Geotechnical properties at DSDP Leg 66 Holes

Delineating the interrelationships between tectonics, sedimentation, and geotechnical properties is particularly important for areas subjected to the dynamic affects of convergence. DSDP Leg 66 drilling within the Middle America Trench complex provided a unique opportunity to investigate these interrelationships along a transect of eight drill sites beginning on the trench outer slope and traversing the trench, trench inner slope, and upper continental slope. Investigations of other convergent margins suggest that deformation occurs most rapidly along the lower trench inner slope and is reflected by the geotechnical properties (Carson, 1977; Seely, 1977; and von Huene, 1979). This study focuses on the geotechnical properties of Middle America Trench sediments and the possible affects of convergence on these properties.

Saving Young Lives: Pathfinder International’s Youth-Friendly Postabortion Care Project

As many as 2.5 million adolescent women seek abortion each year, and nearly 70,000 women die from complications related to unsafe abortion, of which almost half are women under the age of 25. A further 5 million women suffer disability due to unsafe abortion yearly. In most developing countries, abortion is legally restricted or highly inaccessible, which leads young women to seek services from unskilled practitioners often leading to incomplete, septic abortions and massive bleeding, which can result in permanent injury, infertility, and death. Based on our deeply held belief that all people, including adolescents, have a right to sexual and reproductive health services and the importance of addressing adolescent needs within Postabortion Care (PAC) services, Pathfinder used private funds to initiate a Youth-Friendly Postabortion Care (YFPAC) program in eight sub-Saharan African countries. Implemented between June 2007 and May 2008, the YFPAC program offered an opportunity to apply the PAC Consortium’s Technical Guidance on Youth-Friendly PAC, generating promising approaches and lessons learned. The goal of the YFPAC initiative was to increase access to PAC services that are responsive to adolescent needs in sub-Saharan Africa. While outcomes varied according to the country, the overall outcomes included: Increased community support for services and activities that prevent unwanted pregnancy, decreased stigma around abortion, and awareness of the issue of unsafe abortion among adolescent women: 311 peer educators reached almost 17,487 youth and other community members; 171 stakeholders (e.g., religious and traditional leaders, health officials, and local government officials) were sensitized on YFPAC, resulting in a positive shift in communities’ attitudes toward youth in need of PAC services. 125 service providers were trained to deliver YFPAC services and three doctors in Ghana were provided with a technical update on YFPAC. YFPAC services are available in Angola, Ghana, Nigeria, Mozambique, Tanzania, Uganda, Ethiopia, and Kenya. Pathfinder introduced YFPAC services into 25 facilities (in 27 service delivery points), and provided more than 3,800 clients with YFPAC services throughout the eight countries. The number of adolescent PAC clients seen at the project facilities increased— 710 clients were seen in the first quarter, 1,144 were seen in the fourth. The number of adolescent PAC clients who adopt a contraceptive method to prevent future unintended pregnancies has increased. Statistics show an average postabortion contraceptive acceptance of 69%, with the highest acceptance being 83% and the lowest being 44%. Evidence-based approaches, tools, and lessons learned are being disseminated and used for scale-up or replication of YFPAC interventions.

Del hospital a la cárcel. Consecuencias para las mujeres por la penalización sin excepciones, de la interrupción del embarazo en El Salvador

La investigación Del hospital a la cárcel. Consecuencias para las mujeres por la penalización sin excepciones, de la interrupción voluntaria del embarazo en El Salvador, ha sido elaborada por la Agrupación ciudadana para la despenalización del aborto terapéutico, ético y eugenésico de El Salvador, con el fin de aportar información relevante y válida sobre el impacto de la actual legislación penalizadora del aborto en todas sus formas.

Horizontal profiles of longwave and shortwave radiation components over sea ice near Barrow, Alaska during the 2011 melt

An integrated instrument package for measuring and understanding the surface radiation budget of sea ice is presented, along with results from its first deployment. The setup simultaneously measures broadband fluxes of upwelling and downwelling terrestrial and solar radiation (four components separately), spectral fluxes of incident and reflected solar radiation, and supporting data such as air temperature and humidity, surface temperature, and location (GPS), in addition to photographing the sky and observed surface during each measurement. The instruments are mounted on a small sled, allowing measurements of the radiation budget to be made at many locations in the study area to see the effect of small-scale surface processes on the large-scale radiation budget. Such observations have many applications, from calibration and validation of remote sensing products to improving our understanding of surface processes that affect atmosphere-snow-ice interactions and drive feedbacks, ultimately leading to the potential to improve climate modelling of ice-covered regions of the ocean. The photographs, spectral data, and other observations allow for improved analysis of the broadband data. An example of this is shown by using the observations made during a partly cloudy day, which show erratic variations due to passing clouds, and creating a careful estimate of what the radiation budget along the observed line would have been under uniform sky conditions, clear or overcast. Other data from the setup's first deployment, in June 2011 on fast ice near Point Barrow, Alaska, are also shown; these illustrate the rapid changes of the radiation budget during a cold period that led to refreezing and new snow well into the melt season.

Interstitial water chemistry of ODP Leg 103 sites

Interstitial waters were squeezed from strata recovered at Sites 637-641 of ODP Leg 103 on the Galicia margin, along the northwestern Iberian continental margin in the northeast Atlantic. Chemical profiles of Site 638 show the most complexity, which appears to be related to an unconformity in the strata between Cretaceous and Neogene sediments and to rapid deposition of Cretaceous syn-rift sediments upon pre-rift strata. Analyses of waters from all of the Leg 103 sites show generally antithetical trends for calcium and magnesium; calcium increases with depth as magnesium decreases. No calcium-magnesium 'crossover' profiles are observed in these data. Data from Site 637 show an unusual pattern; calcium increases with increasing depth, but magnesium remains relatively constant. Sulfate is either stable or shows an overall decrease with depth, and boron profiles show some structure. At all but one site (Site 638), strontium profiles do not show marked depth structure. The structure of alkalinity and silica profiles is highly site dependent. Bromide profiles are, in general, constant. In nearly every case, observed bromide concentrations are near average seawater values. Relatively low concentrations of iron and manganese are common within the upper 10 m of the sediment sequence and typically are near detection limits at deeper depths

Geochemistry, clay mineralogy and grain size distribution in various sediment cores drilled during ODP Leg 119 on the Antarctic continental shelf off Prydz Bay

Drilling was undertaken at five sites (739-743) on ODP Leg 119 on a transect across the continental shelf of Prydz Bay, East Antarctica, to elucidate the long-term glacial history of the area and to examine the importance of the area with respect to the development of the East Antarctic ice sheet as a whole. In addition to providing a record of glaciation spanning 36 m.y. or more, Leg 119 has provided information concerning the development of a continental margin under the prolonged influence of a major ice sheet. This has allowed the development of a sedimentary model that may be applicable not only to other parts of the Antarctic continental margin, but also to northern high-latitude continental shelves. The cored glacial sedimentary record in Prydz Bay consists of three major sequences, dominated by diamictite: 1. An upper flat-lying sequence that ranges in thickness from a few meters in inner and western Prydz Bay to nearly 250 m in the outer or eastern parts of the bay. The uppermost few meters consist of Holocene diatom ooze and diatomaceous mud with a minor ice-rafted component overlying diamicton and diamictite of late Miocene to Quaternary age. The diamictite is mainly massive, but stratified varieties and minor mudstone and diatomite also occur. 2. An upper prograding sequence cored at Sites 739 and 743, unconformly below the flat-lying sequence. This consists of a relatively steep (4° inclination) prograding wedge with a number of discrete sedimentary packages. At Sites 739 and 743 the sequence is dominated by massive and stratified diamictite, some of which shows evidence of slumping and minor debris flowage. 3. A lower, more gently inclined, prograding sequence lies unconformably below the flat-lying sequence at Site 742 and the upper prograding sequence at Site 739. This extends to the base of both sites, to 316 and 487 mbsf, respectively. It is dominated by massive, relatively clast-poor diamictite which is kaolinite-rich, light in color, and contains sporadic carbonate-cemented layers. The lower part of Site 742 includes well-stratified diamictites and very poorly sorted mudstones. The base of this site has indications of large-scale soft-sediment deformation and probably represents proximity to the base of the glacial sequence. Facies analysis of the Prydz Bay glacial sequence indicates a range of depositional environments. Massive diamictite is interpreted largely as waterlain till, deposited close to the grounding line of a floating glacier margin, although basal till and debris flow facies are also present. Weakly stratified diamictite is interpreted as having formed close to or under the floating ice margin and influenced by the input of marine diatomaceous sediment (proximal glaciomarine setting). Well-stratified diamictite has a stronger marine input, being more diatom-rich, and probably represents a proximal-distal glaciomarine sediment with the glaciogenic component being supplied by icebergs. Other facies include a variety of mudstones and diatom-rich sediments of marine origin, in which an ice-rafted component is still significant. None of the recovered sediments are devoid of a glacial influence. The overall depositional setting of the prograding sequence is one in which the grounded ice margin is situated close to the shelf edge. Progradation was achieved primarily by deposition of waterlain till. The flat-lying sequence illustrates a complex sequence of advances and retreats across the outer part of the shelf, with intermittent phases of ice loading and erosion. The glacial chronology is based largely on diatom stratigraphy, which has limited resolution. It appears that ice reached the paleoshelf break by earliest Oligocene, suggesting full-scale development of the East Antarctic ice sheet by that time. The ice sheet probably dominated the continental margin for much of Oligocene to middle Miocene time. Retreat, but not total withdrawal of the ice sheet, took place in late Miocene to mid-Pliocene time. The late Pliocene to Pleistocene was characterized by further advances across, and progradation of, the continental shelf. Holocene time has been characterized by reduced glacial conditions and a limited influence of glacial processes on sedimentation.

Geochemistry of ODP Leg 125 peridotites

Trace element analyses (first-series transition elements, Ti, Rb, Sr, Zr, Y, Nb, and REE) were carried out on whole rocks and minerals from 10 peridotite samples from both Conical Seamount in the Mariana forearc and Torishima Forearc Seamount in the Izu-Bonin forearc using a combination of XRF, ID-MS, ICP-MS, and ion microprobe. The concentrations of incompatible trace elements are generally low, reflecting the highly residual nature of the peridotites and their low clinopyroxene content (<2%). Chondrite-normalized REE patterns show extreme U shapes with (La/Sm)n ratios in the range of 5.03-250.0 and (Sm/Yb)n ratios in the range of 0.05-0.25; several samples show possible small positive Eu anomalies. LREE enrichment is common to both seamounts, although the peridotites from Conical Seamount have higher (La/Ce)n ratios on extended chondrite-normalized plots, in which both REEs and other trace elements are organized according to their incompatibility with respect to a harzburgitic mantle. Comparison with abyssal peridotite patterns suggests that the LREEs, Rb, Nb, Sr, Sm, and Eu are all enriched in the Leg 125 peridotites, but Ti and the HREEs exhibit no obvious enrichment. The peridotites also give positive anomalies for Zr and Sr relative to their neighboring REEs. Covariation diagrams based on clinopyroxene data show that Ti and the HREEs plot on an extension of an abyssal peridotite trend to more residual compositions. However, the LREEs, Rb, Sr, Sm, and Eu are displaced off this trend toward higher values, suggesting that these elements were introduced during an enrichment event. The axis of dispersion on these plots further suggests that enrichment took place during or after melting and thus was not a characteristic of the lithosphere before subduction. Compared with boninites sampled from the Izu-Bonin-Mariana forearc, the peridotites are significantly more enriched in LREEs. Modeling of the melting process indicates that if they represent the most depleted residues of the melting events that generated forearc boninites they must have experienced subsolidus enrichment in these elements, as well as in Rb, Sr, Zr, Nb, Sm, and Eu. The lack of any correlation with the degree of serpentinization suggests that low-temperature fluids were not the prime cause of enrichment. The enrichment in the high-field-strength elements also suggests that at least some of this enrichment may have involved melts rather than aqueous fluids. Moreover, the presence of the hydrous minerals magnesio-hornblende and tremolite and the common resorption of orthopyroxene indicate that this high-temperature peridotite-fluid interaction may have taken place in a water-rich environment in the forearc following the melting event that produced the boninites. The peridotites from Leg 125 may therefore contain a record of an important flux of elements into the mantle wedge during the initial formation of forearc lithosphere. Ophiolitic peridotites with these characteristics have not yet been reported, perhaps because the precise equivalents to the serpentinite seamounts have not been analyzed.