Thesis (Ph. D.)--University of California, Santa Cruz, 1999. / Includes bibliographical references (leaves 175-180).

Thesis (M.S.)--University of Florida, 2004. / Typescript. Title from title page of source document. Document formatted into pages; contains 71 pages. Includes vita. Includes bibliographical references.

Thesis (M.S.)--University of Florida, 2004. / Typescript. Title from title page of source document. Document formatted into pages; contains 32 pages. Includes Vita. Includes bibliographical references.

Thesis (M.S.)--Uniformed Services University of the Health Sciences, 2006 / Typescript (photocopy)

Thesis (M.S.)--University of Alabama at Birmingham, 2007. / Title from first page of PDF file (viewed Oct. 30, 2007). Includes bibliographical references (p. 47-62).

Thesis (M.S.)--Uniformed Services University of the Health Sciences, 2006 / Typescript (photocopy)

Thesis (M.S.)--University of Alabama at Birmingham, 2007. / Title from first page of PDF file (viewed June 30, 2007). Includes bibliographical references (p. 42-45).

Thesis (M.S.)--University of Alabama at Birmingham, 2007. / Title from first page of PDF file (viewed June 30, 2007). Includes bibliographical references (p. 59-65).

Exposed on Vancouver Island, British Columbia, the Jurassic Bonanza arc is believed to represent the southerly continuation of the Talkeetna arc. Small bodies of mafic and ultramafic cumulates within deeper plutonic levels of the arc constrain the fractionation pathways leading from high-MgO basalt to andesite-dacite compositions. The removal of amphibole from the most primitive non-cumulate compositions controls the compositions of mafic plutons and volcanics until the onset of plagioclase crystallization. This removal is accomplished by the intercumulus crystallization of large amphibole oikocrysts in primitive olivine hornblendite cumulates. Experimental hornblende compositions that crystallize from high-MgO basalts similar to primitive basalts from the Bonanza arc show a good correlation between octahedral Al in hornblende and pressure, and provide a means of estimating crystallization pressures during differentiation of primitive arc basalt. Application of an empirical barometer derived from experimental amphibole data (P = Al(6)/0.056 – 0.143; r2 = 0.923) to natural hornblendes from this study suggests that crystallization of primitive basalts took place at 470-880 MPa. Two-pyroxene thermometry gives a result of 1058 +/- 91 ºC for the only olivine hornblendite sample with both pyroxenes. Lever rule calculations require the removal of 30-45 % hornblende from the most primitive basalt compositions to generate basaltic andesite, and a further 48% crystallization of hornblende gabbro to generate dacitic compositions. Hornblende removal is more efficient at generating intermediate compositions than anhydrous gabbroic fractionating assemblages, which require up to 70% crystallization to reach basaltic andesite from similar starting compositions. There are no magmatic analogues to bulk continental crust in the Bonanza arc; no amount of delamination of ultramafic cumulates will push the bulk arc composition to high-Mg# andesite. Garnet removal appears to be a key factor in producing bulk continental crust.

Submitted by Everaldo Pereira (pereira.evera@gmail.com) on 2018-04-26T18:39:26Z No. of bitstreams: 1 TESE FINAL ANDRA NASCIMENTO - 2017.pdf: 3502693 bytes, checksum: eeb989c0e4953e90e7d6f3700fa54387 (MD5) / Made available in DSpace on 2018-04-26T18:39:26Z (GMT). No. of bitstreams: 1 TESE FINAL ANDRA NASCIMENTO - 2017.pdf: 3502693 bytes, checksum: eeb989c0e4953e90e7d6f3700fa54387 (MD5) / A partir do mapeamento faciológico da plataforma continental de Sergipe foi realizada a caracterização da macrofauna bentônica. Ao todo foram obtidas 16 amostras sedimentares em triplicada com uso de um van Ven 0,1m². Os pontos amostrais foram distribuídos em três setores geomorfológicos distintos sendo: 6 estações sobre o fundo de cascalho, 5 estações sobre o fundo de lama e 5 estações sobre o fundo de areia. A macrofauna esteve composta por 6874 indivíduos distribuídos em 10 filos. Os grupos mais abundantes foram Polychaeta (44,54%), Crustacea (37,88%), Mollusca (13,47%) e Echinodermata (2,61%). Os Polychaeta, por serem o grupo dominante, foram identificados até família, evidenciando um total de 3062 indivíduos distribuídos em 37 famílias. As famílias mais abundantes foram Syllidae (43%), Spionidae (8%), Chrysopetalidae (8%), Eunicidae (4%), Hesionidae (4%) e Capitellidae (3%). Um total de 12 características abióticas aferidas no local da coleta foram comparadas a distribuição da fauna para determinar a significância das diferenças nos setores geomorfológicos. Características físico-químicas da água não apresentaram alterações significativas entre as amostras de cascalho, areia e lama, com exceção da transparência da água. Das variáveis sedimentares (tamanho médio do grão, % de matéria orgânica, % de carbonato de cálcio e selecionamento) apenas o selecionamento não foi significativo para diferir os três setores. As análises multivariadas a partir da abundância da macrofauna total refletem três ambientes distintos que foram confirmados a nível de família de poliquetas. As estações de areia litorânea com alta hidrodinâmica e baixo percentual de matéria orgânica possuem o maior percentual de poliquetas. As amostras com profundidade intermediária e fundo de lama apontam uma tendência a redução no percentual de poliquetas e uma maior contribuição de moluscos. As amostras com fundo de cascalho apresentaram as maiores densidades e diversidade da fauna total com maior contribuição de crustáceos e redução da fauna poliquetológica. Entre as famóilias de poliquetas a maior densidade também esteve relacionada ao agrupamento de cascalho mas os valores de diversidade não variaram de forma significativa entre os ambientes. As análises de similaridade evidenciam associações de famílias características a cada setor com as maiores semelhanças entre os ambientes de areia litorânea e lama. De forma geral o uso de uma matriz mista contendo a identificação da fauna total em níveis taxonômicos menos específicos se mostrou útil para inferências ecológicas na plataforma continental de Sergipe. As variáveis abióticas que mais influenciaram os índices biológicos foram profundidade, tamanho médio do grão, percentual de carbonato de cálcio e percentual de cascalho. / ABSTRACT From the faciological mapping of the continental shelf of Sergipe the characterization of the benthic macrobenthos was carried out. In all, 16 sediment samples were obtained by tripling with the use of a Ven Ven 0.1m². The sampling points were distributed in three distinct geomorphological sectors: 6 stations on the gravel, 5 stations on the mud and 5 stations on the sand. The macrofauna was composed of 6874 individuals distributed in 10 phyla. The main groups were Polychaeta (44.54%), Crustacea (37.88%), Mollusca (13.47%) and Echinodermata (2.61%). The Polychaeta, being the dominant group, were identified until family taxonomic level, evidencing a total of 3062 individuals distributed in 37 families. The most abundant families were Syllidae (43%), Spionidae (8%), Chrysopetalidae (8%), Eunicidae (4%), Hesionidae (4%) and Capitellidae (3%). A total of 12 abiotic characteristics measured at the collection site were compared to the fauna distribution to determine the significance of the differences in the geomorphological sectors. Physicalchemical characteristics of the water did not show significant changes between the gravel, sand and mud samples, except for water transparency. From the sedimentary variables (average grain size,% organic matter,% calcium carbonate and sorting), only the sorting was not significant to differ the three sectors. The multivariate analyzes from total macrofauna abundance reflect three distinct environments that have been confirmed at the polychaete family level. The littoral sand stations with high hydrodynamics and low percentage of organic matter have the highest percentage of polychaetes. The samples with intermediate depth and background of mud indicate a tendency of reduction in the percentage of polychaetes and the greater contribution of molluscs between the sectors. The samples with a background of gravel showed the highest densities and diversity of overall fauna with higher contribution of crustaceans and reduction of polychaete percentages in comparison to the other groups. Among the polychaete families the highest density was also related to the gravel grouping, but the diversity values at the polychaete family level did not vary significantly between the environments. The analyze of similarities show associations of families that are characteristic of each sector with the greatest similarities between coastal sand and mud environments. In general, the use of a mixed matrix with indentification of total fauna in less specific taxonomic levels proved useful for ecological inferences on the Sergipe continental shelf. The abiotic variables that influenced the biological indexes were depth, mean grain size, percentage of calcium carbonate and percentage of gravel. Keywords: Macrobenthos. Continental shelf. Geomorphological sectors. Abiotic factors.