Salt kinematics and regional tectonics across a Permian gas field: a case study from East Frisia, NW Germany

This study presents a reconstruction of the tectonic history of an Upper Rotliegend tight gas field in Northern Germany. Tectonism of the greater study area was influenced by multiple phases of salt movement, which produced a variety of salt-related structural features such as salt walls, salt diapirs as well as salt glaciers (namakiers). A sequential 2D retro-deformation and stratal backstripping methodology was used to differentiate mechanisms inducing salt movement and to discuss their relation to regional tectonics. The quantitative geometric restoration included sedimentary balancing, decompaction, fault-related deformation, salt movement, thermal subsidence, and isostasy to unravel the post-depositional tectonic overprint of the Rotliegend reservoir rock. The results of this study indicate that reactive salt diapirism started during an Early Triassic interval of thin-skinned extensional tectonics, followed by an active diapirism stage with an overburden salt piercement in the Late Triassic, and finally a period of intensive salt surface extrusion and the formation of salt glaciers (namakiers) in Late Triassic and Jurassic times. Since the Early Cretaceous, salt in the study area has been rising by passive diapirism.     

Wharf embankment and strengthening program at the Port of Oakland

The wharf and embankment strengthening program (WESP) is a structural modification project involving approximately 12,000 linear feet of pile-supported, marginal wharf structures. WESP is necessary because the Port of Oakland plans to deepen its berths from −42′ mean lower low water (MLLW) to −52′ MLLW, in conjunction with a Federal Government-sponsored channel dredging project. Unless they are structurally reinforced prior to the dredging, the waterfront components (i.e. wharves and embankments) will be weakened by the berth deepening project. WESP is a three-phase program that establishes the existing structural and seismic capacities of waterfront components, develops designs for improvements necessary to maintain these capacities after the berth deepening, and constructs the improvements. WESP also includes consideration of seismic upgrade improvements. The Port is currently completing the first phase of the WESP program. This paper will describe the design criteria, project phasing, construction type of waterfront components, project organization, and results to date for WESP.     

Late Quaternary lake response to climate change and anthropogenic impact: biomarker evidence from Lake Constance sediments

This study used organic matter in oligotrophic Lake Constance (southern Germany) to reconstruct lake environment and to disentangle the multiple factors, such as climate change and human impacts, which influence sedimentation in large lakes. A sediment core from Upper Lake Constance, which represents 16,000 years of Late Glacial and Holocene lake history, was analysed for organic biomarkers, hydrogen index and elements calcium, strontium, and magnesium. Magnetic susceptibility was measured to establish a high-resolution stratigraphic framework for the core and to obtain further information about changes with respect to relative allochthonous versus autochthonous sedimentation. Dinosterol—a biomarker for dinoflagellates—and calcium have low concentrations in Younger Dryas sediments and consistently high concentrations between 10,500 and 7,000 cal. years BP. These variations are attributed to changes in lake productivity, but are not reflected in the proportion of total organic carbon within the sediment. During the Younger Dryas and between 6,000 and 2,800 cal. years BP, concentrations and accumulation rates of land-plant-derived C₂₉-steroids (β-sitosterol, stigmastanol and stigmasterol), in combination with a relatively low HI, indicate periods of enhanced terrigenous input to the lake. For the Younger Dryas, higher runoff can be attributed to a cold climate, leading to decreased vegetation cover and increased erosion. After 6,000 cal. years BP, high terrestrial input may be explained by enhanced precipitation. Biomarker and HI results, in combination with archaeological studies, raise the question as to whether lakeshore settlements affected sedimentation in Upper Lake Constance between 6,000 and 2,800 cal. years BP.     

Extreme wave event along the Guyana coastline in October 2005

The objective of the research is to analyze in detail the causes and consequences of the unusual event at the coast of Guyana (South America) during October 16–19, 2005. Several sea defense structures were damaged and flooding of low-lying areas occurred. A data analysis of offshore wave and water level characteristics shows an abrupt change in wave direction from east to almost north on October 16, 2005 and a sudden increase in the offshore peak period up to extreme values. The offshore significant wave height was also relatively high, and these wave characteristics coincided with springtide conditions. The long-wave periods and the sharp transition in wave direction indicate that this event is associated with swell waves generated by a depression far away. An analysis of hurricanes and depressions reveals that a severe depression in the Northern Atlantic Ocean during October 11–15 was the origin of this swell event. Numerical computations with SWAN have been carried out to investigate the propagation of the offshore wave characteristics towards the shoreline. The SWAN model includes wave damping due to the presence of soft mud deposits. A calibration of the parameters has been carried out using joint offshore and onshore wave data from November 2006. The numerical simulations of the event in October 2005 clearly demonstrate that the mud banks damp the wave heights, but have almost no effect on the peak period. The resulting waves at the steep sea walls can be classified as surging waves causing severe runup and overtopping. The obtained insights are translated into practical recommendations for the Guyana Sea and River Defence Division in Guyana to build a sustainable management and maintenance of the sea defenses in the future.     

Modeling the temperature of the polar mesopause region: Part II—Intra-seasonal monthly oscillations

Measurements show that the polar mesospheric clouds (PMC) can vary, in the zonal mean, with periods around 1 month [Bailey et al., 2005. Observations of polar mesospheric clouds by the Student Nitric Oxide Explorer. J. Geophys. Res. 110, D13203, doi:10.1029/2004JD005422]. This observation has been the impetus for the present paper, where we describe corresponding temperature oscillations generated by the Numerical Spectral Model (NSM). Our numerical results are taken from the 3D and 2D versions of the NSM, which produce inter-annual and long-term variations in the polar mesopause region, as discussed in the accompanying paper (Part I). In the NSM, the intra-seasonal temperature variations with periods around 2 months are generated by the meridional winds that in turn are accelerated by the momentum deposition from small-scale gravity waves (GW) propagating north/south. The wave-driven dynamical process underlying the oscillations is intrinsically non-linear like that generating the quasi-biennial oscillation (QBO). Our analysis demonstrates that the seasonal annual and semi-annual variations excite the oscillation frequencies through non-linear cascading.     

The Evolution of the Interstellar Medium over Cosmic Time

C23 UV spectroscopy of the PG1159-type star NGC7094 C26 Variations of the radio synchrotron spectral index in the interstellar medium of M33 C38 Angular Momentum Evolution of Young Brown Dwarfs and Low Mass Stars C48 The radio halo of the nearby starburst galaxy NGC 253 C95 Signatures of early metal enrichment in Damped-Lyman Alpha systems C113 CO 4 → 3 and [CI] 1 → 0 in the centers of NGC4945 and Circinus C115 Ratio of atomic and molecular gas and gravitational stabilty in the disk of M51 C130 The Interstellar Mediumat Early Cosmic Times: Molecular Gas in Distant Quasar Host Galaxies C188 Probing the interstellar medium in distant galaxies with SPICA/ESI C191 The evolution of spectral energy distributions of galaxies over cosmic times C197 Observations of 60Fe in the Galaxy with INTEGRAL/SPI C204 Evolution of Interstellar Clouds in a hot Gas Environment C205 The effect of clouds in a galactic wind on the evolution of gas-rich dwarf galaxies C206 Energy and element deposit into the interstellar medium during the lives of massive stars C209 The distribution and kinematics of massive stars in the inner Galaxy mapped with SPI/INTEGRAL 26Al 1.8 MeV line observations C213 PDR modelling of the Galactic FIR line emission C239 Towards a complete picture of the molecular ISM in local Luminous Infrared Galaxies: first results from the JCMT/IRAM line survey C242 The Search for the Very High-redshift Tail of Submillimeter Galaxies     

Monitoring In Situ Biodegradation of MTBE Using Multiple Rounds of Compound‐Specific Stable Carbon Isotope Analysis

At a large industrial facility, methyl tert‐butyl ether (MTBE) was released to the subsurface and dispersed into the light, non‐aqueous phase liquids (LNAPL), in the first aquifer, with the LNAPL serving as a continuous source of MTBE in groundwater. Compound‐specific isotope analysis was conducted on both MTBE and tert‐butyl alcohol (TBA) in groundwater samples collected in 2008, 2011, and 2013 from wells located along and off the center line of the MTBE plume. The study demonstrated the onset and progress of biodegradation of MTBE between 2008 and 2013. The TBA observed in 2008 appears to be derived only in part from MTBE transformation while a significant portion of TBA might be contributed directly from LNAPL sources. In 2011 to 2013, the dominant source of TBA in the mid‐gradient plume was MTBE transformation. A contribution of an offsite LNAPL source, in particular to the down‐gradient area of the plume, is possible but could not be unequivocally confirmed. The time series provided direct evidence for MTBE biodegradation, but also a valuable insight on the sources of TBA.     

Scattered Data Approximation on the Bisphere and Application to Texture Analysis

The paper deals with the approximation and optimal interpolation of functions defined on the bisphere \mathbb S²×\mathbb S²\mathbb {S}^{2}\times \mathbb {S}^{2} from scattered data. We demonstrate how the least square approximation to the function can be computed in a stable and efficient manner. The analysis of this problem is based on Marcinkiewicz–Zygmund inequalities for scattered data which we present here for the bisphere. The complementary problem of optimal interpolation is also solved by using well-localized kernels for our setting. Finally, we discuss the application of the developed methods to problems of texture analysis in material science.     

Oxidation of pyrite during extraction of carbonate associated sulfate

The sulfur isotopic composition of carbonate associated sulfate (CAS) has been used to investigate the geochemistry of ancient seawater sulfate. However, few studies have quantified the reliability of δ³⁴S of CAS as a seawater sulfate proxy, especially with respect to later diagenetic overprinting. Pyrite, which typically has depleted δ³⁴S values due to authigenic fractionation associated with bacterial sulfate reduction, is a common constituent of marine sedimentary rocks. The oxidation of pyrite, whether during diagenesis or sample preparation, could thus adversely influence the sulfur isotopic composition of CAS. Here, we report the results of CAS extractions using HCl and acetic acid with samples spiked with varying amounts of pyrite. The results show a very strong linear relationship between the abundance of fine-grained pyrite added to the sample and the resultant abundance and δ³⁴S value of CAS. This data represents the first unequivocal evidence that pyrite is oxidized during the CAS extraction process. Our mixing models indicate that in samples with much less than 1 wt.% pyrite and relatively high δ³⁴S_pyrite values, the isotopic offset imparted by oxidation of pyrite should be much less than ? 4‰. A wealth of literature exists on the oxidation of pyrite by Fe³⁺ and we believe this mechanism drives the oxidation of pyrite during CAS extraction, during which the oxygen used to form sulfate is taken from H₂O, not O₂. Consequently, extracting CAS under anaerobic conditions would only slow, but not halt, the oxidation of pyrite. Future studies of CAS should attempt to quantify pyrite abundance and isotopic composition.