CARINA: nutrient data in the Atlantic Ocean

Data on carbon and carbon-relevant hydrographic and hydrochemical parameters from previously non-publicly available cruise data sets in the Arctic, Atlantic and Southern Ocean have been retrieved and merged to a new database: CARINA (CARbon IN the Atlantic). These data have gone through rigorous quality control (QC) procedures to assure the highest possible quality and consistency. The data for most of the measured parameters in the CARINA data base were objectively examined in order to quantify systematic differences in the reported values, i.e. secondary quality control. Systematic biases found in the data have been corrected in the data products, i.e. three merged data files with measured, calculated and interpolated data for each of the three CARINA regions; Arctic Mediterranean Seas, Atlantic and Southern Ocean. Out of a total of 188 cruise entries in the CARINA database, 98 were conducted in the Atlantic Ocean and of these 84 cruises report nitrate values, 79 silicate, and 78 phosphate. Here we present details of the secondary QC for nutrients for the Atlantic Ocean part of CARINA. Procedures of quality control, including crossover analysis between cruises and inversion analysis of all crossover data are briefly described. Adjustments were applied to the nutrient values for 43 of the cruises in the Atlantic Ocean region. With these adjustments the CARINA database is consistent both internally as well as with GLODAP data, an oceanographic data set based on the World Hydrographic Program in the 1990s (Key et al., 2004). Based on our analysis we estimate the internal accuracy of the CARINA-ATL nutrient data to be: nitrate 1.5%; phosphate 2.6%; silicate 3.1%. The CARINA data are now suitable for accurate assessments of, for example, oceanic carbon inventories and uptake rates and for model validation

Technical assistance in Nigeria : developing geoscience skills for tomorrow

The World Bank funded Nigerian Geochemical Mapping Technical Assistance Project was started in 2008 within the Nigerian Ministry of Mines and Steel Development, and is now nearing completion. Staff from the Nigerian Geological Survey Agency (NGSA), the Nigerian academic community, British Geological Survey, and Geological Survey of Finland, have worked alongside one another in a comprehensive program of practical training and knowledge exchange. This program has enabled researchers from a range of backgrounds and experience in Africa and Europe to exchange knowledge and develop important geoscience skills. As part of this program key skills in many areas including; GIS, statistics, QC, data management, laboratory analysis, sampling methodologies, has developed the knowledge and skills base within the Nigerian geosciences community, and has maintained momentum for Nigeria’s national geochemical mapping program. An important objective of the Project is knowledge exchange during training of Nigerian geoscientists in conducting regional geochemical surveys as part of a long term mapping program across Nigeria. Practical training in methodologies for geochemical mapping formed the basis of a major field campaign in 2009, during which over 100 personnel were trained in geochemical mapping techniques. A similar number of personnel were involved in specialist training through a series of workshops and training courses in Nigeria and the UK. Two field areas were selected for the geochemical mapping training — one in central Nigeria (the ‘Minna Cell’) and one in south-western Nigeria (the ‘South-western Cell’) — covering a combined area of 52 000 km2. Key challenges involved the procurement of field equipment and consumables, and modernisation of sample preparation laboratories and archiving facilities at the National Geosciences Research Laboratory, Kaduna. New sample preparation and analytical equipment has been purchased and the laboratory staff have received training in the use of the new equipment. In the long-term it is envisaged that the analytical facilities will be developed further, and that all samples will be prepared, analysed and archived in Nigeria. A national geochemical mapping programme involving multi-element analysis of stream sediment samples is used as a primary dataset in the exploration for new economic mineral deposits. Establishing a geochemical baseline is necessary in order to monitor the effects of anthropogenic activities e.g. contamination caused by industrial waste and mining activities, for environmental investigations and medical geology studies both in rural and in urban areas, as well as studies within the agricultural and forestry sectors

Atlantic CFC data in CARINA

Water column data of carbon and carbon-relevant parameters have been collected and merged into a new database called CARINA (CARbon IN the Atlantic). In order to provide a consistent data set, all data have been examined for systematic biases and adjusted if necessary (secondary quality control (QC)). The CARINA data set is divided into three regions: the Arctic/Nordic Seas, the Atlantic region and the Southern Ocean. Here we present the CFC data for the Atlantic region, including the chlorofluorocarbons CFC-11, CFC-12 and CFC-113 as well as carbon tetrachloride (CCl4). The methods applied for the secondary quality control, a crossover analyses, the investigation of CFC ratios in the ocean and the CFC surface saturation are presented. Based on the results, the CFC data of some cruises are adjusted by a certain factor or given a “poor” quality flag

Post-collisional Pan-African granitoids and rare metal pegmatites in western Nigeria: age, petrogenesis, and the ‘pegmatite conundrum’

The Minna area of western Nigeria lies within a Pan-African orogenic belt that extends along the margin of the West African Craton, from Algeria southwards through Nigeria, Benin and Ghana, and into the Borborema Province of Brazil. This belt is characterised by voluminous post-collisional granitoid plutons that are well exposed around the city of Minna. In this paper we present new information about their age and petrogenesis. The Pan-African plutons around Minna can be divided into two main groups: a group of largely peraluminous biotite–muscovite granites that show varying levels of deformation in late Pan-African shear zones; and a younger group of relatively undeformed, predominantly metaluminous hornblende granitoids. Pegmatites, including both barren and rare-metal types, occur at the margins of some of the plutons. New U–Pb zircon dating presented here, in combination with published data, indicates an early phase of magmatism at c. 790–760 Ma in the Minna area. This magmatism could be related either to continental rifting, or to subduction around the margins of an existing continent. The peraluminous biotite–muscovite granites were intruded at c. 650–600 Ma during regional shearing in the orogenic belt, and are likely to have formed largely by crustal melting. Subsequent emplacement of metaluminous granitoids at c. 590 Ma indicates the onset of post-orogenic extension in this area, with a contribution from mantle-derived magmas. The rare-metal pegmatites represent the youngest intrusions in this area and thus are likely to have formed in a separate magmatic episode, post-dating granite intrusion

Revision of the solid geology shown on the 'Assynt District' special geological map : a report on the 2002 fieldwork

The report provides an overview of the main findings from the first field season in the Assynt District of the Moine Thrust Project. Detailed mapping in the eastern part of the Assynt halfwindow has resulted in a new interpretation of the geometry and behaviour of the Ben More Thrust. This reinterpretation of the thrust satisfactorily resolves the conflicts between the various previous models. The remapping confirmed that the Ben More Thrust can be traced, as shown on the published 1923 Assynt District geological map, along the western flank of Na Tuadhan to Bealach a’ Mhadhaidh. The Ben More Thrust is then traced to [NC 30026 24416] where it is displaced across a steep reverse fault to [NC 30514 23953]. It then continues NNW as a readily traceable feature placing gneisses of the Lewisian Gneiss Complex over quartzite along Leathaid Riabhach [NC 298 252]. Here the Ben More Thrust progressively steepens into a sub-vertical structure that has gneiss to the NE and quartzite to the SW. The thrust follows a prominent gully along Leathaid Riabhach to A’ Chailleach. From here the Ben More Thrust more or less follows the top of a monoclinally folded quartzite that forms the summit of Beinn Uidhe and is exposed in the valley floor NW of A’ Chailleach. It retains thrust geometry with hangingwall gneisses and footwall quartzites and becomes a steep feature that approximately follows ‘Glen Beag’ (the un-named glen south of the Stack of Glencoul). The Ben More Thrust meets, but does not displace the Glencoul Thrust at the head of Loch Glencoul. Therefore it is proposed that there is a branch line here where the two thrusts meet so that all the rocks NE of Loch Glencoul and east of Loch Beag are part of the Ben More Thrust Sheet. Figure 2.7 in the report provides a clear pictorial description of the geometry of the Ben More Thrust in the northern part of the Assynt half-window. A significant new ductile structure has been identified within the Ben More Thrust Sheet, termed the Coire a’ Mhadhaidh Detachment, that mostly follows the Lewisian gneisses/quartzite contact. It has been traced from the northern limits of the Loch Ailsh intrusion across Ben More Assynt, along the eastern slopes of Na Tuadhan, across Cailleach an t-Sniomha to the west of Gorm Loch Mòr and immediately west of the Stack of Glencoul into Glen Coul (Figure 2.1 in the report). The sense of shearing in the detachment is almost always top-to-west. Similar smaller shears have also been recognised within the Lewisian gneisses in the thrust sheet. However, no ductile shearing was noted at the gneiss/quartzite contact below the Ben More Thrust. Several of the complex imbricate structures mapped by previous workers were revisited. The imbricates in the Loch an Eircill–Loch nan Caorach area appear to be simpler than shown on the published Assynt District map. An alternative solution is provided for the southern termination of the Glencoul Thrust south of Inchnadamph although it is noted that more detailed work needs to be done, notably south of Conival. Brief descriptions are given of Moine rocks above the Moine Thrust in the north-eastern part of the Assynt District map. There appears to be a lateral facies change with semipelitic schists dominant in upper Glen Cassley and psammites becoming dominant to the north. Fabrics associated with several deformation phases have largely obliterated sedimentary structures although transposed bedding traces can be seen between a spaced foliation that controls the flaggy character of the psammites. Widely spaced traverses across the major Lewisian outcrop areas, within the Assynt half-window as well as in the western foreland to the thrust belt, largely confirmed the work of the primary surveyors. Thus all of the Lewisian comprises orthogneisses, mostly hornblende-gneisses but with more felsic pyroxene-bearing gneisses in the north, that all contain ultramafic and mafic pods and layers. The traces of the various Scourie dykes are correctly shown on the published Assynt District map. The Canisp Shear Zone has been traced eastwards, south of Canisp, eventually disappears under Cambrian quartzites. A second parallel shear has also been delineated north of Loch Assynt. The polyphase nature of ductile deformation in the Lewisian gneisses elucidated by previous workers is confirmed. However, the deformation state of the gneisses is extremely variable on all scales, with intense deformation confined to specific (shear) zones that vary in thickness from several centimetres up to hundreds of metres. Descriptions of the numerous minor intrusions and the Quaternary deposits studied during the fieldwork are given in separate reports

CARINA TCO2 data in the Atlantic Ocean

Water column data of carbon and carbon-relevant hydrographic and hydrochemical parameters from 188 cruises in the Arctic Mediterranean Seas, Atlantic and Southern Ocean have been retrieved and merged in a new data base: the CARINA (CARbon IN the Atlantic) Project. These data have gone through rigorous quality control (QC) procedures so as to improve the quality and consistency of the data as much as possible. Secondary quality control, which involved objective study of data in order to quantify systematic differences in the reported values, was performed for the pertinent parameters in the CARINA data base. Systematic biases in the data have been tentatively corrected in the data products. The products are three merged data files with measured, adjusted and interpolated data of all cruises for each of the three CARINA regions (Arctic Mediterranean Seas, Atlantic and Southern Ocean). Ninety-eight cruises were conducted in the "Atlantic" defined as the region south of the Greenland-Iceland-Scotland Ridge and north of about 30° S. Here we report the details of the secondary QC which was done on the total dissolved inorganic carbon (TCO2) data and the adjustments that were applied to yield the final data product in the Atlantic. Procedures of quality control – including crossover analysis between stations and inversion analysis of all crossover data – are briefly described. Adjustments were applied to TCO2 measurements for 17 of the cruises in the Atlantic Ocean region. With these adjustments, the CARINA data base is consistent both internally as well as with GLODAP data, an oceanographic data set based on the WOCE Hydrographic Program in the 1990s, and is now suitable for accurate assessments of, for example, regional oceanic carbon inventories, uptake rates and model validation

Domain Switching as a Toughening Mechanism in Tetragonal Zirconia

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65640/1/j.1151-2916.1988.tb05943.x.pd

Supermassive Black Hole Binaries: The Search Continues

Gravitationally bound supermassive black hole binaries (SBHBs) are thought to be a natural product of galactic mergers and growth of the large scale structure in the universe. They however remain observationally elusive, thus raising a question about characteristic observational signatures associated with these systems. In this conference proceeding I discuss current theoretical understanding and latest advances and prospects in observational searches for SBHBs.Comment: 17 pages, 4 figures. To appear in the Proceedings of 2014 Sant Cugat Forum on Astrophysics. Astrophysics and Space Science Proceedings, ed. C.Sopuerta (Berlin: Springer-Verlag

All-sky search for long-duration gravitational wave transients with initial LIGO

We present the results of a search for long-duration gravitational wave transients in two sets of data collected by the LIGO Hanford and LIGO Livingston detectors between November 5, 2005 and September 30, 2007, and July 7, 2009 and October 20, 2010, with a total observational time of 283.0 days and 132.9 days, respectively. The search targets gravitational wave transients of duration 10-500 s in a frequency band of 40-1000 Hz, with minimal assumptions about the signal waveform, polarization, source direction, or time of occurrence. All candidate triggers were consistent with the expected background; as a result we set 90% confidence upper limits on the rate of long-duration gravitational wave transients for different types of gravitational wave signals. For signals from black hole accretion disk instabilities, we set upper limits on the source rate density between 3.4×10-5 and 9.4×10-4 Mpc-3 yr-1 at 90% confidence. These are the first results from an all-sky search for unmodeled long-duration transient gravitational waves. © 2016 American Physical Society