A catalogue of major and trace element data for Icelandic Holocene silicic tephra layers

Tephra layers with Icelandic provenance have been identified across the North Atlantic region in terrestrial, lacustrine, marine and glacial environments. These tephra layers are used as marker horizons in tephrochronology including climate studies, archaeology and environmental change. The major element chemistries of 19 proximally deposited Holocene Icelandic silicic tephra layers confirm that individual volcanic systems have unique geochemical signatures and that eruptions from the same system can often be distinguished. In addition, glass trace element chemistry highlights subtle geochemical variations between tephra layers which appear to have identical major element chemistry and thus allows for the identification of some, if not all, tephra layers previously considered identical in composition. This paper catalogues the compositional variation between the widespread Holocene Icelandic silicic tephra deposits.     

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VISTA Variables in the Via Lactea (VVV): The public ESO near-IR variability survey of the Milky Way

We describe the public ESO near-IR variability survey (VVV) scanning the Milky Way bulge and an adjacent section of the mid-plane where star formation activity is high. The survey will take 1929 h of observations with the 4-m VISTA telescope during 5 years (2010–2014), covering ～10⁹ point sources across an area of 520 deg², including 33 known globular clusters and ～350 open clusters. The final product will be a deep near-IR atlas in five passbands (0.9–2.5 μm) and a catalogue of more than 10⁶ variable point sources. Unlike single-epoch surveys that, in most cases, only produce 2-D maps, the VVV variable star survey will enable the construction of a 3-D map of the surveyed region using well-understood distance indicators such as RR Lyrae stars, and Cepheids. It will yield important information on the ages of the populations. The observations will be combined with data from MACHO, OGLE, EROS, VST, Spitzer, HST, Chandra, INTEGRAL, WISE, Fermi LAT, XMM-Newton, GAIA and ALMA for a complete understanding of the variable sources in the inner Milky Way. This public survey will provide data available to the whole community and therefore will enable further studies of the history of the Milky Way, its globular cluster evolution, and the population census of the Galactic Bulge and center, as well as the investigations of the star forming regions in the disk. The combined variable star catalogues will have important implications for theoretical investigations of pulsation properties of stars.     

Meteors in the IAU Meteor Data Center on Hyperbolic Orbits

The hyperbolic meteor orbits among the 4,581 photographic and 62,906 radar meteors of the IAU MDC have been analysed using statistical methods. It was shown that the vast majority of hyperbolic orbits has been caused by the dispersion of determined velocities. The large proportion of hyperbolic orbits among the known meteor showers strongly suggests the hyperbolicity of the meteors is not real. The number of apparent hyperbolic orbits increases inversely proportional to the difference between the mean heliocentric velocity of meteor shower and the parabolic velocity limit. The number of hyperbolic meteors in the investigated catalogues does not, in any case, represent the number of interstellar meteors in observational data. The apparent hyperbolicity of these orbits is caused by a high spread in velocity determination, shifting a part of the data through the parabolic limit.     

Cultural land use and vegetation dynamics in the uplands of northern Portugal from the Middle Ages to the Modern period

In Europe, mountain landscapes have evolved in a long-term relationship with human communities and present-day landscapes reflect that ancient interaction. The present study aims to reconstruct human activity in two mountain areas in northern Portugal using palynological analysis integrated with the available regional historical, archaeological and palaeoenvironmental archives. Pollen records from two sedimentary sequences span the Medieval and Modern periods and show that mixed agriculture and livestock grazing were consistently present in both regions throughout these times. Variations in cultural indicators show that the extent of farming fluctuated throughout time, with a general increase in cultivation during the Medieval period but with contractions likely coinciding with times of social disturbance. Historical sources suggest that sociopolitical factors and population pressure were fundamental in the utilisation of upland spaces. This study did not find any convincing evidence to suggest that fire was a fundamental factor in heathland spread. We conclude that long-term occupation of the uplands was sustained by low-intensity land use throughout the Medieval to post-Medieval periods, and that the present landscape has assumed a very different character following depopulation of the mountain areas and a shift towards commercial forestry.     

Movement patterns of an endangered fishery species,Lithognathus lithognathus (Sparidae), and the role of no-take marine protected areas as a management tool

Understanding movement behaviour is essential for effective management of fishery species. Dart tags were used to study coastal movement patterns of white steenbras Lithognathus lithognathus, an overexploited seabream (Sparidae) in South Africa. In total, 6 962 fish (190–1 080 mm fork length) were tagged throughout the species’ distributional range, in four long-term fish-tagging programmes. The predominant behaviour recorded was residency, with relatively short-ranging movements. More than 60% of the 351 recaptured fish were recaptured within 1 km of their tagging site, some of which were at liberty in excess of three years. Most of the juveniles (93.9%), subadults (71.7%) and adults (64.0%) were recaptured within 10 km. Occasional long-distance movements of up to 800 km were recorded. Recapture distances were positively, but weakly, correlated with fish fork length (n = 257 fish measured at recapture; r² = 0.166, p < 0.001). Low levels of connectivity among coastal areas suggest that large-scale annual spawning migrations, as previously hypothesised for this species, are unlikely, which raises the possibility of multiple spawning sites. Seventy-seven percent of L. lithognathus tagged within three marine protected areas (MPAs) were recaptured within the same MPA, suggesting that area closures provide protection for L. lithognathus through the post-estuarine juvenile, subadult and adult life stages. We confirm that the country’s current network of coastal MPAs plays a vital role in sustaining this species, and suggest that additional closures, or otherwise substantial reductions in catch rates, are necessary for the species’ recovery.     

Estuarine and coastal connectivity of an estuarine-dependent fishery species,Pomadasys commersonnii (Haemulidae)

Understanding the level of connectivity between estuarine and coastal waters is essential for appropriate management of estuarine-associated taxa. Most studies have focused on the role of a single estuary, while limited research exists on the importance of multiple estuaries to individuals of estuarine-associated species. This study used acoustic telemetry to assess the usage of multiple estuaries and coastal waters by the estuarine-dependent spotted grunter Pomadasys commersonnii. Twenty-six adult fish were tagged with acoustic transmitters in the Kariega and Bushmans estuaries, South Africa, and their movements along a 300-km stretch of Indian Ocean coastline were monitored for up to 17 months. Tagged individuals spent most of their time in the estuary where they were tagged (55% and 85% for fish tagged in the two estuaries, respectively), followed by time in the sea (30% and 15%) and in other estuaries (15% and <1%). The mean durations of sea trips for fish tagged in the Kariega Estuary or Bushmans Estuary, respectively, were 25 days (range 3–55) and 12 days (range 2–22). Of the fish that went to sea, 93% from the Kariega Estuary and 60% from the Bushmans Estuary visited other estuaries. Most visits were undertaken to the Swartkops, Bushmans and Kowie estuaries, although the longest durations were spent in the Sundays Estuary. Individuals moved to estuaries up to 130 km away. The total distance travelled between estuaries by an individual during the study was ～529 km, with means of 201 and 184 km, respectively, for fish tagged in the Kariega and Bushmans estuaries. Despite covering large distances between estuaries, individuals often returned to their tagging estuary. Residency in their tagging estuary, combined with frequent visits to a neighbouring estuary, highlights the importance of estuarine habitats for this popular fish species, even after reaching maturity.     

辽宁盖县梁屯—矿洞沟碱性正长岩杂岩体的U—Pb和Sm—Nd年龄及其地质意义

辽宁梁屯 -矿洞沟杂岩体主要由辉石正长岩、霓辉正长岩和霓辉角闪正长岩等碱性岩石组成 ,具有全岩 Rb- Sr等时线年龄 186 6± 115 Ma和 ISr=0 .70 4 9的同位素特征 ,是我国目前报道的最古老的碱性正长岩类。本文报道了该岩体的锆石U- Pb和全岩 Sm- Nd同位素测试资料 ,获得了锆石 U- Pb同位素年龄为 185 7± 2 0 Ma、Sm- Nd等时年龄为 1787± 180 Ma、εNd(t) =- 4 .8～ - 5 .0的数据。它们反映出该杂岩体形成年龄的上限为 185 7± 2 0 Ma、下限不小于 1787± 180 Ma,来源于富集地幔物质。基于这些数据并结合区域地质资料分析 ,作者提出了华北地台北缘古元古宙存在有富集地幔储库 ,以及辽河群主体形成于 190 0 Ma以前的认识