bluuebunny/crossref_metadata_2025_split huggingface dataset:
Morphology and genesis of deep scour holes in the Mackenzie Delta
Authors: Beltaos Spyros , Carter Tom , Prowse Terry 
Published: July 2011

A unique feature that has been detected in the course of past morphological studies of Mackenzie delta channels, and which is of particular concern to the design of pipeline crossings, is the frequent occurrence of very deep scour holes. A recent survey along East Channel revealed many additional holes, with maximum depths ranging from 13 to 37 m. Using the results of recent and past surveys, an inventory of known scour holes and associated morphological parameters is developed. Most holes occur near bends, and often next to recesses in the channel boundaries, known as scour bays. It is shown that presence of scour bays indicates deeper-than-expected holes while repeat surveys of three holes indicate stability. Previously postulated formative mechanisms of bay-associated holes are critically examined; scour under ice jams is eliminated while lake capture is considered likely. Practical implications of the present findings are discussed and research needs outlined.
Mechanical capabilities and fire endurance of natural rubber latex modified concrete
Authors: Ismail Mohammad , Muhammad Bala , Yussuf Abdirahman Ali , Majid Zaiton , Ismail Mohamed ElGelany 
Published: July 2011

Compressive, indirect tensile, and flexural strengths characteristics of natural rubber latex modified concrete (NRLMC) were studied and reported — Part I. In addition, a comparative investigation between normal concrete (NC) and NRLMC, conducted on fire endurance was also presented — Part II. Normal and modified elements containing latex–water ratios within 0–10% were prepared and cured in accordance with the Japan Industrial Standard. Fire endurance capacity was assessed at five temperature levels; ambient temperature (27 °C), 150, 300, 500, and 800 °C. However, elevated heating (800–1300 °C) was further applied for the purpose of monitoring behavior at the verge of disintegration. Specimens were allowed to cool in the oven prior to compressive strength tests until room temperature is attained. Test results indicate that significant mechanical capabilities could be achieved by the inclusion of an appropriate quantity of latex concentrate and proper selection of befitting curing regime. Interestingly, the superiority of NRLMC over NC is maintained even under fire, up to the critical limit of latex-film capability performance.
KAM TORI AND ABSENCE OF DIFFUSION OF A WAVE-PACKET IN THE 1D RANDOM DNLS MODEL
Authors: AUBRY S. 
Published: July 2011

When nonlinearity is added to an infinite system with purely discrete linear spectrum, Anderson modes become coupled with one another by terms of higher order than linear, allowing energy exchange between them. It is generally believed, on the basis of numerical simulations in such systems, that any initial wave-packet with finite energy spreads down chaotically to zero amplitude with second moment diverging as a power law of time, slower than standard diffusion (subdiffusion). We present results which suggest that the interpretation of spreading cannot be described as initially believed and that new questions arise and still remain opened. We show that an initially localized wave-packet with finite norm may generate two kinds of trajectories both obtained with nonvanishing probability.The first kind consists of KAM trajectories which are recurrent and do not spread. Empirical investigations suggest that KAM theory may still hold in infinite systems under two conditions: (1) the linearized spectrum is purely discrete, (2) the considered solutions are square summable and not too large in amplitude. We check numerically that in appropriate regions of the parameter space, indeed many initial conditions can be found with finite probability that generate (nonspreading) infinite dimension tori (almost periodic solutions) in a fat Cantor set in (projected) phase space.The second kind consists of trajectories which look initially chaotic and often spread over long times. We first rigorously prove that initial chaos does not necessarily imply complete spreading e.g. for large norm initial wave-packet. Otherwise, in some modified models, no spreading at all is proven to be possible, despite the presence of initial chaos in contradiction with early beliefs. The nature of the limit state is still unknown.However, we attempt to present empirical arguments suggesting that if a trajectory starts chaotically spreading, there will necessarily exist (generally large) critical spreading distances that depend on the disorder realization where the trajectory will be sticking to a dense set of KAM tori. This effect should induce drastic slowing down of the spreading which could be viewed as "inverse Arnold diffusion" since the trajectory approaches KAM tori regions instead of leaving them. We suggest that this effect should self-organize the chaotic behavior and that at long time, the wave-packet might not be spread down to zero, but could have a limit profile with marginal chaos (with singular continuous spectrum), despite a long spatial tail. Further analytical and numerical investigations are required.
Modelling rock–water interactions in flooded underground coal mines, Northern Appalachian Basin
Authors: Perry Eric F. 
Published: July 2011

Inverse geochemical modelling was used to investigate rock–water interactions in flooded underground coal mines in northern Appalachia, USA. In early flooding, Pittsburgh seam mine waters are usually acidic (
c.
pH 3), with dissolved metals Fe and Al ranging from 10 to >100 mg l
−1
. Within a few decades, however, waters in fully flooded mines usually have pH of about 7 S.U., and alkalinity >300 mg l
−1
CaCO
3
Eq. Eh shifts from oxidizing (
c
. 500 to 700 mv) to reduced (−100 to −200 mv) conditions. Sodium concentrations may increase an order of magnitude; sulphate and iron concentrations may also increase. Water samples were collected from several mine-pools in West Virginia and Pennsylvania. A conceptual model was developed based on quantitative hydrology, mine-pool chemistry, mining conditions and mineralogy. The model was tested with the geochemical code PHREEQC. Simulations included mixing recharge and acid mine waters, precipitation–dissolution reactions involving carbonates, sulphates, oxy-hydroxides and sulphides, and ion adsorption and exchange. Na exchange was a dominant process in all models. Carbonates are orders of magnitude undersaturated in the juvenile mine-pool, but near saturation in the mature mine-pool, suggesting they are a primary source of acid neutralization and alkalinity. The mature mine-pool is simultaneously near equilibrium with iron sulphide, iron carbonate and iron oxy-hydroxide mineral phases. The rapid change in mine-pool water quality has substantial implications for management of these systems. Corresponding author eperry@osmre.gov
Dispersion of gold and associated elements in the lateritic regolith, Mystery Zone, Mt Percy, Kalgoorlie, Western Australia
Authors: Butt C. R. M. 
Published: July 2011

Primary Au mineralization in the Mystery Zone, Mt Percy, occurs in fuchsite–carbonate alteration zones at the contact with felsic porphyries intruding the Hannan’s Lake Serpentinite. The mineralized sequence is concealed beneath an almost complete lateritic regolith over 60 m thick. The regolith consists of 50 m-thick saprolite, which is clay-rich in the top 10 m, plasmic and mottled clays, lateritic residuum (duricrusts and gravels) and pisolitic soils; the surficial horizons contain pedogenic carbonates. Elements occurring with primary Au mineralization are S, Ag, W, As, Sb, Te, K, Rb and, possibly, Ba and Pb, but except for Ag and Te, none has a mineralogical association with Au.
The Au distribution in the regolith is typical for the region, with minor enrichment and lateral dispersion in lateritic residuum, a strong association with pedogenic carbonates, leaching and depletion in the underlying clay-rich horizons and some secondary concentration in the saprolite. Primary and saprolitic Au mineralization is indicated by a broad Au anomaly (100 to >1000 ppb) in the soils and lateritic residuum, and by high concentrations of W (5 to >40 ppm), Sb (7 to >16 ppm) and As (10–200 ppm). High K contents, corresponding to resistant muscovite, give surface expression to the alteration zone. Although Au contents are <100 ppb in the underlying clay-rich horizons, Sb, W and, to a lesser extent, As remain anomalous; similarly, Ba and K contents remain high, indicating the porphyries and alteration zones, respectively.
The porphyries and ultramafic rocks can be discriminated geochemically throughout much of the regolith by relative abundances and ratios of Ti, Zr, Ba and K. However, the lateritic duricrusts overlying the talc–chlorite rocks display abnormal geochemical signatures. They have low Cr contents (<1000 ppm), because primary Cr is present in weatherable chlorite rather than resistant chromite, but are enriched in ‘immobile’ elements (e.g. Zr) derived from the porphyries. The element distribution patterns are products of deep weathering under warm humid conditions in the early Tertiary or earlier, followed by semi-arid conditions that continue to the present. Chemical and physical mobilization of gold was restricted to the surficial lateritic residuum in the humid phases, but depletion and supergene enrichment in the saprolite, and concentration with pedogenic carbonates, are the result of chemical mobility under semi-arid conditions.
Gold mass balance in the regolith, Mystery Zone, Mt Percy, Kalgoorlie, Western Australia
Authors: Sergeev N. B. , Gray D. J. 
Published: July 2011

Mineralized rocks at the Mystery Zone gold deposit, Mt Percy, are overlain by an almost complete lateritic regolith over 60 m thick, within which there are significant variations in Au concentration. This includes an apparent Au depletion in the upper saprolite and clay horizons and enrichment in the surficial residuum and soil. Gold leaching up through the regolith has been quantified by mass balance calculations. In the lower saprolite, 55% of the Au has been leached from the porphyries, but Au is essentially immobile in ultramafic rocks. Higher in the regolith, leaching trends are similar over both lithologies, with 74–90% depletion in the clay saprolite, and 84–95% depletion in the plasmic and mottled clay horizons. Within the surficial lateritic residuum and carbonate, Au concentrations increase to significantly greater than bedrock grade, but the calculations show there is little, if any, absolute Au enrichment, compared to the fresh rock.
Silica is progressively depleted through the regolith, with more leaching over fuchsitic ultramafic rocks. Aluminium tends to remain stable in the saprolite. However, Fe shows contrasting mobility during weathering of the different lithologies. For ultramafic rocks, there is a strong absolute Fe depletion in the clay saprolite, with minor depletion in the overlying mottled and plasmic clay. In contrast, within weathered porphyries, Fe is absolutely accumulated in the most regolith horizons, possibly representing reprecipitation of Fe dissolved from adjacent ultramafic rocks.
Results from this investigation agree well with a previous Au mass balance study based on isovolumetric calculations. However, differences higher in the regolith may be due to partial collapse causing errors in earlier calculations.
Regolith geology and geochemical exploration around the Stellar and Quasar gold deposits, Mt Magnet, Western Australia
Authors: Robertson I. D. M. , King J. D. , Anand R. R. 
Published: July 2011

The Boogardie Synform, at Mt Magnet, in the NE Yilgarn Craton of Western Australia, is difficult to explore due to structural complexity in the basement, a variably truncated, residual regolith beneath a complex, transported overburden and high geochemical backgrounds from numerous mineralized settings. The distributions of Au and associated elements in the regolith around the Stellar and Quasar deposits, within the Boogardie Synform, have been studied to identify optimum sample media and an analytical suite for continuing exploration of this district. Regolith–landform relationships and geochemical dispersion in the district were established by mapping the regolith of an area of 25km
2
around the mines and investigating drill cuttings and pit exposures.

Mining and drilling at both sites revealed a partly eroded lateritic regolith incized by a fluvial palaeochannel, all concealed beneath 5–10 m of polymictic colluvium–alluvium. The sediments have all undergone post-depositional weathering. The Au mineralization is poor in As and Sb, but there are weak anomalies in Bi and Pb in the upper part of the weathered basement. There is no expression of the mineralization in the palaeochannel sediments or colluvium, nor between nearly adjacent layers within the colluvium and its overlying lag. Comparison of data from samples taken from the top of the basement with those from the unconformity, or interface, between basement and colluvium, indicates lower order but broader (200 m) and more consistent anomalies in the interface for Au, Bi and Pb. Useful anomalies can be improved using additive indices of Bi, Pb and Zn. The interface sample is, therefore, the preferred sample medium in this area of buried, truncated regolith, except where there are palaeochannels. Where there has been less regolith truncation and a buried, ferruginous duricrust is present, as at Stellar, duricrust is the optimum sample medium.
Elevated concentrations of Cr, Ni, Cu, V and, possibly, Zn in the basement regolith indicate mafic–ultramafic rocks. The saprolite and mottled zone on the basement rocks have a significantly greater Cr/Fe ratio than the transported materials. Regolith differentiation can be improved by robust canonical variate analysis; the most useful elements appear to be Al, Fe, Ni, Cr, Ga, Y, Zn, Th and Cu.
Komatiite volcanology, volcanological setting and primary geochemical properties of komatiite-associated nickel deposits
Authors: Hill R. E. T. 
Published: July 2011

Komatiite-associated nickel sulphide deposits formed in long-lived lava conduits fed vast komatiite flow fields during the evolution of Archaean Greenstone Belt stratigraphy. Such komatiite flow fields exhibit complex internal volcanic stratigraphy and facies variations. This complex volcanic architecture renders the meaningful interpretation of geophysical and geochemical exploration data almost impossible, without a knowledge of the eruptive processes controlling the emplacement of the flow fields and their associated nickel deposits.
Accordingly, this paper presents an effective model for komatiite volcanism which is derived from a synthesis of extensive geological mapping, geochemistry, and petrology of Archaean komatiites in Western Australia, and studies of Recent and active basaltic eruptions. It discusses the implications of this inflationary model for the interpretation of the geological and geochemical properties of various volcanic facies, and the genesis and geochemical properties of the ore deposits and their immediate environments. It is hoped that this treatize will act as a ‘precautionary tale’ for those formulating nickel exploration programs and interpreting regolith geochemical data.
Weathering, element distribution and geochemical dispersion at Mt Keith, Western Australia: implication for nickel sulphide exploration
Authors: Brand N. W. , Butt C. R. M. 
Published: July 2011

The komatiite–dunite-hosted Ni sulphide deposit at MKD5 (Mt Keith) has a complex regolith consisting of a residual profile (>75 m depth), partly collapsed towards the top, overlain by 40 m of exotic sediments. The weathered komatiites are composed predominantly of degraded serpentine, neo-formed hydrated Mg-silicates, carbonates, silica and Fe oxides. Magnesium concentrations decrease upwards through the lower regolith, whereas those of Fe and Si increase, reflecting degradation of Mg-bearing minerals. A sharp decline of Mg within the profile marks the
Mg discontinuity
, separating Mg-saprolite from the overlying Fe saprolite. The Fe saprolite, dominated by Fe oxides and silica, has pseudo-sedimentary structures indicating partial collapse of the profile. At the unconformity with the sediments, eluviation, mixing and churning have produced zones with chemical and mineralogical characteristics of the underlying, overlying and adjacent lithologies.

Nickel, Co, Mn, Cr and PGE are dominantly hosted by secondary Fe oxides in the regolith, but above the Mg-discontinuity, Ni and Co are locally enriched by co-precipitation with Mn oxides. The oxidation potential, controlled by ferrolysis, ranges from −0.4 to +0.2 volts, and the pH, buffered by bicarbonate ion, irrespective of the presence of sulphides, decreases from 9.5 to 6.0 up through the profile. Copper is not significantly mobile under such conditions and precipitates as inert native metal, commonly spatially associated with Fe oxides. Separation of Ni and Cu occurs in the upper saprolite and pedolith, because metallic Cu (±Pd) is retained and residually concentrated in collapsed Fe saprolite, whereas Ni, adsorbed to goethite, is redissolved and reprecipitated below the Mg-discontinuity.
High Ni concentrations in the regolith cannot alone be used to distinguish between Ni sulphide mineralized (NiS) and barren komatiitic protoliths. The strong correlation between chalcophile elements evident in mineralized protolith is lost with the oxidation of sulphides, and Ni derived from sulphides is indistinguishable from that derived from silicates. Ultramafic-derived regolith materials having Ni/Cu ratios of 7–19 and >19 may indicate the presence of massive and disseminated sulphides, respectively. The ratio at MKD5 is 60. These relationships may be distorted by preferential leaching, or by the influx of either element from wall-rocks. High concentrations of PGE, especially Pt, Pd and Ru, may also indicate mineralized protolith. However, the very low secondary mobility of PGE and Cu greatly restricts target size. Larger targets are given by Ni/Cr and Cu/Zn ratios which, either singly or multiplied together, can be used to identify mineralized komatiitic sequences and provide vectors towards ore. Their value is diminished if the ore and host sequence are decoupled during emplacement.
Carboniferous stratigraphy and context of the Seal Sands No. 1 Borehole, Teesmouth, NE England: the deepest onshore borehole in Great Britain
Authors: Johnson G. A. L. , Somerville Ian D. , Tucker Maurice E. , Cózar Pedro 
Published: July 2011

SUMMARY
Carboniferous rocks totalling 3442 m in thickness were drilled in the Seal Sands No. 1 Borehole at Teesmouth, Cleveland, in 1974–75. Cores taken in the middle and towards the bottom of the Carboniferous section show that the strata are broadly horizontal so the thicknesses drilled are close to true stratigraphical thicknesses. The borehole passed through 727 m of Triassic and Permian strata, which lie unconformably on the Carboniferous rocks. The latter comprise a Mississippian succession of Viséan–Serpukhovian (Holkerian–?Arnsbergian) age that is dominated by near-shore, shallow-water deposits with numerous but mainly thin coal seams. The Serpukhovian (Pendleian–?Arnsbergian) succession of shales and siltstones with thin sandstones, several thin limestones and rare coals is assigned to the Stainmore Formation (135 m). Below this, a thick calcareous interval of limestone and interbedded mudstone is believed to be the Great Limestone (110 m), which forms the top member of the underlying upper Viséan (Brigantian)–lower Serpukhovian (Pendleian) Alston Formation. The remaining strata of the Alston Formation (782 m) are equivalent to the 10 principal cyclothems (Four Fathom–Peghorn limestones) of the Alston Block, together with the underlying Birkdale Limestone at the base of the Alston Formation from which the lowest Brigantian microfossils have been recorded. The underlying Great Scar Limestone Group of late Asbian age (148 m) includes pale limestones of the Melmerby Scar Limestone Formation, similar to the limestones of the same formation on the Alston Block, interbedded with sandstones and mudstones. Below the Great Scar Limestone Group, the new informally defined Cleveland Group comprises three new informally defined formations. At the top of the group, the Greatham Formation (388 m) comprises limestones interbedded with mudstone and sandstone in cyclic sequences of late Asbian age. Below this, the informally defined Teesmouth Formation (539 m), also of late Asbian age, is a more terrigenous succession with numerous coal seams. The oldest unit in the borehole, the informally defined Seal Sands Formation (1338 m), comprises finely interbedded, black fissile mudstone, siltstone, fine-grained sandstone, thin black peloidal limestone beds, black chert and many coal seams. This distinctly black succession is mostly Asbian in age, but Holkerian microfossils occur in the lower part, from 3621 m down to the bottom of the hole at 4169 m. Correlations are made with the Alston Block succession and that of the Stainmore Basin. The unusually thick Mississippian succession, especially in the Asbian (>1800 m thick), is in accordance with the borehole's location within the eastern part of the Stainmore Basin, where a thick Carboniferous sequence is inferred from geophysical data. It is also comparable with a thick Asbian succession in the Northumberland Basin.
The Serpukhovian and Bashkirian (Carboniferous, Namurian and basal Westphalian) faunas of northern England
Authors: Brand P. J. 
Published: July 2011

SUMMARY
The marine fauna in Serpukhovian and Bashkirian strata (Namurian and basal Westphalian) of northern England shows changes in composition and diversity, both stratigraphically and in geographical distribution across the region. The deposits of distinct marine incursions contain characteristic assemblages of fauna, although few forms, if any, are diagnostic of individual incursions. The results of the study suggest that the depositional area formed an open channel during the marine incursions in which the benthic fauna (that comprises the majority of the recorded forms) is, in general, more prolific in the east. The faunas recorded in both block and basin sedimentary rocks are similar, suggesting that the water depth during deposition was also similar. The difference between block and basin lies in the amount of sediment deposited and the subsidence rate. The Subcrenatum Marine Band shows the most varied faunas in the west.
The cladid crinoid
Rhabdocrinus
Wright from the Namurian of Co. Durham, UK
Authors: Donovan S. K. , Birtle M. 
Published: July 2011

SUMMARY

Crinoids from the marine succession near the base of the Namurian (Pendleian, Mississippian) of NE England remain poorly known. Robust crinoid pluricolumnals from the Rookhope Shell Beds Limestone, exposed in the banks of the River Tees near Winston, Co. Durham, are identified as
Rhabdocrinus
sp. cf.
R. swaledalensis
Wright. The broad, cyclocyclic pluricolumnals consist of low, heteromorphic N1 columnals that are unlikely to have been derived from any other English Pendleian crinoid. However, the dististele of
R. swaledalensis sensu stricto
remains unknown, hence the specimens from Winston remain in open nomenclature. Attachment was distal with a dendritic radice; large radice scars are common on some specimens. Evidence shows that
Rhabdocrinus
spp. had long stems, certainly hundreds of mm in length in the species from Winston.