Sulfur geochemistry at ODP Site 112-680 and 112-686

We have measured the concentrations of (1) pore-water sulfide and (2) solid-phase pyrite, iron monosulfide (=acid volatile sulfide), elemental sulfur, and extractable and nonextractable organic ("kerogen") sulfur in sediments from Ocean Drilling Program (ODP) Sites 680 and 686. Pore-water sulfide defines classic "bell-shaped" profiles. Maximum concentrations of 6 to 12 mM occur where sulfate is exhausted, or is most depleted, at depths between 15 and 50 mbsf. Sulfide resulting from bacterial sulfate reduction reacts in three ways: (1) some is reoxidized to elemental sulfur in surface sediments; (2) some reacts with detrital iron minerals to form iron monosulfide and pyrite, primarily in the top meter or two of the sediment; and (3) some reacts with, and is incorporated into, kerogen. Incorporation of reduced sulfur into kerogen occurs over the top 15 m of the sediment at both Sites 680 and 686, after the main phase of pyrite formation. Up to 45% of the total sedimentary sulfur is organically bound, and concentrations of 12 wt% sulfur are reached in the kerogen. These values are like those measured in lithologically similar, but more deeply buried, sediments from the Monterey Formation.

Hydrocarbon gases in Tertiary and Quaternary sediments offshore Peru

Hydrocarbon gases (methane, ethane, propane, isobutane, n-butane, ethene, and propene) are present in Tertiary and Quaternary shelf, upper-slope, and lower-slope deposits of the Peruvian continental margin. Methane dominates the composition of the hydrocarbon gas at all 10 sites examined during Ocean Drilling Program (ODP) Leg 112. Generation of methane is regulated by the amount of sulfate in pore water. Wherever sulfate concentrations approach or equal zero, methane concentrations increase rapidly, reaching values near 100,000 µL/L of wet sediment at eight of the 10 sites. Methane at all 10 sites results from methanogenesis, which is inhibited where sulfate is present and microbial reduction of sulfate occurs. Hydrocarbon gases heavier than methane also are present, but at much lower concentrations than methane. These hydrocarbons are thought to result from early thermal and microbial diagenesis, based on relative gas compositions and trends of concentrations with depth. With few exceptions, the results obtained in the shipboard and shore-based laboratories are comparable for methane and ethane in sediments of Leg 112. Reanalyses of canned sediments from ODP Leg 104 and from Deep Sea Drilling Project (DSDP) Legs 76 and 84 show that gas samples can be stored for as long as 8 yr, but the amounts of individual hydrocarbon gases retained vary. Nevertheless, the trends of the data sets with depth are similar for fresh and stored samples.

Eocene through Pleistocene planktonic foraminifera off Peru

Planktonic foraminifers were studied from 213 samples collected during Leg 112 at 10 sites located on the continental shelf and slope off Peru. Because planktonic foraminifers occur discontinuously downcore, detailed biostratigraphic zonation was not defined. However, it was possible to distinguish early and middle Eocene, early and late Miocene, Pliocene, and Pleistocene sediments on the basis of the planktonic foraminifers. The oldest sediments of Zone P6 of early Eocene age were obtained from the basal part of Hole 688E, which was penetrated to 779.0 m below seafloor (bsf). A biosiliceous facies of the area predominates above the N6-N7 zonal interval of early Miocene age. All sites are within the present coastal upwelling area off Peru, and many of the late Pliocene and Pleistocene assemblages are similar to those that are characteristic of modern upwelling areas. The core samples differ, however, by having a predominance of cold-water elements, such as Neogloboquadrina incompta and N. pachyderma. Warm-water species are prevalent at some horizons in the cores, suggesting shifts of the coastal upwelling centers or warmer climatic events.

Volcanic ash from the Peru continental margin

During Leg 112 off Peru, volcanic material was recorded from middle Eocene to Holocene time. The petrographical and chemical composition of tephra is consistent with an origin from the Andean volcanic arc. The amount and thickness of ash layers provide valuable evidence for explosive volcanic episodicity. The first indication of volcanism was found in mid-Eocene sediments. Three volcanic pulses date from Miocene time. Two intense episodes took place in upper Pliocene and from Pleistocene to Holocene time. Pliocene-Pleistocene tephra are restricted to the southern upper-slope and shelf sites, indicating a removal of the volcanic arc and the extinction of the northern Peru volcanoes. The Cenozoic tectonic phases of the Andean margin may be correlated with the Leg 112 volcanic records. The explosive supply of evolved magmatic products succeeded the Incaic and Quechua tectonic phases. Acidic glasses are related to both andesitic and shoshonitic series. The calc-alkaline factor (CAF) of these glasses exhibited moderate magmatic variations during middle and late Miocene time. A dramatic change occurred during the Pliocene-Pleistocene, reflected in a strong CAF increase and the appearance of potassium-rich evolved shoshonitic glasses. This took place when the Nazca Ridge subduction began. This change in the magma genesis and/or differentiation conditions is probably related to thickening of the upper continental plate and to a new configuration of the Benioff Zone.

Contents, partition, and isotopic composition of sulphur in sediments from ODP Sites 680 and 686

We have determined (1) the abundance and isotopic composition of pyrite, monosulphide, elemental sulphur, organically bound sulphur, and dissolved sulphide; (2) the partition of ferric and ferrous iron; (3) the organic carbon contents of sediments recovered at two sites drilled on the Peru Margin during Leg 112 of the Ocean Drilling Program. Sediments at both sites are characterised by high levels of organically bound sulphur (OBS). OBS comprises up to 50% of total sedimentary sulphur and up to 1% of bulk sediment. The weight ratio of S to C in organic matter varies from 0.03 to 0.15 (mean = 0.10). Such ratios are like those measured in lithologically similar, but more deeply buried petroleum source rocks of the Monterey and Sisquoc formations in California. The sulphur content of organic matter is not limited by the availability of porewater sulphide. Isotopic data suggest that sulphur is incorporated into organic matter within a metre of the sediment surface, at least partly by reaction with polysulphides. Most inorganic Sulphur occurs as pyrite. Pyrite formation occurred within surface sediments and was limited by the availability of reactive iron. But despite highly reducing sulphidic conditions, only 35-65% of the total iron was converted to sulphide; 10-30% of the total iron still occurs as Fe(III). In surface sediments, the isotopic composition of pyrite is similar to that of both iron monosulphide and dissolved sulphide. Either pyrite, like monosulphide, formed by direct reaction between dissolved sulphide and detrital iron, and/or the sulphur species responsible for converting FeS to FeS2 is isotopically similar to dissolved sulphide. Likely stoichiometries for the reaction between ferric iron and excess sulphide imply a maximum resulting FeS2:FeS ratio of 1:1. Where pyrite dominates the pool of iron sulphides, at least some pyrite must have formed by reaction between monosulphide and elemental sulphur and/or polysulphide. Elemental sulphur (S°) is most abundant in surface sediments and probably formed by oxidation of sulphide diffusing across the sediment-water interface. In surface sediments, S° is isotopically heavier than dissolved sulphide, FeS and FeS2 and is unlikely to have been involved in the conversion of FeS to FeS2. Polysulphides are thus implicated as the link between FeS and FeS2.

Sapientia, 1974, Vol. XXIX, nº 112 (número completo)

Contenido: Le príncipe d’idetité chez Saint Thomas / R. Verneaux – Unidad de ser y analogía en Santo Tomás de Aquino / Cesáreo López Salgado – St. Thomas’ solution of the problema of faith and reason / A. G. M. Van Melsen – Necesidad de la directa confrontación de textos / Carlos A. Iturralde Colombres – Notas y comentarios -- Bibliografía

Diário da Constituinte [gravação de vídeo] : [programa n. 112]

Os constituintes evangélicos discutem o novo projeto constitucional e querem suas propostas aprovadas na nova Carta. Manoel Moreira (PMDB-SP) almeja uma Constituição que respeite os direitos dos brasileiros e que acabe com a impunidade generalizada no país. As questões que mais preocupam esse grupo são: família, aborto, o casamento e a liberdade de culto. Salatiel Carvalho (PFL-PE) não concorda com alguns pontos aprovados na Comissão das Garantias tais como os direitos e garantias aos homossexuais e a questão do aborto. Na sessão O Povo Pergunta, cidadão pede atenção para a saúde do nordestino. Inocêncio Oliveira (PFL-PE) responde que a Assembleia Nacional Constituinte (ANC) precisa definir uma lei que proporcione o acesso de todos a rede pública de saúde e melhore a distribuição de renda. A Comissão de Sistematização prevê que os recursos públicos serão destinados para escolas públicas, comunitárias, filantrópicas e confessionais. Agripino Lima (PFL-SP) considera que as verbas públicas devem ser destinadas as escolas públicas, voltadas ao ensino fundamental. Ubiratan Aguiar (PMDB-CE) diz que os recursos são insuficientes e que a educação pública não pode dispersar suas verbas para as escolas particulares. Átila Lira (PFL-PI) acredita no avanço da educação pública e de melhores condições de trabalho para o professor.

Lei nº 8.112/90 [gravação de som] : Lei nº 8112, de dezembro de 1990, que dispõe sobre o regime jurídico dos servidores públicos civis da União, das autarquias e das fundações públicas federais

Apresenta a Lei n. 8112, de dezembro de 1990, que dispõe sobre o regime jurídico dos servidores públicos civis da União, das autarquias e das fundações públicas federais.

Lei nº 8.112/90 : Lei nº 8112, de 11 de dezembro de 1990, que dispõe sobre o regime jurídico dos servidores públicos civis da União, das autarquias e das fundações públicas federais, e legislação correlata

Atualizada até 31/8/2016.

El derecho de información del socio en la S.A. y en la S.R.L. Arts. 112 LSA y 51 LSRL

Este árticulo explica que el derecho de la información es uno de los denominados derechos individuales del accionista o socio, que se deriva de la titularidad de acciones o participaciones, derecho fundamental e inherente a la condición de socio, e inderogable, que se ostenta por normas imperativas que reconocen dicho derecho. Contribuye a un mayor control y participación del socio en la marcha de la sociedad ya que trata de facilitar a los socios un conocimiento directo sobre la situación y gestión social constituyendo, por tanto, uno de los más importantes derechos del mismo.