O depósito de Au-Cu-Mo Paraíba (MT) : integração de técnicas espectrais e convencionais para a exploração mineral

Orientador: Diego Fernando DucartDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de GeociênciasResumo: O Paraíba é um depósito de Au-Cu-Mo localizado na porção sul do cráton Amazônico, na Província Mineral de Alta Floresta, Mato Grosso, Brasil. É formado por veios de quartzo com ouro e por brechas hidrotermais ricas em Cu-Mo, ambos associados a diversas zonas de alteração hidrotermal. Foi aplicado um novo método de estudo, envolvendo uma integração entre técnicas espectrais (espectroscopia pontual e de imageamento) e convencionais (petrografia, geoquímica, microssonda e MEV), com o objetivo de compreender a geometria e evolução do depósito, e utilizar essa informação no desenvolvimento de vetores de exploração para zonas mineralizadas. Mais de 1400 espectros de mica branca, clorita, biotita e epídoto, foram coletados de amostras de testemunhos de sondagem através de um espectrômetro. Adicionalmente, foram geradas imagens hiperespectrais com resolução espacial de 156 e 30 ?m em porções representativas das amostras de testemunhos. A integração desses dados com estudos petrográficos permitiu um mapeamento detalhado da alteração mineral, bem como o reconhecimento das relações temporais e espaciais entre as zonas de alteração. Foram geradas seções litológicas e de alteração, juntamente com uma tabela da sequência paragenética e evolução hidrotermal. Análises por microssonda eletrônica revelaram informações sobre a composição e temperatura de cristalização do minério. A integração deste conjunto de dados de múltiplas fontes mostra que a gênese do depósito Paraíba está associada a dois grandes estágios de mineralização: (i) um metamórfico-hidrotermal (Estágio 1), relacionado aos veios de quartzo ricos em Au, em um Sistema dúctil-rúptil; e (ii) um magmático-hidrotermal (Estágio 2), associado com intrusão de sienogranito porfirítico e mineralização de Cu-Mo. Cada estágio foi dividido em três principais sub-estágios: pré-mineralização, mineralização e pós-mineralização. Estágio 1 compreende zonas de alteração marcadas pela desestabilização do plagioclásio, biotitização, silicificação e alteração da biotita do filonito. O Estágio 2 abrange zonas de alteração cálcica, potássica, sericítica e propilítica, com extensiva epidotização, cloritização e vênulas tardias estéreis. Foram discriminados cinco grupos espectral e quimicamente distintos de mica branca, e três de clorita. O uso combinados da composição, abundância e cristalinidade, extraídos de métricas espectrais para mica branca, representam um forte farejador para zonas mineralizadas. A mineralização de Au-Cu-Mo está associada à abundância de mica branca altamente cristalina, pobre em Al e rica em Mg, predominantemente com composição tendendo a fengita a fengítica. Nesse sentido, a Mica Branca 2 e Mica Branca 4 estão diretamente relacionadas a mineralizações de Au e Cu-Mo, respectivamente, enquanto que a Mica Branca 1,3 e 5, rica em Al e Fe, não apresenta relação com zonas mineralizadas. Grupos da Clorita 1 e 3, com composição rica em Mg, estão relacionados a cloritização de filonitos. Foi estabelecida uma relação espacial entre zonas epidotizadas e altos teores de Cu. A aplicação de técnicas espectrais auxiliou na caracterização mineralógica de diferentes zonas de alteração e na definição de minerais vetores para exploração no depósito Paraíba. Este trabalho demonstra a importância de combinar técnicas espectrais e convencionais para o estudo de sistemas hidrotermais complexosAbstract: The Paraíba is an Au-Cu-Mo deposit located in the southern part of the Amazon Craton, in Alta Floresta Mineral Province, Mato Grosso, Brazil. It is composed by gold-rich quartz veins and Cu-Mo-rich hydrothermal breccias, both associated to several hydrothermal alteration zones. A novel method was applied here, involving the full integration of spectral (pontual and imaging spectroscopy) and conventional techniques (petrography, geochemistry, electron microprobe and SEM), with the aim to understand the geometry and evolution of the deposit and use this information to develop exploration vectors to mineralized zones. More than 1,400 spectra of white mica, chlorite, biotite and epidote-bearing drill core samples were collected along transversal sections in the deposit by a spectrometer. In addition, hyperspectral images, with spatial resolutions of 156 and 30 ?m, were acquired on representative drill core samples. These data, integrated with petrographic studies and core logging, allowed a detailed alteration mineral mapping, as well as the recognition of temporal and spatial relationships among the alterations zones. Lithological and alteration sections, together with a mineral paragenetic sequence table and hydrothermal system evolution, were generated. Electron micro probe analysis revealed further information on the composition and crystallization temperature of the ore. The integration of this multi-source dataset shows that the genesis of the Paraíba deposit is associated with two major mineralizing stages : (i) a first metamorphic-hydrothermal stage (Stage 1), related to Au-rich quartz veins in a ductile shear system; and (ii) a second magmatic-hydrothermal stage (Stage 2), associated with a syenogranite porphyry intrusion and Cu-Mo mineralization. Each stage has been divided into three principal sub-stages of mineralization: pre-ore, ore emplacement and post ore. Stage 1 comprises alteration zones marked by plagioclase destabilization, biotitization, silicification and phyllonite biotite's breakdown. Stage 2 comprises calcic, potassic, sericitic, propylitic alteration zones, with extensive epidotization, chloritization and late barren venules. Five chemically and spectrally different white mica groups, plus three chlorite groups, were discriminated. The combined use of composition, abundance and crystallinity extracted from spectral metrics for white mica represent a strong proxy to mineralized zones. The Au-Cu-Mo mineralization proved to be associated with higher abundance of well-ordered, highly crystalline, Al-poor and Mg-rich white micas, dominantly with tending-to-phengite to phengite composition. In this sense, the White Mica 2 and White Mica 4 are directly related to Au and Cu-Mo mineralization respectively, whereas the Al- and Fe-rich White Mica 1, 3 and 5 do not present relationship with ore zones. Chlorite groups 1 and 3, with a Mg-rich composition, are related to chloritization of phyllonites. A spatial relationship between epidotized zones and higher Cu contents was established. The application of spectral techniques helped in the mineralogical characterization of different alteration zones and definition of mineral vectoring tools for exploration at the Paraíba deposit. This work demonstrates the importance of combining spectral and conventional techniques for the study of hydrothermal systems within complex mineral depositsMestradoGeologia e Recursos NaturaisMestre em Geociências2016/04370-5CAPESFAPES

Use of Natural Agents and Agrifood Wastes for the Treatment of Skin Photoaging

Photoaging is the premature aging of the skin caused by repeated exposure to ultraviolet (UV) rays. The harmful effects of UV rays—from the sun or from artificial sources—alter normal skin structures and cause visible damage, especially in the most exposed areas. Fighting premature aging is one of the most important challenges of the medical landscape. Additionally, consumers are looking for care products that offer multiple benefits with reduced environmental and economic impact. The growing requests for bioactive compounds from aromatic plants for pharmaceutical and cosmetic applications have to find new sustainable methods to increase the effectiveness of new active formulations derived from eco-compatible technologies. The principle of sustainable practices and the circular economy favor the use of bioactive components derived from recycled biomass. The guidelines of the European Commission support the reuse of various types of organic biomass and organic waste, thus transforming waste management problems into economic opportunities. This review aims to elucidate the main mechanisms of photoaging and how these can be managed using natural renewable sources and specific bioactive derivatives, such as humic extracts from recycled organic biomass, as potential new actors in modern medicine

The Bostrichidae of the Maltese Islands (Coleoptera)

The Bostrichidae of the Maltese Islands are reviewed. Ten species are recorded with certainty from this Archipelago, of which 6 namely, Trogoxylon impressum (Comolli, 1837), Amphicerus bimaculatus (A.G. Olivier, 1790), Heterobostrychus aequalis (Waterhouse, 1884), Sinoxylon unidentatum (Fabricius, 1801), Xyloperthella picea (A.G. Olivier, 1790) and Apate monachus Fabricius, 1775 are recorded for the first time. Two of the mentioned species (H. aequalis and S. unidentatum) are alien and recorded only on the basis of single captures and the possible establishment of these species is discussed. Earlier records of Scobicia pustulata (Fabricius, 1801) from Malta are incorrect and should be attributed to S. chevrieri (A. Villa & J.B. Villa, 1835). A zoogeographical analysis and an updated checklist of the 12 species of Bostrichidae recorded from the Maltese Islands and neighbouring Sicilian islands (Pantelleria, Linosa and Lampedusa) are also provided. Rhizopertha dominica (Fabricius, 1792) form granulipennis Lesne in Beeson & Bhatia, 1937 from Uttarakhand (northern India) was overlooked by almost all subsequent authors. Its history is summarized and the following new synonymy is established: Rhizopertha dominica (Fabricius, 1792) form granulipennis Lesne in Beeson & Bhatia, 1937 = Rhyzopertha dominica (Fabricius, 1792), syn. n. Finally, records of Amphicerus bimaculatus from Azerbaijan, of Bostrichus capucinus (Linnaeus, 1758) from Jordan and Syria, of Scobicia chevrieri from Jordan and Italy, of Xyloperthella picea from Italy, and of Apate monachus from Corsica (France) and Italy, are also provided.peer-reviewe

Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Aspetti epidemiologici e valutazione della resistenza alla sharka in nuovi genotipi di pesco.

Sono indicati i principali aspetti epidemiologici del plum pox virus: i vari isolati virali e le loro principali caratteristiche, le modalità di trasmissione a breve, media e lunga distanza, la diffusione secondaria dei vari isolati negli impianti di albicocco, pesco e susino, il ruolo di drupacee spontanee ed erbacee bienni e perenni nel ciclo biologico del patogeno. Vengono infine indicate le principali modalità di controllo della maalttia, basate essenzialmente sulla eradicazione delle piante infette e sul reperimento di germoplasma resistente al patogeno

Multiple-source localization : A new method exploiting the cyclostationarity property

On propose une nouvelle méthode pour estimer le nombre D de sources ponctuelles à longue distance et pour les localiser au moyen d'un réseau rectiligne de M > D capteurs équidistants. La méthode exploite la cyclostationnairité des signaux modulés. Pour appliquer l'approche proposée il faut connaître (s'il y a) la valeur d'une même fréquence de cycle pour tous les signaux; de plus, la matrice de corrélation ciclique des signaux utiles doit être de rang D. La méthode présentée se montre supérieure aux approches classiques lorsque le signal utile est très faible et noyé dans un bruit à bande large et/ou dans une interférence à bande étroite et aussi lorsque le bruit est arbitraire (par exemple, non-stationnaire) et inconnu