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Made available in DSpace on 2021-06-25T15:01:28Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-04-01 Universidade Federal de Santa Catarina Micropaleontology is crucial branch of Earth Sciences, with a pivotal role in the success of the oil and gas industry over the decades. This sector of paleontology is based on the taxonomical description of microfossils, which encompass fossils with size variation from 0.001 mm to 1 m. Normally these microorganisms have a high rate on preservation, thus they are widely accepted as reliable evidence to infer about paleodepositional settings and paleoclimate change. Furthermore, microfossils are critical to understanding the evolution through time, being many of them recognized as index fossil and providing useful biozones to correlation. Since 1950, microfossils have been taxonomically described mainly by stereomicroscopes. However, as the technology progress, traditional ways to study these organisms are challenged and improved by nondestructive three-dimensional imaging techniques, as X-ray tomographic microscopy (SRXTM), three-dimensional X-ray microscopy (3DXRM), the X-ray computed microtomography (microCT) and X-ray computed nanotomography (nanoCT). Recently, one of the most compelling research areas in micropaleontology is the desire to automatize and enhance the details of systematic classification. Thereby, an increasing number of researches have applied the high-resolution X-ray analysis aiming to improve the morphological, taxonomic and taphonomic examination. Most of them have detailed the enhancement provided by the technique when compared with the standard microscopes, and raised questions about the traditional characters used on the microfossil systematic taxonomy. Nevertheless, even with the surpassing detail on microfossil characterization, the application of microCT has been hampered by the costs and sometimes by the needs of specific computer skill. Thus, this research has evaluated the use of microCT as the technique to classify a random bulk of microfossil (comprising foraminifers, ostracods, radiolarians, gastropods and echinoderms) with no further software treatment. No standard microscope analysis was performed. Despite chemical composition of microfossils, most of the specimens morphology, especially internal structures, have been easily acquired and analyzed. 96% of the microfossils of the dataset were identified at least on genus level. Irrespective of the deepness of detail, when considering the overall taxonomic identification, the microCT seems to be effective as the standard microscope. Nonetheless, when problematic specimens are evaluated, the microCT seems to be a more reliable and practical tool than other methods as Scanning Electron Microscopy. Thus, the technique can be used solo or as a complementary method to the stereomicroscope. Additionally, the high-resolution has the potential to lead to the expected automatized & nbsp;micropaleontology, since they can provide numerous images in several planes. This may create a strong database necessary to machine learning and computer identification. Univ Fed Santa Catarina, Dept Mech Engn, Lab Meios Porosos & Propriedades Termofis LMPT, BR-88040535 Florianopolis, SC, Brazil Univ Fed Pernambuco, Dept Geol, Lab Micropaleontol Aplicada LMA, BR-50740540 Recife, PE, Brazil Univ Vale Rio dos Sinos, Inst Tecnol Micropaleontol, Itt Fossil, Sao Leopoldo, RS, Brazil Univ Vale Rio dos Sinos, Geol Grad Program, BR-93022750 Sao Leopoldo, RS, Brazil Univ Estadual Paulista, Fac Ciencias Bauru, Dept Ciencias Biol, Ave Engenheiro Luiz Edmundo Carrijo Coube, BR-17033360 Bauru, SP, Brazil Univ Fed Santa Catarina, Dept Geol, Lab Geoquim LABGEOQ, Rua Engn Agron Andrei Cristian Ferreira S-N, BR-88040535 Florianopolis, SC, Brazil Univ Estadual Paulista, Fac Ciencias Bauru, Dept Ciencias Biol, Ave Engenheiro Luiz Edmundo Carrijo Coube, BR-17033360 Bauru, SP, Brazil

Caddisflies (Trichoptera) are small, cosmopolitan insects closely related to the Lepidoptera (moths and butterflies). Most caddisflies construct protective cases during their larval development. Although the earliest recognisable caddisflies date back to the early Mesozoic (Early and Middle Triassic), being particularly numerous and diverse during the Late Jurassic and Early Cretaceous, the first records of their larval case constructions are known exclusively from much younger, Early to Middle Jurassic non-marine deposits in the northern hemisphere. Here we present fossils from the Early Permian (Asselian–Sakmarian) marine deposits of Brazil which have strong morphological and compositional similarity to larval cases of caddisflies. If they are, which is very probable, these finds not only push back the fossil record of true caddisflies, but also indicate that their larvae constructed cases at the very beginning of their evolution in marine environments. Since modern caddisflies that construct larval cases in marine environments are only known from eastern Australia and New Zealand, we suggest that this marine ecology may have first evolved in western Gondwana during the Early Permian and later spread across southern Pangea.

The Neoproterozoic shoshonitic and mildly alkaline bimodal volcanism of Southernmost Brazil is represented by rock assemblages associated to sedimentary successions, deposited in strike-slip basins formed at the post-collisional stages of the Brasilian/Pan-African orogenic cycle. The best-preserved volcano sedimentary associations occur in the Camaquã and Campo Alegre Basins, respectively in the Sul-riograndense and Catarinense Shields and are outside the main shear belts or overlying the unaffected basement areas. These basins are characterized by alternation of volcanic cycles and siliciclastic sedimentation developed dominantly on a continental setting under subaerial conditions. This volcanism and the coeval plutonism evolved from high-K tholeiitic and calc-alkaline to shoshonitic and ended with a silica-saturated sodic alkaline magmatism, and its evolution were developed during at least 60 Ma. The compositional variation and evolution of post-collisional magmatism in southern Brazil are interpreted as the result mainly of melting of a heterogeneous mantle source, which includes garnet-phlogopite-bearing peridotites, veined-peridotites with abundant hydrated phases, such as amphibole, apatite and phlogopite, and eventually with the addition of an asthenospheric component. The subduction-related metasomatic character of post-collisional magmatism mantle sources in southern Brazil is put in evidence by Nb-negative anomalies and isotope features typical of EM1 sources. O vulcanismo neoproterozóico de afinidades shoshonítica e alcalina sódica saturada em sílica, do sul do Brasil é representado por uma sucessão de rochas vulcânicas, associadas com seqüências sedimentares que foram depositadas em bacias do tipo strike-slip, formadas nos estágios pós-colisionais do ciclo orogênico Brasiliano/Pan-africano. As associações vulcano-sedimentares mais bem representadas ocorrem nas bacias Camaquã e Campo Alegre, respectivamente nos escudos Sul-rio-grandense e Catarinense e situam-se fora das principais zonas de cisalhamento ou sobrepondo áreas não afetadas do embasamento. Estas bacias são caracterizadas pela alternância de ciclos vulcânicos e sedimentação siliciclástica, desenvolvidos dominantemente sob condições subaéreas em ambientes continentais. O vulcanismo é associado com plutonismo, cujo magmatismo evoluiu de afinidades toleítica e cálcio-alcalina alto-K, para shoshonítica e, finalmente, alcalina sódica e saturada em sílica, durante, pelo menos, 60 Ma. A variação composicional e a evolução do magmatismo pós-colisional do sul do Brasil são interpretadas como sendo, principalmente, resultado da fusão de uma fonte mantélica heterogênea, que inclui peridotitos ricos em granada e flogopita, peridotitos venulados com abundância em fases hidratadas, tais como anfibólio, apatita e flogopita e, eventualmente, contando com a adição de um componente astenosférico. A característica metassomática relacionada a subducção das fontes mantélicas deste magmatismo pós-colisional é evidenciada pelas anomalias negativas de Nb e características isotópicas, típicas de fontes do tipo EM1.