Bücker, Christian J · Henrys, Stuart A · Wonik, Thomas
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The CIROS-1 drillhole, which in 1986 reached a depth of 700 m below the seafloor, is still the only deep hole that can provide information on the velocity structure of the upper crust in McMurdo Sound and the Ross Sea, Antarctica. A careful review and quality control of the downhole logging data of CIROS-1 resulted in a new porosity depth function that is consistent with porosity data from the MSSTS-1 and CRP-1 drillholes. Using existing porosity-velocity equations, it was possible for the first time to obtain reliable velocity information for the upper 700 m of strata off the Victoria Land coast. The calculated synthetic seismograms, based on downhole velocity and density data, fit very well with the existing seismic lines IT90A-71, PD90-12, and NBP9601-89. The quality of the correlation confirms that the average velocity of the top 700 m of strata is about 2 000-2 300 m/s, and not 2 800-3 000 m/s, as was previously assumed. In consequence, these distinctly lower velocities result in shallower depths for the seismic unconformities V3/V4 andV4/V5 and thus may have important implications for further drilling off Cape Roberts.
Devi, Monika · Nesterovschi, Ion · Riedesel, Svenja · et al.
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In this study, Radioluminescence (RL), Raman and Fourier Transform Infrared (FTIR) spectroscopy analyses were used to investigate the relationship between structural disorder and self-trapped exciton (STE) luminescence in natural quartz grains measured over a temperature range of 8-300 K. The investigated samples originate from diverse geological settings with crystallisation ages spanning from Ma to Ga and include two granites, one metamorphosed granite and two sedimentary samples. The RL spectra exhibit a dominant blue emission band centred at ~2.6 eV, attributed to STE emission, which disappears at higher temperatures (> 200 K). Analysis of RL intensity as a function of temperature (50-150 K) using an Arrhenius model yields quenching energies in the range of 22-46 meV. The variation of full width at half maximum (FWHM) with temperature was modelled to estimate phonon energies, which ranged from ~10 to 47 meV. Raman spectroscopy reveals systematic shifts and broadening of the 127 cm -1 and 203 cm -1 bands, indicating variations in lattice strain and structural disorder. FTIR measurements further demonstrate progressive changes in the structural organisation of the Si-O-Si framework through variations in structural order index derived from the 778 cm -1 and 692 cm -1 vibrational bands. Well-ordered natural quartz samples exhibited higher quenching and phonon energies, narrow RL, Raman and FTIR bands and higher FTIR structural order indexes, indicating more stable STEs than the structurally disordered natural quartz samples. Compared to synthetic quartz reported in the literature, natural quartz samples exhibit broader RL emission bands, lower quenching energies and earlier thermal quenching, reflecting a higher degree of structural disorder and defect concentration. The combined RL, Raman, and FTIR results demonstrate that STE emission in natural quartz is strongly controlled by lattice disorder and geological history, confirming the critical role of exciton-phonon interactions in determining STE luminescence behaviour.
Moerz, Tobias · Laronga, R · Lauer-Leredde, C · et al.
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Site 1103 was one of a transect of three sites drilled across the Antarctic Peninsula continental shelf during Leg 178. The aim of drilling on the shelf was to determine the age of the sedimentary sequences and to ground truth previous interpretations of the depositional environment (i.e., topsets and foresets) of progradational seismostratigraphic sequences S1, S2, S3, and S4. The ultimate objective was to obtain a better understanding of the history of glacial advances and retreats in this west Antarctic margin. Drilling the topsets of the progradational wedge (0-247 m below seafloor [mbsf]), which consist of unsorted and unconsolidated materials of seismic Unit S1, was very unfavorable, resulting in very low (2.3%) core recovery. Recovery improved (34%) below 247 mbsf, corresponding to sediments of seismic Unit S3, which have a consolidated matrix. Logs were only obtained from the interval between 75 and 244 mbsf, and inconsistencies on the automatic analog picking of the signals received from the sonic log at the array and at the two other receivers prevented accurate shipboard time-depth conversions. This, in turn, limited the capacity for making seismic stratigraphic interpretations at this site and regionally. This study is an attempt to compile all available data sources, perform quality checks, and introduce nonstandard processing techniques for the logging data obtained to arrive at a reliable and continuous depth vs. velocity profile. We defined 13 data categories using differential traveltime information. Polynomial exclusion techniques with various orders and low-pass filtering reduced the noise of the initial data pool and produced a definite velocity depth profile that is synchronous with the resistivity logging data. A comparison of the velocity profile produced with various other logs of Site 1103 further validates the presented data. All major logging units are expressed within the new velocity data. A depth-migrated section with the new velocity data is presented together with the original time section and initial depth estimates published within the Leg 178 Initial Reports volume. The presented data confirms the location of the shelf unconformity at 222 ms two-way traveltime (TWT), or 243 mbsf, and allows its seismic identification as a strong negative and subsequent positive reflection.
ANDRE, Pascal · MAOUHOUB-ANDRE, Essaadia · RAT, Vincent
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C 2 H 5 : Ethyl Collection of spectroscopic data: vibrational frequencies, rotational constants, electronic energies, and enthalpies of formation. Calculation of thermodynamic properties as a function of temperature under thermal equilibrium and non-equilibrium conditions: heat capacity at constant pressure (Cp), enthalpy (h), entropy (s), Gibbs free energy (g), internal partition function (Zint), and translational partition function (Ztr).
ANDRE Pascal · MAOUHOUB-ANDRE, Essaadia · RAT, Vincent
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C 2 H 3 : Ethenyl Collection of spectroscopic data: vibrational frequencies, rotational constants, electronic energies, and enthalpies of formation. Calculation of thermodynamic properties as a function of temperature under thermal equilibrium and non-equilibrium conditions: heat capacity at constant pressure (Cp), enthalpy (h), entropy (s), Gibbs free energy (g), internal partition function (Zint), and translational partition function (Ztr).
ANDRE, Pascal · MAOUHOUB-ANDRE, Essaadia · RAT, Vincent
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NH 4 + : Ammonium Collection of spectroscopic data: vibrational frequencies, rotational constants, electronic energies, and enthalpies of formation. Calculation of thermodynamic properties as a function of temperature under thermal equilibrium and non-equilibrium conditions: heat capacity at constant pressure (Cp), enthalpy (h), entropy (s), Gibbs free energy (g), internal partition function (Zint), and translational partition function (Ztr).
ANDRE, Pascal · MAOUHOUB-ANDRE, Essaadia · RAT Vincent
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C 2 H 6 : Ethane Collection of spectroscopic data: vibrational frequencies, rotational constants, electronic energies, and enthalpies of formation. Calculation of thermodynamic properties as a function of temperature under thermal equilibrium and non-equilibrium conditions: heat capacity at constant pressure (Cp), enthalpy (h), entropy (s), Gibbs free energy (g), internal partition function (Zint), and translational partition function (Ztr).
The test data and inversion results for "Seismic traveltime tomography with deep neural network reparameterization: The method and its application to central Chile". absolute.dat: Synthetic travel-time data event.dat: Event information, including hypocenter location and origin time vel_DNRtomo.xyz: Velocity model obtained from DNRtomo vel_ini.xyz: Input velocity model used for synthetic travel-time calculations vel_tomoDD.xyz: Velocity model obtained from tomoDD
The dataset contains two compressed folders: Results.rar and Results_discussion.rar. The folder "Results" contains all the data used to generate Fig.3 and Fig.4 in Section 3, and the folder "Results_discussion" contains the data used to generate Fig.6. The data files are divided into two categories: "Interior Structure" and "Tidal parameteres". The file name indicate the combination of temperature model and viscoelastic model (e.g., TYPE-I@Maxwell); (N) indicates the results based on optimal estimates, and (N-sigma)/(N+sigma) indicate the results based on +/- 1-\sigma. The "Interior Structure" files include radius ([m]), density ([kg/m^3]),seismic velocity (m/s), temperature (K), and viscosity (Pa.s); The "Tidal parameteres" files include periods ([s]), k_2, h_2, and Q.
This dataset includes a shear-wave velocity model inferred from surface-wave tomography, the group- and phase-velocity dispersion curves from ambient-noise Green's functions and earthquakes. DSurfTomo.inMeasure.dat_corrected17-50s is the shear wave velocity (Vs) model with a data format of lon/lat/depth (km)/Vs(km/s). All_pha_withbiascorrection and All_gro_withbiascorrection files are the phase and group velocity curves with a data format of period(s)/velocity(km/s)/lon/lat/lon/lat
ANDRE, Pascal · MAOUHOUB-ANDRE, Essaadia · RAT, Vincent
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N 2 O 5 : Dinitrogen pentoxide Collection of spectroscopic data: vibrational frequencies, rotational constants, electronic energies, and enthalpies of formation. Calculation of thermodynamic properties as a function of temperature under thermal equilibrium and non-equilibrium conditions: heat capacity at constant pressure (Cp), enthalpy (h), entropy (s), Gibbs free energy (g), internal partition function (Zint), and translational partition function (Ztr).
Kasten, Sabine · Glasby, Geoffrey P · Schulz, Horst D · et al.
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The mineralogy and geochemistry of a suite of nine manganese nodules from the South Atlantic have been determined. The Ce/La ratios of the nodules were investigated to see if they could be used as redox indicators to trace the oxygen content of the ambient water mass and the flow path of the Antarctic Bottom Water as has previously been successfully carried out in the Pacific Ocean. The Ce/La ratios of the nodules decrease in the sequence Lazarev Sea, Weddell Sea (10.4 and 9.7)>East Georgia Basin (6.5 and 7.1)>Argentine Basin (5.0), but then increase in the Brazil Basin (6.2) and Angola Basin (9.8 and 15.1). A further decrease was observed in the Cape Basin (7.6). An extremely high Ce/La ratio of 24.4 had already been determined for nodules sampled north of the Nares Abyssal Plain in the western North Atlantic. These data reflect the more complicated pattern of bottom water flow in the South Atlantic than in the South Pacific. The penetration of more oxygenated North Atlantic Deep Water into the South Atlantic accounts for the higher Ce/La ratios in the nodules from the Angola and Brazil basins. Based on this study, the flow path of the Antarctic Bottom Water could only be traced as far north as the Argentine Basin. The unique geochemistry of nodules from the central Angola Basin (high Mn/Fe and Ce/La ratios, high contents of Ni, Cu, Zn and Mo) appears to be a function of the nature of the overlying water mass and of the multiple diagenetic sources of metals to the nodules.
Twenty four core samples from CRP-1, seven from Quaternary strata (20-43.55 meters below sea floor or mbsf) and seventeen from early Miocene strata (43.55 to 147.69 mbsf), have been analysed for their grain-size distribution using standard sieve and Sedigraph techniques. The results are in good agreement with estimates of texture made as part of the visual core description for the 1 :20 core logs for CRP-1 (Cape Roberts Science Team, 1998). Interpretation of the analyses presented here takes into account the likely setting of the site in Quaternary times as it is today, with CRP-1 high on the landward flank of a well-defined submarine ridge rising several hundred metres above basins on either side. In contrast, seismic geometries for strata deposited in early Miocene times indicate a generally planar sea floor dipping gently seaward. Fossils from these strata indicate shallow water depths (< 100 m), indicating the possibility that waves and tidal currents may have influenced sea floor sediments. The sediments analysed here are considered in terms of 3 textural facies: diamict, mud (silt and clay) and sand. Most of the Quaternary section but only 30% of the early Miocene section is diamict, a poorly sorted mixture of sand and mud with scattered clasts, indicating little wave or current influence on its texture. Although not definitive, diamict textures and other features suggest that the sediment originated as basal glacial debris but has been subsequently modified by minor winnowing, consistent with the field interpretation of this facies as ice-proximal and distal glaciomarine sediment. Sediments deposited directly from glacier ice appear to be lacking. Mud facies sediments, which comprise only 10% of the Quaternary section but a third of the early Miocene section, were deposited below wave base and largely from suspension, and show features (described elsewhere in this volume) indicative of the influence of both glacial and sediment gravity flow processes. Sand facies sediments have a considerable proportion of mud, normally more than 20%, but a well-sorted fine-very fine sand fraction. In the context of the early Miocene coastal setting we interpret these sediments as shoreface sands close to wave base.
Drillhole CRP-3 in northern McMurdo Sound (Ross Sea, Antarctica) targeted the western margin of the Victoria Land basin to investigate Neogene to Palaeogene climate and tectonic history by obtaining continuous core and downhole logs. Well logging of CRP-3 has provided a complete and comprehensive data set of in situ geophysical measurements down to nearly the bottom of the hole (920 m below sea floor (mbsf)).This paper describes the evaluation and interpretation of the downhole logging data using the multivariate statistical methods of factor and cluster analysis. The factor logs mirror the basic geological controls (i.e., grain size, porosity, clay mineralogy) behind the measured geophysical properties, thereby making them easier to interpret geologically. Cluster analysis of the logs delineates individual logging or sedimentological units with similar downhole geophysical properties. These objectively and independently defined units help differentiate lithological and sedimentological characteristics (e.g. grain size, sediment provenance, glacial influence).For CRP-3, the three factor logs derived from the downhole measurements reflect sediment grain size (proxy for lithology), the occurrence of diamict and/or conglomerate (glacial influence), and sediment provenance. It is possible to divide the borehole into three main sections on the basis of cluster analysis of the three factor logs. The top section down to about 200 mbsf is dominated by mudstone with clearly different physical properties from the mudstones occurring below this depth. Beneath 200 mbsf sandstones dominate the lithology. Two types of sandstones were characterised in the early Oligocene/late Eocene sequence, with a division between the two types occurring at about 630 tnbsf. These two types of sandstones, which are differentiated mainly on the basis of their magnetic and radiogenic properties, can be correlated by detrital mode provenance analysis. Comparison of the results of the factor and cluster analyses with the reflection seismic profiles shows that the major change in sediment source from the Victoria Group to the Taylor Group at 630 mbsf (earliest Oligocene) is not seen by seismic sequence analysis. This observation may have important consequences for the entire Ross Sea seismic stratigraphy.
Brachfeld, Stefanie A · Guyodo, Yohan · Acton, Gary D
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During Ocean Drilling Program (ODP) Leg 178, we drilled three sites on sediment drifts deposited on the continental rise on the western margin of the Antarctic Peninsula. These hemipelagic drifts were targeted for their potential to preserve a continuous record of the behavior of the West Antarctic Ice Sheet over the last 10 m.y. It has been proposed that drift development is linked to advances and retreats of the Antarctic continental ice sheet (Pudsey and Camerlenghi, 1998, doi:10.1017/S0954102098000376, and references therein; Barker, Camerlenghi, Acton, et al., 1999, doi:10.2973/odp.proc.ir.178.1999). However, the sediment is characterized by a very low carbonate content, with foraminifers restricted to very narrow intervals. This lack of carbonate precludes the construction of a delta18O or CaCO3 stratigraphy, depriving these sites of an important chronologic tool and global ice volume proxy.
Jarrard, Richard D · Brink, Jason · Bücker, Christian J · et al.
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Bedding dips in the CRP-2A drillhole were determined in two ways (1) analysis of a dipmeter log, and (2) identification of bed boundaries on digital images of the outer core surface. The two methods document the downhole increase in structural dip, to a maximum of 15° in the lowest 150 m of the hole. Dipmeter data, which are azimuthally oriented, indicate a 75° azimuth for structural tilting, in agreement with seismic reflection profiles. Core and log dips indicate that structural dip increases by 5-7° between 325 and 480 mbsf. Both, however, also exhibit high dip inhomogeneity because of depositional (e.g., cross bedding) and post-depositional (e.g., softsediment deformation) processes. This variability adds ambiguity to the search for angular unconformities within the CRP-2A drillhole. Dip directions of different lithologies are generally similar, as are dip directions for the four kinds of systems tracts. Downdip azimuths of sands and muds are slightly different from those of diamicts, possibly reflecting the divergence between ENE offshore dip and ESE glacial advance.
The carbon isotope ratio (delta13C) and cadmium content (Cd/Ca) of benthic foraminifera shells have been used to reconstruct deep-water circulation patterns of the glacial oceans. These tracers co-vary with phosphorus in the modern ocean because they are nearly quantitatively regenerated from sinking biological debris in the upper water column. Hence they can be used to reconstruct the distribution of labile nutrients in glacial water masses. Independent constraints on glacial deep-ocean circulation patterns could be provided by a tracer of the distribution of silica and alkalinity, the deeply regenerated constituents of planktonic hard parts. Barium shares key aspects of its behaviour with these refractory nutrients because it is removed from solution in surface waters and incorporated into sinking particles which slowly dissolve deep in the water column and in the sediments. The fractionation of Ba between deep-water masses of the major ocean basins is largely controlled by thermohaline circulation patterns, so Ba conforms to different boundary conditions from Cd and 13C. As Ba substitutes into trigonal carbonates, it is a potential palaeoceano-graphic tracer if the Ba content of foraminifera shells reflects ambient dissolved Ba concentrations. Here we present data from Recent core-top benthic foraminifera which indicate that the Ba content of some recent calcitic benthic foraminifera does co-vary with bottom-water Ba.
The carbonate shell of the bivalve Arctica islandica has been recognized, for more than a decade, as a potentially important marine geochemical biorecorder owing to this species' great longevity (200+ years) and wide geographic distribution throughout the northern North Atlantic Ocean, a region vital to global climate and ocean circulation. However, until now this potential has not been realized owing to the difficulty of precisely sampling the shell of this slow growing species. Using newly available automated microsampling techniques combined with micromass stable isotope mass spectrometry, a stable oxygen isotope record (1956-1957 and 1961-1970) has been obtained from a live-captured, 38-year-old A. islandica specimen collected near the former position of the Nantucket Shoals Lightship (41°N. 69°W). The shell's delta18O signal is compared with an expected signal derived from ambient bottom temperature and salinity data recorded at the lightship for the same period. The results show that A islandica's delta18O record (1) is in phase with its growth banding, confirming the annual periodicity of this species' growth bands, (2) is in oxygen isotopic equilibrium with the ambient seawater, (3) shows a consistent shell growth shutdown temperature of ~6°C. which translates into an ~8-month (May–December) shell growth period at this location, and (4) records the ambient bottom temperature with a precision of ~ +/-1.2°C. These results add important information on the life history of this commercially important shellfish species and demonstrate that A. islandica shells can be used to reconstruct inter- and intra-annual records of the continental shelf bottom temperature.
Fielding, Christopher R · Baker, Julian C · Woolfe, Ken · et al.
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During the course of the 1997 drilling campaign, lithostratigraphic boundaries were assigned to the CRP-l core on the basis of perceived changes in lithology. The geologically most important boundary in the core, between the Miocene and overlying Quaternary sections, was placed at 43.55 mbsf. This horizon was described in the core logs (Cape Roberts Science Team, 1998) as a contact between muddy, finegrained sandstone (which were assigned a Lower Miocene age based on diatom biostratigsaphy) and overlying diamictons containing Quaternary diatoms. This boundary is a major unconformity, recognisable on seismic reflection records. As such, it has considerable significance in the ongoing scientific analysis of the drillcore. During a re-examination of the core, focusing on the archive half held at the Antarctic Geology Research Facility of the Florida State University at Tallahassee; the authors noted that the core across the published boundary (43.55 mbsf) did not show any lithological change, but logged a sharp contact between dark olive grey, muddy sandstone and overlying diamicton at 43.15 mbsf (Fig. l). We suggest, therefore, that the core log in appendix l of Cape Roberts Science Team (1998) is misleading over this interval. In order to test the veracity of the suggested boundary revision, a series of thin-sections was examined and point-counted for framework grain abundances.
A transformer monitoring device has one or more voltage sensors and/or one or more current sensors integral with a housing for detecting a voltage of a power cable of a transformer. The transformer monitoring device can be configured to monitor voltage levels, and cause alerts to be issued if voltage levels drop and/or spike beyond operator-established tolerance(s). The transformer monitoring device further has one or more environmental sensors including a smoke sensor, ambient temperature sensor, external transformer temperature sensor, a fire/wildfire sensor, a humidity sensor, a noxious gases sensor, a seismic or vibration sensor, and/or a surface and/or ground temperature sensor configured to detect smoke, and/or temperature change indicators, and/or other environmental changes in an area surrounding the transformer, and a processor configured to monitor the smoke sensor, temperature sensors, and/or other environmental change sensors, the processor configured to transmit an alert if smoke, temperature and/or other environmental conditions are detected surrounding the transformer.
The present disclosure is drawn to methods and systems for determining a seismic response of a man-made structure to a given input earthquake. Sensors are used to obtain vibration data for data collection locations from one or more floors of the man-made structure, which may be ambient vibration data or vibration data resulting from forced vibration or shock testing. The vibration data is used to determine modal characteristics for the man-made structure, including mode shapes, natural frequencies, and damping ratios. The mass, centre-of-mass, and moment of inertia is also determined for the floors of the man-made structure. The modal characteristics are then translated from the data collection locations to the centre-of-mass based on the structure of the floors. Then, a seismic response of the man-made structure to an input earthquake is determined using the translated modal characteristics and the mass and moment of inertia of the floors.
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