bluuebunny/crossref_metadata_2025_split huggingface dataset:
Geologist-controlled trends versus computer-controlled trends: introducing a high-resolution approach to subsurface structural mapping using well-log data, trend surface analysis, and geospatial analysisA companion paper to Mei, S. 2009. New insights on faults in the Peace River Arch region, northwest Alberta, based on existing well-log data and refined trend surface analysis. Canadian Journal of Earth Sciences, 46(1): 41–65.
Authors: Mei Shilong 
Published: August 2009

This paper introduces a refined trend surface analysis (TSA) for detecting faults with small, metre-scale offsets (5–20 m). Conventional TSA uses a global polynomial method to model the trend; the power of the polynomial (e.g., first, second, or third order) is the only parameter for input. The refined approach is different in that it uses local-fit techniques to generate the trend. The refined approach provides greater flexibility for inputting geological knowledge in the trend surface modelling process. This results in a trend surface with the maximum amount of unwanted information, which is removed from the residual surface after removal of the trend from the data, leaving features of interest optimally highlighted in the residuals. Such a trend is referred to as a geologist-controlled trend to differentiate it from the trend surface modelled by conventional TSA, which is primarily a computer-controlled global polynomial surface. The refined approach goes one step beyond conventional TSA by incorporating advanced geostatistics for modelling the trend, interpolating the resultant residuals, and then extracting formation-top offset patterns from the residual surface using spatial analysis. Modelling the geologist-controlled trend in the refined approach results in higher resolution in detecting formation-top offsets and higher accuracy in digitizing fault locations, compared with various techniques that have been traditionally used in subsurface structure mapping of the West Canada Sedimentary Basin (WCSB) (e.g., structural and isopach contour mapping, cross-section construction, and seismic and aeromagnetic data interpretation). The refined approach is demonstrated using the Basal Fish Scale Zone in the Peace River Arch region as an example.
Stratigraphy of the Fort Selkirk Volcanogenic Complex in central Yukon and its paleoclimatic significance: Ar/Ar and paleomagnetic data
Authors: Nelson Faye E. , Barendregt René W. , Villeneuve Mike 
Published: August 2009

Brunhes, Matuyama, Kaena, and Mammoth age basaltic lava flows (Tertiary–Quaternary Selkirk Volcanics) were sampled in west-central Yukon. The mean characteristic remanent magnetization (ChRM) direction of the flows sampled in this and previous studies has a declination of 348.7° and an inclination of 70.8° (n = 42, k = 99.6, α95 = 2.2°) (all on lower hemisphere). The time range represented in this study (ca. 3.25 to ca. 0.004 Ma) is great enough to have confidently averaged secular variation. Sediment associated with the basalt has a mean declination of 7.6° and inclination of 78.8° (n = 5, k = 5.6, α95 = 35.7°). A new 40Ar–39Ar date on the reversely magnetized basal basalts at Ne Ch’e Ddhäwa places the eruption in the Mammoth subchron of the Gauss Normal Chron. The newly dated basal basalt at Ne Ch’e Ddhäwa precedes the initial continental glaciation in Yukon and is older than the Fort Selkirk vent (Lower Mushroom), which was previously thought to be the oldest eruption at Fort Selkirk Volcanic Complex (FSVC). This basal flow at Mushroom is dated at 1.82 ± 0.03 Ma and the uppermost flow is reproducibly dated at 1.36 ± 0.04 Ma. Till on the flanks of a subglacial volcanic mound called Ne Ch’e Ddhäwa (informal) is older than previously thought; its reverse magnetization indicates an Early Pleistocene age rather than the Reid glaciation, which falls during the Brunhes Normal Chron. The paleomagnetism of Tertiary–Quaternary Selkirk Volcanics outcrops outside the FSVC was studied for the first time. The ChRM direction of basalt at the northern edge of the northern Cordillera volcanic province agrees with FSVC directions, suggesting that this flow reflects the same period of volcanism. This suggests that an Eocene K–Ar date, previously thought to be unreliable, may well be correct.
Paleomagnetism and U–Pb geochronology of the Lac de Gras diabase dyke swarm, Slave Province, Canada: implications for relative drift of Slave and Superior provinces in the PaleoproterozoicGeological Survey of Canada Contribution 20080350.
Authors: Buchan Kenneth L. , LeCheminant Anthony N. , van Breemen Otto 
Published: August 2009

Lac de Gras diabase dykes trend north to NNE across the central Slave Province of the Canadian Shield. U–Pb baddeleyite ages of 2023 ± 2 and 2027 ± 4 Ma are interpreted as dyke emplacement ages. These ages are similar to that of the Booth River igneous complex, exposed along the margins of Kilohigok Basin near the northern end of the dyke swarm. Ten paleomagnetic sites (from four to six dykes) yield a mean paleopole at 11.8°N, 92.1°W (dm = 8.4°, dp = 6.0°). A positive baked contact test where a Lac de Gras dyke crosscuts a NE-trending Malley dyke demonstrates that this pole is primary. It represents the first key Paleoproterozoic pole from the Slave Province and, hence, the first Paleoproterozoic Slave pole suitable for reconstructing paleocontinents. Although a direct comparison is not available with precisely dated paleopoles of identical age from other Archean cratons, a comparison is made with a sequence of precisely dated poles from Superior Province dyke swarms, including those 40–50 million years older and 25 million years younger. It yields two options depending on the relative magnetic polarity assumed for data from the two cratons. The two cratons were either at similar latitudes, but not in their present relative orientations, when the swarms were emplaced, or separated in latitude by ∼40°–60°. In either case, they may have drifted separately or formed part of a single (super)continent that subsequently broke up with the two cratons drifting separately to attain their present configuration. Additional key paleopoles are required to distinguish between these interpretations.
Is ambient chitobiase activity a monitoring tool for impacts on secondary production in lotic systems?
Authors: Conley Justin M. , Schorr Mark S. , Hanson Mark L. , Symes Steven J. , Richards Sean M. 
Published: August 2009

Chitobiase is one of two enzymes responsible for cleaving the chitin polymers that form arthropod exoskeletons and has been found to be predictive of secondary production for marine and freshwater zooplankton. Since chitobiase is released into water during molting by aquatic arthropods, it is possible that ambient chitobiase activity may be a useful proxy of secondary production in aquatic systems. In the present study, surface water samples from the upper Tennessee River basin, USA, were collected and analyzed for chitobiase to determine how enzyme levels vary with season, water depth, and proximity to sewage treatment outfalls. Additionally, chitobiase activity was correlated with three pharmaceutical compounds to assess if changes in chitobiase activity were associated with contaminants derived from sewage treatment plants. Chitobiase activity was significantly (p < 0.05) elevated in the fall relative to other seasons. Further, chitobiase activity displayed significant positive correlation (p < 0.05) between surface and subsurface samples and was negatively correlated (p < 0.05) with pharmaceutical concentrations in summer samples. These results indicate the potential for chitobiase as an assessment tool in estimating secondary production and as an ecotoxicological indictor.
10 m standpipe tests on oil sands tailings: long-term experimental results and prediction
Authors: Jeeravipoolvarn S. , Scott J. D. , Chalaturnyk R. J. 
Published: August 2009

Three large 10 m high standpipe tests were set up at the University of Alberta in 1982 to simulate large-scale compression behavior of oil sands tailings in a controlled environment. The objectives of the tests were to study material behavior and to provide consolidation performance for theoretical verification. Three tailings materials (fine tailings and two mixes of fine tailings and sand) were used. Test results showed that the fine tailings, standpipe 1, strained more than 30% over a 25 year monitoring period by self-weight with very little to no effective stress developing, while the mix of fine tailings and sand, standpipe 3, compressed with a significant effective stress development. The tailings in standpipe 1 can be regarded as a class of material where a reduction in volume is not governed by a unique relationship between effective stress and void ratio, whereas the tailings in standpipe 3 can be categorized as slurry with conventional behavior. To investigate the capability of the finite strain consolidation theory on these tailings, a numerical model with appropriate material constitutive relationships was developed and used to make predictions. Numerical results, compared with the performance of the standpipe tests, indicated that the theory overestimated the compression behavior of the standpipe 1 material, but it could predict the standpipe 3 consolidation behavior.
Case studies on bermed excavation in Taipei silty soil
Authors: Liao H. J. , Lin C. C. 
Published: August 2009

Bermed excavation (deep excavation supported by an excavation wall and a berm) can be an economical method for basement construction in urban areas if ground movement around the excavation is not the primary concern and the excavation site is large and (or) irregular in shape. This paper reviews three bermed excavation projects carried out in the Taipei Basin. One project was successful, one was successful after near failure, and one was a failure. Ironically, extensive ground improvement work had been done for the near-failure and failure cases; but no ground improvement was done for the successful case. It is of interest to find the similarities and differences among these bermed excavation projects. The causes of instability that result in unsuccessful bermed excavation projects and the applications of limit equilibrium analysis to the stability of bermed excavation are also discussed here. These three cases show that the existence of grout columns does not help to effectively increase the stability of the berm if the original safety factor against sliding of a berm slope is less than 1.0 and the improvement ratio of grout columns is low (say <20%).
Photoelectrochemical studies on poly[1-(2-aminophenyl)pyrrole] — Creation of a photoactive inorganic–organic semiconductor interface (IOI)
Authors: Kasem Kasem K. , Menges Sara , Jones Stephenie 
Published: August 2009

The compound 2-APPy [1-(2-aminophenyl)pyrrole] as an organic phase in an inorganic–organic semiconductor interface (IOI) assembly was the subject of photoelectrochemical studies in aqueous solutions. Results show that thin films of poly(2-APPy) can be prepared using oxidative electropolymerization. Furthermore, absorption spectroscopic studies indicate that the protonated 2-APPy polymer’s ionization potential (IP) is 4.7 eV, the electron affinity (EA) is 1.90 eV, and a gap of 2.80 eV separates the higher occupied molecular orbital’s (HOMO) and lower unoccupied molecular orbital’s (LUMO) energy levels of this polymer. Impedance measurements under illumination show an increase in the film charge capacitance compared with those measured under darkened conditions. The behavior of the poly(2-APPy) film as a host for redox-active dopants was also explored. The results show that the film did not alter the redox potentials of a large dopant such as PMo12O403–. The photoactivities of the IOI assemblies consisting of 2-APPy and nanoparticles of ZnO, and of Fe2O3 were investigated using fluorescence emissions. Results show that the fluorescence emissions generated by 2-APPy were quenched by 5% and 55% on ZnO and on Fe2O3, respectively. The charge injection rate constants, kct, at the inorganic metal oxide–2-APPy interface, were calculated.
SPACETIME FROM SYMMETRY: THE MOYAL PLANE FROM THE POINCARÉ–HOPF ALGEBRA
Authors: BALACHANDRAN A. P. , MARTONE M. 
Published: August 2009

We show how to get a noncommutative product for functions on spacetime starting from the deformation of the coproduct of the Poincaré group using the Drinfel'd twist. Thus it is easy to see that the commutative algebra of functions on spacetime (ℝ4) can be identified as the set of functions on the Poincaré group invariant under the right action of the Lorentz group provided we use the standard coproduct for the Poincaré group. We obtain our results for the noncommutative Moyal plane by generalizing this result to the case of the twisted coproduct. This extension is not trivial and involves cohomological features.As is known, spacetime algebra fixes the coproduct on the diffeomorphism group of the manifold. We now see that the influence is reciprocal: they are strongly tied.
The contribution of malacology in dating the Pleistocene submarine levels of the English Channel
Authors: Danukalova Guzel , Lefort Jean-Pierre 
Published: August 2009

Abstract:
The submerged Pleistocene beach conglomerate is an underwater shelly and cobble-rich formation that has been found only on the southern flanks of the English Channel. It resulted from the cementation of beach deposits that were overlain by loessic silts at a time of lower sea level. Study of the fauna within this conglomerate allows the separation of three shelly belts located between −24 and −54 m around the Channel Islands of the Normano-Breton Gulf, −40 and −65 m off Tregor, and −52 and −80 m off Leon. These belts are correlated with three regressive Pleistocene episodes. A comparison with one of Shackleton's published sea-level curves has produced age estimates that date the three beach deposits at around 105–110, 73–80 and 30–57 ka, respectively. These beaches were sealed by three phases of loess deposition around 103, 67 and 18 ka. We assume that there are at least three different Pleistocene beach conglomerates in the English Channel. Some of them show differences in their fossil fauna that could be partly a factor of contemporaneous water temperature. A fourth beach conglomerate without fossil fauna may exist at −93 m.
Evidence of multi-phase Cretaceous to Quaternary alkaline magmatism on Tore–Madeira Rise and neighbouring seamounts from
40
Ar/
39
Ar ages
Authors: Merle Renaud , Jourdan Fred , Marzoli Andrea , Renne Paul R. , Grange Marion , Girardeau Jacques 
Published: August 2009

Abstract:

The Tore–Madeira Rise is a seamount chain located 300 km off the Portugal and Morocco coasts attributed to hotspot activity. U–Pb ages of lavas from the northern and central Tore–Madeira Rise range between 103 and 80.5 Ma whereas
40
Ar/
39
Ar ages from the central and southern Tore–Madeira Rise yield ages ranging from 94.5 to 0.5 Ma. We performed new
40
Ar/
39
Ar measurements to better understand the geodynamic history of the Tore–Madeira Rise. Plagioclase ages from the Bikini Bottom and Torillon seamounts suggest ages of >90 Ma and ≥60 Ma, respectively. Amphiboles from the Seine seamount yield an age of 24.0 ± 0.8 Ma. Biotites from lavas of the Ashton seamount give ages of 97.4 ± 1.1 Ma and 97.8 ± 1.1 Ma. The geochronological database available on the Tore–Madeira Rise has been filtered on statistical criteria to eliminate unreliable ages. The resulting database reveals three pulses of alkaline magmatism on the Tore–Madeira Rise at 103–80.5 Ma, at
c
. 68 Ma and between 30 Ma and the present. The magmatism was continuous from 103 Ma until
c
. 68 Ma and from
c
. 30 Ma until the present on the Tore–Madeira Rise, the surrounding seamounts and the Portugal coast. We suggest that the space–time distribution of this magmatism results from the interaction between a wide thermal anomaly emitting magmatic pulses and the complex motion of the Iberian plate.

Supplementary material:

A detailed Ar measurements dataset is available at
http://www.geolsoc.org.uk/SUP18359
.
Surface-water freshening and high-latitude river discharge in the Eocene North Sea
Authors: Zacke Anne , Voigt Silke , Joachimski Michael M. , Gale Andrew S. , Ward David J. , Tütken Thomas 
Published: August 2009

Abstract:

A shark-tooth apatite δ
18
O record of the early Palaeogene North Sea reflects changes in regional hydrography by showing variable temperatures and salinities. A 2–4 Ma period in the early Eocene was particularly influenced by substantial surface-water freshening, indicated by a 3–4‰ reduction of δ
18
O values. The magnitude of the δ
18
O decrease indicates a depletion in
18
O of surface waters by 2–3‰ relative to Eocene mean ocean water. This value is lower than that of coeval lakes reconstructed from freshwater gastropod δ
18
O values from the Paris Basin, suggesting that large rivers with high-latitude catchment areas drained into the North Sea. The period of surface-water freshening began close to the Palaeocene – Eocene thermal maximum, when relative sea-level fall, tectonic uplift and basaltic volcanism caused a temporary isolation of the North Sea. North Atlantic and North Sea surface waters became reconnected during a series of early Eocene transgressions.
New range data for marine invertebrate species across the early Toarcian (Early Jurassic) mass extinction
Authors: Caswell Bryony A. , Coe Angela L. , Cohen Anthony S. 
Published: August 2009

Abstract:

We have reinvestigated the marine mass extinction interval that occurred during the early Toarcian, which was a time of widespread marine anoxia. The ranges of marine benthic invertebrates are significantly altered using new observations from the Cleveland Basin, UK.
Goniomya rhombifera
is reported for the first time from the Whitby Mudstone Formation and together with an increased epifaunal bivalve diversity indicates a brief, relatively oxygenated period towards the end of the event. The new data, together with published results, suggest three apparent extinction horizons on a global scale; the first is just above the Pliensbachian–Toarcian boundary, and the following two are in the
semicelatum
ammonite Subzone. As a result of the Signor–Lipps effect there may be only one, or possibly two, true extinctions. The youngest extinction horizon coincides with the first of the abrupt carbon isotope shifts that characterize this interval, and with increases in sea surface temperature, continental weathering rates, and seawater anoxia.
Pseudomytiloides dubius
is the only abundant benthic macroinvertebrate during the most hostile environmental conditions but it and all other benthic species are almost entirely absent for many thousands of years immediately after each abrupt negative carbon isotope shift.

Supplementary material:

A compilation of the Late Pliensbachian and Early Toarcian marine biotic changes and a discussion of the systematics of the key faunal elements are available at
http://www.geolsoc.org.uk/SUP18353
.
How cold were the Early Permian glacial tropics? Testing sea-surface temperature using the oxygen isotope composition of rigorously screened brachiopod shells
Authors: Angiolini Lucia , Jadoul Flavio , Leng Melanie J. , Stephenson Michael H. , Rushton Jeremy , Chenery Simon , Crippa Gaia 
Published: August 2009

Abstract:

Brachiopod carbonate from Early Permian brachiopod shells from low palaeolatitude north Iran and higher palaeolatitude Pakistan Karakorum were screened for diagenesis and analysed for oxygen isotope ratios to derive seawater palaeotemperatures. Screening techniques employed included SEM ultrastructural analysis, cathodoluminescence (CL), image analysis of CL images, trace-element (Sr, Mn, Fe) determinations, and carbon and oxygen stable-isotope determinations. The Karakorum shells were found to be diagenetically altered, but those from north Iran were judged to be pristine. Using data from pristine material, two distinct time slices were analysed: the early and middle Asselian. Two contrasting δ
18
O values for seawater (0‰ and +1.0‰ V-SMOW) were used to account for different extensions of the Gondwanan ice caps. The δ
18
O data from north Iran indicate a range of seawater temperatures from +24.3 to +30.3 °C (for δ
18
O
seawater
= 0‰ V-SMOW) or from +30.3 to +35.4 °C (for δ
18
O
seawater
= +1.0‰ V-SMOW) for the early Asselian. Results for δ
18
O from the middle Asselian indicate seawater temperatures of +24.4 to +28.0 °C (for δ
18
O
seawater
= 0‰) or +29.2 to +32.8 °C (for δ
18
O
seawater
= +1.0‰). The maximum calculated temperatures in the middle Asselian are about 2 °C lower than those for the early Asselian. The average temperature for both time slices is similar to modern tropical sea-surface temperatures, indicating that low-latitude Early Permian ocean waters in Iran did not undergo significant cooling during the final Glacial III episode of Gondwanan glaciation. This confirms other evidence based on biotic provinces, which suggests that during the Permo-Carboniferous glaciation, the low-latitude warm belt became narrower and confined to the western Tethys and Cathaysian provinces, and was not subject to a reduction in temperature, but rather a reduction in size.
A composite C-isotope profile for the Neoproterozoic Dalradian Supergroup of Scotland and Ireland
Authors: Prave A.R. , Fallick A.E. , Thomas C.W. , Graham C.M. 
Published: August 2009

Abstract:

The Neoproterozoic Dalradian Supergroup is a dominantly siliciclastic metasedimentary succession in the Caledonian orogenic belt of Scotland and Ireland. Despite polyphase deformation and greenschist- to upper amphibolite-facies metamorphism, carbonate units distributed throughout the Dalradian record marked δ
13
C
carbonate
excursions that can be linked to those associated with key environmental events of Neoproterozoic time. These include: (1) tentative correlation of the Ballachulish Limestone with the
c
. 800 Ma Bitter Springs anomaly; (2) the presence of the pre-Marinoan Trezona anomaly and 635 Ma Marinoan-equivalent cap carbonate sequence in rocks of the middle Easdale Subgroup; (3) the terminal Proterozoic (
c
. 600–551 Ma) Wonoka–Shuram anomaly in the Girlsta Limestone on Shetland. These linkages strengthen previously inferred correlations of the Stralinchy–Reelan formations and the Inishowen–Loch na Cille–MacDuff ice-rafted debris beds to the respectively 635 Ma Marinoan and 582 Ma Gaskiers glaciations, and suggest that the oldest Dalradian glacial unit, the Port Askaig Formation, represents one of the
c
. 750–690 Ma Sturtian glacial episodes. These δ
13
C data and resulting correlations provide more robust constraints on the geological evolution of the Dalradian Supergroup than anything hitherto available and enhance its utility in helping refine understanding of Neoproterozoic Earth history.
A magmatic age and four successive metamorphic events recorded in zircons from a single meta-anorthosite sample in the Central Zone of the Limpopo Belt, South Africa
Authors: Mouri H. , Whitehouse M.J. , Brandl G. , Rajesh H.M. 
Published: August 2009

Abstract:

Ion microprobe U–Th–Pb analyses combined with cathodoluminescence imaging of zircons from a meta-anorthosite from the Central Zone of the Limpopo Belt record five distinct events. The most concordant ages of cores of zircon yielded a weighted mean
207
Pb/
206
Pb age of 3344 ± 3.6 Ma, representing the protolith age. The unzoned overgrowths yielded four discrete groups with weighted mean
207
Pb/
206
Pb ages of 3150 ± 15 Ma, 2614 ± 4 Ma, 2488 ± 22 Ma and 2009 ± 28 Ma, representing four possible metamorphic events in the Central Zone. This is the first time that a succession of several metamorphic events has been demonstrated in a single rock-type from the Limpopo Belt.

Supplementary material:

Analytical methods and data are available at
http://www.geolsoc.org.uk/SUP18368
.