Transgressive dune formation along a cliffed coast at 75 ka in Sardinia,Western Mediterranean: a record of sea‐level fall and increased windiness

Transgressive dunes develop frequently along strandplain coastlines; however, they may also form along rocky coasts dominated by cliffs and embayments. Two lithified transgressive dune systems developed along the cliffed Alghero coast (NW Sardinia, Italy) have been investigated. One aeolian system forms a cliff‐front anchored aeolian dune accumulation; the other is a valley‐head anchored sand‐ramp system. Optically stimulated luminescence ages indicate that both systems formed around 75 ka. This period, which corresponds to the beginning of MIS 4, was characterized by a relatively low sea‐level stand (15 m below the present sea level) and was preceded by a sea‐level highstand (+1 m asl) around 81 ka (MIS 5a). Our results show that this rapid sea‐level fall exposed an enormous amount of marine sand, which was transported inland by strong northerly winds and deposited in front of cliffs or in valley heads. Therefore, sediment supply and sea‐level fall seem to be critical factors controlling dune formation along rocky coasts, which generate time‐transgressive aeolianites. Terra Nova, 00, 000–000, 2010     

Multidimensional thermal structure of magnetized neutron star envelopes

Recently launched X-ray telescopes have discovered several candidate isolated neutron stars. The thermal radiation from these objects may potentially constrain our understanding of nuclear physics in a realm inaccessible to terrestrial experiments. To translate the observed fluxes from neutron stars into constraints, one needs precise calculations of the heat transfer through the thin insulating envelopes of neutron stars. We describe models of the thermal structure of the envelopes of neutron stars with magnetic fields up to 10¹⁴ G. Unlike earlier work, we infer the properties of envelope models in two dimensions and precisely account for the quantization of the electron phase-space. Both dipole and uniformly magnetized envelopes are considered.     

Regional Be production rate calibration for the past 12 ka deduced from the radiocarbon-dated Grøtlandsura and Russenes rock avalanches at 69° N, Norway

Two rock avalanches in Troms County – the Grøtlandsura and Russenes – were selected as CRONUS-EU natural cosmogenic ¹⁰Be production-rate calibration sites because they (a) preserve large boulders that have been continuously exposed to cosmic irradiation since their emplacement; (b) contain boulders with abundant quartz phenocrysts and veins with low concentrations of naturally-occurring ⁹Be (typically < 1.5 ppb); and (c) have reliable minimum radiocarbon ages of 11,424 ± 108 cal yr BP and 10,942 ± 77 cal yr BP (1σ), respectively. Quartz samples (n = 6) from these two sites contained between 4.28 × 10⁴ and 5.06 × 10⁴ at ¹⁰Be/g using the 1.387 Myr ¹⁰Be half-life. Determination of these concentrations accounts for topographic and self-shielding, and effects on nuclide production due to isostatic rebound are shown to be negligible. Persistent, constant snow and moss cover cannot be proven, but if taken into consideration they may have reduced ¹⁰Be concentrations by 10%. Using the ¹⁰Be half-life of 1.387 Myr and the Stone scaling scheme, and accounting for snow- and moss-cover, we calculate an error-weighted mean total ¹⁰Be production rate of 4.12 ± 0.19 at/g/yr (1σ). A corresponding error-weighted mean spallogenic ¹⁰Be production rate is 3.96 ± 0.16 at/g/yr (1σ), respectively. These are in agreement within uncertainty with other ¹⁰Be production rates in the literature, but are significantly, statistically lower than the global average ¹⁰Be production rate. This research indicates, like other recent studies, that the production of cosmogenic ¹⁰Be in quartz is lower than previously established by other production-rate calibration projects. Similarly, our findings indicate that regional cosmogenic production rates should be used for determining exposure ages of landforms in order to increase the accuracy of those ages. As such, using the total ¹⁰Be production rate from our study, we determine an error-weighted mean surface-exposure age of a third rock avalanche in Troms County (the Hølen avalanche) to be 7.5 ± 0.3 kyr (1σ). This age suggests that the rock avalanche occurred shortly after the 8.2 kyr cooling event, just as the radiocarbon ages of the Grøtlandsura and Russenes avalanches confirm field evidence that those rock-slope failures occurred shortly after deglaciation.     

Sea‐level markers identified in ground‐penetrating radar data collected across a modern beach ridge system in a microtidal regime

Sea‐level rise has been related to global warming. The modern system on the northern coast of Anholt, Denmark, may well be analogous to other beach ridge systems formed in microtidal regimes and our results should have impact on estimation of past sea‐level variation. Ground‐penetrating radar data collected across the modern (<30 years old) berm, beach ridge and swale deposits resolve downlapping reflections interpreted to mark sea level at the time of deposition. Existing time series of sea‐level data constrain actual sea‐level variation. Nineteen readings of sea‐level markers made along our profile fluctuate within ?0.42 and 0.57 m above present mean sea level, consistent with 95% of the sea‐level data. These fluctuations reflect tidal effects and meteorological conditions. Main data uncertainties are well‐known and the sea‐level markers may be identified with a high degree of confidence.     

The BEEP project in the Baltic Sea: overview of results and outline for a regional biological effects monitoring strategy

Field studies in the framework of the EU funded BEEP project (Biological Effects of Environmental Pollution in Marine Coastal Ecosystems, 2001-2004) aimed at validating and intercalibrating a battery of biomarkers of contaminant exposure and effects in selected indicator species in the Mediterranean, the North Atlantic and the Baltic Seas. Major strategic goals of the BEEP project were the development of a sensitive and cost-efficient biological effects monitoring approach, delivery of information and advice to end-user groups, and the implementation of a network of biomarker researchers around Europe. Based on the main results obtained in the Baltic Sea component of the BEEP the present paper summarises and assesses the applicability of biomarkers for different regions and species in this sea area. Moreover, a general strategy and some practical considerations for the monitoring of biological effects in the Baltic Sea are outlined.     

TESSIN VISLab—laboratory for scientific visualization

Scientific visualization is an integral part of the modeling workflow, enabling researchers to understand complex or large data sets and simulation results. A high-resolution stereoscopic virtual reality (VR) environment further enhances the possibilities of visualization. Such an environment also allows collaboration in work groups including people of different backgrounds and to present results of research projects to stakeholders or the public. The requirements for the computing equipment driving the VR environment demand specialized software applications which can be run in a parallel fashion on a set of interconnected machines. Another challenge is to devise a useful data workflow from source data sets onto the display system. Therefore, we develop software applications like the OpenGeoSys Data Explorer, custom data conversion tools for established visualization packages such as ParaView and Visualization Toolkit as well as presentation and interaction techniques for 3D applications like Unity. We demonstrate our workflow by presenting visualization results for case studies from a broad range of applications. An outlook on how visualization techniques can be deeply integrated into the simulation process is given and future technical improvements such as a simplified hardware setup are outlined.     

A new look at population change and regional development in Aotearoa New Zealand

In New Zealand, population change is interlinked with regional development. Places growing in population attract regional investment, while regional investment—or lack thereof—can change migration patterns. However, to determine the appropriate response to population change for a community, it is important to understand that population change involves much more than “just” migration. Specifically, it involves interactions between the three components of population change: natural change (births minus deaths), net migration (international and internal) and population ageing (changing cohort size). For example, migration can be negative, but growth can be positive due to underlying natural increase or growth in cohort size. Responses need to differ, depending on these drivers. The goal of this article is to provide new insights into these interactions using data for 275 cities, towns and rural centres (hereafter “urban places”) in New Zealand for the period 1976 to 2013. The results show that natural change has been consistently positive for most urban places up to the present, although projections indicate that in the future this component will become negative across much of the country. At the same time, net migration shows considerable spatial variation, not only in terms of volume, but also direction (negative or positive), which differs markedly by age. A net gain of people of retirement age can offset a net loss of young adults to deliver overall growth, and vice‐versa, but the two have very different implications for longer term growth. An analysis of the drivers of net migration using GIS and machine learning techniques provides an indication of the importance of economic conditions (land‐use and access to markets), lifestyle, access to essential services (hospitals and education) and their interaction with age in regional change. The results show that population age is the best predictor of migration. Younger people are moving to cities for tertiary education and work and older people near or in retirement are moving to smaller lifestyle towns but also want to be close to amenities such as hospitals and international airports. The research also shows that natural lifestyle characteristics (landscape and climate), in combination with age are just as important as economic conditions for understanding migration. Regional development, such as infrastructure that helps business (ports and services) is important for the working age population but not necessarily the retirement age group. When regional development, age/life‐cycle stage and lifestyle come together, such as in Queenstown and Tauranga, net migration gain is high.     

Seismic geomorphology and growth architecture of a Miocene barrier reef,Browse Basin,NW-Australia

The Cenozoic succession of Browse Basin is characterized by a carbonate system, that developed from a non-tropical ramp in Eocene-lower Miocene times to a tropical rimmed platform in the middle Miocene. The evolution of the platform was unraveled through the interpretation of the seismic geomorphology and borehole data of the middle Miocene tropical reef system. The first reef structures developed during the early middle Miocene as narrow linear reef belts with an oblique orientation with respect to shelf strike direction. Subsequently, they prograded toward the platform margin to form a barrier reef with a minimum length of 40 km. The barrier reef itself comprises three distinct ridges separated by progradational steps. The second and third step are separated by a karstified horizon, which is interpreted to represent the global sea-level fall shortly before the Serravallian/Tortonian boundary. The following third ridge formed in a slightly downstepped position during the sea-level lowstand and initial transgressive phase. Further sea-level rise during the early Tortonian first drowned the barrier-reef system and subsequently also the patch reefs and relic atolls that had established in a backstepped position in the platform interior. The similar evolution of the Browse Basin reef system and other contemporaneous carbonate systems indicates a strong impact of eustatic sea-level changes. Relatively large subsidence rates in the study area possibly augmented the eustatic sea-level rise in the Tortonian and hence contributed to the drowning of the reef system. However, the initiation and final demise of the reef system was also governed by global and regional climate variations. The first seismically-defined reefs developed simultaneous to a maximum in the transport capacity of the Indonesian throughflow, which brings warm low-salinity waters to the North-West Shelf. Reef drowning followed the restriction of this seaway close to the middle to early Miocene boundary. This near closure of the Indonesian seaway possibly led to a regional amplification of the global middle to late Miocene cooling trend and hampered the potential of the reef system to keep up with the rising sea-level.