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The northwestern Avalon Terrane, Newfoundland, is underlain by Neoproterozoic rocks traditionally divided into older Love Cove Group, medial Connecting Point Group, and the unconformably overlying Musgravetown Group. New lithogeochemical, isotopic, and updated U-Pb (zircon) age data demand changes to stratigraphic nomenclature and maps and help constrain the tectonomagmatic evolution. U-Pb age constraints include 620 [+ or -] 2 Ma for the calc-alkaline Broad Island Group (former Love Cove Group); 605 [+ or -] 1.2 Ma for rhyolite from near Bull Arm (type area, Bull Arm Formation, lower Musgravetown Group); 589 [+ or -] 2.0 Ma for a schist from the Love Cove type locality; 568.7 [+ or -] 1.4 Ma for rhyolite of the Rocky Harbour Formation, upper Musgravetown Group; and 572 [+ or -] 2 Ma for Louil Hills granite. In light of these results, remnants of the main Avalonian arc are re-designated 'Broad Island Group', for the site of the dated 620 Ma tuff. The ca. 589 Ma schist from Love Cove is included in the Musgravetown Group and may be a tectonized equivalent of Bull Arm Formation. Our data outline a tectonomagmatic change from arc-dominated magmatism at ca. 620 Ma, to an extensional regime ca. 605589 Ma, culminating in alkaline magmatism by ca. 572 Ma. eNdt values (t = 620-569 Ma) for felsic rocks range from 3.7 to 5.6 and yield [T.sub.DM] ages consistent with derivation from a juvenile Neoproterozoic (878-730 Ma) basement. Maficrocks exhibit a time-progressive increase in [[epsilon]Nd.sub.t], indicating more juvenile mantle sources through time. Further delimitation of map units of the area await integrated lithostratigraphy, precise modern U-Pb geochronology, and lithogeochemistry. Key words: Avalonia, Neoproterozoic, geochronology, Sm-Nd isotope chemistry, lithogeochemistry, felsic and maficmagmatism. Le nord-ouest du terrane d'Avalon (Terre-Neuve) est sous-tendu par des roches neoproterozoiques traditionnellement divisees en trois groupes, soit leGroupe de LoveCove, plus ancien, leGroupe intermediaire de Connecting Point et, reposant en discordance, le groupe de Musgravetown au-dessus. De nouvelles donnees lithogeochimiques et isotopiques et des ages U-Pb sur zircons a jour appellent des modifications a la nomenclature stratigraphique et aux cartes et permettent de mieux definir l'evolution tectonomagmatique. Les ages U-Pb comprennent des ages de 620 [+ or -] 2 Ma pour le Groupecalcoalcalin de Broad Island (anciennement le Groupe de Love Cove), de 605 [+ or -] 1, 2 Ma pour une rhyolite des environs de Bull Arm (region type, Formation de Bull Arm, Groupe de Musgravetown inferieur), de 589 [+ or -] 2, 0 Ma pour un schiste de la localitetype de Love Cove, de 568, 7 [+ or -] 1, 4 Ma pour une rhyolite de la Formation de Rocky Harbour, du Groupe de Musgravetown superieur, et de 572 [+ or -] 2 Ma pour le granite de Louil Hills. A la lumiere de ces resultats, les restes de l'arc avalonien principal sont renommes[much less than] Groupe de Broad Island [much greater than], pour la localite du tuf de 620 Ma. Le schiste d'environ 589 Ma de Love Cove est inclus dans le Groupe de Musgravetown et pourrait etre un equivalent tectonise de la Formation de Bull Arm. Nos donnees font ressortir une transition tectonomagmatique qui passe d'un magmatisme a dominance d'arc vers 620 Ma a un regime d'extension vers 605-589 Ma, culminant en un magmatisme alcalin vers 572 Ma. Les valeurs de [[epsilon]Nd.sub.t] (t = 620-569 Ma) pour les roches felsiques vont de 3, 7 a 5, 6 et donnent des ages TDM qui concordent avec l'interpretation que ces roches seraient derivees d'un socle neoproterozoique juvenile (878-730 Ma). Les roches mafiques presentent une augmentation au fil du temps des valeurs de [[epsilon]Nd.sub.t], ce qui indique des sources mantelliques de plus en plus juveniles. Une meilleure delimitation des unites cartographiques de la region necessitera l'integration de leur lithostratigraphie, de leur geochronologie U-Pb precise et moderne et de leur lithogeochimie. [Traduit par la Redaction] Mots-cles : Avalonie, Neoproterozoique, geochronologie, chimie des isotopes de Sm-Nd, lithogeochimie, magmatisme felsique et mafique., Introduction The Avalon Terrane in Newfoundland is the type locality for the microcontinent Avalonia, one of the peri-Gondwanan terranes accreted to the Laurentian margin by the latest Silurian as the [...]

An essential task in many geotechnical projects is delineation of subsurface soil stratigraphy from scatter measurements. Geotechnical engineers often use their knowledge on local geology and interpret soil strata boundaries by linear interpolation of measured data. This usual practice may encounter difficulties when interpreting complex deposits, particularly when measurements are limited. In this study, a novel nonparametric, data-driven method based on multiple point statistics (MPS) is proposed to interpolate subsurface soil stratigraphy from sparse measurements. MPS maybe formulated as Bayesian supervised machine learning, which adaptively learns high-order spatial information (e.g., curvilinear features of soil layers) using sparse measurements obtained in a specific site and training image that reflects pre-existing engineering knowledge on similar geological settings. The proposed method is the first ever purely data-driven method (i.e., without using any pre-specified parametric functions) for geotechnical site characterization. The proposed method is illustrated by a simulated example and real data from a reclamation site in Hong Kong. The proposed method not only accurately interpolates the subsurface soil stratigraphy from sparse measurements, but also quantifies uncertainty associated with the interpolation. Effects of governing parameters in the proposed method are explicitly investigated, and parameters appropriate for subsurface soil stratigraphy are identified. Key words: multiple point statistics, soil stratigraphy, spatial interpolation, sparse measurements. Une tache essentielle dans de nombreux projets geotechniques est la delimitation de la stratigraphie du sol de subsurface a partir de mesures de dispersion. Les ingenieurs geotechniques utilisent souvent leurs connaissances sur la geologie locale et interpretent les limites des strates du sol par interpolation lineaire des donnees mesurees. En utilisant cette pratique habituelle, on peut rencontrer des difficultes lors de l'interpretation de depots complexes, notamment lorsque les mesures sont limitees. Dans cette etude, une nouvelle methode non parametrique et basee sur les donnees, basee sur les statistiques en points multiples (<< MPS >>), est proposee pour interpoler la stratigraphie du sol de surface a partir de mesures eparses. La methode MPS peut etre formulee comme l'apprentissage machine supervise bayesien, qui apprend de maniere adaptative des informations spatiales de haut ordre (par exemple, les caracteristiques curvilignes des couches de sol) en utilisant des mesures eparses obtenues sur un site specifique et une image de formation qui reflete les connaissances techniques preexistantes sur des contextes geologiques similaires. La methode proposee est la toute premiere methode purement basee sur les donnees (c'est-a-dire sans utiliser de fonctions parametriques predefinies) pour la caracterisation geotechnique des sites. La methode proposee est illustree par un exemple simule et des donnees reelles provenant d'un site de polderisation a Hong Kong. La methode proposee permet non seulement d'interpoler avec precision la stratigraphie du sol de subsurface a partir de mesures eparses, mais aussi de quantifier l'incertitude associee a l'interpolation. Les effets des parametres directeurs dans la methode proposee sont explicitement etudies, et les parametres appropries pour la stratigraphie du sol de subsurface sont identifies. [Traduit par la Redaction] Mots-cles : statistiques en points multiples, stratigraphie des sols, interpolation spatiale, mesures peu nombreuses., 1. Introduction An essential task for geotechnical site characterization is subsurface soil classification and stratification, which involves demarcation of soil stratigraphic boundaries, types of soil layers, and distribution of lenses, [...]

A change in sea level (or lake level) causes a change in accommodation space and sediment compensation, which then controls the formation and evolution of sequences. A multidisciplinary approach based on the integration of clay minerals, major and trace elements, paleosalinity, and three-dimensional seismic data were applied to interpret the stratigraphic sequence of the Dongying Formation in the Liaoxi low uplift. The sequence surface indicates that multistage tectonic action, paleoclimate, paleosalinity, and lake level change jointly controlled the sequence stratigraphy. The illite and illite-smectite mixed layers indicate an arid to semi-arid climate, whereas kaolinite implies humid conditions. Based on this principle, it is clear that the stratigraphic sequence is closely related to paleoclimate. Interpretation of the continental or marine character of the sediments via paleosalinity is increasingly based on the concentration of some trace elements. Hence, the sequence surface can be better evaluated through paleosalinity data. Based on the Sr/Ba and boron content, paleosalinity was evaluated and the sequence boundary was identified. Analysis of the concentration of major and trace elements was used to identify the lithology of the sedimentary region and further discern the stratigraphic sequence. These sequences are composed of lowstand, transgressive, and highstand system tracts. The work herein aimed to understand the reasons for the changes in sequences under the paleoclimate. In addition, major and trace elements, studied together with paleosalinity and clay mineral content, result in the determination of implications for sequence stratigraphy in many other basins. This paper can provide a novel method for comprehensively discerning a sequence surface. Key words: sequence stratigraphy, Dongying Formation, Liaoxi low uplift, Bohai Bay Basin, major and trace elements, paleosalinity. Un changement du niveau de la mer (ou du niveau d'un lac) entraine un changement de l'espace d'accommodation et de la compensation de sediments qui, lui, controle la formation et l'evolution des sequences. Une approche multidisciplinaire reposant sur l'integration de donnees sur les argiles, les elements majeurs et en traces et la paleosalinite et de donnees de sismique tridimensionnelle a ete appliquee a l'interpretation de la sequence stratigraphique de la Formation de Dongying dans le soulevement bas de Liaoxi. La surface de la sequence indique qu'une activite tectonique en plusieurs etapes, le paleoclimat, la paleosalinite et les changements des niveaux de lac ont controle conjointement la stratigraphie sequentielle. Les couches d'illite et d'illite-smectite mixtes indiquent un climat aride a semi-aride, alors que la kaolinite temoigne de conditions humides. Partant de ce principe, il est clair que la sequence stratigraphique est etroitement reliee au paleoclimat. L'interpretation du caractere continental ou marin des sediments a partir de la paleosalinite repose de plus en plus sur la concentration de certains elements en traces. La surface de la sequence est donc mieux evaluee a la lumiere de donnees de paleosalinitie. Les valeurs des rapports Sr/Ba et les teneurs en bore ont ete utilisees pour evaluer la paleosalinite et etablir la limite de la sequence. L'analyse des concentrations d'elements majeurs et en traces a ete utilisee pour etablir la lithologie de la region sedimentaire et caracteriser plus en detail la sequence stratigraphique. Ces sequences sont composees de corteges de bas niveau, transgressifs et de haut niveau. Les travaux presentes visent a etablir les causes des changements dans les sequences au vu du paleoclimat. Les elements majeurs et en traces etudies de concert avec la paleosalinite et les concentrations des argiles jettent en outre un meilleur eclairage sur la stratigraphie sequentielle dans de nombreux autres basins. L'article presente une nouvelle approche pour delimiter de maniere exhaustive la surface d'une sequence. [Traduit par la Redaction] Mots-cles : stratigraphie sequentielle, Formation de Dongying, soulevement bas de Liaoxi, bassin de la baie Bohai, elements majeurs et en traces, paleosalinite., Introduction Sequence stratigraphy is a new subdiscipline formed by the combination of tectonic geology and sedimentology (Bouaziz et al. 2002; Gharbi et al. 2015; Jacquin et al. 1991). As a [...]

Abstract: The Potsdam Group is a Cambrian to Lower Ordovician siliciclastic unit that crops out along the southeastern margins of the Ottawa graben. From its base upward, the Potsdam consists [...]

Abstract: New high-resolution chemostratigraphy, in combination with updated biostratigraphy, refines the chronostrati-graphic resolution of the nearly 2 km thick Ordovician section below Anticosti Island. A total of 1414 horizons, spaced [...]

Abstract: One of the best-exposed and most complete stratigraphic records from paleotropical areas spanning the Ordovician-Silurian (O-S) boundary is located on Anticosti Island, eastern Canada. Our study is the first [...]

Abstract: The 'butter shale' Lagerstatten of the Cincinnati Arch have produced an abundance of articulated trilobites, along with assorted bivalves and cephalopods. These bluish gray shales are rich in clay, [...]

Abstract: The lithostratigraphic term 'Eramosa' was introduced in Ontario more than a century ago to include a distinctive package of thin- to medium-bedded, black to medium-brown dolostones that make up [...]

Lithostratigraphic, [sup.14]C, and palynologic analyses of peat and silty peat at three nearby sites reveal a 25 000 year vegetation and climate history of the Olympia Interstade for the Fraser Lowland, British Columbia, 300 km within the southern limit of the Cordilleran Ice Sheet. At Lynn Valley, Polypodiaceae fern spores and nonarboreal pollen dominate >47.8 [sup.14]C ka BP, reflecting unstable and cold landscapes. A Pinus-Poaceae zone follows, representing pine parkland and cool dry climate. Fluctuating values of Picea and Tsuga mertensiana pollen at Lynn and Seymour valleys and Port Moody characterize most of the Olympia Interstade during local peat deposition in Cyperaceae and Myrica wetlands until about 26.7 [sup.14]C ka BP under a cool and moist climate. A brief Pinus-Tsuga heterophylla zone at Lynn Valley 44-39 [sup.14]C ka BP suggests a climatic optimum. A Poaceae-Artemisia assemblage and deposition of silty sand after 26.7 [sup.14]C ka BP reflect cooling and drying after which a unique Lycopodium assemblage at Lynn Valley suggests cold arid climate and Fraser Glaciation onset. These sequences have no progression to vegetation typical of warm, interglacial, Holocene-like climates, indicating an interstadial not an interglacial interval. Correlation with vegetation changes elsewhere in western North America suggests that the Olympia Interstade started about ~52 [sup.14]C ka BP (~57 cal ka BP) and ended about 26 [sup.14]C ka BP (30 cal ka BP). Des analyses lithostratigraphiques, de carbone 14 et palynologiques de tourbe et de tourbe silteuse de trois sites voisins ont revele une vegetation vieille de 25 000 ans et une historique du climat de l'interstade Olympia pour les basses- terres du Fraser, Colombie-Britannique, soit a 300 km a l'interieur de la limite sud de l'inlandsis de la Cordillere. Dans la vallee Lynn, des spores de fougeres de la famille des Polypodiacees et du pollen non arboricole dominent >47,8[sup.14]C ka avant le present (BP), ce qui reflete des paysages froids et instables. Suit ensuite une zone a Poacees Pinus representant une foret-parc de pin et un climat frais et sec. Les valeurs fluctuantes de pollens de Picea et de Tsuga mertensiana dans les vallees Lynn et Seymour et a Port Moody caracterisent la plus grande partie de l'interstade Olympia durant la deposition locale de la tourbe dans des milieux humides a Cyperacees et Myrica jusqu'a environ 26,7 [sup.14]C ka BP sous un climat frais ethumide. Une breve zone a Pinus-Tsuga heterophylla dans la vallee Lynn a 44-39 [sup.14]C ka BP suggere un optimum climatique. Un assemblage de Poacees Artemisia et la deposition d'un sable silteux apres 26,7 [sup.14]C ka BP sont le reflet d'un refroidissement et d'un assechement apres quoi un assemblage unique de Lycopodium dans la vallee Lynn suggere un climat aride et froid et le debut de la glaciation Fraser. Ces sequences ne progressent pas vers une vegetation typique de climats chauds interglaciaires de style Holocene, ce qui indique un intervalle interstadiaire et non un intervalle interglaciaire. Selon une correlation avec des changements de vegetation ailleurs dans l'ouest de l'Amerique du Nord, l'interstade Olympia aurait debute vers ~52[sup.14]C ka BP (~57 ka calendaires BP) et fini vers 26 [sup.14]C ka BP (30 ka calendaires BP). [Traduit par la Redaction], Introduction The Olympia nonglacial interval preceded major Late Wisconsin ice advances and has long been of interest in northwest North America (Heusser 1977; Clague and MacDonald 1989; Mathewes 1991; Cosma [...]

The Moose River Basin in Ontario, Canada, contains nearly 1 km of Silurian marine strata, and although it has been studied for more than a century, its precise correlation globally has not been constrained. Herein, a core from the Victor Mine in the Moose River Basin was examined for conodont biostratigraphy and carbonate carbon (δ[sup.13][C.sub.carb]) isotope chemostratigraphy to provide a detailed chronostratigraphic framework for the Silurian strata (Severn River, Ekwan River, and Attawapiskat formations) in the Moose River Basin. The recovery of Aspelundia expansa, Aspelundia fluegeli fluegeli, Distomodus staurognathoides, Ozarkodina polinclinata estonica, Pterospathodus eopennatus, and Aulacognathus bullatus, as well as the lower Aeronian, upper Aeronian, lower Telychian (Valgu), and ascending limb of the Sheinwoodian (Ireviken) positive carbonate carbon (δ[sup.13][C.sub.carb]) isotope excursions provide significantly improved chronostratigraphic correlation of Llandovery strata in the Moose River Basin. Le bassin de la riviere Moose (Ontario, Canada) renferme pres de 1 km de strates marines siluriennes et, bien qu'il ait ete etudie pendant plus d'un siecle, sa correlation planetaire precise n'a pas ete etablie. Une carotte de la mine Victor dans le bassin de la riviere Moose a ete examinee pour en determiner la biostratigraphie des conodontes et la chimiostratigraphie des isotopes du carbone (δ[sup.13][C.sub.carb]) dans les carbonates afin d'etablir un cadre chronostratigraphique detaille pour les strates siluriennes (Formations de la riviere Severn, de la riviere Ekwan et d'Attawapiskat), dans le bassin de la riviere Moose. La recuperation Aspelundia expansa, Aspelundia fluegeli fluegeli, Distomodus staurognathoides, Ozarkodina polinclinata estonica, Pterospathodus eopennatus et Aulacognathus bullatus, ainsi que les excursions positives des isotopes du carbone (δ[sup.13][C.sub.carb]) dans les carbonates de l'Aeronien inferieur, de l'Aeronien superieur, du Telychien inferieur (Valgu) et du membre ascendant du Sheinwoodien (Ireviken) ameliorent significativement la correlation chronostratigraphique des strates llandoveriennes du bassin de la riviere Moose. [Traduit par la Redaction], Introduction The Hudson Platform (central Canadian Shield, Fig. 1) was located in the tropical climate belt during the Silurian Period at low latitudes (between 0°S and 10°S) just south of [...]

The Paleoproterozoic Hottah terrane is the westernmost exposed bedrock of the Canadian Shield and a critical component for understanding the evolution of the Wopmay Orogen. Thirteen new high-precision U-Pb zircon crystallization ages are presented and support field observations of a volcano-plutonic continuum from Hottah terrane through to the end of the Great Bear magmatism, from >1950 to 1850 Ma. The new crystallization ages, new geochemical data, and newly published detrital zircon U-Pb data are used to challenge hitherto accepted models for the evolution of the Hottah terrane as an exotic arc and microcontinent that arrived over a west-dipping subduction zone and collided with the Slave craton at ca. 1.88 Ga. Although the Hottah terrane does have a tectonic history that is distinct from that of the neighbouring Slave craton, it shares a temporal history with a number of domains to the south and east--domains that were tied to the Slave craton by ca. 1.97 Ga. It is interpreted herein that Hottah terrane began to the south of its current position and evolved in an active margin over an always east-dipping subduction system that began prior to ca. 2.0 Ga and continued to ca. 1.85 Ga, and underwent tectonic switching and migration. The stratigraphy of the ca. 1913-1900 Ma Hottah plutonic complex and Bell Island Bay Group includes a subaerial rifting arc sequence, followed by basinal opening represented by marginal marine quartz arenite and overlying ca. 1893 Ma pillowed basalt flows and lesser rhyodacites. We interpret this stratigraphy to record Hottah terrane rifting off its parental arc crust--in essence the birth of the new Hottah terrane. This model is similar to rapidly rifting arcs in active margins--for example, modern Baja California. These rifts generally occur at the transition between subduction zones (e.g., Cocos-Rivera plates) and transtensional shear zones (e.g., San Andreas fault), and we suggest that extension-driven transtensional shearing, or, more simply, terrane translation, was responsible for the evolution of Bell Island Bay Group stratigraphy and that it transported this newly born Hottah terrane laterally (northward in modern coordinates), arriving adjacent to the Slave craton at ca. 1.88 Ga. Renewed east-dipping subduction led to the Great Bear arc flare-up at ca. 1876 Ma, continuing to ca. 1869 Ma. This was followed by voluminous Great Bear plutonism until ca. 1855 Ma. The model implies that it was the westerly Nahanni terrane and its subducting oceanic crust that collided with this active margin, shutting down the >120 million year old, east-dipping subduction system. Le terrane de Hottah (Paleoproterozoique) est le roc de socle affleurant le plus a l'ouest dans le Bouclier canadien; il est aussi une composante essentielle a la comprehension de l'evolution de l'orogene de Wopmay. Treize nouveaux ages de cristallisation, de haute precision, determines par U-Pb sur des zircons, sont presentes et ils supportent les observations sur le terrain d'un continuum volcano-plutonique pour le terrane de Hottah jusqu';! la fin du magmatisme Great Bear, soit de >1950 a 1850 Ma. Les nouveaux ages de cristallisation, de nouvelles donnees geochimiques et des donnees nouvellement publiees d'ages U-Pb sur des zircons detritiques sont utilises pour contester les modeles jusqu'ici acceptes pour l'evolution de terrane de Hottah en tant qu'un arc exotique et un microcontinent qui est arrive par-dessus une zone de subduction a pendage vers l'ouest et qui est entre en collision avec le craton des Esclaves il y a environ 1,88 Ga. Bien que le terrane de Hottah ait un historique tectonique distinct de celui du craton des Esclaves avoisinant, il partage un historique temporel avec de nombreux autres domaines au sud et a l'est, des domaines qui etaient relies au craton des Esclaves il y a environ 1,97 Ga. Il est interprete ici que le terrane de Hottah a debute au sud de sa position actuelle et qu'il a evolue dans une bordure active par-dessus un systeme de subduction avec un pendage toujours a l'est, commencant avant environ 2,0 Ga et continuant jusqu'a 1,85 Ga, par la suite subissant un echange tectonique et une migration. La stratigraphie du complexe plutonique de Hottah, ~1913 a 1900 Ma, et du Groupe de Bell Island Bay comprend une sequence subaerienne de rifting d'arc, suivie d'une ouverture de bassin, representee par une arenite quartzique de bordure marine, sur lesquels reposent sur des ecoulements de basalte en coussins ~1893 Ma, et des quantites moindres de rhyodacites. Nous interpretons cette stratigraphie comme un enregistrement du rift du terrane de Hottah depuis sa croute d'arc parental, ce qui en essence constitue la naissance du nouveau terrane de Hottah. Ce modele est semblable aux arcs subissant un rifting dans des bordures actives, par exemple, la Basse Californie moderne. Ces rifts se trouvent generalement a la transition entre les zones de subduction (p. ex. les plaques Cocos-Rivera) et les zones de cisaillement de transtension (p. ex. la faille de San Andreas); nous suggerons que le cisaillement de transtension, pousse par l'extension, ou plus simplement la translation du terrane, etait responsable de l'evolution de la stratigraphie du Groupe de Bell Island Bay et que cette transtension a transporte ce terrane de Hottah, nouvellement cree, lateralement (soit vers le nord, selon les coordonnees modernes), arrivant adjacent au craton des Esclaves vers 1,88 Ga. Une reprise de la subduction avec pendage vers l'est a conduit a la poussee active de l'arc de Great Bear vers 1876 Ma et jusqu';! 1869 Ma. Cela a ete suivi par beaucoup de plutonisme Great Bear jusqu';! vers 1855. Selon le modele, c'est le terrane de Nahanni, vers l'ouest, et sa croute oceanique de subduction qui sont entres en collision avec cette bordure active, fermant ainsi le systeme de subduction a pendage est, age de plus de 120 millions d'annees. [Traduit par la Redaction], Introduction In September 2012, NASA's Curiosity rover discovered an outcrop of alluvial-derived conglomerate in Gale Crater, Mars, and it was named Hottah, after Hottah Lake, Northwest Territories, Canada (Williams et [...]

Marine mudstone of the Coniacian Muskiki Member was deposited by storms on a shallow-marine ramp across southern Alberta and northern Montana. The rocks range from the C. crassus crassus Zone of the upper lower Coniacian to the S. depressus Zone of the upper Coniacian; however, upper Coniacian strata are only a few metres thick at Kevin Montana and appear to be thin to absent beneath parts of the adjacent Alberta Plains, probably because of minimal contemporaneous subsidence. The Muskiki Member is partitioned into three packages by subtle bevelling unconformities, cut during regional tectonic tilting. The lower package indicates flexural subsidence in the NW, whereas the middle package indicates subsidence in the SW. The rotation of the axis of subsidence may indicate an along-strike shift of the region of active thickening in the orogenic wedge. The upper package is dominated by a NW-trending region of stratal thickening, forming a trough-shaped rock body 100 km wide, >250 km long, and up to 50 m thick, filled with eastward-accreting mud clinothems. Clinothems toplap against an unconformity that marks the base of the overlying Santonian Dowling Member. Magnetic anomalies in the Archean basement directly underlie an inferred hinge zone in the middle Muskiki package, suggesting differential flexure of the foredeep about a weak zone. The NE boundary of the 'trough' in the upper Muskiki coincides spatially with an underlying Archean thrust ramp that is interpreted to have undergone extensional reactivation in the late Coniacian, forming a surficial sag. Although the study area embraces the Precambrian Vulcan structure, the Bow Island arch and Kevin-Sunburst dome, none of these structures appear to have affected Coniacian sedimentation, despiteinfluencing both older and younger Cretaceous rocks. Un mudstone marin du Membre Muskiki d'age coniacien a ete depose par des tempetes sur une rampe marine peu profonde couvrant le sud de l'Alberta et le nord du Montana. Les roches vont de la zone a C. crassus crassus de la partie superieure du Coniacien inferieur a la zone a S. depressus du Coniacien superieur. Les strates coniaciennes ne font toutefois que quelques metres d'epaisseur et semblent etre minces a absentes sous certaines parties des plaines de l'Alberta attenantes, vraisemblablement du fait de la tres faible subsidence contemporaine. Le Membre Muskiki est subdivise en trois blocs par de subtiles discordances biseautantes formees durant un basculement tectonique regional. Le bloc inferieur temoigne d'une subsidence flexurale au nord-ouest, alors que le blocmedian temoigne d'une subsidence dans le sud-ouest. La rotation de l'axe de subsidence pourrait indiquer un deplacement parallele a la direction des couches de la zone d'epaississement actif du prisme orogenique. Le bloc superieur est domine par une zone orientee NO d'epaississement des strates formant une masse de roches en forme de fosse de 100 km de largeur, plus de 250 km de longueur et jusqu' a 50 m d'epaisseur, comblee par des clinothemes argileux progressant vers l'est. Ces clinothemes debordent une discordance marquant la base du Membre Dowling sus-jacent, d'age santonien. Des anomalies magnetiques dans le socle archeen sont situees directement sous une zone de charniere inferee dans le bloc median du Membre Muskiki, ce qui suggere une flexion differentielle de l'avant-fosse axee sur une zone de faiblesse. La limite NE de la [mucho menor que] fosse [mucho mayor que] du bloc Muskiki superieur coincide dans l'espace avec une rampe de chevauchement archeenne sous-jacente interpretee comme ayant subi une reactivation normale durant le Coniacien tardif, formant un affaissement en surface. Bien que la region a l'etude englobe la structure precambrienne de Vulcan, l'arche de Bow Island et le dome de Kevin--Sunburst et bien que ces structures aient influence des roches cretacees plus vieilles et plus jeunes, elles ne semblent pas avoir eu une incidence sur la sedimentation coniacienne. [Traduit par la Redaction], Introduction For almost a century, it has been recognized that the Phanerozoic strata of southern Alberta and northern Montana have been deformed into a variety of antiformal structures of varying [...]

The U-Pb age spectrum of detrital zircons in sandstone of the fluvial Middle Jurassic Ionia Formation in the Michigan basin, United States, resembles the age spectra in Jurassic eolianites of the Colorado Plateau, except that a Neoproterozoic (725-510 Ma) subpopulation present in the eolianites is absent from the Michigan basin strata. The detrital zircon data are compatible with the hypothesis that the Ionia Formation was deposited by northern tributaries of a transcontinental Jurassic paleoriver system that transported detritus from headwaters in Atlantic rift highlands of the Appalachian region to floodplains and deltas in the present northern Rocky Mountains region. Previous detritai zircon studies have indicated that sedimented lowlands in that paleogeographic position were deflated by paleowinds to feed eolian sand southward (in present coordinates) into the Colorado Plateau ergs (sand seas). doi: 10.1130/G30509.1

Integrated graptolite, conodont and chitinozoan biostratigraphical data are presented from the Llandovery and Wenlock of the Kolka-54 core, Latvia. Correlations between graptolite and chitinozoan biozones are consistent with those published from other East Baltic sections and the Welsh Basin. While most correlations between graptolite and conodont biozones agree with those presented in previous studies, there are important exceptions. Significantly, we report here the discovery of Distomodus staurognathoides Biozone conodonts in the lowest Aeronian Demirastrites triangulatus graptolite Biozone. The base of the D. staurognathoides Biozone was previously considered to lie much higher in the Aeronian. Also it is shown that Walliserodus survived the late Wenlock Mulde Event, during which it was considered previously to have become extinct. Keywords: graptolites, chitinozoan, conodonts, Silurian, biostratigraphy, Llandovery, Wenlock. doi: 10.1017/S0016756809990574

Sieve deposits were once considered to be one of the building blocks in alluvial fan stratigraphy. Later reinterpretation of sieve lobes as debris-flow deposits, favored because no visual records of active sieve deposition had been reported, undermined their significance, divided opinions, and left this issue unresolved. Here I document active deposition of sieve lobes in natural settings, in support of the original model. Sieve deposition can easily occur in natural settings such as proglacial outwash fans, small arid alluvial fans, or perennial streams when there is a scarcity of fine material, significant bedload, high slope, permeable ground, and discharges moderate enough to allow infiltration. The only hydrodynamic requirement for sieve deposition is a high rate of water loss promoted by permeable bed sediments. Under some circumstances alluvial fans can be built almost entirely of sieve deposits, as shown here. One effect of the rapid extraction of water is the creation of sigmoidal fan profiles. A gradation from sieve deposition to sheetflood occurs if sediment becomes progressively less permeable or if water flow increases, overcoming bed permeability. Sieve deposition is a universal depositional process based simply on infiltration, and it explains matrix-poor clast-supported gravels, while alternative hypotheses, such as matrix winnowing of debris flows used to dispute the sieve model, still need to be proven by observations in nature. doi: 10.1130/G30504.1

The structural style of the folds from the central part of the Lurestan salient located in the NW portion of the Zagros Fold-Thrust Belt has been studied by constructing a regional balanced cross-section from field data, existing geological maps, seismic profiles, stratigraphic surface sections and well data. The regional balanced structural cross-section that is constructed from the High Zagros Fault to the Mountain Front Fault highlights the difference in the folding style across the area. The vertical and lateral changes in the style of the folding indicate the influence of mechano-stratigraphic contrast between the sedimentary units. Three main decollement levels (the basal Lower Palaeozoic, the intermediate Triassic, and the upper Upper Cretaceous-Lower Palaeocene) have been interpreted. Folds developed during the Zagros Fold-Thrust Belt evolution above and below these decollement horizons are decoupled from each other and are different in both geometry and size. Similarly, thickness and facies changes of some formations across the region cause lateral variation in folding pattern from the north to the south. Polyharmonic folds exist in the south, where the different structural levels are relatively strongly coupled. To the north, however, strongly disharmonic folding occurs where a combination of increased decollement thickness and decreased mechanical competence has led to decoupling at different structural levels. This change in folding style has a direct impact on hydrocarbon exploration in the area. To reduce structural risk in exploration, the incorporation of high-resolution deep seismic data with the surface geology is recommended for future hydrocarbon exploration activities within the Lurestan region. doi: 10.1144/0016-76492008-162.

We propose a framework for the hierarchy of sedimentary units observed in stratigraphic data that is based entirely on the geometric relationship of the strata. This framework of geometries is assumed to result from repeated successions of accommodation creation and sediment fill (here named accommodation succession). We have modified existing hierarchal frameworks to describe depositional units resulting from accommodation successions of varying magnitude and duration, across a depositional profile. Each full succession consists of component partial succession sets that are, sequentially, lowstand--progradation to aggradational; transgressive--retrogradation; and highstand--aggradation to progradation to degradation. The terms 'highstand' and 'lowstand' as originally defined to label systems tracts relative to a shelf edge, and with an implied relationship between sea level and systems tracts, have been the root of confusion. We propose that these terms be used in the strict sense of the original definition, because their meaning has been lost when applied to the many depositional settings and high-resolution data sets to which the concepts of sequence stratigraphy are now applied. We propose that the concept of accommodation succession stacking be used in the interpretation of stratigraphic data within a hierarchal framework of depositional sequences, sequence sets, and composite sequences. This will allow an interpreter to accurately categorize observations, provide a basis for predictions away from control points, and develop a framework that allows revisions as higher-resolution data become available.

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.solener.2009.05.007 Byline: Stefan Goppert, Rolf Lohse, Thorsten Urbaneck, Ulrich Schirmer, Bernd Platzer, Philipp Steinert Keywords: Solar storage tanks; Inlet stratifiers; Computation Abstract: The efficiency of low-flow solar systems is strongly influenced by the quality of the thermal stratification in the storage tank. The better a thermal stratification can be generated and maintained, the higher can be the yield of the solar system. Fluid mechanical charge systems are often used for this purpose, which cause, however, undesirable sucking effects. Therefore, the knowledge of the appearing fluid flows as well as the knowledge of the consequences of constructive changes are very important for the design of such charge systems. However, simulations with CFD (Computational Fluid Dynamics) are very costly and time-consuming. In this article a new and much simpler computation method is introduced making the determination of the individual fluid flows and the estimation of the effects of constructive changes possible. The computations can be carried out within short time. The comparison with CFD gives a qualitatively good agreement for a simple charge system. The results of a constructive modification of the charge system reducing the sucking effect are discussed. The remaining quantitative differences result from the discrepancies between the non-ideal behaviour of the real fluid and the model assumptions and point out improvement potentials. Author Affiliation: Department of Technical Thermodynamics, Chemnitz University of Technology, Reichenhainer Str. 70, 09126 Chemnitz, Germany Article History: Received 22 August 2008; Revised 11 May 2009; Accepted 18 May 2009 Article Note: (miscellaneous) Communicated by: Associate Editor Halime Paksoy

The Neoproterozoic-Early Cambrian rifted margin of eastern Laurentia is framed by promontories and embayments defined by northeast-trending rifts offset by northwest-trending transforms. A regional first-order synthesis of the available stratigraphic data in the northern Appalachians reveals significant along-strike variations in the thickness, composition, age, and facies of synrift and early postrift stratigraphy. These variations are consistent with models for low-angle detachment rift systems and allow for resolution of regional structures specific to low-angle detachments, including upper-plate margins, lower-plate margins, and transform faults that bound zones of oppositely dipping low-angle detachments.

A scheme of grouped lithostratigraphical units ('beds') proposed for the English Upper Jurassic Kimmeridge Clay Formation has been claimed to be also chronostratigraphical, but some of the resulting time-correlations conflict with those of the standard chronozonation based on ammonite biostratigraphy. Review of some critical ammonite species reaffirms the validity of the ammonite zonal scheme and shows that mismatching of lithologies (facies-correlations) has led to incorrect time-correlations. Because the numbering scheme of 'beds' was based on correlations of attenuated successions, it is on too coarse a time-scale to identify many non-sequences, and its usefulness as a chronostratigraphical tool is questioned. Evidence suggests that at least some calcareous concretions in the Kimmeridge Clay formed at shallow depths, which is relevant to discussions of the succession in terms of basin analysis. Keywords: correlation, lithostratigraphy, biostratigraphy, chronostratigraphy, Kimmeridge Clay Formation, concretions.

Soil characterization and distribution on a narrow ridge strath terrace bordering the Ohio River in the northern panhandle of West Virginia was evaluated to determine the stratigraphic context of the cultural remains of two prehistoric archaeological sites. Five soil map units were delineated in the project area based on the distribution of regolith materials and associated soil characteristics. Shale and sandstone residuum in the central crest of the ridge is covered with a laterally discontinuous mantle of Pleistocene alluvium, 0.25 to >1.2 m thick, and a continuous mantle of Irate Pleistocene loess, 0.25 to 1.1 m thick. Hapludalfs formed in the loess over alluvium, or in loess over residuum, indicate moderate to long-term (e.g., 12,000 yr) pedogenesis. On steep shoulder slopes, Dystrudepts in shallow residuum with little to no loess indicate limited pedogenesis and possible early to mid-Holocene erosion. Panhandle Archaic inhabitants of Site 46Br31 (~6090-3400 yr BP) harvested freshwater mussels from the Ohio River below the ridge, and after consumption discarded the shells on the shoulder slopes at the southern end of the ridge. The resultant shell middens, largely disturbed by 20th century relic hunters, form a complex map unit of Dystrudepts and Udorthents. The distribution of soils on this ridge and the associated archaeological remains indicate that the successive occupations of prehistoric Native American inhabitants lived on the same ground surface. 'The resultant cultural remains were not buried or stratigraphically separated. The modern soil surface is an approximate, although eroded, remnant of the occupied ground surface. The vertical distribution of artifacts reflects several millennia on a mature soil surface with an evolving biomantle.

Dinoflagellate cysts and sequence stratigraphy are used to date accurately the Tunnel-Canal Dock section, which contains the most complete record of marine Pliocene deposits in the Antwerp harbour area. The Zanclean Kattendijk Formation was deposited between 5.0 and 4.4 Ma during warm-temperate conditions on a shelf influenced by open-marine waters. The overlying Lillo Formation is divided into four members. The lowest is the Luchtbal Sands Member, estimated to have been deposited between 3.71 and 3.21 Ma, under cooler conditions but with an open-water influence. The Oorderen Sands, Kruisschans Sands and Merksem Sands members of the Lillo Formation are considered a single depositional sequence, and biostratigraphically dated between 3.71 and c. 2.6 Ma, with the Oorderen Sands Member no younger than 2.72-2.74 Ma. Warm-temperate conditions had returned, but a cooling event is noted within the Oorderen Sands Member. Shoaling of the depositional environment is also evidenced, with the transgressive Oorderen Sands Member passing upwards into (near-)coastal highstand deposits of the Kruisschans Sands and Merksem Sands members, as accommodation space decreased. Applying sequence stratigraphy to our section implies that the Kattendijk/Lillo Formation boundary corresponds to the sequence boundary (SB) Za2 (4.04 Ma), the Luchtbal/Oorderen sands boundary to SB Pia1 (3.21 Ma), and the top of the Merksem Sands to SB Pia2 (2.76 Ma). Finally, the Belgian deposits are compared with marine Pliocene deposits of eastern England. Keywords: dinoflagellate cyst, palynology, Pliocene, North Sea, sequence stratigraphy.

Isotopic and stratigraphic ages of the ~80 km diameter Puchezh-Kamnki (Russia; 220 [+ or -] 10 to 167 [+ or -] 3 Ma) and the ~20 km diameter Obolon (Ukraine; 215 [+ or -] 25 to 169 [+ or -] 7 Ma) impact structures are associated with significant age uncertainties. As a case study, reconstructions of the palaeogeography at the time of crater formation (Late Triassic to Middle Jurassic) based on recent palaeogeographic maps help further to constrain impact ages. Palaeogeographic studies suggest that Puchezh-Katunki is older than 170 Ma and that Obolon is younger than 185 Ma. This also rules out that Obolon formed during a ~214 Ma Late Triassic multiple impact event as recently discussed. Keywords: impact structure, dating, palaeogeography, marine impact.

New biostratigraphical evidence and a high-precision isotope dilution thermal ionization mass spectrometry U-Pb zircon age provide refined age constraint for the Ordovician Tyrone Volcanic Group of the Tyrone Igneous Complex. In a graptolite fauna from Slieve Gallion, the presence of Isograptus victoriae lunatus, the index fossil of the victoriae lunatus graptolite zone, indicates a correlation with the Australasian Castlemainian (Cal) Stage. The U-Pb zircon age of 473 [+ or -] 0.8 Ma dates a volcanic arc-related rhyolite body that is stratigraphically below graptolitic mudstones of Slieve Gallion. The U-Pb isotopic and biostratigraphical age constraints closely match an interpolated age for the base of the Middle Ordovician and indicate a Whitlandian age for the upper Tyrone Volcanic Group, which supports the regional correlation with the Ballantrae Complex, Midland Valley Terrane, Scotland.

[[delta].sup.13][C.sub.org] and TOC data are presented from the upper spiralis Biozone (Telychian, Llandovery, Silurian) through to the upper Sheinwoodian (Wenlock, Silurian) of the Banwy River section, Wales. In laminated hemipelagites from the Telychian, [[delta].sup.13][C.sub.org] values rise through the upper lapworthi Biozone to a maximum in the lower insectus Biozone after which they decline slightly. The most conspicuous feature of the [[delta].sup.13][C.sub.org] curve is the prolonged positive excursion in the Sheinwoodian, commencing in the upper murchisoni Biozone and ending in strata yielding Monograptus flexilis. This Sheinwoodian positive [[delta].sup.13]C excursion in the Banwy River section correlates precisely with that recognized in the East Baltic. The interval with the highest [[delta].sup.13][C.sub.org] values also records the highest TOC values, suggesting that for the Sheinwoodian at least, burial of carbon may have contributed to the positive [[delta].sup.13]C excursion. Bioturbated strata yield very low TOC values; whether the [[delta].sup.13][C.sub.org] values from these beds reflect a primary signal or the result of biostratinomic or diagenetic modification is uncertain. Keywords: carbon isotope, Silurian, Telychian, Sheinwoodian, Llandovery, Wenlock.

The Tinu Formation of Oaxaca State is the only fossiliferous lower Palaeozoic unit between the Laurentian platform in northwest Mexico and Gondwanan successions in Andean South America. The Tinu traditionally has been referred to the Lower Ordovician (Tremadoc) and regarded as having a provincially mixed fauna with Laurentian, Avalonian, and Gondwanan elements. Bio- and lithostratigraphic re-evaluation demonstrates that the Tinu is a Gondwanan, passive margin succession. It includes a lower, thin (to 16 m), condensed, uppermost Cambrian Yudachica Member (new). The Yudachica nonconformably overlies middle Proterozoic basement as a result of very high late Late Cambrian eustatic levels. The Yudachica changes from storm-dominated, but slightly dysoxic, shelf facies (fossil hash limestone and shale) in the south to an upper slope facies with debris flows 50 km to the north. Three biostratigraphically distinct depositional sequences comprise the Yudachica. The Yudachica has Gondwanan-aspect trilobites with low-diversity conodonts characteristic of unrestricted marine/temperate facies. The upper Tinu, or Rio Salinas Member (new), is a Lower Ordovician (Tremadoc) depositional sequence that records strong early, but not earliest, Tremadoc eustatic rise marked by graptolite- and olenid-bearing dysoxic mudstones. Higher strata shoal upward into shell-hash limestones and proximal tempestite sandstones with upper lower Tremadocian unrestricted marine/temperate conodonts. New taxa include Orminskia rexroadae Landing gen. et sp. nov. from the Cordylodus andresi Zone; this euconodont is related to hyaline coniform genera best known from Ordovician tropical platform successions. Cornuodus? clarkei Landing sp. nov. resembles the coeval, upper lower Tremadoc tropical species Scalpellodus longipinnatus (Ji & Barnes). Keywords: Cambrian, Ordovician, Gondwana, Mexico, conodonts, sequence stratigraphy.

A lower Cambrian eodiscoid trilobite fauna and an associated holmiid trilobite, Holmia sp., are described from a bioclastic limestone at the top of the Tornetrask Formation in the Luobakti section, south of Lake Tornetrask, northern Sweden. Other associated polymerid trilobites include Orodes? lapponica and Strenuaeva inflata. The precise age of the trilobite fauna cannot be determined, but its generic composition and stratigraphical position at the top of the lower Cambrian suggest that it was recovered from the Ornamentaspis? linnarssoni Assemblage Zone. Two species of eodiscoids are present: Neocobboldia aff. dentata and Chelediscus acifer. The latter species is known previously from England and southeastern Newfoundland, and provides a novel link between upper lower Cambrian successions in Baltica and Avalonia. Keywords: eodiscoids, trilobites, correlation, biostratigraphy, lower Cambrian, Sweden.

Many sedimentary successions are composed of metre- to decametre-scale cycles exhibiting various stratal architectures that depend on the complex interplay among several syndepositional controlling factors. These controlling factors may produce extremely different stratal and facies architectures along relatively brief distances in the same basin, but in contrast they also may form similar architectures in basins that experience a radically different tectonic setting. The recognition of factors that controlled the architecture of small-scale cycles, therefore, is very important to reconstruct the depositional history of sedimentary successions. These factors include: 1) the interplay between the rate of accommodation development and the rate of sediment supply (MS); 2) the amplitude and shape of the relative sea-level curve; 3) the position in the shoreface-shelf system; 4) the basin physiography; 5) the shoreline trajectory; 6) the climate-driven environmental energy; 7) the siliciclastic input vs. carbonate production. Shoreface to shelf small-scale cycles can be grouped into three main categories: R cycles, showing a dominant regressive interval; T-R cycles, with transgressive and regressive intervals of similar thickness; T cycles, showing a dominant transgressive interval. Although some depositional settings may favour the deposition of a particular type of cycle, these cycle motifs appear to be mainly controlled by the interaction of local and wider-scale controlling factors. For example, Tcycles may be present in both subsiding and uplifting settings, depending on the interplay between the A/S and the other factors cited above. As a result, R, T-R and Tcycles may be recognized within the same depositional system. These evidences suggest that care must be taken to apply general models that predict the stratal architecture of cycles mainly in function of the long-term A/S. The correct prediction of the cycle architecture is important also for hydrocarbon researches, as the thickness of potential reservoir deposits is the result of the interplay among factors discussed here. Keywords: small-scale cycles; stratal architecture; sequence stratigraphy; parasequences; controlling factors