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  1. Semi-Markov Arnason-Schwarz models.

    Science.gov (United States)

    King, Ruth; Langrock, Roland

    2016-06-01

    We consider multi-state capture-recapture-recovery data where observed individuals are recorded in a set of possible discrete states. Traditionally, the Arnason-Schwarz model has been fitted to such data where the state process is modeled as a first-order Markov chain, though second-order models have also been proposed and fitted to data. However, low-order Markov models may not accurately represent the underlying biology. For example, specifying a (time-independent) first-order Markov process involves the assumption that the dwell time in each state (i.e., the duration of a stay in a given state) has a geometric distribution, and hence that the modal dwell time is one. Specifying time-dependent or higher-order processes provides additional flexibility, but at the expense of a potentially significant number of additional model parameters. We extend the Arnason-Schwarz model by specifying a semi-Markov model for the state process, where the dwell-time distribution is specified more generally, using, for example, a shifted Poisson or negative binomial distribution. A state expansion technique is applied in order to represent the resulting semi-Markov Arnason-Schwarz model in terms of a simpler and computationally tractable hidden Markov model. Semi-Markov Arnason-Schwarz models come with only a very modest increase in the number of parameters, yet permit a significantly more flexible state process. Model selection can be performed using standard procedures, and in particular via the use of information criteria. The semi-Markov approach allows for important biological inference to be drawn on the underlying state process, for example, on the times spent in the different states. The feasibility of the approach is demonstrated in a simulation study, before being applied to real data corresponding to house finches where the states correspond to the presence or absence of conjunctivitis. © 2015, The International Biometric Society.

  2. Johann P. Arnason & Kurt A. Raaflaub, The Roman Empire in Context: Historical and Comparative Perspectives (Chichester: Wiley & Sons, 2011

    Directory of Open Access Journals (Sweden)

    Michael Gibbons

    2012-03-01

    Full Text Available Arnason and Raaflaub’s edited volume, The Roman Empire in Context: Historical and Comparative Perspectives, is the fifth volume in a series entitled The Ancient World: Comparative Histories. The overarching aim of the series is to bring a comparative perspective to studies of ancient histories, and earlier titles focus either on content or geography. This is the only volume to date that focuses on a specific civilization, and Rome is of course significant enough to merit its own volume.

  3. Phytochemicals in nutrition and health

    National Research Council Canada - National Science Library

    Meskin, Mark S

    2002-01-01

    ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . JOHN T. ARNASON, SHANNON E. BINNS, and BERNARD R. BAUM 9 CHAPTER 3 Phytochemicals in the Vaccinium Family: Bilberries, Blueberries, and Cranberries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ....

  4. Toxity of Gedunin, Piperine and Crude Extracts of their Natural ...

    African Journals Online (AJOL)

    Toxity of Gedunin, Piperine and Crude Extracts of their Natural Products on Growth and Development of Ostrinia Nubilalis Hbner (Lepidoptera: Pyrarlidae). F K Ewete, J T Arnason, T Durst, S Mackinnon ...

  5. Browse Title Index

    African Journals Online (AJOL)

    Items 401 - 427 of 427 ... F K Ewete, J T Arnason, T Durst, S Mackinnon. Vol 19 (2007):, Transition from Brittle Failure to Ductile Flow in a Sandy Soil, Abstract. AY Gitau, LO Gumbe. Vol 9, No 3 (1997), Trichomes and Resistance to Major Insect Pests in Cowpea, Vigna unguiculata (L.) Walp: A Review, Details. Sunday Oghiakhe.

  6. Deuterium and tritium profile through the Vatnajoekull icecap

    International Nuclear Information System (INIS)

    Arnasson, B.

    1974-06-01

    During the years 1971-73 a research project was carried out at the Science Institute of the University of Iceland with the financial support of the IAEA. A rotary drill for deep coring in temperate ice has been developed, and a 415 m deep hole was drilled during the summer of 1972 into the temperate accumulation area of the Vatnajoekull glacier, Iceland, at an altitude of 1800 m a.s.l. The core recovery was 99%. The bottom, at 480-500 m depth, was not reached because of a fault in the cable. Detail on the drill is given in: Arnason, Bjoernsson and Theodorsson, J. of Glaciology, 13, 133 (1974). Several volcanic ash layers have been recognized in the ice core and associated with historically known eruptions. This provides the age-depth relationship. Isotopic analyses along the core show that precipitation in the period 1931-1960 is enriched by 5 per mil in deuterium with respect to that in the period 1891-1920, in agreement with the 1degC increase in the mean air temperature occurred from the beginning of the century. Tritium analyses show appreciable isotopic exchange due to water percolation (summer rains and ice melting). The Na + and Cl - content decreases with depth (from 1 μg/g ice to 0.1 μg/g ice). This decrease has been attributed to dissolution of ions in water percolating along the ice crystals. Other studies of the ice core, in progress or planned, include: size and orientation of ice crystals, size and pressure of air bubbles, measurement of F - , SO 4 -- and Hg

  7. AUDIT OF INJURIES IN A PREMIERSHIP FOOTBALL SQUAD OVER A FIVE-YEAR PERIOD

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    Aslam Chougle

    2005-06-01

    Full Text Available Football is currently the most popular sport in the world. The competitive nature of the sport makes it prone to injuries with the estimated frequency being 10 to 35 per 1000 playing hours (Dvorak and Junge, 2000. The aim of this study was to identify the injury patterns and rehabilitation periods with specific injuries in a premiership football club. Player injuries were retrospectively analysed from a local database (Microsoft Access 2000 at the Blackburn Rovers Football Club, UK from December 1998 to March 2004. The club physiotherapist and physician recorded details of all injuries sustained during both training and matches during that period. Clear distinctions were made between acute and overuse injuries and rehabilitation times for each injury were noted (Arnason et al., 2004. Data was analysed using SPSS (Chicago, Illinois, USA. Differences between the groups were assessed using the independent samples t-test. P values of < 0.05 were considered statistically significant. There were 483 injuries in 91 players. Of these 133 injuries occurred as a result of overuse and 350 as a result of direct trauma. 440 injuries were treated conservatively while 43 were treated operatively. Table 1 shows the range and number of injuries, which occurred during this period along with the average rehabilitation time for each injury. Injuries grouped as "Other" in table 1 accounted for less than 1% of all injuries and could not always be directly attributed to football even though this appeared to be the precipitating factor in all cases. There was no statistical difference between rehabilitation times for acute injuries (18 days, standard deviation 30 as compared to overuse injuries (20 days, standard deviation 39 (p = 0.640. The mean rehabilitation time however for injuries treated conservatively (15 days , standard deviation 24 as compared to injuries treated surgically (61 days, standard deviation 67 was found to be statistically significant (p = 0

  8. Abundance estimation and conservation biology

    Science.gov (United States)

    Nichols, J.D.; MacKenzie, D.I.

    2004-01-01

    Abundance is the state variable of interest in most population–level ecological research and in most programs involving management and conservation of animal populations. Abundance is the single parameter of interest in capture–recapture models for closed populations (e.g., Darroch, 1958; Otis et al., 1978; Chao, 2001). The initial capture–recapture models developed for partially (Darroch, 1959) and completely (Jolly, 1965; Seber, 1965) open populations represented efforts to relax the restrictive assumption of population closure for the purpose of estimating abundance. Subsequent emphases in capture–recapture work were on survival rate estimation in the 1970’s and 1980’s (e.g., Burnham et al., 1987; Lebreton et al.,1992), and on movement estimation in the 1990’s (Brownie et al., 1993; Schwarz et al., 1993). However, from the mid–1990’s until the present time, capture–recapture investigators have expressed a renewed interest in abundance and related parameters (Pradel, 1996; Schwarz & Arnason, 1996; Schwarz, 2001). The focus of this session was abundance, and presentations covered topics ranging from estimation of abundance and rate of change in abundance, to inferences about the demographic processes underlying changes in abundance, to occupancy as a surrogate of abundance. The plenary paper by Link & Barker (2004) is provocative and very interesting, and it contains a number of important messages and suggestions. Link & Barker (2004) emphasize that the increasing complexity of capture–recapture models has resulted in large numbers of parameters and that a challenge to ecologists is to extract ecological signals from this complexity. They offer hierarchical models as a natural approach to inference in which traditional parameters are viewed as realizations of stochastic processes. These processes are governed by hyperparameters, and the inferential approach focuses on these hyperparameters. Link & Barker (2004) also suggest that our attention

  9. Abundance estimation and Conservation Biology

    Directory of Open Access Journals (Sweden)

    Nichols, J. D.

    2004-06-01

    Full Text Available Abundance is the state variable of interest in most population–level ecological research and in most programs involving management and conservation of animal populations. Abundance is the single parameter of interest in capture–recapture models for closed populations (e.g., Darroch, 1958; Otis et al., 1978; Chao, 2001. The initial capture–recapture models developed for partially (Darroch, 1959 and completely (Jolly, 1965; Seber, 1965 open populations represented efforts to relax the restrictive assumption of population closure for the purpose of estimating abundance. Subsequent emphases in capture–recapture work were on survival rate estimation in the 1970’s and 1980’s (e.g., Burnham et al., 1987; Lebreton et al.,1992, and on movement estimation in the 1990’s (Brownie et al., 1993; Schwarz et al., 1993. However, from the mid–1990’s until the present time, capture–recapture investigators have expressed a renewed interest in abundance and related parameters (Pradel, 1996; Schwarz & Arnason, 1996; Schwarz, 2001. The focus of this session was abundance, and presentations covered topics ranging from estimation of abundance and rate of change in abundance, to inferences about the demographic processes underlying changes in abundance, to occupancy as a surrogate of abundance. The plenary paper by Link & Barker (2004 is provocative and very interesting, and it contains a number of important messages and suggestions. Link & Barker (2004 emphasize that the increasing complexity of capture–recapture models has resulted in large numbers of parameters and that a challenge to ecologists is to extract ecological signals from this complexity. They offer hierarchical models as a natural approach to inference in which traditional parameters are viewed as realizations of stochastic processes. These processes are governed by hyperparameters, and the inferential approach focuses on these hyperparameters. Link & Barker (2004 also suggest that

  10. Soil development as limiting factor for shrub expansion in southwestern Greenland

    Science.gov (United States)

    Caviezel, Chatrina; Hunziker, Matthias; Zoller, Oliver; Wüthrich, Christoph; Kuhn, Nikolaus J.

    2014-05-01

    Southern Greenland currently experiences an increase in summer temperatures and a prolonged growing season (Masson-Delmotte et al. 2012), resulting in an increased shrub cover at the boreal - tundra border ecotone (Normand et al. 2013). These findings suggest the beginning of a greener Greenland in which tundra vegetation is transformed to a boreal woody flora. However, vegetation at borderline ecotones is influenced by further ecologic factors than just temperature. In this study, the ecologic conditions at a selection of sites along an elevation gradient near Igaliku in southern Greenland were examined to identify potential factors limiting the expansion of woody vegetation apart from temperature. The sites differ in elevation, topography, shrub density and soil parent material. The three study sites comprise i) well established birch shrubs growing between 50 and 180 m a.s.l., where the parent material origins from the Julianehab granite (Brooks 2012); ii) extended shrub patches at about 250 m a.s.l., where the parent material consists of Gardar Sandstones and Lavas (Brooks 2012) and iii) restricted shrub patches at an elevation of 250 m a.s.l., where the soil parent material originates from the Gardar intrusions (Brooks 2012). The extent of the shrub areas, topography and soil moisture were mapped, additionally soil samples were analyzed for C-and N-content, texture including coarse fraction and pH and used as soil development indicators. Our results show that the topographic setting regulates the existence or absence of soil while the soil parent material is an important limiting factor for soil moisture. According to these findings, we suggest that a high proportion of areas where temperature increase would allow the increase of shrub cover is not suitable for a woody flora. Brooks, Kent. 2012. "A Tale of Two Intrusions—where Familiar Rock Names No Longer Suffice." Geology Today 28 (1): 13-19. doi:10.1111/j.1365-2451.2012.00815.x. Masson-Delmotte, V., D

  11. Unravelling the sulphur isotope systematics of an alkaline magmatic province: implications for REE mineralization and exploration

    Science.gov (United States)

    Hutchison, W.; Finch, A.; Boyce, A.; Friis, H.; Borst, A. M.; Horsburgh, N. J.

    2017-12-01

    Some of the world's best alkaline rare earth element (REE) deposits are formed in magmatic systems that are sealed (i.e., those that are autometasomatised and maintain reducing conditions). Conversely, in open systems where oxidizing fluids infiltrate, it is commonly assumed that REE are redistributed over a wider (less concentrated) zone. Sulphur isotope fractionation is sensitive to variations in temperature and redox, and, although sulphide minerals are relatively abundant in alkaline systems, there have been few attempts to test these hypotheses and develop a sulphur isotope proxy for alkaline metasomatism and formation of associated REE deposits. The Gardar Rift Province in southern Greenland was volcanically active in two periods between 1300 and 1100 Ma and is an ideal natural laboratory to explore sulphur isotope systematics because a near-complete alkaline magmatic lineage is exposed. We present new δ34S from across the province with a particular focus on three alkaline systems (Ilímaussaq, Motzfeldt and Ivigtût) that also host major REE deposits. Primitive mafic rocks from regional Gardar dykes and lavas have a restricted range of δ34S between 0 and 3 ‰ and fractional crystallization imparts no observable change in δ34S. In a few cases high-δ34S rocks (>15 ‰) occur when intrusive units have assimilated local sedimentary crust (δ34S = 25 ‰). Most δ34S variation takes place in the roof zones of alkaline intrusions during late-magmatic and hydrothermal stages, and we identify clear differences between the complexes. At Ilímaussaq, where the magmatic series is exceptionally reduced (below QFM buffer), roof zone δ34S remains narrow (0-3 ‰). At Motzfeldt, a more open oxidizing roof zone (MH buffer), δ34S ranges from -12 ‰ in late-stage fluorite veins to +12 ‰ where local crust has been assimilated. Ivigtût is intermediate between these end-members varying between -5 to +5 ‰. The δ34S variations primarily relate to temperature and

  12. Uranium occurrences in the Granite Zone

    International Nuclear Information System (INIS)

    Nyegaard, P.; Armour-Brown, A.

    1986-04-01

    This report describes the work and results of the South Greenland Exploration Programme (Sydex) during the 1984 field season in the Granite Zone, and discusses the results and conclusions that can be drawn from them. It also contains a structural analysis of the Ivigtut-Julianehaab region, which will help in future exploration by indicating the likely directions of uraniferous faults and fractures. It also includes suggestions for future work with both exploration and scientific aspects. The project was carried out by the Geological Survey Greenland (GGU) in co-operation with Risoe National Laboratory. It was financed by the Danish Ministry of Energy. The structural analysis was carried out using previous geological maps, our own field observations and an analysis of lineament frequencies taken from aerial photographs and satellite images. Major lineaments in the region are due to E-W sinistral wrench faults and NE-SW normal faults. Analysis of the minor lineaments showed that the region could be divided into three blocks which have each reacted differently to the same regional stress field which was active throughout the Gardar period. A northern block which has been influenced by an older system of faults in the Archaean gneiss, a central block dominated by a graben, and a southern block where there is a change to a less intensively faulted area. 2 maps, 27 refs. (EG)

  13. Large-scale deep-water seafloor mapping from the Rockall to the Hatton basins, NE Atlantic

    Science.gov (United States)

    Monteys, X.; Thébaudeau, B.; Murcia, C.; Duncan, N.

    2016-02-01

    Multibeam data acquired in 2000 and 2001 during the Irish National Seabed Survey (INSS) are used for the first detailed investigation of the seabed geomorphology and sediment type in the Hatton-Rockall basin area of the North East Atlantic Ocean, covering an area of approximately 80,000 km². The original multibeam survey produced bathymetric and backscatter datasets that allowed the creation of a Digital Terrain Models of approximately 50 m in resolution in water depths between 500 and 3500 m. Near-surface sediments for the entire region haven been classified using features derived from multibeam angular backscatter data (12kHz) and robust unsupervised clustering techniques. Additionally, sub bottom data imaging the shallow stratigraphy and geomagnetic measurements collected at the time of the MBES survey are combined to further characterise some of the features identified. The features presented in detail include parts of the Hatton and Gardar contourite drifts, volcanic mounds identified by their morphology and magnetic signature, deep-water coral mounds, iceberg scours as well as canyons, gullies and escarpments along and down the slopes of the banks and mounds. This study highlights for the first time the variety and complexity of the seafloor present at the seabed in the Irish Hatton-Rockall basin area

  14. The petrology and petrogenesis of the Swaldale region, Motzfeldt Center, South Greenland

    Science.gov (United States)

    Reekie, Callum; Finch, Adrian

    2016-04-01

    Motzfeldt is one of several high-level alkaline plutonic centers that collectively define the mid-Proterozoic Gardar Province of South Greenland. Despite pyrochlore-hosted Ta-enrichment (± Nb-Zr-REE), the petrology, geochemistry and petrogenesis across the center remain to be fully constrained. We present petrological and geochemical data for the Swaldale region, an arcuate band of nepheline syenite and associated intrusives on Motzfeldt's NW margin. Work for this present study was undertaken in collaboration with the license holder, Regency Mines plc. Swaldale comprises two geochemically distinct magmatic members. The largest, the Motzfeldt Sø Formation (MSF; EuN/Eu*N = 0.35), is a suite of diverse syenite variants that show significant petrological and geochemical heterogeneity. These rocks have a relatively restricted SiO2 range (57.4-62.9 wt.%) with concurrent variation in (Na+K)/Al (0.75-0.95), Mg/(Mg+Fe) (2.18-19.82) and ΣREE (595.0-3095.9 ppm), emphasizing their evolved but not peralkaline nature. Fractionation is mirrored by pyroxene geochemistry with evolution from aegirine-augite, aegirine-hedenbergite, to aegirine. Accessory pyrochlore, titanite, and zircon are rare; however, anomalous facies of zircon-rich (~2 wt.%) syenite are observed. Intercumulus fluorite is a common accessory within MSF rocks. Hydrothermal alteration, marked by hematized alkali-feldspar, is pervasive and ubiquitous. Further peraluminous syenite of the Geologfjeld Formation ((Na+K)/Al = 0.74; EuN/Eu*N = 1.60) marks the truncated remnant of an early syenite stock to the north of the MSF. These rocks contain salite, which, in addition to a lower ΣREE and higher Mg/(Mg+Fe) (18.01), demonstrates the less-fractionated nature of this stock in comparison with the MSF. Sheeted intrusions of peralkaline syenite ((Na+K)/Al = 1.1; Ta = 32.4 ppm) truncate the MSF across central Swaldale. On a mineralogical basis, it is hypothesized that such intrusions reflect outward sheeting of the

  15. Enigma of lamprohyres

    Science.gov (United States)

    Vasyukova, Elena

    2013-04-01

    -chuya area rocks, where Ba-celestine was found, marked Ba and Sr minima. Accordingly this fact Ba and Sr couldn't be brought into the system. And Ba-celestine is the residual sign of the segregated liquid, enriched in Ba, Sr, Ca ? P. 1. Rock, N. M. S., 1991. Lamprophyres. Blackie and Son Ltd, Glasgow and London, 285 pp. 2. J. Woodard Genesis and Emplacement of Carbonatites and Lamprophyres in the Svecophennian Domain, Academic Dissertation, University of Turku, Finland, 50 p., 2010 3. I.M.Coulson, K.M. Goodenough, N.J.G. Pearce, M.J. Leng Carbonatites and lamprophyres of the Gardar Province - a "window" to the sub-Gardar mantle? // Mineralogical Magazine, October 2003, Vol. 67(5), pp. 855-872. 4. McDonough, W.F. and Sun, S.-S. (1995). Composition of the Earth. Chemical Geology 120: 223-253. doi: 10.1016/0009-2541(94)00140-4.

  16. Millennial-scale interaction between ice sheets and ocean circulation during marine isotope stage 100

    Directory of Open Access Journals (Sweden)

    Masao eOhno

    2016-05-01

    Full Text Available Waxing/waning of the ice sheets and the associated change in thermohaline circulation have played an important role in global climate change since major continental ice sheets appeared in the northern hemisphere about 2.75 million years ago. In the earliest glacial stages, however, establishment of the linkage between ice sheet development and ocean circulation remain largely unclear. Here we show new high-resolution records of marine isotope stage 100 recovered from deep-sea sediments on the Gardar Drift, in the subpolar North Atlantic. Results of a wide range of analyses clearly reveal the influence of millennial-scale variability in iceberg discharge on ocean surface condition and bottom current variability in the subpolar North Atlantic during marine isotope stage 100. We identified eight events of ice-rafted debris, which occurred mostly with decreases in sea surface temperature and in current components indicating North Atlantic Deep Water. These decreases are interpreted by weakened deep water formation linked to iceberg discharge, similarly to observations from the last glacial period. Dolomite fraction of the ice-rafted events in early MIS 100 like the last glacial Heinrich events suggests massive collapse of the Laurentide ice sheet in North America. At the same time, our early glacial data suggest differences from the last glacial period: absence of 1470-year periodicity in the interactions between ice sheets and ocean, and northerly shift of the ice-rafted debris belt. Our high-resolution data largely improve the picture of ice-sheet/ocean interactions on millennial time scales in the early glacial period after major Northern Hemisphere glaciation.

  17. The South Greenland uranium exploration programme

    International Nuclear Information System (INIS)

    Armour-Brown, A.; Tukiainen, T.; Wallin, B.

    1982-11-01

    This is the final report of the reconnaissance phase of the SYDURAN Project which was initiated in 1st. December 1978 to outline areas of increased uranium potential where more detailed prospection would be warranted. Districts and smaller zones in South Greenland which have the potential for containing economically exploitable uranium occurrences were defined using airborne gamma-spectroscopic, reconnaissance geochemical and geological methods. Other districts and areas have been shown to have no uranium potential and can be eliminated. The three promising districts are: 1. a 2000 square kilometre sub-circular district surrounding Ilimaussaq complex in which there are small high grade pitchblende occurences in faults and fractures in the surrounding granite. 2. the eastern area of the Motzfeldt Centre where large parts of the centre is mineralised and may give rise to exploitable, large tonnage, low grade uranium ore with associated niobium and rare earth elements in extractable quantities. 3. uraniferous rich districts or zones associated with the migmatitic supracrustal units in the area between Kap Farvel and Lindenows Fjord. The areas which were eliminated from having any uranium potential include: the Ketilidian supracrustal unit. the Nunarssuit alkaline complex. The uranium mineralisation in South Greenland is confined to two Proterozoic episodes: a) a late phase of granitisation and migmatisation with the formation of disseminated uraninite in the Migmatite Complex in the south of the project area between 1700-1800 m.y. and, b) hydrothermal activity associated with Gardar magmatic events between 1090-1170 m.y. in the central Granite Zone. Future work should be directed towards the definition and location of drilling targets. (EG)

  18. Cosmogenic 10Be signature of geomagnetic dipole moment variations over the last 2 Ma

    Science.gov (United States)

    Simon, Q.; Thouveny, N.; Bourlès, D. L.; Valet, J. P.; Bassinot, F. C.; Savranskaia, T.; Duvivier, A.; Choy, S.; Gacem, L.; Villedieu, A.

    2017-12-01

    strengthens the occurrence of several Matuyama's excursions (Kamikatsura, Santa Rosa, Punaruu, Bjorn, Gilsa, Gardar) that were reported only from sparse locations.

  19. Cosmogenic signature of geomagnetic reversals and excursions from the Réunion event to the Matuyama-Brunhes transition (0.7-2.14 Ma interval)

    Science.gov (United States)

    Simon, Quentin; Bourlès, Didier L.; Thouveny, Nicolas; Horng, Chorng-Shern; Valet, Jean-Pierre; Bassinot, Franck; Choy, Sandrine

    2018-01-01

    Rosa, Punaruu, Bjorn, Gilsa, Gardar) that were until now reported from only sparse locations.

  20. Tests for orbital influences on the geomagnetic field, and Quarternary magnetic records from North Atlantic and Arctic deep-sea sediments

    Science.gov (United States)

    Xuan, Chuang

    paleomagnetic data and facilitates the calculation of paleomagnetic directions and RPI proxies. This new software incorporates new methods of analysis, particularly in the generation of RPI proxies. U-channel NRM measurements at Integrated Ocean Drilling Program (IODP) Site U1304 yield continuous high resolution paleomagnetic records for the last ˜1.5 Ma. Sediments from IODP Site U1304 clearly recorded the Brunhes/Matuyama boundary, the Jaramillo subchron, and the Cobb Mountain subchron, as well as the Kamikatsura excursion and the Gardar excursion. Age model for the site is established by correlating IODP Site U1304 RPI record to the PISO-1500 RPI stack using automated dynamic programming method with limited number of tie points. No significant orbital periods were detected in RPI record from the site. Various evidences indicate that the episodic deposits of laminated diatom ooze throughout the IODP Site U1304 sediments, appear to dilute the magnetic concentrations of the sediments with elevated sedimentation rates, but do not debilitate the reliability of the acquired paleomagnetic direction and intensity data. Rock magnetic experiments carried out under various temperature ranges, along with scanning electron microscopy (SEM) and X-ray energy-dispersive spectroscopy (EDS) observations as well as X-ray diffraction (XRD) analyses, on bulk Arctic deep-sea sediments and magnetic extracts from seven cores collected by the Healy-Oden Trans-Arctic Expedition 2005 (HOTRAX05), indicate that (titano)magnetite and titanomaghemite are the magnetic remanence carriers. It appears that the titanomaghemite carries a chemical remanent magnetization (CRM) that is partially self-reversed relative to the detrital remanent magnetization (DRM) carried by the host titanomagnetite, causing the apparent magnetic 'excursions' in the Arctic deep-sea sediment records. The partial self-reversal could have been accomplished by ionic ordering during oxidation, thereby changing the balance of the magnetic