bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural characterization of a cell wall polysaccharide from Penicillium vermoesenii: chemotaxonomic application
Authors: Ahrazem Oussama , Gómez-Miranda Begoña , Prieto Alicia , Barasoaín Isabel , Bernabé Manuel , Leal J Antonio
Published: April 2011

The water-soluble polysaccharides (F1SS) obtained from the alkali extracts of the cell wall of two strains of Penicillium vermoesenii Biourge, Fusarium javanicum Koorders, Fusarium solani (Martius) Saccardo, and Fusarium oxysporum Schlechtendahl represented 8.7 to 10.7% of the dry cell wall material. All polysaccharides were composed of galactose (22.0-27.4%), glucose (18.4-30.3%), mannose (7.8-23.1%), and glucuronic acid (3.0-6.0%, except in F. oxysporum that contained 16.8%). Methylation analysis and 1H-NMR spectra of the polysaccharides of these fungi were similar except for F. oxysporum, which showed a higher peak of glucuronic acid than of glucose. The chemical and structural analyses performed indicated that F1SS polysaccharides of the species studied have a skeleton of beta-(1–>6) galactofuranose, fully substituted at positions O-2 by a single residue of glucopyranose or by short side chains containing one glucuronic acid residue and beta-mannopyranose. This polysaccharide is linked to a mannose core consisting of a short chain of alpha-(1–>6)-linked D-mannopyranose. Immunological methods confirm the structural relatedness among these polysaccharides. No similarities were found with the 1H-NMR spectra of F1SS polysaccharides from other species of Penicillium or Gliocladium. These results show that P. vermoesenii is closer to the genus Fusarium than to Penicillium or Gliocladium.Key words: Penicillium vermoesenii, cell wall polysaccharides, chemotaxonomy, NMR, polyclonal antibodies.
Ionic relations of Phillyrea latifolia L. plants during NaCl stress and relief from stress
Authors: Tattini Massimiliano , Gucci Riccardo
Published: April 2011

Two experiments were conducted on Phillyrea latifolia L. plants exposed to increasing NaCl concentrations at the root zone in hydroponic culture. Growth, ion fluxes within the plant, and rates of excretion by glandular trichomes were measured during both salinity stress and relief periods. The reduction in relative growth rate (RGR) of plants treated with 100 and 200 mM external NaCl was more marked when RGR was calculated on a fresh weight (FW) basis than on a dry weight (DW) basis. The RGR of previously salt-treated plants, expressed on a FW basis, did not differ from that of the controls over 5 weeks of relief from stress, whereas RGR calculated on a DW basis did not fully recover. Fluxes of Na+ and K+ appeared highly regulated. Sodium transport to the leaf of 100 mM salt-treated plants equalled that of the controls, whereas Na+ transport to the leaf was higher in 200 mM salt-treated plants. Selectivity ratio for K+ and Na+ transport to the leaf was increased by salt treatments. The exclusion ability for Cl- was markedly lower than that for Na+ at 300 and 400 mM external NaCl. The excretion of Na+ and Cl- by glandular trichomes was very low at all external NaCl concentrations and substantially higher in basal leaves than in apical leaves. These results indicate that in P. latifolia, mechanisms of salt tolerance operate by excluding sodium and maintaining high selectivity for uptake and transport of K+, whereas the excretion of toxic ions is of minor significance.Key words: chloride, excretion, growth, Phillyrea latifolia, potassium, sodium.
The Festuca violacea aggregate (Poaceae) in the Alps and Apennines (central southern Europe)
Authors: Foggi B , Rossi G , Signorini M A
Published: April 2011

The Festuca violacea aggregate in the Alps and Apennines was the subject of full morphological, biosystematic, chorological, and ecological investigations carried out on herbarium specimens, living plants under cultivation, and wild populations. In the two mountain ranges, seven taxa were found to occur in the summit area: Festuca violacea Gaudin ssp. violacea, Festuca violacea ssp. puccinellii (Parl.) Foggi, Graz. Rossi et Signorini, Festuca violacea ssp. italica Foggi, Graz. Rossi et Signorini, Festuca melanopsis Foggi, Graz. Rossi et Signorini, Festuca norica (Hack.) K. Richt., Festuca picturata Pils, and Festuca nitida Schultes ssp. nitida. Synonyms, descriptions, original iconography, karyological data (new data for F. violacea ssp. puccinellii), distribution, and ecology were gathered for each taxon, together with original identification keys. The possible origin and diffusion of the different entities are discussed. Special attention was given to F. melanopsis and to the three subspecies of F. violacea, for which morphometric multivariate analyses (cluster analysis and discriminant analysis) were performed. A new taxonomic treatment of the aggregate is proposed.Key words: Festuca, Poaceae, Europe, morphometric analyses, systematics.
Belowground traits of herbaceous species in young coniferous forests of the Olympic Peninsula, Washington
Authors: Lezberg Ann L , Antos Joseph A , Halpern Charles B
Published: April 2011

Variation in belowground traits of herbaceous species may influence their ability to persist and spread during and after the closed-canopy period of forest development. In 40- to 60-year-old closed-canopy, coniferous forests of the Olympic Peninsula, Washington, we excavated root and rhizome systems of 11 herbaceous species to compare morphology, vegetative spread, and proportion of biomass in belowground structures. All species were perennial and most were rhizomatous; four species were nonclonal. Of the seven clonal species, only two (Maianthemum dilatatum and Oxalis oregana) spread extensively (mean lateral spread >50 cm) by belowground perennating structures. The proportion of total biomass in belowground structures varied considerably among species (21-85%) and was higher for deciduous than for evergreen species. High variability in belowground traits suggests that multiple strategies may contribute to survival during closed-canopy conditions. For species with a high proportion of belowground biomass, we suggest that the ability to store resources or to acquire new resources through lateral spread may contribute to persistence in dense coniferous forests.Key words: biomass allocation, canopy closure, forest understory plants, rhizomes, root systems, succession.
Do mitochondria provide the oxygen diffusion barrier in root nodules of Coriaria and Datisca?
Authors: Silvester Warwick B , Langenstein Birgit , Berg R Howard
Published: April 2011

Root nodules of Coriaria Lindsay and Datisca Baill. display a unique anatomy in which the symbiotic vesicles radiate inwards towards a central vacuole. Use of the confocal microscope and the redox dye cyano-tetrazolium chloride demonstrates that the vesicles are the sites of reducing potential and that there is a sharp cut-off in reducing potential at the base of the vesicles. The use of the lipophylic cationic dye rhodamine 123 revealed a continuous blanket of mitochondria in this zone. This was verified by transmission electron microscope views of nodule cells. Further studies reveal that the mitochondrial layer also forms a discontinuous layer around the intercellular air spaces. The nodules of plants grown with root systems at 5 and 40 kPa O2 did not show any differences in the thickness of the mitochondrial layer. Microtubules are also radially arranged in these cells and mitochondria are likely to reach their position by moving along this radial framework.Key words: actinorhiza, mitochondria, nitrogen fixation, nitrogenase, nodule, oxygen protection.
Genetic characterization of MexicanFrankiastrains nodulatingCasuarina equisetifolia
Authors: Pérez Néstor-Octavio , Olivera Hiram , Vásquez Luis , Valdés María
Published: April 2011

There is a need to increase the utilization of the Casuarina equisetifolia J.R. Forst. & G. Forst. - Frankia symbiosis and be sure of its effectiveness in Mexico. This may be facilitated by selecting appropriate bacterial strains for which ecological characteristics are known. We tested various typing methods to develop genetic markers for ecological studies. DNA, extracted from clonal cultures of native strains or from reference cultures of Casuarina-infective Frankia strains, was used as the template in polymerase chain reactions (PCR) with primers targeting different DNA regions. nifH and 16S rDNA probes from the reference strain Frankia Br were utilized to authenticate the isolates. Polymorphisms of the restricted fragments of the intergenetic spacer between the 16S-23S rDNAs were analyzed. Repetitive extragenic palindromic sequences (rep-PCR) (BOXA1R primer) were used to generate genomic fingerprints. All studied strains showed two copies of the ribosomal operon and a single copy of the nifH gene. PCR - restriction fragment length polymorphism patterns of the 16S-23S intergenetic spacer (IGS) were similar for all Frankia isolates; however, the rep-PCR technique was sensitive enough to distinguish between some of these Frankia strains. The Mexican cultured strains of Frankia nodulating C. equisetifolia appeared to be closely related to the isolated and nodular Frankia from trees growing outside Australia.Key words: Frankia, Casuarina, 16S rRNA, 16S-23S IGS, nifH, repetitive sequence polymerase chain reaction.
Multiple ribosomal RNA gene loci in the genome of the homosporous fernCeratopteris richardii
Authors: McGrath J Mitchell , Hickok Leslie G
Published: April 2011

The genomes of homosporous ferns are largely uncharacterized, but they appear to differ from gymnosperms and angiosperms in key aspects, such as high chromosome numbers at the diploid level, and thus provide a unique perspective on plant genome structure and evolution. Using the model homosporous fern Ceratopteris richardii, loci encoding ribosomal RNA sequences (rDNA genes) were detected using fluorescent in situ hybridization. At least two major rDNA loci were visible in all cases, and six or more weakly hybridizing signals were observed in most cytological preparations. These results are consistent with models of homosporous fern evolution via cycles of polyploidy followed by gene silencing. They are also consistent with other models of fern genome evolution. With the exception of the weakly hybridizing signals, these data are similar to analogous reports of one or two major rDNA loci in diploid angiosperms. These results suggest that the gross morphology of rDNA loci are similar between diploid homosporous ferns and angiosperms, but that important clues to rDNA gene and chromosome evolution in homosporous ferns may reside in the analysis of their minor rDNA sequences.Key words: rDNA, in situ hybridization, homosporous ferns, evolution, gene silencing, polyploidy.
The nitrate-tolerant symbiosis of Glycine max (L.) Merr. nts382 and Bradyrhizobium japonicum is also tolerant of ammonium
Authors: Vessey J Kevin , Luit Bert
Published: April 2011

Previously, we have shown that the Glycine max (L.) Merr. -Bradyrhizobium japonicum symbiosis is very sensitive to inhibition by NH4+. The current study addresses whether the supernodulating soybean mutant, nts382, which is known to be tolerant of NO3-, is also tolerant of NH4+. The nts382 mutant and its wild-type parent, Bragg, were grown in continuous-flow hydroponic culture in the presence of 0, 0.25, 0.5, or 1.0 mM 15N-enriched NH4+. Plants were harvested at 14, 21, and 28 days after inoculation. Both cultivars had the highest dry weight (DW) at each harvest date when grown on 0.25 mM NH4+. At 0.25 mM NH4+, whole plant DW increased by 5.3- and 3.2-fold in Bragg and nts382, respectively, compared with the 0.0 mM NH4+ control by the end of the experiment. As expected, whole-plant nodulation (nodules per plant), DW-specific nodulation (nodules per gram root dry weight), and nodule DW were severely inhibited in Bragg at all levels of NH4+. However, in nts382, whole-plant nodulation was not affected by NH4+ treatment, and nodule DW increased by as much as fivefold. Whereas DW-specific nodulation decreased by 94% in Bragg, this parameter decreased by only 52% in the nts382 mutant. Likewise, while the nitrogen derived from the atmosphere decreased by approximately 40% in NH4+-supplied Bragg, it increased 2.8-fold at 0.25 and 0.5 mM NH4+ in nts382. This study demonstrates that both nodulation and N2 fixation in nts382 are more tolerant of NH4+ than in the wild-type Bragg.
A comparison of ectomycorrhiza communities from three conifer species planted on forest gap edges
Authors: Kranabetter J M , Hayden S , Wright E F
Published: April 2011

We examined the ectomycorrhiza communities on lodgepole pine (Pinus contorta var. latifolia Engelm), white spruce (Picea glauca (Moench) Voss), and subalpine fir (Abies lasiocarpa (Hook.) Nutt) seedlings planted together on mature-forest edges in northwestern British Columbia. We examined 32 seedlings of each tree species, grouped by pairs along the north and south edges of eight gaps. We found 74 morphotypes in total, with an average of 52 morphotypes per tree species. Morphotypes with emanating hyphae or strands made up 60% of the overall ectomycorrhiza community. Multihost fungi averaged almost 60% of total morphotypes in species comparisons, although some of the multihost fungi appeared to have tree host preferences. The average community similarity, based on morphotype abundance, was 52% between conifer species, and 37% for morphotypes with emanating hyphae or strands. Within planted groups, between seedlings 1-2 m apart, community similarity ranged from 2 to 40% for morphotypes with emanating hyphae or strands. In mature, mixed forests, the infrequent occurrence of many multihost ectomycorrhizae created a wide range in the probability of hyphal linkages between neighboring seedlings.Key words: ectomycorrhizae, community similarity, multiple host, host specificity, Pinus contorta, Picea glauca, Abies lasiocarpa
Effect of weather factors on the release of ascospores of Uncinula necator, the cause of grape powdery mildew, in the Bordeaux region
Authors: Jailloux F , Willocquet L , Chapuis L , Froidefond G
Published: April 2011

During a 5-year period (1993-1997), the release of Uncinula necator (Schweiniz) Burrill ascospores was monitored under natural conditions in the Bordeaux region. Ascospore release always began after bud burst and generally ended before blossoming. The release periods of ascospores were always associated with a rainfall higher than 2 mm, a wetting duration greater than 2.5 h, an average temperature generally above 11°C and a daily mean temperature sum from November 1 to the first ascospore release above 1100°C. There was no relation between earliness, number of ascospores released, and disease severity on grapes (Vitis vinifera L. cv. Merlot). The primary infection did not appear to be important for the increase of the powdery mildew population; on the other hand, the weather conditions of April (rainfall and temperature) seemed to strongly influence disease severity on berries by enabling good growth of the pathogen on leaves. These findings could be used to determine the optimal dates of the first fungicide treatments for powdery mildew according to the weather conditions.Key words: cleistothecia, ascospores, release, weather conditions, powdery mildew, Uncinula necator, grapevine.
Entry and colonization of Asparagus officinalis roots by arbuscular mycorrhizal fungi with emphasis on changes in host microtubules
Authors: Matsubara Yoh-ichi , Uetake Yukari , Peterson R. Larry
Published: April 2011

First-order lateral roots of Asparagus officinalis L. have a dimorphic exodermis consisting of short and long cells. Short cells have a thickened outer tangential wall, retain their cytoplasm, appear to have high levels of Ca2+, and undergo suberization later than contiguous long cells. In regions of the root in which the dimorphic nature of the exodermis is clearly evident, short cells have numerous cortical microtubules arranged predominantly in the transverse plane in reference to the long axis of the root. Arbuscular mycorrhizal fungi (either indigenous unidentified species in field-grown plants or Glomus intraradices Schenck & Smith in colonized plants in a growth chamber) form appressoria on epidermal cells located above exodermal short cells and infection hyphae then penetrate the outer tangential wall of short cells. A hyphal coil forms in short cells, and microtubules become closely associated with the coil; some cortical microtubules are retained in colonized short cells. A typical Arum type of arbuscular mycorrhizal association forms in the cortex, and concomitant with this, a rearrangement of microtubules occurs. During arbuscule formation, microtubules are associated with the large trunk hypha and with the fine arbuscule branches; cortical microtubules, although reduced in number, are present. As the arbuscule degenerates, a few microtubules are still associated with the hyphal clump and many cortical microtubules, oriented primarily in a transverse plane, are present. This study shows that arbuscular mycorrhizal fungi interact closely with the microtubular component of the cytoskeleton from the earliest stages of entry through arbuscule degeneration. These results support the concept that biotrophic fungal species have evolved intimate associations with plant cells.Key words: asparagus, roots, mycorrhizas, exodermis, microtubules.
Variation in the mitochondrial DNA of the potential biological control agent Chondrostereum purpureum
Authors: Ramsfield Tod D , Shamoun Simon F , Punja Zamir K , Hintz William E
Published: April 2011

The mitochondrial DNA (mtDNA) of Chondrostereum purpureum (Pers.:Fr.) Pouzar was extracted and purified, and the size ranged from 51.8 to 66.4 kb. One isolate each from British Columbia, Alberta, Finland, the Netherlands, and New Zealand were found to have identical BamHI mtDNA restriction patterns, resulting in a mitochondrial genome of 63.8 kb. An additional isolate from British Columbia and one from Switzerland had different banding patterns, however, resulting in mitochondrial genomes of 66.4 kb and 51.8 kb, respectively. A sequence-characterized amplified region (SCAR) assay, based on a polymerase chain reaction, was developed to rapidly screen a larger population of 84 isolates from North America, Europe, and New Zealand. Two SCARs, one encoding the NADH 4 gene (3 kb) and the second encoding the ATPase VI and cytochrome b genes (5.1 kb), were digested with 24 restriction enzymes. There were no polymorphisms in the NADH 4 containing SCAR, while a single polymorphism was detected by NsiI in the ATPase VI - cytochrome b containing SCAR. Two mitochondrial haplotypes that were distributed throughout the sample population were thus identified. The coancestry coefficient (<$Q7A0D00000010446D80BFFEFF88A524F5343905055B98C420120907B4DDA9ECB1F0>) for all subpopulations of the sample population was calculated to be 0.0353. The level of gene diversity in the mtDNA ofC. purpureum suggested that the chance introduction of novel mitochondrial genes following biological control applications of the fungus is relatively low.
Fungal screening for biological removal of extractives fromEucalyptus globuluswood
Authors: Martínez María Jesús , Barrasa José María , Gutiérrez Ana , Carlos del Río José , Martínez Angel T
Published: April 2011

Wood extractives cause production troubles during pulp and paper manufacture. The potentiality of fungal strains for biotechnological removal of extractives from Eucalyptus globulus Labill. wood is evaluated here. First, a survey of fungi present in eucalypt woodlands in western Spain was carried out, and 90 species, including fungi strictly associated with eucalypt trees, were collected. Then, a total of 33 basidiomycetes, 21 ascomycetes, and 19 conidial fungi (including some strains from culture collections) were compared in terms of their capacity to decrease the acetone extract of eucalypt wood. High extractive removal (50-70% of initial content) was obtained with Ophiostoma, Mollisia, and Pleurotus species, as well as with Funalia trogii (Berk. in Trog) Bond. & Singer, Melanotus hepatochrous (Berk.) Singer, and Paecilomyces sp. Microscopic observation of the degraded wood revealed a correlation between extractive degradation and removal of spherical deposits in wood rays. Moreover, when extractive biodegradation was analyzed by gas chromatography - mass spectrometry it was found that some of the basidiomycetes were able to remove both free and esterified sitosterol (75-100% degradation by Poria subvermispora Pilát, Phlebia radiata Fr., F. trogii, and Bjerkandera adusta (Willd.) P. Karsten), which has been identified as a major constituent of pitch deposits in eucalypt pulps, whereas the action of ascomycetes was mainly limited to hydrolysis of the sitosterol esters.
Sex expression in the clonal gynodioecious herbGlechoma hederacea(Lamiaceae)
Authors: Widén Marie , Widén Björn
Published: April 2011

The frequency of sex morphs of the clonal plant, Glechoma hederacea L., was recorded at ramet, clone, and population levels in the province of Skåne, South Sweden. In a random sample of 748 ramets at 31 sites, 68% of the ramets possessed only hermaphrodite flowers, 22% possessed only female flowers, and 10% were partially male sterile with both hermaphrodite and female flowers. At one-third of the sites, only one sex morph was found (mostly hermaphrodites). At the other sites, the proportion of female ramets and partially male-sterile ramets ranged from 3 to 100%. Multilocus genotypes were established using isozyme electrophoresis to study sex expression (stamen fertility) at different levels (among flowers within ramets, among ramets within genets, and among genets) in the field and for transplants raised under uniform greenhouse conditions. Sex expression was found to be genotype specific. Some genets were stable females or stable hermaphrodites, others being partially male sterile with a specific level of stamen fertility both in the field and in cultivation. Some multilocus genotypes showed great variation in stamen fertility among plots both in the field and in cultivation, indicating that sex expression in these genets was greatly influenced by environmental conditions. Stamen fertility varied temporally and spatially in ramets of the partially male-sterile sex types. Flower size was positively correlated with stamen fertility.
Vegetation patterns around Eriophorum vaginatum L. tussocks in a cut-away peatland in southern Finland
Authors: Tuittila Eeva-Stiina , Rita Hannu , Vasander Harri , Laine Jukka
Published: April 2011

We studied the vegetation patterns around cottongrass tussocks with varying characteristics in a cut-away peatland 20 years after abandonment. When the effect of water table level variation was eliminated, the remaining variation in vegetation was related to (i) tussock characteristics and (ii) distance and orientation from a particular tussock. Logit regression showed a positive interaction between distance from the base of a tussock and a tussock's sheltering properties for all the studied plant species, indicating that the smaller the tussock the nearer plants have to be to find a favourable microsite. A southerly direction, which is the most exposed to solar irradiation, was the most inhospitable microsite. Our results indicated that cottongrass tussocks may offer a variety of microsites for colonizers with varying ecological requirements.Key words: cut-away peatland, colonization, Eriophorum vaginatum, facilitation, logit models, ordination.
Relations entre longueur des pétioles et longueur des entre-noeuds chez Manihot esculenta Crantz clones Pétiolules : la formation d'entre-noeuds courts est liée à l'accélération de la surrection foliaire
Authors: Médard Roger
Published: April 2011

Deux clones de manioc, le clone Pétiolule Madagascar et le clone Pétiolule Congo présentent des feuilles dont la longueur du pétiole varie très fortement. Cette longueur est, chez ces clones, un marqueur de la vitesse de surrection du premier primordium foliaire. Chez ces deux clones, particulièrement chez le 'Pétiolule Madagascar', on observe la formation régulière d'entre-noeuds courts, insérés entre une feuille à pétiole court située au-dessous, et une feuille à pétiole long située au-dessus. Un raccourcissement temporaire de la longueur de l'entre-noeud est donc lié à une accélération de la surrection foliaire. Ce raccourcissement est déterminé lors de la première phase de l'élaboration de l'entre-noeud, qui s'effectue à la base du méristème apical, juste au-dessus du premier primordium. Il traduit une modification du fonctionnement de cette seule zone basale du méristème apical. La relation existant entre entre-noeud court et allongement du pétiole apporte quelques précisions sur les caractéristiques de la première phase de formation de l'entre-noeud, une phase particulièrement mal connue.Mots clés : manioc, entre-noeud, feuille, apex de tige, croissance.
Comparative reproductive biology of the six species of Rhododendron (Ericaceae) in Hong Kong, South China
Authors: Ng Sai-chit , Corlett Richard T
Published: April 2011

Six rhododendron species grow wild in Hong Kong: Rhododendron farrerae Tate and Rhododendron simsii Planch. are common and widespread, Rhododendron moulmainense Hook. f. is restricted, and Rhododendron championiae Hook. f., Rhododendron hongkongense Hutch., and Rhododendron simiarum Hance are rare. The length and timing of the flowering period varied between species, but peak flowering for all was between late February and early May, when weather is variable and unpredictable. All species were more or less self-sterile, had sucrose-dominated nectar, and were visited by diverse insects, of which Apis cerana, Bombus eximius, and Xylocopa spp. are the major pollinators. Seeds of all species, except R. simiarum, had a light requirement for germination. There were large differences between species in the pollen/ovule ratio (176-1343), daily nectar production (0.9-38.7 µL per flower), large bee visits (0.35-4.28 per flower per 100 h) and total visits (0.92-14.53), mean seed production per flower (2-135) and per plant (100 - 14 800), and mean seed weight (0.11-0.45 mg). The large-bee visitation rate was significantly correlated across species with mean daily nectar production and mean seed set. The two common species had the smallest flowers, lowest nectar production, lowest pollen/ovule ratios, fewest large bee visitors, and produced fewest seeds.Key words: breeding system, China, pollination, rarity, Rhododendron, seeds.
Introduction to Special Issue 2 on the NATMAP Shield Margin Project: The Flin Flon Belt, Trans-Hudson Orogen, Manitoba and Saskatchewan
Authors: Lucas S B , Syme E C , Ashton K E
Published: April 2011

The Shield Margin Project of the National Geoscience Mapping Program (NATMAP) resulted in a new understanding of the Paleoproterozoic Flin Flon Belt (Manitoba and Saskatchewan) in four dimensions. A multidisciplinary approach was utilized in the NATMAP project, based on partnerships with government, university, and private sector geoscientists, and close cooperation with the Lithoprobe's Trans-Hudson Orogen Transect. Research areas spanned from bedrock and surficial geoscience, to crustal and mantle geophysics, to high precision U-Pb geochronology and tracer isotope studies. This Special Issue contains nine papers covering a wide variety of topics related to the NATMAP Shield Margin Project, including volcanic-hosted massive sulphide deposits in the Flin Flon and Snow Lake camps; structural geology of the Flin Flon townsite and southern flank of the Kisseynew Domain; geochronology and the U-Pb systematics of monazite in metasedimentary rocks; and the geoelectrical and crustal conductivity structure of the Flin Flon Belt.
40Ar/39Ar and Pb-Pb study of individual hornblende and feldspar grains from southeastern Baffin Island glacial sediments: implications for the provenance of the Heinrich layers
Authors: Hemming S R , Gwiazda R H , Andrews J T , Broecker W S , Jennings A E , Onstott T C
Published: April 2011

Lead isotope analysis of individual feldspar grains and 40Ar/39Ar analysis of individual hornblende grains from three samples taken from Baffin Island ice-proximal till deposits are consistent with a provenance recording a two-stage geologic history including formation of continental crust in the Late Archean and partial isotopic resetting and (or) reequilibration during major Paleoproterozoic regional metamorphism and magmatism. Significantly, although the populations are small, and the two-stage Archean-Paleoproterozoic history of their sources are similar, the Pb isotope compositions of samples from Baffin Island do not match the results from Heinrich layer H2 in core HU87-033-009 from northeast of the Hudson Strait in the Labrador Sea. Specifically, in H2 samples from HU87-033-009, the 207Pb/204Pb is high for a given value of 206Pb/204Pb. Additionally, the range in 206Pb/204Pb is greater in HU87-033-009 samples, and there are two distinct trajectories of 208Pb/204Pb. The steeper of the 208Pb/204Pb versus 206Pb/204Pb trends is not seen in the studied Baffin Island glacial sediment samples. Samples of feldspar grains from Heinrich layers H1, H2, H4, and H5 from core V28-82 in the eastern North Atlantic have a 207Pb/204Pb versus 206Pb/204Pb relation similar to that of Baffin Island till samples, but there is also a high 208Pb/204Pb that we have not captured in this suite of glacial sediment samples. Our results highlight the strength of a combined radiogenic isotope approach to characterizing the geological history of sediment sources and provide a first step in assessing the variability in isotope character in this region of dynamic glacial events during the late Quaternary Period.
Kanairiktok shear zone: the boundary between the Paleoproterozoic Makkovik Province and the Archean Nain Province, Labrador, Canada.
Authors: Culshaw N , Brown T , Reynolds P H , Ketchum J WF
Published: April 2011

The polyphase Kanairiktok shear zone (KNSZ) separates gneissic rocks of the Archean Nain craton from their reworked equivalents in the Paleoproterozoic Kaipokok domain of the Makkovik Province. In its early stages, the KNSZ bounded the Kaipokok domain as it was thermally softened by 1895-1870 Ma Andean-type magmatism, accompanied by dextral oblique convergence and resultant penetrative deformation. The amphibolite-facies tectonite that developed in this stage was widely overprinted by greenschist-facies mylonite. Laserprobe and spectral 40Ar/39Ar ages of recrystallized and porphyroclastic muscovite, from the greenschist-facies mylonite and from muscovite in a syntectonic quartz vein, bracket the age of deformation between 1740 and 1710 Ma with the best estimate at 1715 Ma. These ages are similar to those of A-type granites within the Makkovik Province and amphibole cooling ages from the province interior. Together with the petrological similarity of the greenschist-facies mylonite to localized low-grade shear zones elsewhere in the Makkovik Province, they are suggestive of a widespread, lithosphere-scale event. The 40Ar/39Ar data do not provide good constraints on the early activity of the KNSZ. However, preservation of relationships between granitoid sheets correlated with the 1895-1870 Ma Island Harbour Bay plutonic suite and early fabrics imply that the granites were emplaced syntectonically in the KNSZ. Thus, the KNSZ was a major, long-lived structure in the Makkovik Province that decoupled events in the reactivated Nain craton from an inert cratonic region.
Mesoproterozoic graphite deposits, New Jersey Highlands: geologic and stable isotopic evidence for possible algal origins
Authors: Volkert Richard A , Johnson Craig A , Tamashausky Albert V
Published: April 2011

Graphite deposits of Mesoproterozoic age are locally abundant in the eastern New Jersey Highlands, where they are hosted by sulphidic biotitequartzfeldspar gneiss, metaquartzite, and anatectic pegmatite. Gneiss and metaquartzite represent a shallow marine shelf sequence of locally organic-rich sand and mud. Graphite from massive deposits within metaquartzite yielded δ13C values of 26 ± 2 (1σ), and graphite from massive deposits within biotite-quartz-feldspar gneiss yielded δ13C values of 23 ± 4. Disseminated graphite from biotitequartzfeldspar gneiss country rock was 22 ± 3, indistinguishable from the massive deposits hosted by the same lithology. Anatectic pegmatite is graphitic only where generated from graphite-bearing host rocks; one sample gave a δ13C value of 15. The δ34S values of trace pyrrhotite are uniform within individual deposits, but vary from 0 to 9 from one deposit to another. Apart from pegmatitic occurrences, evidence is lacking for long-range mobilization of carbon during Grenvillian orogenesis or post-Grenvillian tectonism. The field, petrographic, and isotope data suggest that massive graphite was formed by granulite-facies metamorphism of Proterozoic accumulations of sedimentary organic matter, possibly algal mats. Preservation of these accumulations in the sedimentary environment requires anoxic basin waters or rapid burial. Anoxia would also favour the accumulation of dissolved ferrous iron in basin waters, which may explain some of the metasediment-hosted massive magnetite deposits in the New Jersey Highlands.
A reconstruction of Moorhead and Emerson Phase environments along the eastern margin of glacial Lake Agassiz, Rainy River basin, northwestern Ontario
Authors: Bajc A F , Schwert D P , Warner B G , Williams N E
Published: April 2011

Mapping of Quaternary geology in the Rainy River lowland, northwestern Ontario resulted in discovery of several fossil-bearing localities. Organic remains are associated with both the Moorhead and Emerson phases of glacial Lake Agassiz. Wood samples recovered from Moorhead Phase deposits have radiocarbon ages ranging between 10.8 and 9.9 ka BP. The wood is detrital and cannot be used to date the beginning of the low-water phase. Nearshore, deltaic, alluvial, peatland, open-water wetland, and upland soil environments are represented in the Moorhead Phase sediment records. Emerson Phase transgressive deposits overlie Moorhead Phase sediments and erosional surfaces. Wood samples recovered from flotsam layers in Emerson Phase nearshore deposits have yielded radiocarbon ages ranging between 10.5 and 9.5 ka BP. Stratigraphic and sedimentologic evidence suggests that the transgression began approximately 9.9 ka BP. Pollen, plant macrofossil, insect, and mollusc assemblages have been affected by long-distance transport, sorting, and reworking by fluvial and nearshore processes. They represent a wide spectrum of terrestrial and aquatic habitats indiscriminantly brought together during high-water periods. The Moorhead and Emerson phase assemblages indicate conditions similar to those in the region today, but there is a distinct component whose modern range is much farther north and west of the study region. In this respect, the assemblages are similar to the mixed communities described from other late-glacial sites of the mid-continent.
Minette bodies and cognate mica-clinopyroxenite xenoliths from the Milk River area, southern Alberta: records of a complex history of the northernmost part of the Archean Wyoming craton
Authors: Buhlmann Arndt L , Cavell Patricia , Burwash Ronald A , Creaser Robert A , Luth Robert W
Published: April 2011

Minettes exposed in southern Alberta near the Milk River are the northern outliers of the Eocene Sweet Grass Hills igneous complex of the Montana alkalic igneous province. These minettes often contain coarse-grained xenoliths of phlogopite + clinopyroxene ± apatite. The parent magmas of the minettes were generated at pressures [Formula: see text]17 kbar in equilibrium with clinopyroxene + phlogopite ± olivine. Fractional crystallization and mixing provided a spectrum of evolved minettes and cumulates, the latter of which were sampled by subsequent minette magmas as xenoliths. Two xenoliths were dated at 49.0 ± 0.8 Ma and 52 ± 1.7 Ma. The host dyke of the latter xenolith gave an age of 50 ± 0.3 Ma. The minettes and their xenoliths have overlapping values of 87Sr/86Sri, εNdT, 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb, similar to those of alkaline igneous rocks from farther south in the Montana alkalic igneous province. The Sweet Grass Hills lie north of the Great Falls Tectonic Zone, previously interpreted as a Proterozoic suture zone separating the Archean Medicine Hat block from the Archean Wyoming craton to the south. Geochemical data for the Milk River minettes provide evidence for a history of the mantle underneath the Medicine Hat block, similar to that found previously for mantle-derived rocks of the Wyoming craton, including a significant Proterozoic mantle enrichment event. Given this similarity, we suggest that the Wyoming craton extends into southern Alberta, and that the Great Falls Tectonic Zone does not represent a Proterozoic suture of two Archean blocks.
Seismic imaging of the upper mantle beneath the Rocky Mountain foreland, southwestern Alberta
Authors: Eaton David W , Ross Gerald M , Cook Frederick A , VanderVelden A
Published: April 2011

The Vibroseis Augmented Listen Time (VAuLT) experiment is a special seismic-reflection survey designed to image the fine-scale structure of the continental upper mantle of the Rocky Mountain foreland in southwestern Alberta to depths of 200 km or more. Two mutually perpendicular profiles were acquired across and within the Vulcan structure, a roughly east-west-trending tectonic belt in the crystalline basement beneath the Western Canada Sedimentary Basin that separates the Medicine Hat block from the Loverna block. Relative-amplitude-preserving processing procedures were developed to estimate the seismic-signal-penetration limit, which varies between 100 and 220 km depth. Amplitude-decay analysis and Q estimation show that a seismically unreflective zone within the Vulcan structure is not caused by inadequate signal penetration. This blank zone is interpreted as part of an intrusive complex that has overprinted the preexisting structural fabric. Unlike most other parts of Alberta, the reflection Moho is indistinct and the uppermost mantle (4560 km depth) is reflective, particularly for sourcereceiver offsets >10 km. South-dipping reflectivity in the lower crust and upper mantle beneath the Loverna block and northern Vulcan structure gives way to subhorizontal reflectivity beneath the Medicine Hat block. We interpret this reflectivity as compositional layering and (or) zones of ductile deformation that were previously part of the mafic lower crust, but that have now undergone metamorphic transformation to eclogite. The deepest observed reflection is an isolated, gently north-dipping event at ~120 km depth.
Newly identified Carboniferous units (the Pointe Sawyer and Chemin-des-Pêcheurs formations) in the Gaspé Peninsula, Quebec; implications regarding the evolution of the northwestern sector of the Maritimes Basin
Authors: Jutras Pierre , Prichonnet Gilbert , Utting John
Published: April 2011

The Upper Member of the Cannes-de-Roches Formation was recently recognized overlying the Bonaventure Formation in the New Carlisle area, over 100 km southwest of the previously documented exposures of this unit. Moreover, remnants of the La Coulée Formation, which are unconformably overlain by the Bonaventure Formation, have also been recognized underlying, with a similar type of contact, the Lower Member of the Cannes-de-Roches Formation. From this and from facies similarities, the Lower and Middle members of the Cannes-de-Roches Formation are now considered to be equivalent to the Bonaventure Formation. It is proposed to abandon these two member designations and to only keep the Bonaventure Formation. The remaining Upper Member of the Cannes-de-Roches Formation is renamed the Pointe Sawyer Formation. A late Viséan to early Namurian age is attributed to this grey clastic formation from spore analysis. Dark reddish-brown sandstone conformably overlie the Pointe Sawyer Formation in the Mal Bay area. They correspond to the beginning of sedimentation from more distant sources within the regional Carboniferous stratigraphic succession, which was until then characterized by sedimentation from proximal sources. This previously unidentified unit is here referred to as the Chemin-des-Pêcheurs Formation.
The conglomerate of Churn Creek: Late Cretaceous basin evolution along the InsularIntermontane superterrane boundary, southern British Columbia
Authors: Riesterer J W , Mahoney J Brian , Link Paul Karl
Published: April 2011

Upper Cretaceous coarse clastic rocks exposed in the canyon of Churn Creek, south-central British Columbia, record active basin tectonism and coeval volcanism adjacent to the boundary between the Intermontane and Insular superterranes. Mid to late Albian (~104 Ma UPb), calc-alkaline andesite and basaltic andesite flows, with minor conglomerate and reworked epiclastic deposits and tuffs correlative with the Spences Bridge Group of the Intermontane superterrane are exposed in the canyon. In depositional contact above the volcanic rocks is the conglomerate of Churn Creek, which contains a thick (>1 km) sequence of complexly intertonguing conglomerate and sandstone that is divided into two members composed of four lithofacies. The lower member was deposited unconformably on the underlying Albian volcanic unit and contains late AlbianCenomanian chert-pebble (>50% chert) conglomerate and interbedded chert- and volcanic-lithic sandstone. It is interpreted to have been deposited in a braided stream system flowing from southeast to northwest. The source for the chert was most likely the Bridge River terrane, a Mississippian to Jurassic ocean floor assemblage located to the southwest of Churn Creek, south of the Yalakom fault. Gradationally overlying the lower member throughout much of the basin is a mixed chert, plutonic, and volcaniclastic lithofacies of the upper member. Plutonic debris was provided to the mixed and plutonic lithofacies of the upper member by the Little Basin pluton, which was uplifted along the northeast-directed Little Basin thrust fault on the southwest margin of the basin. The upper member also contains a volcanic-rich lithofacies composed of chaotic volcanic conglomerate and local lithic tuff derived from a coeval proximal volcanic source. The conglomerate of Churn Creek records active northeast-vergent compressional tectonism and development of piggyback basins along the boundary between the Insular and Intermontane superterranes during AlbianSantonian time. The conglomerate of Churn Creek has been correlated to the Silverquick  Powell Creek succession of the Methow terrane, based on age, stratigraphic, lithologic, structural, geochemical, and paleomagnetic similarities, and may, therefore, represent an overlap assemblage linking the superterranes in the Late Cretaceous.
Age, chemo- and biostratigraphy of Haiti spherule-rich deposits: a multi-event KT scenario
Authors: Keller Gerta , Adatte Thierry , Stinnesbeck Wolfgang , Stüben Doris , Berner Zsolt
Published: April 2011

Examination of two new expanded KT transitions and reexamination of road outcrops near Beloc, Haiti, reveals that deposition of the glass spherule-rich deposit (SRD) occurred within the early Danian Parvularugoglobigerina eugubina (Pla(1)) Zone, followed by an Ir anomaly, and 50 cm above it, a second Pd-dominated platinum group element (PGE) anomaly. The KT boundary is at an erosional unconformity between the base of the SRD and underlying Maastrichtian limestone, where an interval representing about 100250 thousand years appears to be missing (juxtaposition of planktic foraminiferal zones (Pla(1)) and Plummerita hantkeninoides (CF1)). It is possible that the spherule layers are reworked from original deposits at or below the KT boundary. The Ir anomaly is of roughly chondritic-type and compatible with an impact event, whereas the Pd-dominated PGE anomaly is a more basalt-type and compatible with a magmatic origin. This suggests a multi-event scenario consistent with one impact followed by a major volcanic event in the Caribbean or elsewhere.
Oxygen isotope systematics of the Precambrian basement of Alberta: implications for Paleoproterozoic and Phanerozoic tectonics in northwestern Alberta
Authors: Burwash Ronald A , Chacko Thomas , Muehlenbachs Karlis , Bouzidi Youcef
Published: April 2011

We have conducted a regional survey of the oxygen isotope compositions of drill core samples from the Precambrian basement of the Alberta sedimentary basin. The majority of samples have whole-rock δ18O (SMOW) values between +7 and +11, as is typical of crustal rocks. However, there are also a significant number of samples with δ18O values less than +5. In these samples, high-grade minerals such as pyroxene, amphibole, and biotite commonly show retrograde alteration to chlorite and (or) epidote. The majority of low-δ18O samples are from a 250 x 50 km zone in northwestern Alberta, which we refer to as the Kimiwan isotope anomaly. The anomaly is significant in that the most reasonable explanation for generating such a laterally extensive zone of rocks, with δ18O values below +5, is through high-temperature interaction with surface-derived fluids in an extensional tectonic setting. We propose, therefore, that the low-δ18O samples define a hitherto unrecognized extensional zone in the Alberta basement. Available geochronological data indicate that fluid-rock interaction and associated 18O depletion occurred at ca. 1800 Ma. Oxygen and hydrogen isotope data on mineral separates from this zone indicate that the surface fluids responsible for 18O depletion were of meteoric origin. Seismic reflection profiles acquired during the Lithoprobe Alberta Basement Transect reveal the presence of basement faults spatially associated with the zone of 18O depletion. We propose that these faults were extensional in nature at ca. 1800 Ma. Periodic reactivation of these basement structures during the Phanerozoic played an important role in the development of faults in the overlying sedimentary basin.
Introduction to special issue of Canadian Journal of Earth Sciences: The Alberta Basement Transect of Lithoprobe
Authors: Ross Gerald M
Published: April 2011

From outcrops in northeastern Alberta to exposures within structural culminations in the Canadian Cordillera, the crystalline basement that lies buried beneath the Phanerozoic Alberta Basin of western Canada represents a significant part of the Canadian Shield, ca. 750 000 km2. The advent of modern high resolution aeromagnetic data and UPb geochronology have opened the doors for the next era of investigation of the crystalline basement of the Alberta Basin. Aeromagnetic data and geochronology provided important physical and temporal links to the exposed Canadian Shield, which allowed its structural framework to be extrapolated into the subsurface. The most recent chapter in this evolving story has been the Alberta Basement Transects of Lithoprobe, a 12-year program, which has used multi disciplinary geoscience studies to further elucidate the nature, history, and geometric characteristics of basement domains beneath the Alberta Basin. This special issue is the second in a three issue set of publications that synthesize the results of over a decade of Lithoprobe research in the Alberta Basin. The first issue, published in the Bulletin of Canadian Petroleum Geology, concentrated on the shallow sedimentary record and new insights gained from linking deep seismic reflection profiles with the evolution of the sedimentary succession. The present issue presents a crustal perspective and concentrates on the results from mapping, geochronology, igneous petrology, and seismic investigation of the crystalline basement of the Alberta Basin. The diversity of disciplines covered in this issue address questions about the evolution of the crust and mantle of western Canada and offer unique perspectives on the insight gained from the merger of reflection seismology, magnetotellurics, potential field studies, and field based observations. New breakthroughs in mantle dynamics and its role in sedimentary basin formation, as well as our ability to image mantle structure and relate it to surface tectonic processes, are important steps forward.