A large arthropod trackway from the Gaspé Sandstone Group (Middle Devonian) of eastern Canada

1998 ◽  
Vol 35 (10) ◽  
pp. 1116-1122 ◽  
Author(s):  
Simon J Braddy ◽  
Andrew RC Milner
Keyword(s):  
Shallow Water ◽  
Middle Devonian ◽  
Eastern Canada

A large arthropod trackway from the Cap-aux-Os Member of the Battery Point Formation (Gaspé Sandstone Group, Middle Devonian), from the Baie de Gaspé, eastern Canada, is described and assigned to the ichnotaxon Palmichnium (= Paleohelcura) antarcticum (Gevers et al., 1971). A large stylonurid eurypterid or scorpion is considered the most likely producer. A shallow-water marginal fluvial environment is inferred as the setting, the animal making a transition from walking to swimming along the course of the trackway.

scholarly journals Foraminiferal Distribution in the Central and Western Parts of the Late Pleistocene Champlain Sea Basin, Eastern Canada

2007 ◽  
Vol 43 (1) ◽  
pp. 3-26 ◽  
Author(s):  
Jean-Pierre Guilbault
Keyword(s):  
Shallow Water ◽  
Deep Water ◽  
Bottom Water ◽  
Late Glacial ◽  
Clay Layer ◽  
Eastern Canada ◽  
Deep Waters ◽  
High Zone ◽  
Water Stratification ◽  
Late Wisconsinan

ABSTRACT Marine sediments from the late-glacial Champlain Sea have been sampled at 20 localities representing the deeper part of the basin, between Ottawa and the Rivière St-François, Québec. Foraminiferal assemblages have been extracted and a sequence of three deep water and two shallow water ecozones recognized. The lowermost zone (A) is characterized by Cassidulina reniforme, Islandiella helenae and I. norcrossi and represents a paleosalinity of 25 to 30%o. The overlying zone B is dominated by Elphidium excavatum. It represents salinities decreasing from 25 to as low as 10%o. The uppermost zone (C) contains only a sparse assemblage of a morphotype of E. excavatum. If suggests a paleosalinity of no more than 10%o. A mostly unfossiliferous silt and clay layer of variable thickness (post-C) occurs above zone C. It is probably lacustrine. Below zone A and above the Late Wisconsinan till there is a pre-A interval whose variable assemblages represent hyposaline environments east of Montréal, predominantly lacustrine conditions west of Montréal and alternating hyposaline/ lacustrine environments near and south of Montréal. Bottom water temperatures were probably "Arctic" (within a few degrees of 0°) from the pre-A interval up to zone B inclusively. The data from zone C are too poor to estimate temperatures. The shallow water zones indicate environments with high (zone EH) or low (zone EA) salinities but of shallower depths than the deep water zones. The existence of two sequences is interpreted as the result of (probably seasonal) water stratification. The data does not allow to determine the depth of the limit between the shallow and deep waters.

Habitat selection by common eiders in winter and its interaction with flock size

1993 ◽  
Vol 71 (6) ◽  
pp. 1259-1266 ◽  
Author(s):  
Magella Guillemette ◽  
John H. Himmelman ◽  
Cyrille Barette ◽  
Austin Reed
Keyword(s):  
Habitat Selection ◽  
Shallow Water ◽  
Prey Density ◽  
Sea Urchins ◽  
Day Length ◽  
Antipredator Behaviour ◽  
Somateria Mollissima ◽  
Flock Size ◽  
Eastern Canada ◽  
Diving Depth

We studied habitat selection in relation to prey density and water depth in the common eider, Somateria mollissima L., wintering in the Gulf of St. Lawrence, eastern Canada. In this region, eiders are confronted with low temperatures, ice cover, and reduced day length. We predicted that they should select feeding habitats characterized by high prey density and shallow water to minimize the time and energy spent while diving. About 1000 flocks were localized by triangulation on our study site (20.5 km2). We inferred the diving depth and the habitat being used from the position of eiders on bathymetric and community maps. The highest density of prey occurred in shallow water reefs where there were patches of blue mussels, Mytilus edulis L., and green sea urchins, Strongylocentrotus droebachienensis (Müller). Despite the fact that eiders can dive to depths as great as 42 m to feed, they strongly aggregate in shallow water, and their distribution closely coincides with the highest density of prey. The degree of selection for the reef habitat varies with seasonal variations in the size of flocks and in the total number of eiders present. Although flocking as an antipredator behaviour cannot be rejected, we interpret the high degree of flocking by eiders in our study area as a strategy to facilitate feeding in winter.

The Upper Givetian (Middle Devonian) Subterminus Conodont Zone in North America, Europe and North Africa

2010 ◽  
Vol 84 (4) ◽  
pp. 588-625 ◽  
Author(s):  
Katarzyna Narkiewicz ◽  
Pierre Bultynck
Keyword(s):  
New Species ◽  
North America ◽  
Shallow Water ◽  
North Africa ◽  
Middle Devonian ◽  
Holy Cross Mountains ◽  
The North ◽  
Conodont Zone ◽  
Montagne Noire ◽  
Stratigraphic Range

Late Givetian and early Frasnian conodont communities with Icriodus subterminus have been revised on the basis of collections from Iowa (USA), the Boulonnais and the Ardennes (northern France and Belgium), the Radom-Lublin area and Holy Cross Mountains (Poland), and the Ma'der-Tafilalt region (southeast Morocco). As a result an Icriodus subterminus Zone with a threefold subdivision is defined. The three subzones correspond approximately to the “Lower and Upper subterminus Fauna” and the “insita Fauna” commonly used in N America for the study of shallow-water platform carbonate successions.The base of the subterminus Zone corresponds to a level within the uppermost part of the hermanni Zone; the top is characterized by the occurrence of the earliest Ancyrodella taxa, Montagne Noire Zones MN 1 and the base of MN 2 or slightly above the base of the falsiovalis Zone.The diagnosis of Icriodus subterminus is amended and two morphotypes are recognized. The stratigraphic range of the alpha morphotype is confined to an interval between the uppermost part of the hermanni Zone and the top of the MN 3 Zone; the beta morphotype may range into the MN 6 Zone.The holotype of Icriodus subterminus from the North Liberty beds in Iowa is most likely a specimen that was reworked from the Cedar Valley Limestone. Icriodus cedarensis and Icriodus tafilaltensis are described as new species, and the diagnoses of Icriodus excavatus and Icriodus expansus are amended. Between the Icriodus difficilis and Icriodus symmetricus zones, an Icriodus expansus Zone is defined.

The Late Ordovician – Middle Devonian Gaspé Belt in eastern Canada — recent advances

2004 ◽  
Vol 41 (5) ◽  
pp. 483-487 ◽  
Author(s):  
Denis Lavoie ◽  
Michel Malo ◽  
Alain Tremblay
Keyword(s):  
Continental Margin ◽  
Middle Devonian ◽  
Late Ordovician ◽  
Research Progress ◽  
Special Issue ◽  
Eastern Canada ◽  
Recent Research Progress ◽  
Research Endeavour ◽  
Mapping Program ◽  
Organization Research

The Appalachian Forelands and Platform NATMAP (National Geoscience Mapping Program) project in eastern Canada is a multi-discipline and multi-organization research endeavour aimed at the understanding of the evolution and architecture of the ancient continental margin of Laurentia. This Canadian Journal of Earth Sciences Special Issue presents some recent research progress for our knowledge of the Silurian–Devonian Gaspé Belt of that ancient margin.

Conodont biostratigraphy of the Little Cedar and Lower Coralville Formations of the Cedar Valley Group (Middle Devonian) of Iowa and significance of a new species of Polygnathus

1998 ◽  
Vol 72 (4) ◽  
pp. 726-737 ◽  
Author(s):  
Frederick S. Rogers
Keyword(s):  
New Species ◽  
Shallow Water ◽  
Middle Devonian ◽  
Russian Platform ◽  
Large Numbers ◽  
Conodont Zonation ◽  
Coralville Formation ◽  
A New Species ◽  
Water Carbonate ◽  
Shallow Water Carbonate

The Little Cedar and lower Coralville formations of the Cedar Valley Group (Middle Devonian) of Iowa were deposited on a cratonic, shallow-water, carbonate and evaporite shelf during the Taghanic onlap. Four conodont subzones, zones, or cratonic biofacies faunas can be recognized in this sequence of strata. They are, in ascending order, the Middle varcus Subzone (recognized in the lower Little Cedar Formation), the hermanni zone (recognized in the middle Little Cedar Formation), the Lower subterminus Fauna (recognized in the upper Little Cedar Formation), and the Upper subterminus Fauna (recognized in the lower Coralville Formation). The Lower subterminus Fauna and the Upper subterminus Fauna represent a possible zonal span from the Lower hermanni Zone to the Upper disparilis Zone of the standard conodont zonation.In the Polygnathus- and Icriodus-dominated conodont faunas studied is a biostratigraphically useful new species. Polygnathus klugi new species is a Polygnathus dubius-like form that occurs sporadically and in small numbers in the Middle varcus Subzone, the hermanni Zone, and the Upper subterminus Fauna. However, it occurs consistently and in large numbers in the Lower subterminus Fauna, where it is the characterizing species. It has also been recovered from core samples both in central Alberta, Canada, and the Russian Platform. In both areas, it is associated with conodonts of the subterminus faunal interval.

The Middle Devonian Marine Transgression in North Devon and West Somerset

1965 ◽  
Vol 102 (6) ◽  
pp. 478-488 ◽  
Author(s):  
B. D. Webby
Keyword(s):  
Shallow Water ◽  
Sea Level ◽  
Middle Devonian ◽  
Intermediate Phase ◽  
Marine Transgression

AbstractThe lithological and faunal changes through the transition from non-marine Hangman Grits to marine Ilfracombe Beds of North Devon and West Somerset suggest the presence of a major depositional marine transgression. A fauna of thick-shelled lamellibranchs and gastropods occurs in beds lying stratigraphically between the flu-viatile Hangman deposits below, and the shallow-water marine Ilfracombe Beds above, and is considered to indicate an intermediate phase of intertidal depositional conditions. The transgression appears to have advanced across the region in a north-north-easterly direction during Lower-Middle Givetian times following coastal subsidence and possibly an associated rise of sea level.

New occurrences of trimerophytes from the Devonian of eastern Canada

1978 ◽  
Vol 56 (24) ◽  
pp. 3052-3068 ◽  
Author(s):  
Jeffrey B. Doran ◽  
Patricia G. Gensel ◽  
Henry N. Andrews
Keyword(s):  
Middle Devonian ◽  
Early Stage ◽  
Lateral Branch ◽  
Main Axis ◽  
Eastern Canada ◽  
Morphologic Variation ◽  
Lateral Branches ◽  
Branch Type ◽  
Established Species ◽  
New Occurrences

Pertica dalhousii n.sp. is described from the late Lower or early Middle Devonian of New Brunswick. The plant is known from a central axis with spirally arranged, mostly dichotomous lateral branches. Some lateral branches terminate in erect clusters of 32–128 fusiform sporangia. Spores are circular, trilete, with a detachable outer sculptured layer, and resemble the dispersed spore genus Apiculiretusispora Streel. A trimerophyte from Gaspé is described and provisionally designated as cf. Pertica sp.; the specimens are too incompletely preserved to be assigned to any established species, but they add further information about morphologic variation in the genus Pertica.With the addition of new plant types referable to the trimerophytes, distinctions between genera and species are becoming less readily apparent, supporting the suggestion that the trimerophytes are a group of closely related plants in which considerable evolution was occurring in late Lower and Middle Devonian times. Additionally, these plants appear to represent an early stage in the differentiation of a distinct main axis – lateral branch type of organizaiton that probably led to the later evolution of megaphyllous leaves.

scholarly journals Trilobite assemblage of Calceola-bearing beds in Acanthopyge Limestone (Choteč formation, Middle Devonian, Eifelian, Prague Basin, the Czech Republic)

2019 ◽  
Vol 75 (1) ◽  
pp. 79-91
Author(s):  
Petr Budil ◽  
Michal Mergl
Keyword(s):  
Czech Republic ◽  
Shallow Water ◽  
Middle Devonian ◽  
Precise Determination ◽  
Rare Occurrence ◽  
The Czech Republic ◽  
Prague Basin ◽  
Generic Composition ◽  
High Dynamic

Abstract The trilobite assemblage of Calceola-bearing beds in the upper part of Acanthopyge Limestone (Choteč Formation, Eifelian) in the Koněprusy area, the Czech Republic, is described. Together with occurrence of Calceola, it indicates absence of significant palaeogeographic barriers restricting the distribution of the Rhenish-Type faunas in the Middle Devonian. The generic composition of the gathered trilobite assemblage somewhat differs from typical Acanthopyge-Phaetonellus assemblage characteristic for the Acanthopyge Limestone facies in possible absence and/or very rare occurrence of Phaetonellus, and only infrequent occurrence of Acanthopyge. Phacopid Chotecops cf. hoseri (Hawle et Corda, 1847) distinctly dominates; all other taxa are rather rare. Important is an occurrence of scutelluids of the Scutellum sensu lato group (preservation of remains does not enable more precise determination) and Longiproetus(?). Trilobite remnants are generally poorly preserved and very fragmented (only minute shields are not affected), which support a high-dynamic, shallow-water original environment.

Carboniferous tetrapod footprint biostratigraphy, biochronology and evolutionary events

2021 ◽  
pp. SP512-2020-235
Author(s):  
Spencer G. Lucas ◽  
Matthew R. Stimson ◽  
Olivia A. King ◽  
John H. Calder ◽  
Chris F. Mansky ◽  
...  
Keyword(s):  
Nova Scotia ◽  
New Brunswick ◽  
Middle Devonian ◽  
Prince Edward Island ◽  
Early Permian ◽  
Eastern Canada ◽  
High Fiber ◽  
Maritimes Basin ◽  
Insight Into

AbstractThe Carboniferous record of tetrapod footprints is mostly of Euramerican origin and provides the basis for a footprint biostratigraphy and biochronology of Carboniferous time that identifies four tetrapod footprint biochrons: (1) stem-tetrapod biochron of Middle Devonian-early Tournaisian age; (2) Hylopus biochron of middle-Tournaisian-early Bashkirian age; (3) Notalacerta-Dromopus interval biochron of early Bashkirian-Kasimovian age; and (4) Dromopus biochron of Kasimovian-early Permian age. Particularly significant is the Carboniferous tetrapod footprint record of the Maritimes basin of eastern Canada (New Brunswick, Nova Scotia and Prince Edward Island), which encompasses well-dated and stratigraphically superposed footprint assemblages of Early Mississippian-early Permian age. The Carboniferous tetrapod footprint record provides these important biostratigraphic datums: (1) oldest temnospondyls (middle Tournaisian); (2) oldest reptiliomorphs, likely anthracosaurs (middle Tournaisian); (3) oldest amniotes (early Bashkirian); and (4) oldest high fiber herbivores (Bashkirian). Carboniferous tetrapod footprints thus provide significant insight into some major events of the Carboniferous evolution of tetrapods.

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