atlanticpalaeoenvironmental setting in Portugal (Sao Julião section, Lusitanian Basin, Horikx et al., 2014). Micro-X-RayFluorescence (XRF) scanning yields quantitative line scans and semi-quantitative 2D maps that highlight thedistribution of trace elements in the fossil shells. Trace element and stable isotope profiles - measured along thegrowth axis - allow for the identification of seasonal cycles recorded in the shell.Here, a multivariate statistical approach is presented to identify the influence of different types of diagenesis onthese multi-proxy records, and to isolate the seasonal cyclicity recorded in the shells. Results of this multi-proxyapproach allow discussion of inter-species differences in preservation, seasonal cyclicity and incorporation ofpalaeoenvironmental proxies into the shell calcite. Most importantly, this approach sheds light on the feasibility ofusing the here investigated bivalve shells for future deep-time palaeoseasonality reconstructions