Geochemistry of the oceanic crust from ocean drilling samples

This book presents new data on chemical and mineral compositions and on density of altered and fresh igneous rocks from key DSDP and ODP holes drilled on the following main tectonomagmatic structures of the ocean floor: 1. Mid-ocean ridges and abyssal plains and basins (DSDP Legs 37, 61, 63, 64, 65, 69, 70, 83, and 91 and ODP Legs 106, 111, 123, 129, 137, 139, 140, 148, and 169); 2. Seamounts and guyots (DSDP Legs 19, 55, and 62 and ODP Legs 143 and 144); 3. Intraplate rises (DSDP Legs 26, 33, 51, 52, 53, 72, and 74 and ODP Legs 104, 115, 120, 121, and 183); and 4. Marginal seas (DSDP Legs 19, 59, and 60 and ODP Legs 124, 125, 126, 127, 128, and 135). Study results of altered gabbro from the Southwest Indian Ridge (ODP Leg 118) and serpentinized ultramafic rocks from the Galicia margin (ODP Leg 103) are also presented. Samples were collected by the authors from the DSDP/ODP repositories, as well as during some Glomar Challenger and JOIDES Resolution legs. The book also includes descriptions of thin sections, geochemical diagrams, data on secondary mineral assemblages, and recalculated results of chemical analyses with corrections for rock density. Atomic content of each element can be quantified in grams per standard volume (g/1000 cm**3). The suite of results can be used to estimate mass balance, but parts of the data need additional work, which depends on locating fresh analogs of altered rocks studied here. Results of quantitative estimation of element mobility in recovered sections of the upper oceanic crust as a whole are shown for certain cases: Hole 504B (Costa Rica Rift) and Holes 856H, 857C, and 857D (Middle Valley, Juan de Fuca Ridge).

Diatom events and Neogene nannofossils of ODP Hole 201-1225A

Shipboard investigation of magnetostratigraphy and shore-based investigation of diatoms and calcareous nannofossils were used to identify datum events in sedimentary successions collected at Ocean Drilling Program (ODP) Leg 201 Site 1225. The goal was to extend the magnetic record previously studied at the same site, ODP Leg 138 Site 851, and provide a comprehensive age model for Site 1225. Two high-magnetic intensity zones at 0-70 and 200-255 meters below seafloor (mbsf) were correlated with lithologic Subunits IA and IC in Hole 1225A. Subunit IA (0-70 mbsf) contains the magnetic reversal record until the Cochiti Subchronozone (3.8 Ma) and has a sedimentation rate of 1.7 cm/k.y. This agrees with previous work done at Site 851. Subunit IC (200-255 mbsf) was not sampled at Site 851. Diatom and nannofossil biostratigraphy constrained this subunit, and we found it to contain the magnetic reversal record between Subchrons C4n.2r and C5n.2n (8.6-9.7 Ma), yielding a sedimentation rate of 2.7 cm/k.y. Biostratigraphy was used to establish the sedimentation rates within Subunits IB and ID (70-200 mbsf and 255-300 mbsf, respectively). These subunits had higher sedimentation rates (~3.4 cm/k.y.) and coincide with the late Miocene-early Pliocene biogenic bloom event (4.5-7 Ma) and the Miocene global cooling trend (10-15 Ma). High biogenic productivity associated with these subunits resulted in the pyritization of the magnetic signal. In lithologic Subunit ID, basement flow is another factor that may be altering the magnetic signal; however, the good correlation between the biostratigraphy and magnetostratigraphy indicates that the magnetic record was locked-in near the seafloor and suggests the age model is robust.

Family diversity in social exclusion situations. Results and reflections on research, teaching and knowledge transfer activities

The purpose of this paper is to characterize the configurations of the families that live in contexts of social exclusion; provide conceptualizations of their operation mode; highlight the formative effects that neighborhood interdisciplinary practices with such families produce in the just graduated psychologists, included on the Extension Program. We wish to contribute to produce systematic knowledge that can account for such family configurations as potential receiver of integration policies. We are also interested on transferring the approach to diversity in the training of young professionals, in order not to be regarded as a deviation from ideal models, but as an expression of different strategies built by members of a community, to resolve children breeding and to bear their existences. This work is the result about reflections on productions inside a research fellowship: The complexities that takes the breeding in families who lives in a social exclusion situation; researches about breeding, carried out from signature Developmental Psychology II, and from de interdisciplinary work with psychologically assisted families in twelve suburbs of the city of La Plata (University Extension Program "Free Legal Offices" (Convention between Law and Social Sciences and Psychology Faculties, U.N.L.P.). From a qualitative methodology and an interdisciplinary participation, the results have arrive at the characterization and proposed conceptualizations of the included families and at the same time determine the benefits that brings with the work that articulates research and extension activities for the training of advanced students and young graduates.

La diversidad familiar en situaciones de exclusión social. Resultados y reflexiones sobre actividades de investigación, formación y transferencia de conocimientos

El presente artículo se propone caracterizar las configuraciones familiares que habitan en contextos de exclusión social; aportar conceptualizaciones sobre sus modos de funcionamiento a través de la sistematización de los datos recogidos y destacar los efectos formativos que las prácticas interdisciplinarias barriales con esas familias, van produciendo en los psicólogos recién graduados, a través de una tarea de transferencia del enfoque sobre la diversidad tanto en el interior de las investigaciones como a partir de las intervenciones realizadas con las familias en las tareas de incorporados al Programa de Extensión. Asimismo, nos ha interesado poder efectuar una tarea de transferencia del enfoque sobre la diversidad en la formación de los profesionales jóvenes, tanto en el interior de las investigaciones como en el de las intervenciones realizadas con familias en las tareas de extensión. Este trabajo surge de resultados y reflexiones provenientes de tres fuentes: de lo producido en el marco de una Beca de iniciación a la Investigación; de las investigaciones sobre parentalidad, que desde el año 2001 venimos realizando en la Cátedra de Psicología Evolutiva II y del trabajo interdisciplinario con familias asistidas psicológicamente en el interior del Programa de Extensión Universitaria ?Consultorios Jurídicos Gratuitos?, asentados en doce barrios suburbanos de la ciudad de La Plata (convenio entre la Facultad de Ciencias Jurídicas y Sociales y la Facultad de Psicología, U.N.L.P.) A partir de una metodología cualitativa, con participación interdisciplinaria, los resultados obtenidos han permitido por un lado arribar a la caracterización y conceptualizaciones propuestas acerca de las familias incluidas y al mismo tiempo precisar los beneficios que para la formación de estudiantes avanzados y jóvenes graduados trae aparejado el trabajo que articula actividades de investigación y extensión

Geochemistry of ODP Leg 129 igneous rocks

This report presents all the available major and trace elemental analyses and Sr, Nd, and Pb isotopic compositions of basaltic rocks recovered from Ocean Drilling Program Sites 800, 801, and 802 during Leg 129 (Table 1). Its main purpose is to provide other investigators a complete summary of geochemical data for Leg 129 basement basalts that they can use for later work. Detailed discussions of the data are presented elsewhere in the volume by Floyd and Castillo (Site 801 geochemistry and petrogenesis, dataset: doi:10.1594/PANGAEA.779154) Floyd et al. (Sites 800 and 802 geochemistry and petrography, dataset: doi:10.1594/PANGAEA.779129), Alt et al. (Site 801 alteration, dataset: doi:10.1594/PANGAEA.779207), and Castillo et al. (Sr, Nd, and Pb isotope geochemistry of Leg 129 basalts, dataset: doi:10.1594/PANGAEA.779191).

Family diversity in social exclusion situations. Results and reflections on research, teaching and knowledge transfer activities

The purpose of this paper is to characterize the configurations of the families that live in contexts of social exclusion; provide conceptualizations of their operation mode; highlight the formative effects that neighborhood interdisciplinary practices with such families produce in the just graduated psychologists, included on the Extension Program. We wish to contribute to produce systematic knowledge that can account for such family configurations as potential receiver of integration policies. We are also interested on transferring the approach to diversity in the training of young professionals, in order not to be regarded as a deviation from ideal models, but as an expression of different strategies built by members of a community, to resolve children breeding and to bear their existences. This work is the result about reflections on productions inside a research fellowship: The complexities that takes the breeding in families who lives in a social exclusion situation; researches about breeding, carried out from signature Developmental Psychology II, and from de interdisciplinary work with psychologically assisted families in twelve suburbs of the city of La Plata (University Extension Program "Free Legal Offices" (Convention between Law and Social Sciences and Psychology Faculties, U.N.L.P.). From a qualitative methodology and an interdisciplinary participation, the results have arrive at the characterization and proposed conceptualizations of the included families and at the same time determine the benefits that brings with the work that articulates research and extension activities for the training of advanced students and young graduates.

La diversidad familiar en situaciones de exclusión social. Resultados y reflexiones sobre actividades de investigación, formación y transferencia de conocimientos

El presente artículo se propone caracterizar las configuraciones familiares que habitan en contextos de exclusión social; aportar conceptualizaciones sobre sus modos de funcionamiento a través de la sistematización de los datos recogidos y destacar los efectos formativos que las prácticas interdisciplinarias barriales con esas familias, van produciendo en los psicólogos recién graduados, a través de una tarea de transferencia del enfoque sobre la diversidad tanto en el interior de las investigaciones como a partir de las intervenciones realizadas con las familias en las tareas de incorporados al Programa de Extensión. Asimismo, nos ha interesado poder efectuar una tarea de transferencia del enfoque sobre la diversidad en la formación de los profesionales jóvenes, tanto en el interior de las investigaciones como en el de las intervenciones realizadas con familias en las tareas de extensión. Este trabajo surge de resultados y reflexiones provenientes de tres fuentes: de lo producido en el marco de una Beca de iniciación a la Investigación; de las investigaciones sobre parentalidad, que desde el año 2001 venimos realizando en la Cátedra de Psicología Evolutiva II y del trabajo interdisciplinario con familias asistidas psicológicamente en el interior del Programa de Extensión Universitaria ?Consultorios Jurídicos Gratuitos?, asentados en doce barrios suburbanos de la ciudad de La Plata (convenio entre la Facultad de Ciencias Jurídicas y Sociales y la Facultad de Psicología, U.N.L.P.) A partir de una metodología cualitativa, con participación interdisciplinaria, los resultados obtenidos han permitido por un lado arribar a la caracterización y conceptualizaciones propuestas acerca de las familias incluidas y al mismo tiempo precisar los beneficios que para la formación de estudiantes avanzados y jóvenes graduados trae aparejado el trabajo que articula actividades de investigación y extensión

U and Th concentrations and isotope ratios of samples from ODP Leg 166

Constraining the history of seawater (234U/238U) is important because this ratio is used to assess the validity of U/Th ages, and because it provides information about the past rate of physical weathering on the continents. This study makes use of U-rich slope sediments from the Bahamas in an attempt to reconstruct seawater (234U/238U) for the last 800 kyr. For the last 360 kyr, U/Th dating of these sediments provides ages and initial (234U/238U) values. Sixty-seven samples, largely from marine highstands, have initial (234U/238U) which scatter somewhat about the modern seawater value (~1.145) but neither this scatter nor the average value increases with age of sample. These data contrast with published coral data and suggest that seawater (234U/238U) has remained within 15? of the modern value for the last 360 kyr. This confirms the rejection of coral U/Th ages where the initial (234U/238U) is significantly different from modern seawater. Data from older highstands, dated with delta18O stratigraphy or by the presence of the Brunhes/Matuyama (B/M) reversal at 780 kyr, allow seawater (234U/238U) to be assessed prior to the range of the 230Th chronometer. Unfortunately, diagenetic scatter in the data between the B/M reversal and 360 kyr is rather large, probably relating to low U concentrations for these samples. But there is no indication of a trend in seawater (234U/238U) with age. High U samples from close to the B/M reversal show less diagenetic scatter and an initial (234U/238U) that averages 1.102. This lower value can be explained by lower seawater (234U/238U) at the time of the B/M reversal, or by progressive loss of 234U from the sediment by alpha-recoil. A simple box model is presented to illustrate the response of seawater (234U/238U) to variations in riverine input, such as might be caused by changes in continental weathering. Comparison of the Bahamas (234U/238U) data with model results indicates that riverine (234U/238U) has not varied by more than 65? for any 100 kyr period during the last 360 kyr. It also indicates that the ratio of physical to chemical weathering on the continents has not been higher than at present for any extended period during the last 800 kyr.

Paleomagnetic, stable oxygen isotope ratios, and U/Th activities of ODP Site 172-1062

Geomagnetic excursions are recognized as intrinsic features of the Earth's magnetic field. High-resolution records of field behaviour, captured in marine sedimentary cores, present an opportunity to determine the temporal and geometric character of the field during geomagnetic excursions and provide constraints on the mechanisms producing field variability. We present here the highest resolution record yet published of the Blake geomagnetic excursion (~125 ka) measured in three cores from Ocean Drilling Program (ODP) Site 1062 on the Blake-Bahama Outer Ridge. The Blake excursion has a controversial structure and timing but these cores have a sufficiently high sedimentation rate (~10cm/ka) to allow detailed reconstruction of the field behaviour at this site during the excursion. Palaeomagnetic measurements of the cores reveal rapid transitions (<500 yr) between the contemporary stable normal polarity and a completely reversed state of long duration which spans a stratigraphic interval of 0.7 m. We determine the duration of the reversed state during the Blake excursion using oxygen isotope stratigraphy, combined with 230Th excess measurements to assess variations in the sedimentation rates through the sections of interest. This provides an age and duration for the Blake excursion with greater accuracy and with constrained uncertainty. We date the directional excursion as falling between 129 and 122 ka with a duration for the deviation of 6.5±1.3 kyr. The long duration of this interval and the fully reversed field suggest the existence of a pseudo-stable, reversed dipole field component during the excursion and challenge the idea that excursions are always of short duration.

Family diversity in social exclusion situations. Results and reflections on research, teaching and knowledge transfer activities

The purpose of this paper is to characterize the configurations of the families that live in contexts of social exclusion; provide conceptualizations of their operation mode; highlight the formative effects that neighborhood interdisciplinary practices with such families produce in the just graduated psychologists, included on the Extension Program. We wish to contribute to produce systematic knowledge that can account for such family configurations as potential receiver of integration policies. We are also interested on transferring the approach to diversity in the training of young professionals, in order not to be regarded as a deviation from ideal models, but as an expression of different strategies built by members of a community, to resolve children breeding and to bear their existences. This work is the result about reflections on productions inside a research fellowship: The complexities that takes the breeding in families who lives in a social exclusion situation; researches about breeding, carried out from signature Developmental Psychology II, and from de interdisciplinary work with psychologically assisted families in twelve suburbs of the city of La Plata (University Extension Program "Free Legal Offices" (Convention between Law and Social Sciences and Psychology Faculties, U.N.L.P.). From a qualitative methodology and an interdisciplinary participation, the results have arrive at the characterization and proposed conceptualizations of the included families and at the same time determine the benefits that brings with the work that articulates research and extension activities for the training of advanced students and young graduates.

La diversidad familiar en situaciones de exclusión social. Resultados y reflexiones sobre actividades de investigación, formación y transferencia de conocimientos

El presente artículo se propone caracterizar las configuraciones familiares que habitan en contextos de exclusión social; aportar conceptualizaciones sobre sus modos de funcionamiento a través de la sistematización de los datos recogidos y destacar los efectos formativos que las prácticas interdisciplinarias barriales con esas familias, van produciendo en los psicólogos recién graduados, a través de una tarea de transferencia del enfoque sobre la diversidad tanto en el interior de las investigaciones como a partir de las intervenciones realizadas con las familias en las tareas de incorporados al Programa de Extensión. Asimismo, nos ha interesado poder efectuar una tarea de transferencia del enfoque sobre la diversidad en la formación de los profesionales jóvenes, tanto en el interior de las investigaciones como en el de las intervenciones realizadas con familias en las tareas de extensión. Este trabajo surge de resultados y reflexiones provenientes de tres fuentes: de lo producido en el marco de una Beca de iniciación a la Investigación; de las investigaciones sobre parentalidad, que desde el año 2001 venimos realizando en la Cátedra de Psicología Evolutiva II y del trabajo interdisciplinario con familias asistidas psicológicamente en el interior del Programa de Extensión Universitaria ?Consultorios Jurídicos Gratuitos?, asentados en doce barrios suburbanos de la ciudad de La Plata (convenio entre la Facultad de Ciencias Jurídicas y Sociales y la Facultad de Psicología, U.N.L.P.) A partir de una metodología cualitativa, con participación interdisciplinaria, los resultados obtenidos han permitido por un lado arribar a la caracterización y conceptualizaciones propuestas acerca de las familias incluidas y al mismo tiempo precisar los beneficios que para la formación de estudiantes avanzados y jóvenes graduados trae aparejado el trabajo que articula actividades de investigación y extensión

Sediment composition and sedimentation rates of four Holes in ODP Leg 166

To date, work on the Great Bahama Bank's western, leeward margin has centred chiefly on seismic-scale expressions of carbonate sequences and systems tracts. However, periplatform, slope sediments also exhibit very well developed cyclicity on scales of decimetres to several metres. It is these small-scale, high-frequency cycles within the larger-scale facies successions of the Quaternary which form the main topic of this paper. Previous studies have shown that the small-scale cycles correlate to the orbitally forced, high-frequency sea-level changes. Therefore these cycles should indicate how sea level has affected the slope development and thus platform-margin evolution during this period. Through detailed, high-resolution sequence stratigraphy of the Great Bahama Bank's leeward margin, obtained via delta18O isotope and mineralogical (XRD) analyses, confined by U/Th dating and nannofossil bioevents, a greater understanding of the bedding geometries within the Pleistocene-Holocene seismic sequences and clues as to the nature of the slope development has been achieved. The high-resolution seismic profiles indicate that since the Plio-Pleistocene change in geometry, in which the Great Bahama Bank developed into a rimmed platform, continued steepening and subsequent progradation of the leeward margin has typified slope development during the Quaternary, which is described as an accretionary slope. However, on the basis of our observations we conclude that only the early to lower middle Pleistocene section (isotope stages 45-20) and the Holocene (isotope stage 1) of the leeward margin is accretionary. This indicates that a degree of erosion and/or by-passing has occurred on the leeward margin since the lower middle Pleistocene (isotope stage 19). During the first part of this period (isotope stages 19-12) erosion and/or by-passing occurred in the middle to lower slope regions and toe-of-slope. By the end of the upper middle to late Pleistocene phase (isotope stages 11-2) erosion also occurred on the upper slope. This erosion by currents at the toe-of-slope and oversteepening of the upper and middle slopes have led to back-cutting upslope and resulted in the progressive retreat of the toe-of-slope towards the platform to the east. However, the rise in sea level since the Last Glacial Maximum to its present-day level has allowed high productivity on the platform top during the Holocene and the deposition of a thick sediment wedge on the slope and sedimentation across the entire leeward flanks. This has led to the redevelopment of an accretionary slope and continued westward progradation of the Great Bahama Bank's western, leeward margin.

Major, trace and rare earth element concentrations of sediments from ODP Leg 207 sites

The Cretaceous and Paleogene sediments recovered during Ocean Drilling Program Leg 207 can be divided into three broad modes of deposition: synrift clastics (lithologic Unit V), organic matter-rich, laminated black shales (Unit IV), and open-marine chalk and calcareous claystones (Units III-I). The aim of this study is to provide a quantitative geochemical characterization of sediments representing these five lithologic units. For this work we used the residues (squeeze cakes) obtained from pore water sampling. Samples were analyzed for bulk parameters (total inorganic carbon, total organic carbon, and S) and by X-ray fluorescence for major (Si, Ti, Al, Fe, Mn, Mg, Ca, Na, K, and P) and selected minor (As, Ba, Co, Cr, Cu, Mo, Ni, Pb, Rb, Sr, U, V, Y, Zn, and Zr) elements. Inductively coupled plasma-mass spectrometry analyses for rare earth elements (REEs) were performed on acid digestions of the squeeze cake samples from Site 1258. The major element composition is governed by the mixture of a terrigenous detrital component of roughly average shale (AS) composition with biogenous carbonate and silica. The composition of the terrigenous detritus is close to AS in Units II-IV. For Unit I, a more weathered terrigenous source is suggested. Carbonate contents reach >60 wt% on average in chalks and calcareous claystones of Units II-IV. The SiO2 contribution in excess of the normal terrigenous-detrital background indicates the presence of biogenous silica, with highest amounts in Units II and III. The contents of coarse-grained material (quartz) are enhanced in Unit V, where Ti and Zr contents are also high. This indicates a high-energy depositional environment. REE patterns are generally similar to AS. A more pronounced negative Ce anomaly in Unit IV may indicate low-oxygen conditions in the water column. The Cretaceous black shales of Unit IV are clearly enriched in redox-sensitive and stable sulfide-forming elements (Mo, V, Zn, and As). High phosphate contents point toward enhanced nutrient supply and high bioproductivity. Ba/Al ratios are rather high throughout Unit IV despite the absence of sulfate in the pore water, indicating elevated primary production. Manganese contents are extremely low for most of the interval studied. Such an Mn depletion is only possible in an environment where Mn was mobilized and transported into an expanded oxygen minimum zone ("open system"). The sulfur contents show a complete sulfidation of the reactive iron of Unit IV and a significant excess of sulfur relative to that of iron, which indicates that part of the sulfur was incorporated into organic matter. We suppose extreme paleoenvironmental conditions during black shale deposition: high bioproductivity like in recent coastal upwelling settings together with severe oxygen depletion if not presence of hydrogen sulfide in the water column.