bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Titanium in Nickel-Base Superalloys on the Performance of Thermal Barrier Coatings Utilizing γ−γ′ Platinum Bond Coats
Authors: Tawancy H. M. , Al-Hadhrami Luai M.
Published: November 2010

Titanium is a key element in nickel-base superalloys needed with aluminum to achieve the desired volume fraction of the strengthening γ′-phase. However, depending upon its concentration, titanium can degrade the adherence of aluminum oxide by forming TiO2 particles near the oxide-metal interface. This effect is extended to thermal barrier coating systems where in this case, the bond coat replaces the superalloy as the underlying substrate. Noting that the onset of failure of thermal barrier coating systems coincides with the first spall of the thermally grown oxide, titanium level in the superalloy can have an important effect on the useful life of the coating. Therefore, this study was undertaken to examine the effect of titanium on the performance of a thermal barrier coating system. Included in the study were two Ni-base superalloys with similar chemical composition except for the Ti content and a Pt-containing bond coat consisting of γ′+γ-phases all top coated with zirconia stabilized by 7 wt % yttria. Coating performance was evaluated from thermal exposure tests at 1150°C with a 24 h cycling period to room temperature. Various electron-optical techniques were used to characterize the microstructure. The coating system on the low-Ti alloy was found to outperform that on the high-Ti alloy. However, for both alloys, failure was observed to occur by loss of adhesion between the thermally grown oxide and underlying bond coat.
Extreme ultraviolet mask surface cleaning effects on lithography process performance
Authors: George Simi A. , Baclea-an Lorie Mae , Naulleau Patrick P. , Chen Robert J. , Liang Ted
Published: November 2010

Extreme UV (EUV) masks are expected to undergo cleaning processes in order to maintain the lifetimes necessary for high volume manufacturing. For this study, the impact of repetitive cleaning of EUV masks on imaging performance is evaluated. Two high quality industry standard EUV masks are used, with one of the masks undergoing repeated cleaning and the other one kept as a reference. Lithographic performance, in terms of process window analysis and line edge roughness, was monitored after every two cleans and was compared to the reference mask performance. Surface analysis by atomic force microscopy did not show changes in the midspatial frequency roughness measured after each clean. After a total of eight cleans, minimal degradation is observed in the lithographic performance of the mask. From these observations, the authors conclude that the cleaning cycles completed thus far did not damage the mask multilayer or the absorber structures. The cleaning cycles will be continued until significant loss in imaging fidelity is found.
Arabidopsis
Type I Metacaspases Control Cell Death
Authors: Coll Nuria S. , Vercammen Dominique , Smidler Andrea , Clover Charles , Van Breusegem Frank , Dangl Jeffery L. , Epple Petra
Published: November 2010

The Yin and Yang of Plant Caspases

The function of plant metacaspases, identified by limited sequence homology to the animal caspases that control cell death, has remained elusive.

Coll
et al.

(p.
1393
) have now elucidated the actions of two metacaspases in the small plant
Arabidopsis
. One metacaspase, AtMC1, promoted cell death, and the other, AtMC2, acted antagonistically to stall cell death. The results help to elucidate the mechanisms by which plants control cell survival during development and defend against pathogen attack.
Glucose and Weight Control in Mice with a Designed Ghrelin O-Acyltransferase Inhibitor
Authors: Barnett Brad P. , Hwang Yousang , Taylor Martin S. , Kirchner Henriette , Pfluger Paul T. , Bernard Vincent , Lin Yu-yi , Bowers Erin M. , Mukherjee Chandrani , Song Woo-Jin , Longo Patti A. , Leahy Daniel J. , Hussain Mehboob A. , Tschöp Matthias H. , Boeke Jef D. , Cole Philip A.
Published: November 2010

Metabolism Without Modification

Obesity-associated metabolic disease has rapidly become a public health priority in the developed world and is being addressed through prevention strategies aimed at lifestyle changes and through pharmacological approaches.

Barnett
et al.

(p.
1689
, published online 18 November) designed a drug that inhibits the action of ghrelin, a circulating peptide hormone that increases fat mass and food intake. The drug, a bisubstrate analog called GO-CoA-Tat, is a selective antagonist of ghrelin O-acyltransferase (GOAT), an enzyme that catalyzes a posttranslational modification that is essential for ghrelin activity. Injection of GO-CoA-Tat into wild-type mice on a high-fat diet improved glucose tolerance and reduced weight gain, probably through changes in metabolic activity. Because GO-CoA-Tat is a peptide-based drug that requires repeated injection, it is unsuitable for clinical use, but GOAT does represent a potentially valuable target for future drug development efforts in metabolic disease.
Body weight: a risk factor for subtherapeutic antithrombotic therapy in neurovascular stenting
Authors: Drazin Doniel , Choulakian Armen , Nuño Miriam , Kornbluth Penelope , Alexander Michael J
Published: November 2010

Background

Patients with cervical carotid and intracranial stenting are routinely premedicated with antithrombotic agents, clopidogrel and aspirin (ASA), and intraprocedurally with heparin. The levels of antithrombotic therapy necessary for these neurovascular therapies have yet to be well defined.

Method

A retrospective review of 52 patients who underwent neurovascular stenting procedures was carried out. Measurements obtained intraoperatively included: activating clotting time, antiplatelet inhibition (from Accumetrics) recorded as ASA reaction units (ARU), P2Y12 reaction units (PRU), baseline (BASE), and percentage inhibition. Percentage P2Y12 platelet inhibition <20% and ARU >550 were defined as suboptimal clopidogrel and ASA responses, respectively.

Results

52 patients (mean age 62.6 years) underwent stent implantation for wide necked aneurysms (28, 54%), symptomatic intracranial stenosis (13, 25%) and cervical carotid stenosis (11, 21%). Mean ARU assays were 463.0±84.7. The response was suboptimal in seven patients. For clopidogrel, the mean BASE, PRU and percentage inhibition were 374.0±54.9, 279.5±78.5 and 30.7%±22.6%, respectively. 19 patients (36.5%; p<0.01) showed suboptimal responses for percentage inhibition. Multivariate analysis showed that body weight (82.0±11 vs 73.6±14 kg; p =0.04) and body mass index were significant predictors (OR 1.18, 95% CI 1.01 to 1.18; p =0.003) in the suboptimal group. One case of intraprocedural thrombosis (2%) was observed in the suboptimal group and no cases were seen in the therapeutic group.

Conclusion

Data obtained in this study suggest a suboptimal clopidogrel response in patients with greater body weight and body mass index. Adjusted dosing according to weight may help achieve adequate therapeutic platelet inhibition and reactivity while decreasing thromboembolic complications.
Clinicopathological and ultrasonographic findings in 40 water buffaloes (Bubalus bubalis) with traumatic pericarditis
Authors: Mohamed T.
Published: November 2010

Forty buffaloes with traumatic pericarditis were examined to characterise the ultrasonographic findings in buffaloes with traumatic pericarditis, determine the extent of the lesions and assess the prognosis. The most noticeable clinical presentations were presternal oedema (73 per cent) and jugular and mammary vein distension (88 per cent). Laboratory findings included neutrophilic leucocytosis, elevated total protein concentration, hypoalbuminaemia, hypergammaglobulinaemia and increased concentration of free fatty acids. Ultrasonographically, fluid in the pericardium appeared as either mild or massive anechoic accumulations containing fibrin threads or were imaged as homogenous, echogenic pericardial effusions. Moderate to severe corrugation of the reticular wall was observed. Deposits of fibrinous tissue interspersed with fluid pockets were seen between the reticulum, dorsal ruminal sac and diaphragm. Perireticular and mediastinal abscesses were imaged and appeared as echogenic lines with anechoic, echogenic, homogenous or heterogeneous contents. Additional ultrasonographic findings included hepatomegaly, dilation of the caudal vena cava, hepatic and portal veins, ascites, echogenic pleural effusions and vegetations of the tricuspid, mitral and pulmonary valves. The ultrasonographic findings were confirmed at postmortem examination.
Factors affecting the mortality of weaned piglets during commercial transport between farms
Authors: Averós X. , Knowles T. G. , Brown S. N. , Warriss P. D. , Gosálvez L. F.
Published: November 2010

Factors affecting the number of weaned piglets found dead after commercial transport between farms were studied by means of multilevel Poisson regression. Information relating to 58,682 piglets during 109 journeys in different EU countries was collected at the end of each journey by means of questionnaires. Overall, 0.07 per cent of all the transported piglets were found dead on arrival, and deaths of piglets were recorded in 13.8 per cent of journeys. The final regression model, which was calculated using the complete records from 105 journeys, included the total duration of the journey, the mean outside temperature during the journey, whether the piglets were fasted before transport, whether drinking water was provided, the type of ventilation in the vehicle and the interaction between journey duration and the mean outside temperature. The duration of the journey and the mean outside temperature showed a significant interaction effect, with a gradual increase in the predicted number of dead piglets with increasing journey duration as the outside temperature increased. Providing the piglets with drinking water and having mechanically assisted ventilation (fans) in the vehicle during the journey significantly reduced the number of deaths, as did fasting the piglets before transport.
The influence of clay-sized particles on seismic velocity for Canadian Arctic permafrost
Authors: King M. S.
Published: November 2010

Seismic-wave velocities have been measured on 37 unconsolidated permafrost samples as a function of temperature in the range -16 to +5 °C. The samples, taken from a number of locations in the Canadian Arctic islands, the Beaufort Sea, and the Mackenzie River valley, were tighty sealed immediately upon recovery in several layers of polyethylene film and maintained in their frozen state during storage, specimen preparation, and until they were tested under controlled environmental conditions. During testing, the specimens were subjected to a constant hydrostatic confining stress of 0.35 MPa (50 psi) under drained conditions. At no stage was a deviatoric stress applied to the permafrost specimens. The fraction of clay-sized particles in the test specimens varied from almost zero to approximately 65%. At temperatures below -2 °C the compressional-wave velocity was observed to be a strong function of the fraction of clay-sized particles, but only a weak function of porosity. At temperatures above 0 °C the compressional-wave velocity was observed to be a function only of porosity, with virtually no dependence upon the fraction of clay-sized particles. Calculation of the fractional ice content of the permafrost pore space from the Kuster and Toksöz theory showed that for a given fraction of clay-sized particles the ice content increases with an increase in porosity. It is concluded that the compressional-wave velocity for unconsolidated permafrost from the Canadian Arctic is a function of the water-filled porosity, irrespective of the original porosity, clay content, or temperature.
Alteration, mineralization, and metamorphism in the area of the East South "C" ore zone, 24th level of the Dickenson mine, Red Lake, northwestern Ontario
Authors: Mathieson Neil A. , Hodgson C. Jay
Published: November 2010

The area of the East South "C" (ESC) orebody of the Dickenson mine, Red Lake, consists of variably altered and mineralized basalt, basaltic volcaniclastic rocks, minor sulphidic iron formation, and a series of mainly postdeformation dykes. Except for the dykes, the rocks are in general well foliated. The macroscopic structural geometry of the stratiform rocks has been determined to a large extent by movement on schistosity-parallel faults.Three broad types of mineralization or alteration are recognized: an Na–Ca–Mg depletion with associated Fe–Mn enrichment controlled by primary permeable structures in basalt; a series of carbonate and quartz or "chert" veins emplaced into fissures; and auriferous silicified and sulphidized zones controlled by vein-filled fractures. The last is the main mineralization type in the ESC orebody on the 24th level of the mine, which was the focus of this study. Although all mineralization types occur within the mine, they are not directly associated either temporally or spatially on a mesoscopic scale. All, however, appear to have been overprinted by or formed synchronously with the amphibolite-facies metamorphism.A rich variety of metamorphic mineral assemblages occurs in the volcanic rocks because of the chemical effect of pre- or synmetamorphic hydrothermal alteration. These assemblages and the composition and mineral associations of arsenopyrite in the ESC orebody closely constrain the conditions of metamorphism to 520–540 °C and 3.8–4.2 kbar (380–420 MPa) fluid pressure.
Chemostratigraphic division of the Blake River Group, Rouyn–Noranda area, Abitibi, Quebec
Authors: Gélinas Léopold , Trudel Pierre , Hubert Claude
Published: November 2010

The effusive rocks of the Blake River Group in the Abitibi volcanic belt, Rouyn–Noranda region, belong to a bimodal sequence in which andesites and rhyolites clearly dominate. The identification of calc-alkaline and tholeiitic affinities is made upon examination of the major, trace, and rare earth element (REE) content. Thus, the andesites (58% normalized SiO2 value without volatiles) of the calc-alkaline units have average K (4800 ppm), Ba (160 ppm), and Rb (13 ppm) values that are greater than the average K (1800 ppm), Ba (130 ppm), and Rb (3 ppm) values for andésites (57% SiO2) that belong to associated tholeiitic units. Furthermore, tholeiitic andesites have distinctive average values of Ti (9600 ppm) and Y (40 ppm) that are higher than the average values of Ti (6700 ppm) and Y (25 ppm) of calc-alkaline andesites. An effective discrimination between the calc-alkaline and tholeiitic affinities is obtained using the Zr/Y and Ti/Zr ratios, which are, respectively, less than 4 and greater than 70 in andesites of the tholeiitic units.REE profiles of tholeiitic andesites are flat when compared with those of calc-alkaline andesites, which show an enrichment in light rare earths.The tholeiitic units of the Blake River Group are found in the proximity of the Porcupine-Destor and Larder Lake – Cadillac faults, the major faults of the region, and at the periphery of an ensemble of calc-alkaline units. Four of the five tholeiitic units are differentiated, showing an enrichment of iron passing from basalt to andesite. These units possess felsic variole-bearing flows, the result of an unmixing, which was probably responsible for the formation of minor associated quantities of porphyries and rhyolitic volcaniclastites.A progressive increase in the concentration of hygromagmatophile elements (REE, Zr, Nb) is observed in the tholeiitic units from the Pelletier unit beginning at the base and passing through the Trémoy, Destor, and Dufresnoy units, at the top of the Blake River Group. The calc-alkaline units are characterized by an alternation of rhyolitic complexes and calc-alkaline andesites. This cyclic repetition occurs without significant modification of the calc-alkaline andesite composition.It is proposed that the volcanism responsible for the formation of the Blake River Group was restricted to a concentric zone centring on a continental environment. Mafic magmas nourished the central reservoir where melting of the sialic crust took place. The rhyolitic magma occupying the upper part of this reservoir mixed with the basaltic magma, producing calc-alkaline andesites. Successive mantle melt products were also emplaced into subsidiary reservoirs peripheral to the central chamber. Injections of tholeiitic magma in the peripheral reservoirs underwent differentiation and unmixing during emplacement of a part of the magma at the surface.
Flow, thermal structure, and subglacial conditions of a surge-type glacier
Authors: Clarke Garry K. C. , Collins Sam G. , Thompson David E.
Published: November 2010

Temperature measurements in a subpolar surge-type glacier reveal a distinctive thermal structure associated with the boundary between the ice reservoir and receiving areas. In the receiving area the glacier is cold based, but bottom temperature has increased as much as 0.5 °C between 1981 and 1982, and the basal heat flux is roughly 10 times the expected geothermal flux. Water percolation through permeable subglacial material is the probable energy source. Deformation of the substrate could destroy this drainage system and trigger a surge.
Middle Ordovician conodonts from the Buchans Group, central Newfoundland, and their significance for regional stratigraphy of the Central Volcanic Belt
Authors: Nowlan Godfrey S. , Thurlow J. Geoffrey
Published: November 2010

Conodonts have been recovered from carbonate clasts within breccia units in the Buchans Group of central Newfoundland. The assemblage is characterized by specimens of "Cordylodus" horridus Barnes and Poplawski and Histiodella holodentata Ethington and Clark. These and other species recovered suggest a Whiterockian (latest Arenig–early Llanvirn) age for the clasts. This is somewhat older than the whole-rock Rb–Sr age of 447 ± 18 Ma on volcanics of the Buchans Group. The carbonate clasts are considered to be derived from the area of deposition of the Buchans Group rather than from some exotic source. This interpretation is based on knowledge of local tectonics, inferred paleogeogaphy, and geographic distribution of the conodont assemblage. All other clasts in the breccia units are considered of local origin. If the conodonts are of local Buchans Group origin then they indicate a Whiterockian age for the unit. In view of this, current regional models for the Central Volcanic Belt may require substantial revision. A Whiterockian age for the Buchans Group is consistent with the observation that all significant volcanogenic massive sulphides of the Canadian Appalachians are of Caradoc or older Ordovician age. It is suggested that the Buchans Group is thrust southeastwards over the Victoria Lake Group, which is a probable distal facies equivalent.
Évolution postglaciaire des hauts sommets alpins et subalpins de la Gaspésie
Authors: Payette Serge , Boudreau Francis
Published: November 2010

The stratigraphy of surficial deposits located in a snow-patch site, at an altitude of 1200 m in the Mount Jacques-Cartier area, provides evidence of a Late Glacial to mid-Holocene deglaciation. During the Late Glacial, or at the beginning of the Holocene, the diamictons on the high summits of the McGerrigle Mountains were affected by a severe periglacial climate, responsible for the formation of most of the periglacial landforms, such as sorted polygons, sorted stripes, stone-banked lobes, and block fields. During the Holocene, these landforms were fossilized by vegetation, and podzolic soil profiles developed within the stony deposits. After the Hypsithermal, a cooling trend was registered in snow-patch sites, where gelifluction was active after ca. 5200, 3470 – 3340, 2500, 2100, 1860, 1490, and 650 BP. Subalpine meadows followed the opening of the forest, at least since 2200 BP, and were due to neoglacial cooling. Within the alpine belt, the coniferous cover regression is registered at least since 1400 BP. During the so-called Little Ice Age of the past centuries, conifers retracted because of periglacial activity, which was followed by the formation of sorted stripes and gelifluction lobes. The extinction of tree species in the alpine tundra is related to periglacial activity, an ecological situation rather specific to the high summits of Gaspé.
Origin of quartzofeldspathic gneisses at Montauban-les-Mines, Quebec
Authors: Prabhu M. K. , Webber G. R.
Published: November 2010

Quartzofeldspathic gneisses near zinc–lead–gold mineral deposits at Montauban-les-Mines, Quebec, have been examined geochemically to determine whether their protoliths were dominantly sedimentary or igneous. The gneisses are generally similar in average compositions to both rhyolitic rocks and sandstones (greywackes in particular). The most useful methods of protolith discrimination were found to be: (1) log (SiO2/Al2O3) versus log [(CaO + Na2O)/K2O]; (2) Niggli si versus mg; (3) normative quartz; (4) Shaw's discriminant function. Application of these criteria indicates that the Montauban quartzo-feldspathic gneisses were derived dominantly from quartzose sandstone or greywacke protoliths (or both).
Harmonic distortion on a seismic reflection profile across the Quebec Appalachians: relation to Bouguer gravity and implications for crustal structure
Authors: Cook Frederick A.
Published: November 2010

Seismic reflection data obtained across the Quebec Appalachians using the VIBROSEIS (trademark Conoco) technique were recorded with parameters that allowed harmonic distortion arrivals to interfere with layered reflections. The data exhibit reflections from layered miogeoclinal rocks dipping eastward beneath the allochthonous rocks of the orogen; the layering appears to terminate beneath the Notre Dame Anticlinorium. However, as the apparent termination of the layers also occurs at the arrival times of high-amplitude noise harmonics, it may have no geological significance. Precambrian Grenville crust, which probably underlies the layered sediments, extends at least as far east as the apparent termination, and may extend much farther. Examination of the Bouguer gravity field in relation to the seismic reflection data shows that a major gravity change is due to density differences that occur considerably west of the eastern limit of Precambrian Grenville crust. The gravity thus shows no correlation with surface structures proposed as suture zones. An actualistic model incorporates subduction of a passive (Atlantic-type) margin beneath an arc terrain during the Ordovician.
La répartition du pergélisol dans la région du détroit de Manitounuk, côte est de la mer d'Hudson, Canada
Authors: Seguin Maurice K. , Allard Michel
Published: November 2010

Forty-four AC electrical resistivity soundings have been made on the Manitounuk Islands (55°30′N, east coast of Hudson Bay) as well as in post-glacial and Recent marine sediments of the supratidal zone along the east shore of Manitounuk Strait. The results indicate that permafrost, which may have a thickness of 30 m, is present within basalts and quartzites of the cuestas at elevations above 20 m. The thermal effect of the sea and the possible infiltration of sea water in the structural elements prevent the formation of permafrost at lower altitudes. Rocky sites where permafrost has been detected are windswept areas devoid of snow. Heaved bedrock landforms are numerous on those sites. Along the east coast of Manitounuk Strait permafrost is scattered in patches and the permafrost landforms are degrading. Seasonal freeze–thaw processes are responsible for many features, such as thufurs, boulder heaving, clastic dykes, mud volcanoes, and others. The processes are related to year to year variability in the temperature regime, snow depth over the land surface, groundwater movement, thermal effects of the tides, and shore ice on the tidal flat.
Holocene white-tailed deer (Odocoileus virginianus) from the foothills northwest of Calgary, Alberta, Canada
Authors: Wilson Michael Clayton , Hills Leonard V.
Published: November 2010

The first subfossil antlers of Odocoileus virginianus from Alberta are described. They were associated with fragmentary postcranial and dental remains referred to the same species and obtained from an Alberta foothills bison bone bed (Hitching Post Ranch site) 3600 radiocarbon years old. Those antlers with burrs present had been shed, suggesting derivation from resident deer, and no conclusive evidence for human predation is present. It is argued that white-tailed deer remains have potential as indicators of paleoclimatic conditions, particularly severity of winter snow.
Alkaline peridotite, pyroxenite, and gabbroic intrusions in the Oman Mountains, Arabia
Authors: Searle Michael P.
Published: November 2010

High-level intrusions of highly undersaturated alkalic ultrabasic and gabbroic rocks occur in four areas of the Oman Mountains. They all intrude either the Haybi volcanic – Oman Exotic limestone (Permo-Triassic) thrust slice immediately beneath the Semail Ophiolite (Cenomanian) or the uppermost thrust slice of the underlying Hawasina (Permian to Cenomanian) Tethyan sediments. Detailed structural mapping indicates that the sills were all emplaced prior to the Late Cretaceous thrusting of the Oman allochthon onto the Mesozoic continental margin of Arabia, and therefore in an oceanic setting. These differentiated sills consist of biotite wehrlites at the base and kaersutite-bearing jacupirangites above, with kaersutite gabbros at the top. Olivine occurs only at the base. Titanaugite, kaersutite, titanium phlogopite, apatite, and opaque iron–titanium oxides are common mineral phases.Fractional crystallization and gravity differentiation processes and a rapid increase in volatile components at decreasing pressures all played a part in the petrogenesis of these uncommon intrusive rocks. K–Ar ages on biotites span the mid-Jurassic to Cenomanian, and in the northern Oman Mountains kaersutite jacupirangites are incorporated into the Cenomanian–Turonian amphibolite facies metamorphic sheet beneath the Semail Ophiolite. Alkaline magmas were present at depth along the passive continental margin, right up until Cenomanian times when northeast subduction was initiated and compressional tectonics began. Alkaline volcanism of Cenomanian age in the Dibba Zone indicates that tensional rifting processes were operative along the continental margin at the same time as compressional thrusting was occurring outboard. The alkaline rocks are unrelated to the ophiolite but are artifacts of Mesozoic rifting events in Tethys now preserved in footwall thrust slices beneath the ophiolite.
Kaolinite and mixed-layer illite–smectite in Lower Cretaceous bentonites from the Peace River coalfield, British Columbia
Authors: Spears D. A. , Duff P. McL. D.
Published: November 2010

The X-ray diffraction analysis of 75 thin volcanic clay bands in the Lower Cretaceous of the Peace River coalfield shows kaolinite and mixed-layer illite–smectite to be the two clay minerals present. Kaolinite is dominant in the clay bands (tonsteins) in the coal-bearing Gething and Gates formations, whereas illite–smectite is dominant in the clay bands (K-bentonites) in the marine Moosebar Formation. A complete gradation exists between the two clay minerals, demonstrating their common volcanic origin. Volcanic textures are seen in thin section. The relationship between clay composition and depositional environment corresponds with the clay stability fields with smectite the precursor of the mixed-layer clay. The proportion of illite in the latter averages 22% and corresponds with the coal rank. The major-element analyses mainly reflect the clay composition but with contributions from resistate and diagenetic minerals. Amongst the trace elements there are those that are both immobile in the alteration process and diagnostic of a specific volcanic composition. Based on such trace elements the ash composition is thought to have ranged from rhyolite to dacite, perhaps due in part to original grain-size variation as in tephra beds.
Late Pleistocene and early Holocene environmental history of southwestern Washington State, U.S.A.
Authors: Barnosky Cathy W.
Published: November 2010

A comparison of pollen records and associated plant remains from sites along a major precipitation gradient in southwestern Washington enables reconstruction of the late Quaternary environment during glacial and early Holocene time. During the Evans Creek Stade (25 000 – 17 000 years BP) little moisture reached lowlands east of the Olympic Mountains and as a result both the Puget Trough and the Columbia Basin featured a cold dry climate and parkland–tundra vegetation In glacial time, greatest aridity seems to have occurred between 19 000 and 17 000 years BP. After 17 000 years BP the development of mesophytic subalpine parkland suggests that maritime conditions extended farther east into the Puget Trough, and the Cascade Range became an important precipitation divide. Conditions warmer and (or) drier than today developed throughout western Washington between 10 000 and 8000–6000 years BP. Vegetation on opposite sides of the Cascade Range became dissimilar as early as 17 000 years BP, but this trend was accentuated in late glacial and early Holocene time.
Allard stock, La Plata Mountains, Colorado—an alkaline rock-hosted porphyry copper – precious metal deposit
Authors: Werle James L. , Ikramuddin Mohammed , Mutschler Felix E.
Published: November 2010

The Allard stock, which hosts a porphyry Cu–Ag–Au–Pt metals deposit, is an epizonal Laramide pluton at the southwest end of the Colorado mineral belt. The stock and associated mineralization evolved by a complex interaction of igneous and metasomatic processes as follows. Stage 1: forceful emplacement of syenite plutons. Stage 2: intense hydrothermal argillization of stage 1 syenites. Stage 3: intrusion of mafic syenite plutons, some of which are layered, along shear zones. Stage 4: violent escape of volatiles, producing intrusive breccia pipes. Stage 5: intense K-metasomatic alteration of the older stock units with production of a fenitelike alteration halo extending 1000 m beyond the stock and simultaneous intrusion of carbonate-bearing alkali feldspar dikes. Stage 6: emplacement of trachyte, syenite pegmatite, and mafic pegmatite dikes. Stage 7: deposition of metallic minerals, sanidine, quartz, calcite, and fluorite as veinlets and disseminated replacement masses from hydrothermal solutions.The stock shows enrichment of volatiles (CO2, F, and S), high concentrations of Ba and Sr, low concentrations of Rb, high concentrations of Cu, Ag, Au, Bi, Te, Pt, and Pd, with little or no enrichment in Nb, U, Y, and Zr.The Allard stock and its associated mineralization are unlike the calc-alkaline porphyry copper deposits of the western United States and Canada. Although the Allard syenites are silica saturated (quartz-normative), some aspects of Allard alteration and mineralization show affinities with copper and (or) precious metal deposits hosted by alkaline silica-undersaturated (nepheline- or leucite-normative) plutons and carbonatite complexes including the "alkaline suite" porphyry copper deposits of British Columbia, the Palabora, South Africa, copper deposit, and the Cripple Creek, Colorado, gold telluride deposit. Computer-assisted evaluation of major-element analyses of igneous rocks suggests that Allard-type Cu – precious metal deposits may occur in other North American alkaline rock provinces. Epithermal gold telluride deposits in subvolcanic alkaline rocks may grade downward into alkaline porphyry Cu – precious metal deposits.
Pre-Grenvillian and Grenvillian lithotectonic regions in eastern Labrador—correlations with the Sveconorwegian Orogenic Belt in Sweden
Authors: Gower Charles F. , Owen Victor
Published: November 2010

The Trans-Labrador batholith, Groswater Bay Terrane, and Lake Melville Terrane are three major crustal segments located adjacent to or within the Grenville Province in eastern Labrador. Each crustal segment is a distinct lithotectonic entity displaying contrasts with each other in proportions of rock types, structural style, and metamorphic imprint. Together they indicate a unilateral polarity to the region, partly reflecting Grenvillian tectonism, which sliced the region into thrust-bound blocks.In all three crustal segments, an Archean or Aphebian gneissic basement is inferred onto or adjacent to which ca. 1900–1700 Ma supracrustal rocks were deposited. Deformation, metamorphism, and granitoid pluton emplacement were partly coeval with and partly postdated the supracrustal assemblages. In the north, tectonothermal effects can be assigned to Hudsonian–Ketilidian orogenesis but their peak was 50–100 Ma later farther south. Post-tectonic granitoid plutons and layered mafic intrusions were emplaced at about 1650–1600 Ma, and further pulses of mafic intrusion occurred prior to the Grenvillian Orogeny.Comparison with the Sveconorwegian Orogenic Belt in southern Sweden shows remarkable similarities in lithologies, geological histories, and structural style. The Småland–Värmland granitoid belt, Eastern Pregothian mega-unit, and Western Pregothian mega-unit are interpreted here to be the Scandinavian counterparts of the Trans-Labrador batholith, Groswater Bay Terrane, and Lake Melville Terrane, respectively. This correlation is taken to indicate that both regions were part of the same tectonic margin during Middle Proterozoic times.The implication of this correlation is that the opening and closing of the lapetus Ocean resulted in a 2000 km sinistral "offset" of the Grenvillian–Sveconorwegian Front and other Precambrian features on either side of the Caledonides suture.
Strain partitioning and magnetic fabrics in particulate flow
Authors: Borradaile Graham J. , Tarling Don
Published: November 2010

Strongly deformed Archean sandstones and conglomerates in northwestern Ontario show extreme heterogeneity of strain, with pebbles deformed more than feldspar grains, which are more deformed than quartz grains. Despite the heterogeneous changes of shape, particulate flow has preserved a strong preferred grain orientation and the magnetic susceptibility ellipsoid usually still tracks the orientations of the principal strains.
Depositional environments and paleogeography in the Albian Moosebar Formation and adjacent fluvial Gladstone and Beaver Mines formations, Alberta
Authors: Taylor David R. , Walker Roger G.
Published: November 2010

The marine Moosebar Formation (Albian) has a currently accepted southerly limit at Fall Creek (Ram River area). It consists of marine mudstones with some hummocky and swaley cross-stratified sandstones indicating a storm-dominated Moosebar (Clearwater) sea. We have traced a tongue of the Moosebar southward to the Elbow River area (150 km southeast of Fall Creek), where there is a brackish-water ostracod fauna. Paleoflow directions are essentially northwestward (vector mean 318°), roughly agreeing with turbidite sole marks (329°) in the Moosebar of northeastern British Columbia.The Moosebar sea transgressed southward over fluvial deposits of the Gladstone Formation. In the Gladstone, thick channel sands (4–8 m) are commonly multistorey (up to about 15 m), with well developed lateral accretion surfaces. The strike of the lateral accretion surfaces and the orientation of the walls of channels and scours indicate northwestward flow (various vector means in the range 307–339°). The Moosebar transgression was terminated by construction of the Beaver Mines floodplain, with thick, multistorey sand bodies up to about 35 m thick. Flow directions are variable, but various vector means roughly cluster in the north to northeast segment. This indicates a major change in dispersal direction from the Gladstone and Moosebar formations.A review of many Late Jurassic and Cretaceous units shows a dominant dispersal of sand parallel to regional strike. This flow is mostly north-northwestward (Passage beds, Cadomin, Gladstone, Moosebar, Gates, Chungo), with the southeasterly dispersal of the Cardium being the major exception. Only at times of maximum thickness of clastic input (Belly River and higher units, and possibly Kootenay but there are no published paleocurrent data) does the sediment disperse directly eastward or northeastward from the Cordillera toward the Plains.
Rare earth element concentrations in Quaternary volcanic rocks of southwestern British Columbia
Authors: Green Nathan L. , Henderson Paul
Published: November 2010

A suite of hy-normative hawaiites, ne-normative mugearite, and calc-alkaline andesitic rocks from the Garibaldi Lake area exhibits fractionated, slightly concave-upward REE patterns (CeN/YbN = 4.5–15), heavy REE contents about 5–10 times the chondritic abundances, and no Eu anomalies. It is unlikely that the REE patterns provide information concerning partial melting conditions beneath southwestern British Columbia because they have probably been modified substantially by upper crustal processes including crustal contamination and (or) crystal fractionation. The REE contents of the Garibaldi Lake lavas are not incompatible with previous interpretations that (1) the hawaiites have undergone considerable fractionation of olivine, plagioclase, and clinopyroxene; and (2) the individual andesitic suites were derived from separate batches of chemically distinct magma that evolved along different high-level crystallization trends. In general, however, the andesites are characterized by lower light REE contents than the basaltic andesites. These differences in LREE abundances may reflect different amounts of LREE-rich accessory phases, such as apatite, sphene, or allanite, assimilated from the underlying quartz diorites.
Magmatic composition and tectonic setting of altered, volcanic rocks of the Fennell Formation, British Columbia
Authors: Aggarwal Pradeep K. , Fujii Toshitsugu , Nesbitt Bruce E.
Published: November 2010

The upper Paleozoic Fennell Formation in south-central British Columbia consists of basalts and associated marine sediments metamorphosed at low greenschist facies conditions. Although the microphenocrysts of plagioclase and Fe–Ti oxides are almost completely altered, those of augite and amphibole have survived this metamorphism. In the vicinity of the Chu Chua mineral deposit, relict augite microphenocrysts, which constitute a major proportion of the microphenocryst assemblage, are enriched in Al and Ti and are similar in composition to those from alkalic and transitional basalts. Relict amphiboles are also enriched in Ti (4.5–5.9% TiO2) and are classified as kaersutites. The occurrence of kaersutite and the chemistry of relict augites indicate that in this area the Fennell Formation basalts were originally alkalic and transitional in composition. On conventional Ti–(Zr/P2O5) and (Nb/Y)–(Zr/P2O5) immobile-element discrimination diagrams, both the kaersutite-bearing and kaersutite-free rocks plot in the tholeiitic basalt field. Accordingly, it is suggested that these diagrams may not provide clear evidence for the magmatic composition of altered volcanic rocks.Based on the lead isotopic compositions, petrographic features, and alkalic character of the Fennell Formation basalts, it is interpreted that these basalts were formed in a tectonic setting similar to that of present-day oceanic islands or seamounts.
Rare earth elements in volcanic rocks of the Buchans area, Newfoundland
Authors: Strong D. F.
Published: November 2010

Rare earth elements (REE) were determined for 57 samples representative of the range of stratigraphic units, both mineralized and unmineralized, associated with the high-grade polymetallic volcanogenic sulphide deposits at Buchans, Newfoundland. These data do not indicate any features indicative of magmatic fractionation processes, e.g., enrichment of total REE or any europium depletion anomaly, in the mineralized relative to the unmineralized volcanics, suggesting that such processes did not play an important role in the formation of these ore deposits. These results also emphasize the need for caution in any attempts to use the rare earth elements as a general tool for discrimination between barren and mineralized volcanic sequences.
Deformation associated with gypsum karst in the Salt River Escarpment, northeastern Alberta
Authors: Tsui Po C. , Cruden David M.
Published: November 2010

An escarpment formed by the carbonate Keg River and evaporitic Chinchaga formations of Middle Devonian age extends southwards from the Slave River 30 km west of Fort Smith, Northwest Territories. Newly described folds in the bedrock are due to hydration of the anhydrite to gypsum in the Chinchaga Formation underlying the escarpment. Local groundwater flow has also dissolved subsurface cavities in the Chinchaga Formation. As these openings grew, the carbonates of the Keg River Formation subsided along stepped normal faults. Depressions within the fault blocks occurred where subsidence was concentrated along joints.
A mechanical analysis of the late Archean Gwillim Lake shear belt, Chibougamau area, Quebec
Authors: Dimroth Erich , Archambault Guy , Goulet Normand , Guha Jayanta , Mueller Wulf
Published: November 2010

Deflection of older structures (stratification, schistosities, fold axes, and thrust faults) defines a major left-lateral transcurrent shear belt associated with the Gwillim Lake fault in the Chibougamau area. Stratigraphic and sedimentological work in the Waconichi syncline permitted determination of vertical and lateral movement components of the Gwillim Lake fault and its associated second-order faults. Comparison with experimental and theoretical studies suggests an interpretation as follows: north to east-northeast trending minor faults are Riedel (R) shears, northwest trending minor faults are conjugate Riedel (R′) shears, and east-trending minor faults are thrust (or restraint) shears (P). The Gwillim Lake fault is the principal displacement (D) shear. The main regional compressive stress had a N10°E direction. The shear belt formed during late Archean time and has been slightly reactivated after the deposition of the Early Proterozoic Chibougamau Formation.
The Wathaman batholith: largest known Precambrian pluton
Authors: Fumerton S. L. , Stauffer M. R. , Lewry J. F.
Published: November 2010

The Early Proterozoic Wathaman batholith, in northern Saskatchewan and Manitoba, is a 900 km long, megacrystic granite–granodiorite intrusion that straddles the junction between ensialic miogeoclinal and probably ensimatic eugeoclinal–island-arc terranes of the "Trans-Hudson Orogen," of the western Churchill Province. Although the largest Precambrian batholith known, it is, apart from marginal complexities, remarkably homogeneous throughout and, unlike comparably sized and situated Phanerozoic batholiths, shows no evidence of multiple intrusion, nor does it have comagmatic early mafic phases. However, it may be considered as just one phase of a larger batholithic belt that also includes numerous smaller plutons. Taken as a whole the composite batholithic belt is similar in many aspects to Mesozoic Pacific rim batholithic belts, and like them probably was emplaced during plate collision.The batholith is affected by pervasive internal deformation, is bounded on the northwest by major blastomylonite zones, and is transected internally by splaying shear zones. It is a mid- to late-synkinematic Hudsonian intrusion, emplaced within a markedly compressional, crustal regime. On the basis of petrological, geochemical, and isotopic criteria the batholith is an "I-type" intrusion, but the origin of the magma and the emplacement mechanisms are still unresolved problems.
Mise en place et pétrologie du granite associé au complexe ophiolitique de Thetford Mines, Québec
Authors: Laurent Roger , Taner Mehmet F. , Bertrand Jean
Published: November 2010

Sheets of granite are confined to shear zones in the tectonite peridotite unit of the Thetford Mines ophiolite complex. Their orientation is parallel to the thrust plane at the base of the complex. The granite, which is calc-alkaline and rich in potassium, does not belong to the ophiolite sequence. We show that it was tectonically incorporated within the partially serpentinized peridotite during thrusting and emplacement of the complex.During this process, the granite was strongly deformed and recrystallized at low pressure (500 bar (50 MPa)) and low temperature (500 °C or less), which gave rise to the mineral assemblage orthoclase, albite, hydromuscovite, and hydrothermal biotite. This episode was followed by a rodingite alteration, characterized by the formation of grossular, which was associated with the development of economic chrysotile within the enclosing peridotite. The K–Ar ages of biotite, muscovite, and feldspar from the granite cluster around 450 Ma. These cooling ages suggest that the emplacement and alteration of the granite and peridotite had ended by Late Ordovician time.
Profiles of modern prograding deltas
Authors: Matyas Elmer L.
Published: November 2010

Surface profiles of a tailings delta and several modern prograding river deltas are described by the equation y = axb, where x and y are horizontal and vertical distances, respectively, from the edge of the delta lip. This relationship is used to determine the slope of a profile at any specified point and to determine the location of the transition point between foreset and bottomset beds. A dimensionless equation of the form Y = XB is used to compare the shapes of different deltas; the exponent B has an average value of about 0.5 and 0.9 for lake and ocean deltas, respectively. The depth of the water in the receiving basin is a key factor that influences the shape of the foreset beds. The shape of the profile for foreset beds of lake deltas can be closely predicted by y = Kx0.533, where K is a coefficient that correlates with the maximum depth of water, ymax, in the lake near the delta front. For ocean deltas, where ymax is undefined, K must be correlated with some other reference parameter such as y1, which locates the toe of the foreset bed.
Kinematics of mylonites in the Priest River "metamorphic core complex," northern Idaho and northeastern Washington
Authors: Rhodes Brady P. , Hyndman Donald W.
Published: November 2010

Spokane dome, located in the southern Priest River complex, is defined by a zone of gently dipping mylonitic rocks about 4 km thick. In contrast to more "typical" core complexes, the mylonitic deformation gradually fades both above and below the zone without an intervening, nearly concordant zone of chloritic brecciation. Thin, younger, mylonitic rocks within the synformal Newport Fault Zone overlie Spokane dome to the north, and a younger, low-angle(?) fault cuts the mylonites in the Purcell Trench to the east.The mylonitic rocks within Spokane dome contain C and S surfaces and other mesoscopic structures indicating, in all cases, top to the east movement. In contrast, the mylonitic rocks within the Newport Fault Zone formed during normal movement on both the eastern and western limbs of the fault. The mylonites of Spokane dome probably formed during large-scale, Mesozoic, top to the east intracontinental shear, whereas the Newport Fault records Eocene extension and crustal "megaboudinage."