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.

Physical and geotechnical properties of Norwegian Sea sediments

Sediment composition and rate of deposition are the primary factors responsible for determining the spatial distribution of geotechnical properties on the Wring Plateau. Grain size and depth of burial have no significant influence. Vertical and lateral changes in geotechnical properties are associated with vertical and lateral composition changes in which biogenic silica is the most important variable. Anomalous trends of decreasing density and increasing porosity and water content with depth are associated with increasing silica content downsection. Void ratios, inferred in-situ permeability, and change in void ratio during consolidation testing are relatively high in siliceous sediments and tend to increase as the biogenic silica content increases. Portions of the section are overconsolidated, probably as a result of changes in sediment accumulation rates. However, the higher permeabilities of siliceous sediments may also be a factor influencing consolidation state.

Geochemistry at DSDP Leg 75 Holes

Samples of sediments and rocks collected at DSDP Sites 530 and 532 were analyzed for 44 major, minor, and trace elements for the following purposes: (1) to document the downhole variability in geochemistry within and between lithologic units; (2) to document trace-element enrichment, if any, in Cretaceous organic-carbon-rich black shales at Site 530; (3) to document trace-element enrichment, if any, in Neogene organic-carbon-rich sediments at Site 532; (4) to document trace-element enrichment, if any, in red claystone above basalt basement at Site 530 that might be attributed to hydrothermal activity or weathering of basalt. Results of the geochemical analyses showed that there are no significant enrichments of elements in the organic-carbon-rich sediments at Site 532, but a number of elements, notably Cd, Co, Cr, Cu, Mo, Ni, Pb, V, and Zn, are enriched in the Cretaceous black shales. These elements have different concentration gradients within the black-shale section, however, which suggests that there was differential mobility of trace elements during diagenesis of interbedded more-oxidized and less-oxidized sediments. There is little or no enrichment of elements from hydrothermal activity in the red claystone immediately overlying basalt basement at Site 530, but slight enrichments of several elements in the lowest meter of sediment may be related to subsea weathering of basalt

Chemical composition of clinopyroxenes and melt inclusions in clinopyroxenes from rocks of the Malaita Island, Ontong Java Plateau (Pacific Ocean)

The paper is based on new results of melt inclusion studies in minerals. Physicochemical and geochemical parameters of plateau basalt magmatic systems of the Siberian Platform and Ontong Java Plateau (Pacific Ocean) have been established. The studied melts are enriched in Fe. That differs them from magmatic melts of mid-ocean ridges (MOR). A comparative analysis of data on inclusions has shown a similarity of continental and oceanic plateau basalt magmatic systems. They considerably differ from those of MOR and intraplate oceanic islands. Crystallization of oceanic plateau basalts took place at lower temperatures and pressures as compared with similar rocks of the Siberian Platform. The data on inclusions evidence that the melts of the Siberian Platform and the Malaita Island underwent a serious evolution in contrast to magmas of the Nauru Basin that have more stable geochemical parameters. The most fractionated low-temperature high-Fe magmas with elevated contents of trace and rare-earth elements occur in the Malaita Island (Ontong Java Plateau) magmatic system.