We present a study of the magnetic properties of a group of basalt samples from the Saldanha Mass... more We present a study of the magnetic properties of a group of basalt samples from the Saldanha Massif (Mid-Atlantic Ridge-MAR-36 • 33 54 N, 33 • 26 W), and we set out to interpret these properties in the tectono-magmatic framework of this sector of the MAR. Most samples have low magnetic anisotropy and magnetic minerals of single domain grain size, typical of rapid cooling. The thermomagnetic study mostly shows two different susceptibility peaks. The high temperature peak is related to mineralogical alteration due to heating. The low temperature peak shows a distinction between three different stages of low temperature oxidation: the presence of titanomagnetite, titanomagnetite and titanomaghemite, and exclusively of titanomaghemite. Based on established empirical relationships between Curie temperature and degree of oxidation, the latter is tentatively deduced for all samples. Finally, swath bathymetry and sidescan sonar data combined with dive observations show that the Saldanha Massif is located over an exposed section of upper mantle rocks interpreted to be the result of detachment tectonics. Basalt samples inside the detachment zone often have higher than expected oxidation rates; this effect can be explained by the higher permeability caused by the detachment fault activity.
ABSTRACT The complexes [Cu(CTZ)(4)]Cl(2).2H(2)O (1), [Cu(CTZ)Cl(2)](2) (2), [Cu(KTZ)(3)Cl(2)] (3)... more ABSTRACT The complexes [Cu(CTZ)(4)]Cl(2).2H(2)O (1), [Cu(CTZ)Cl(2)](2) (2), [Cu(KTZ)(3)Cl(2)] (3), and [Cu(KTZ)Cl(2)](2).2H(2)O (4) were prepared by reaction of CuCl(2) with CTZ and KTZ (where CTZ = 1-[[(2-chlorophenyl)diphenyl]methyl]-1H-imidazole and KTZ = cis-1-acetyl-4-[4-[[2-(2,4-dichlorophenyl)-2-(1H-imidazol-1-ylmethyl)-1,3-dioxolan-4-yl]methoxy]phenyl]piperazine), respectively, in acetonitrile at different ligand to metal molar ratios. Gold complexes [Au(PPh(3))(CTZ)]PF(6) (5) and [Au(PPh(3))(KTZ)]PF(6).H(2)O (6) were synthesized by reaction of AuClPPh(3), with KPF(6) and CTZ or KTZ in acetonitrile. All the new compounds were characterized by NMR spectroscopy and microanalytical methods, and for the paramagnetic species EPR spectroscopy and DC magnetic susceptibility measurements were also employed. The solid-state structure of 1 has been determined by X-ray crystallography. 1 crystallizes in the triclinic space group P(-)1, with a = 12.773(2) A, b = 15.326(4) A, c = 11.641(2) A, V = 1957.4(7) A(3), Z = 1, and D(calcd) = 1.284 g/cm(3). The structure refinement converged at R1 = 0.0731 and wR2 = 0.1962. Complex 1 displayed a square-planar structure typical for tetrakis(imidazole)copper(II) complexes. The new compounds were tested for in vitro activity against cultures of epimastigotes of Trypanosoma cruzi, the causative agent of Chagas disease. At concentrations equivalent to 10(-6) M of total CTZ or KTZ (in DMSO) all the complexes exhibited significantly higher growth inhibitory activity than their respective parental compounds.
The Saldanha Massif is a small dome shaped feature detached from the Famous segment western wall ... more The Saldanha Massif is a small dome shaped feature detached from the Famous segment western wall where diffuse hydrothermal degassing was observed during SALDANHA mission. We present an interpretation of high-resolution swath bathymetry, TOBI images and dives to constrain its tectonic setting. The dome structure is marked by a series of low amplitude steps or ridges, that strike in the
In this work we present magnetic fabric results from ten sampled sites along a segment of Jurassi... more In this work we present magnetic fabric results from ten sampled sites along a segment of Jurassic dyke, known as Foum-Zguid in Morocco. The fieldwork was executed in a segment with approximately 100km of this mega structure with an age of approximately 180 Ma. Morphologically the Foum-Zguid dyke, in the studied area, is characterized by ridge with a height of
We present a study of the magnetic properties of a group of basalt samples from the Saldanha Mass... more We present a study of the magnetic properties of a group of basalt samples from the Saldanha Massif (Mid-Atlantic Ridge-MAR-36 • 33 54 N, 33 • 26 W), and we set out to interpret these properties in the tectono-magmatic framework of this sector of the MAR. Most samples have low magnetic anisotropy and magnetic minerals of single domain grain size, typical of rapid cooling. The thermomagnetic study mostly shows two different susceptibility peaks. The high temperature peak is related to mineralogical alteration due to heating. The low temperature peak shows a distinction between three different stages of low temperature oxidation: the presence of titanomagnetite, titanomagnetite and titanomaghemite, and exclusively of titanomaghemite. Based on established empirical relationships between Curie temperature and degree of oxidation, the latter is tentatively deduced for all samples. Finally, swath bathymetry and sidescan sonar data combined with dive observations show that the Saldanha Massif is located over an exposed section of upper mantle rocks interpreted to be the result of detachment tectonics. Basalt samples inside the detachment zone often have higher than expected oxidation rates; this effect can be explained by the higher permeability caused by the detachment fault activity.
ABSTRACT The complexes [Cu(CTZ)(4)]Cl(2).2H(2)O (1), [Cu(CTZ)Cl(2)](2) (2), [Cu(KTZ)(3)Cl(2)] (3)... more ABSTRACT The complexes [Cu(CTZ)(4)]Cl(2).2H(2)O (1), [Cu(CTZ)Cl(2)](2) (2), [Cu(KTZ)(3)Cl(2)] (3), and [Cu(KTZ)Cl(2)](2).2H(2)O (4) were prepared by reaction of CuCl(2) with CTZ and KTZ (where CTZ = 1-[[(2-chlorophenyl)diphenyl]methyl]-1H-imidazole and KTZ = cis-1-acetyl-4-[4-[[2-(2,4-dichlorophenyl)-2-(1H-imidazol-1-ylmethyl)-1,3-dioxolan-4-yl]methoxy]phenyl]piperazine), respectively, in acetonitrile at different ligand to metal molar ratios. Gold complexes [Au(PPh(3))(CTZ)]PF(6) (5) and [Au(PPh(3))(KTZ)]PF(6).H(2)O (6) were synthesized by reaction of AuClPPh(3), with KPF(6) and CTZ or KTZ in acetonitrile. All the new compounds were characterized by NMR spectroscopy and microanalytical methods, and for the paramagnetic species EPR spectroscopy and DC magnetic susceptibility measurements were also employed. The solid-state structure of 1 has been determined by X-ray crystallography. 1 crystallizes in the triclinic space group P(-)1, with a = 12.773(2) A, b = 15.326(4) A, c = 11.641(2) A, V = 1957.4(7) A(3), Z = 1, and D(calcd) = 1.284 g/cm(3). The structure refinement converged at R1 = 0.0731 and wR2 = 0.1962. Complex 1 displayed a square-planar structure typical for tetrakis(imidazole)copper(II) complexes. The new compounds were tested for in vitro activity against cultures of epimastigotes of Trypanosoma cruzi, the causative agent of Chagas disease. At concentrations equivalent to 10(-6) M of total CTZ or KTZ (in DMSO) all the complexes exhibited significantly higher growth inhibitory activity than their respective parental compounds.
The Saldanha Massif is a small dome shaped feature detached from the Famous segment western wall ... more The Saldanha Massif is a small dome shaped feature detached from the Famous segment western wall where diffuse hydrothermal degassing was observed during SALDANHA mission. We present an interpretation of high-resolution swath bathymetry, TOBI images and dives to constrain its tectonic setting. The dome structure is marked by a series of low amplitude steps or ridges, that strike in the
In this work we present magnetic fabric results from ten sampled sites along a segment of Jurassi... more In this work we present magnetic fabric results from ten sampled sites along a segment of Jurassic dyke, known as Foum-Zguid in Morocco. The fieldwork was executed in a segment with approximately 100km of this mega structure with an age of approximately 180 Ma. Morphologically the Foum-Zguid dyke, in the studied area, is characterized by ridge with a height of
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Papers by Pedro Silva