Shetlands Islands field trip May 2014 : summary of results

This report provides a record of a field excursion to the Shetland Islands in May 2014 to investigate sediments deposited from tsunamis generated from submarine landslides mainly located off the coast of Norway. The research was funded under a NERC Consortium Grant for a project entitled ‘Will climate change in the Arctic increase the landslide-tsunami risk to the UK?’ It was part of Work Block 2 (WB2): ‘What is the timing of tsunami deposits on the UK coastline, and how is it related to the age of major Arctic slides’? The best known and most studied tsunami from the Norwegian submarine landslides is the Storegga event dated at 8,200BP. Sediments deposited from this tsunami are commonly found along the west coast of Norway, east coast of mainland Scotland, and also on the Shetland and Faeroe islands. However, there are other landslides off of Norway for which no associated tsunami has been identified, which poses the question as to whether these events did not generate a tsunami or whether the evidence for a tsunami has not yet been found. Although evidence for seabed slumping off Norway was first discovered in the 1950’s (Holtedahl, 1955, 1971) and the scale and morphology of a massive submarine landslide, subsequently termed Storegga, mapped in the 1970’s (Bugge, 1983), it was not until 1985 that an associated tsunami was first proposed (Svendsen, 1985). The first supporting sedimentary evidence of the tsunami was first identified on mainland Scotland in 1988 (Dawson et al., 1988) then, subsequently, similar sediments were identified on the Shetland Islands (Smith, 1993a). The Storegga Slide has been dated to 8,150BP (Haflidason et al., 2005), however more recent research on the deposits on the Shetlands suggests that some may not all be from Storegga, because 14C age dating gives younger ages of ~5,000 and 1,500 cal yr BP (Bondevik et al., 2005). A major challenge posed by the ages of these younger dates is that they are confined to the Shetlands; there is no indication of these younger tsunamis on mainland Scotland. If the dating is correct and the sediments are indeed from tsunamis, then the submarine landslides off Norway would be an unlikely source, so a local source seems most likely, but none has yet been identified. Alternatively a non-tsunami source for the sediments may explain their presence. The objectives of WB2 therefore are to investigate the tsunami deposits on Shetland that post-date the Storegga Slide, to validate their ages and, if possible, identify possible source locations of the submarine landslides that generated the tsunamis. On Shetland research on tsunami sediments was mainly based on evidence from coastal exposures around Sullom Voe where tsunami sands are dated as coeval with Storegga. The younger sands are mainly preserved in lake cores at locations on Shetland Mainland (Bondevik et al., 2005) where those of 5,000 BP overlie sands of Storegga age at 8,200 years BP age. At coastal sites along Basta Voe on Yell and at a mainland site at Dury Voe very young age dates of ~1,500 BP suggest an additional and very recent, late Holocene event (Bondevik et al., 2005; Dawson et al, 2006). A preliminary field excursion to the Shetlands carried out in 2013 discovered possible new tsunami deposits preserved in peat on central Yell at Whale Firth, Mid Yell Voe and Kirkabister. Subsequent 14C age dating of these deposits resulted in a variety of ages, many much younger than that of Storegga. The 14C method is known to be subject to major uncertainties because of contamination, for example initial age dating in the 1990’s at sites around Sullom Voe returned ages of around 5,000 years BP, although these were subsequently rejected in favour of the earlier, 8,200 BP Storegga event. Thus, validating the ages of the deposits on Yell, prospectively from a number of deposits laid down successively at one site (thereby reducing the sole reliance on 14C dating) was critical in validating the presence of more than one tsunami event on Shetland. The objective of the 2014 field visit to the Shetlands, therefore, was to return to Yell and validate the preliminary results from 2013; revisiting the sites at Whale Firth, Mid Yell and Kirkabister and searching the coastlines of Unst, Fetlar, Yell and north Mainland for additional sites where tsunami sediments might be preserved. Just before the visit new 14C dates from Mid Yell from samples collected in 2013 confirmed the previous results from other locations that had given a wide range of ages; at Whale Firth a single date gave a ‘young’ age of ~5,000 years BP, a range of ages with the oldest at 8,200 years BP were returned from Mid Yell Voe. We first visited sites on north Mainland around Sullom Voe, as it was here that the first indications of the Storegga tsunami were identified on Shetland in 1992. The deposits are classic as they contain rip-up clasts characteristic of tsunami deposits elsewhere. We then visited the sites at Basta Voe, Whale Firth, Mid Yell and Kirkabister. We carried out reconnaissance surveys on Unst, Fetlar, Yell and north Mainland. Preliminary results: 1. The new evidence supports the presence of tsunami sediments on Yell at Mid Yell Voe and Whale Firth, but the age of these sediments requires further research to confirm previous dating and their possible sources, 2. The youngest dated sediments (~1,500 BP) at Vasta Voe are most likely from a tsunami, but their limited areal extent suggests a local source, as yet undetermined, 3. The presence of three events at Mid Yell Voe based on surveys in 2013 was not confirmed, 4. The similarity of the deposits on Mid Yell with those around Sullom Voe on Mainland are suggestive of a similar source, 5. The wide range of the preliminary age dating at the Mid Yell sites (Whale Firth and Mid Yell Voe) is analogous to the early age dating of coastal deposits around Sullom Voe, suggesting the possibility of contamination of the peat material dated, 6. Whereas the 5,500BP event is identified in lake cores, no strongly supportive evidence for sands of this age were identified in the coastal sections, 7. Of the proposed three tsunami events proposed for Shetland only one, Storegga, has a confirmed source, 8. Further analysis of the peat stratigraphy at the coastal sites, reflects vegetation changes over the past ~8,000 years related to climate change, and these could be used to provide a broader context for the 14C age dating that may resolve the present dating issues, 9. Newly discovered sediments at Kirkabister require further research to determine their origin, 10. The origin(s) of the laminated deposits at Whale Firth, Mid Yell and Vatsetter is/are uncertain, but they are probably not from a tsunami, 11. No additional coastal exposures of peat with tsunami sands were located during the reconnaissance surveys on Mainland, Yell, Unst and Fetlar. Postscript; Immediately after this report was finalised, age dating of peat sections at Whale Firth and Mid Yell Voe confirmed that the sands preserved in the woody peat here are of Storegga age, ~8,200 cal yr BP

Covariant Vortex In Superconducting-Superfluid-Normal Fluid Mixtures with Stiff Equation of State

The integrals of motion for a cylindrically symmetric stationary vortex are obtained in a covariant description of a mixture of interacting superconductors, superfluids and normal fluids. The relevant integrated stress-energy coefficients for the vortex with respect to a vortex-free reference state are calculated in the approximation of a ``stiff'', i.e. least compressible, relativistic equation of state for the fluid mixture. As an illustration of the foregoing general results, we discuss their application to some of the well known examples of ``real'' superfluid and superconducting systems that are contained as special cases. These include Landau's two-fluid model, uncharged binary superfluid mixtures, rotating conventional superconductors and the superfluid neutron-proton-electron plasma in the outer core of neutron stars.Comment: 14 pages, uses RevTeX and amssymb, submitte

Corinth Excavations Archaeological Manual

“The publication of the Corinth Excavation Manual offers us a unique view into real-life archaeological practice on one of the most important Classical sites in the Mediterranean.” Adam Rabinowitz, Associate Professor and Assistant Director, Institute of Classical Archaeology, University of Texas, Austin The Corinth Excavations Archaeological Manual is the first major field manual published from an American excavation in Greece and among a very small number of manuals published from the Eastern Mediterranean in the last generation. The appearance of this book is timely, however, as there is a growing interest in field methods and the history of excavation practices throughout the discipline of archaeology. Moreover, Corinth Excavations has long held a special place in American archaeology in Greece as the primary training excavation for graduate students associated with the American School of Classical Studies at Athens. As a result, the field manual has had a particular influence among American excavators and projects in Greece, among Mediterranean archaeologists, and in archaeology classrooms. Published as a technical field manual, an archival document, and a key statement of practice from a major excavation, the Corinth Excavations Archaeological Manual presents a guide for daily procedures at the Corinth Excavations, a complete record of documentation forms used in the field, and a practical glimpse into the functioning of a complex, major, project. The manual is a landmark text appropriate for the university student, the scholar of methodology, and the working field archaeologist. “The Corinth manual has grown over the years into a comprehensive and authoritative guide to open-area, stratigraphic excavation, covering everything from excavation of pits, wells, and robbing trenches to the removal of deposits to inventorying objects in the museum. ” David Pettegrew, Associate Professor, Messiah College and author of The Isthmus of Corinth (2016). All of the authors have worked on the excavations at Corinth in various capacities. This manual was developed under the directorship of Dr. Guy Sanders by former field directors Alicia Carter Johnson and Dr. Sarah James. Additional contributions come from past and present Corinth staff including assistant director Dr. Ioulia Tzonou-Herbst, architect James Herbst, conservator Nicol Anastasatou, and archaeologist Katerina Ragkou. The authors would also like to recognize the contributions of the many students from the American School of Classical Studies at Athens who offered valuable feedback on earlier versions of this manual over the past 10 years.https://commons.und.edu/press-books/1005/thumbnail.jp

Uniformly accelerating black holes in a de Sitter universe

A class of exact solutions of Einstein's equations is analysed which describes uniformly accelerating charged black holes in an asymptotically de Sitter universe. This is a generalisation of the C-metric which includes a cosmological constant. The physical interpretation of the solutions is facilitated by the introduction of a new coordinate system for de Sitter space which is adapted to accelerating observers in this background. The solutions considered reduce to this form of the de Sitter metric when the mass and charge of the black holes vanish.Comment: 6 pages REVTeX, 3 figures, to appear in Phys. Rev. D. Figure 2 correcte

Polarized Dirac fermions in de Sitter spacetime

The tetrad gauge invariant theory of the free Dirac field in two special moving charts of the de Sitter spacetime is investigated pointing out the operators that commute with the Dirac one. These are the generators of the symmetry transformations corresponding to isometries that give rise to conserved quantities according to the Noether theorem. With their help the plane wave spinor solutions of the Dirac equation with given momentum and helicity are derived and the final form of the quantum Dirac field is established. It is shown that the canonical quantization leads to a correct physical interpretation of the massive or massless fermion quantum fields.Comment: 19 pages, LaTeX w AMS sym

Equatorial circular orbits in the Kerr-de Sitter spacetimes

Equatorial motion of test particles in the Kerr-de Sitter spacetimes is considered. Circular orbits are determined, their properties are discussed for both the black-hole and naked-singularity spacetimes, and their relevance for thin accretion discs is established.Comment: 24 pages, 19 figures, REVTeX

U-Pb detrital zircon geochronology of the lower Danube and its tributaries; implications for the geology of the Carpathians

We performed a detrital zircon (DZ) U-Pb geochronologic survey of the lower parts of the Danube River approaching its Danube Delta- Black Sea sink, and a few large tributaries (Tisza, Jiu, Olt and Siret) originating in the nearby Carpathian Mountains. Samples are modern sediments. DZ age spectra reflect the geology and specifically the crustal age formation of the source area, which in this case is primarily the Romanian Carpathians and their foreland with contributions from the Balkan Mountains to the south of Danube and the East European Craton. The zircon cargo of these rivers suggests a source area that formed during the latest Proterozoic and mostly into the Cambrian and Ordovician as island arcs and backarc basins in a Peri-Gondwanan subduction setting (~600 -440 Ma). The Inner Carpathian units are dominated by a U-Pb DZ peak in the Ordovician (460-470 Ma) and little inheritance from the nearby continental masses, whereas the Outer Carpathian units and the foreland has two main peaks, one Ediacaran (570-610 Ma) and one in the earliest Permian (290-300 Ma), corresponding to granitic rocks known regionally. A prominent igneous Variscan peak (320-350 Ma) in the Danube’s and tributaries DZ zircon record is difficult to explain and points out to either an extra Carpathian source or major unknown gaps in our understanding of Carpathian geology. Younger peaks corresponding to arc magmatism during the Alpine period make up as much as about 10% of the DZ archive, consistent with the magnitude and surface exposure of Mesozoic and Cenozoic arcs

Ricci flat rotating black branes with a conformally invariant Maxwell source

We consider Einstein gravity coupled to an $U(1)$ gauge field for which the density is given by a power of the Maxwell Lagrangian. In $d$-dimensions the action of Maxwell field is shown to enjoy the conformal invariance if the power is chosen as $d/4$. We present a class of charge rotating solutions in Einstein-conformally invariant Maxwell gravity in the presence of a cosmological constant. These solutions may be interpreted as black brane solutions with inner and outer event horizons or an extreme black brane depending on the value of the mass parameter. Since we are considering power of the Maxwell density, the black brane solutions exist only for dimensions which are multiples of four. We compute conserved and thermodynamics quantities of the black brane solutions and show that the expression of the electric field does not depend on the dimension. Also, we obtain a Smarr-type formula and show that these conserved and thermodynamic quantities of black branes satisfy the first law of thermodynamics. Finally, we study the phase behavior of the rotating black branes and show that there is no Hawking--Page phase transition in spite of conformally invariant Maxwell field.Comment: 13 pages, one figur

Topological Charged Black Holes in High Dimensional Spacetimes and Their Formation from Gravitational Collapse of a Type II Fluid

Topological charged black holes coupled with a cosmological constant in $R^{2}\times X^{D-2}$ spacetimes are studied, where $X^{D-2}$ is an Einstein space of the form ${}^{(D-2)}R_{AB} = k(D-3) h_{AB}$. The global structure for the four-dimensional spacetimes with $k = 0$ is investigated systematically. The most general solutions that represent a Type $II$ fluid in such a high dimensional spacetime are found, and showed that topological charged black holes can be formed from the gravitational collapse of such a fluid. When the spacetime is (asymptotically) self-similar, the collapse always forms black holes for $k = 0, -1$, in contrast to the case $k = 1$, where it can form either balck holes or naked singularities.Comment: 14 figures, to appear in Phys. Rev.

An orientifold of adS_5xT^11 with D7-branes, the associated alpha'^2- corrections and their role in the dual N=1 Sp(2N+2M)xSp(2N) gauge theory

We study the N=1 Sp(2N+2M)xSp(2N) gauge theory on a stack of N physical and M fractional D3-branes in the background of an orientifolded conifold. The gravity dual is a type IIB orientifold of adS_5xT^11 (with certain background fluxes turned on) containing an O7-plane and 8 D7-branes. In the conformal case (M=0), we argue that the alpha'^2-corrections localized on the 8 D7-branes and the O7-plane should give vanishing contributions to the supergravity equations of motion for the bulk fields. In the cascading case (M not equal to 0), we argue that the alpha'^2-terms give rise to corrections which in the dual Sp(2N+2M)xSp(2N) gauge theory can be interpreted as corrections to the anomalous dimensions of the matter fields.Comment: 28 pages, 3 figures, LaTeX; v2: references added; v3: minor change