Structural Succession, Nomenclature, and Interpretation of Transported Rocks in Western Newfoundland

1975 ◽  
Vol 12 (11) ◽  
pp. 1874-1894 ◽  
Author(s):  
Harold Williams
Keyword(s):  
North America ◽  
Subduction Zone ◽  
Continental Margin ◽  
North American ◽  
Sedimentary Rocks ◽  
Eastern North America ◽  
Stacking Order ◽  
Ophiolite Suite ◽  
Plutonic Rocks

The Humber Arm and Hare Bay Allochthons of Western Newfoundland are made up of a variety of sedimentary rocks and volcanic and plutonic rocks that originated toward the east and record the evolution and destruction of the ancient continental margin of Eastern North America. Five contrasting rock assemblages that constitute different structural slices are defined and delineated in the Humber Arm Allochthon. Six contrasting rock assemblages constitute the Hare Bay Allochthon. In each allochthon, the lower structural slices consist of sedimentary rocks and the highest structural slice consists of the ophiolite suite. The stacking order and mode of assembly indicate that progressively higher slices travelled increasingly greater distances, so that their present vertical superposition represents a former west-to-east juxtaposition.Most of the transported rocks have direct lithic correlatives in central Newfoundland. These occur west of the Dunnage Mélange, so that if the Dunnage marks the vestige of a North American subduction zone, then all the transported sequences once lay between a continental margin and a nearby oceanic trench.

Ophiolitic mélange and its significance in the Fleur de Lys Supergroup, northern Appalachians

1977 ◽  
Vol 14 (5) ◽  
pp. 987-1003 ◽  
Author(s):  
Harold Williams
Keyword(s):  
Continental Margin ◽  
Full Range ◽  
Sedimentary Rocks ◽  
Ultramafic Rocks ◽  
Eastern North America ◽  
Plate Boundaries ◽  
Polyphase Deformation ◽  
Ophiolitic Mélange ◽  
Ophiolite Suite ◽  
Clastic Sedimentary

Ophiolitic mélange consists of a chaotic mixture of sedimentary rocks and igneous rocks derived from the ophiolite suite of rock units. Its formation involves surficial mass wastage, gravity sliding, and tectonism at consuming plate boundaries. Most worldwide examples relate to ophiolite obduction and the destruction of stable continental margins.The Fleur de Lys Supergroup of the northern Appalachians consists of polydeformed and metamorphosed, mainly clastic sedimentary rocks that accumulated at the Hadrynian to early Paleozoic stable continental margin of eastern North America. Greenschists at or near the top of the succession in the east (Birchy Complex) contain zones of typical ophiolitic mélange. These contain large blocks of serpentinized ultramafic rocks, actinolite–fuchsite alterations of smaller ultramafic blocks, altered gabbro, a variety of clastic sedimentary blocks, and marble. All of the rocks are multideformed and metamorphosed so that the mélange was subjected to the full range of Fleur de Lys deformations.The presence of polydeformed and metamorphosed ophiolitic mélange in the Fleur de Lys Supergroup implies an early disruption or imbrication of its rock units. This disruption and mélange formation are interpreted to be related to transport of ophiolite complexes such as the Bay of Islands Complex across an initially undisturbed continental rise prism, the Fleur de Lys Supergroup. Later polyphase deformation and metamorphism of the Fleur de Lys Supergroup are possible results of continued structural submergence and telescoping of the continental margin beneath a thick cover of transported ophiolite rock units.

Tectonic setting of Avalonian volcanic and Plutonic rocks in the Caledonian Highlands, southern New Brunswick, Canada

1996 ◽  
Vol 33 (2) ◽  
pp. 156-168 ◽  
Author(s):  
S. M. Barr ◽  
C. E. White
Keyword(s):  
New Brunswick ◽  
Subduction Zone ◽  
Continental Margin ◽  
Tectonic Setting ◽  
Sedimentary Rocks ◽  
Igneous Activity ◽  
Appalachian Orogen ◽  
Group Form ◽  
Plutonic Rocks ◽  
Clastic Sedimentary

The Caledonian Highlands of southern New Brunswick consist of Late Proterozoic to Cambrian rocks generally considered typical of the Avalon terrane of the northern Appalachian Orogen. Mainly tuffaceous volcanic and sedimentary rocks of the Broad River Group and cogenetic dioritic to granitic plutons with ages ca. 620 Ma form most of the eastern Caledonian Highlands. They have petrological features indicative of origin in a continental margin subduction zone. Significantly younger ca. 560–550 Ma dacitic to rhyolitic lapilli tuffs and flows, laminated tuffaceous siltstone, basaltic and rhyolitic flows, and clastic sedimentary rocks of the Coldbrook Group form most of the western highlands, and occur locally throughout the highlands. The mainly tuffaceous lower part of the group has been intruded by gabbroic and syenogranitic plutons that are interpreted to be cogenetic with basaltic and rhyolitic flows in the upper part of the group. This voluminous subaerial magmatism may have formed during postorogenic extension in the earlier ca. 620 Ma subduction zone complex represented by the Broad River Group and associated plutons. This tectono-magmatic model differs from other interpretations that related most of the igneous units to ca. 630–600 Ma subduction, and did not recognize the importance of ca. 560–550 Ma magmatism. The ca 620 Ma subduction-related volcanic and plutonic rocks of the Caledonian Highlands are comparable to units in other parts of the Avalon terrane, but voluminous ca. 560–550 Ma igneous activity like that represented by the Coldbrook Group and related plutons has not been documented yet in other Avalonian areas.

New multituberculate mammal from the Early Cretaceous of eastern North America

2013 ◽  
Vol 50 (3) ◽  
pp. 315-323 ◽  
Author(s):  
Richard L. Cifelli ◽  
Cynthia L. Gordon ◽  
Thomas R. Lipka
Keyword(s):  
North America ◽  
Iberian Peninsula ◽  
Early Cretaceous ◽  
North American ◽  
Lower Cretaceous ◽  
Late Jurassic ◽  
Relative Length ◽  
Central Position ◽  
Eastern North America ◽  
The North

Multituberculates, though among the most commonly encountered mammalian fossils of the Mesozoic, are poorly known from the North American Early Cretaceous, with only one taxon named to date. Herein we describe Argillomys marylandensis, gen. et sp. nov., from the Early Cretaceous of Maryland, based on an isolated M2. Argillomys represents the second mammal known from the Arundel Clay facies of the Patuxent Formation (Lower Cretaceous: Aptian). Though distinctive in its combination of characters (e.g., enamel ornamentation consisting of ribs and grooves only, cusp formula 2:4, presence of distinct cusp on anterobuccal ridge, enlargement of second cusp on buccal row, central position of ultimate cusp in lingual row, great relative length), the broader affinities of Argillomys cannot be established because of non-representation of the antemolar dentition. Based on lack of apomorphies commonly seen among Cimolodonta (e.g., three or more cusps present in buccal row, fusion of cusps in lingual row, cusps strongly pyramidal and separated by narrow grooves), we provisionally regard Argillomys as a multituberculate of “plagiaulacidan” grade. Intriguingly, it is comparable in certain respects to some unnamed Paulchoffatiidae, a family otherwise known from the Late Jurassic – Early Cretaceous of the Iberian Peninsula.

scholarly journals Six new species and reports of Hydnum (Cantharellales) from eastern North America

MycoKeys ◽  
2018 ◽  
Vol 42 ◽  
pp. 35-72 ◽  
Author(s):  
Rachel A. Swenie ◽  
Timothy J. Baroni ◽  
P. Brandon Matheny
Keyword(s):  
North America ◽  
North American ◽  
Phylogenetic Analyses ◽  
Eastern North America ◽  
Phylogenetic Species ◽  
Additional Species ◽  
Taxonomic Descriptions ◽  
Molecular Phylogenetic ◽  
Herbarium Collections ◽  
Environmental Sequences

Five species of Hydnum have been generally recognized from eastern North America based on morphological recognition: H.albidum, H.albomagnum, H.repandum and varieties, H.rufescens, and H.umbilicatum. Other unique North American species, such as H.caespitosum and H.washingtonianum, are either illegitimately named or considered synonymous with European taxa. Here, seventeen phylogenetic species of Hydnum are detected from eastern North America based on a molecular phylogenetic survey of ITS sequences from herbarium collections and GenBank data, including environmental sequences. Based on current distribution results, sixteen of these species appear endemic to North America. Of these, six species are described as new: H.alboaurantiacum, H.cuspidatum, H.ferruginescens, H.subconnatum, H.subtilior, and H.vagabundum. Geographic range extensions and taxonomic notes are provided for five additional species recently described as new from eastern North America. A new name, H.geminum, is proposed for H.caespitosum Banning ex Peck, non Valenti. Overall, species of Hydnum are best recognized by a combination of morphological and molecular phylogenetic analyses. Taxonomic descriptions are provided for seventeen species, including epitype designations for H.albidum, H.albomagnum, and H.umbilicatum, taxa described more than 100 years ago, and molecular annotation of the isotype of H.washingtonianum. Photographs and a key to eastern North American Hydnum species are presented.

Telephinaand Other Trilobites from the Pratt Ferry Beds, Ordovician of Alabama, U.S.A.

2014 ◽  
Vol 88 (3) ◽  
pp. 545-555 ◽  
Author(s):  
Frederick C. Shaw
Keyword(s):  
North America ◽  
North American ◽  
Original Description ◽  
Eastern North America ◽  
Zone Boundary ◽  
Middle Ordovician ◽  
Conodont Zone ◽  
Stratigraphic Range ◽  
Single Locality

The Pratt Ferry beds are a three meter thick bioclastic carbonate unit containing thePygodus serrus–P. anserinusconodont zone boundary and lying just below theNemagraptus gracilisgraptolite zone at a single locality in Alabama.TelephinaMarek at Pratt Ferry and other eastern North American localities is represented by at least six species. These are judged widespread and in part conspecific with Scandinavian or Asian forms of similar age. Most of the fifteen Appalachian telephinid species proposed by Ulrich (1930) are reviewed and some synonymized.BevanopsisCooper is present, extending its stratigraphic range viaB. buttsi(Cooper). The original description ofCeraurinella buttsiCooper is augmented. Other recorded but poorly represented genera includeAmpyxina,Arthrorhachis,Calyptaulax,Hibbertia,Lonchodomas,Mesotaphraspis,Porterfieldia, andSphaerexochus. The entire faunule represents a mixture of ‘inshore’ and ‘offshore’ or planktonic faunal elements rarely seen elsewhere in the latest Middle Ordovician (Darriwilian) of eastern North America.

North American biogeography and taxonomy of Cryptolithus (Trilobita, Ordovician)

1994 ◽  
Vol 68 (4) ◽  
pp. 808-823 ◽  
Author(s):  
Frederick C. Shaw ◽  
Pierre J. Lespérance
Keyword(s):  
North America ◽  
North American ◽  
Type Species ◽  
Time Span ◽  
Eastern North America ◽  
Evolutionary Mechanisms ◽  
Variable Character

Museum and field restudy of Cryptolithus from all known geographic and stratigraphic occurrences in eastern North America shows that the principal variable character in this genus is the number of fringe pit arcs. Because this character varies within populations and even single individuals, it cannot be used to distinguish the earlier, typologically defined species of the genus. Instead, a neotype is designated here for the type species, Cryptolithus tessellatus Green, 1832, and morph designations are used for all pit arc variants. Over the time span considered, the species increased the number of pit arcs, but the ecological and evolutionary mechanisms responsible cannot be identified with certainty.

North American Devonian Carydiidae (Bivalvia): systematics, phylogeny, and implications in early diversification of the class

1986 ◽  
Vol 60 (2) ◽  
pp. 302-326 ◽  
Author(s):  
J. Bowman Bailey
Keyword(s):  
North America ◽  
Diagnostic Criteria ◽  
North American ◽  
The Other ◽  
Eastern North America ◽  
Higher Taxa ◽  
Early Diversification ◽  
European Family

Although past authors have regarded the Carydiidae as a European family, six species of Carydium are reported here from the Devonian of eastern North America. Two of these belong to a single morphocline common in the Hamilton shales; another (Carydium clarkei) is new. Due to lack of well preserved hinges most of these species were earlier placed in Nucula because serrations or striations on dental elements were mistaken for a taxodont dentition.New data require modification of carydiid phylogenies of earlier authors. 1) Two independent pre-Devonian derivations from Lyrodesma are inferred. 2) Noradonta shergoldi, a carydiid-like lyrodesmatid from the Ordovician of Australia, is recognized as an important phyletic link between the Carydiidae and the Lyrodesmatidae. 3) The previous view of three distinct lineages within Carydium is not supported. Anamorphic data suggest as few as two main lineages and show two of the hinge types to be homeomorphic grades appearing separately or within one or the other of the main lineages.Though too young to be directly involved in the early diversification of the Bivalvia, the actinodont, subheterodont, and pseudotaxodont hinge morphologies of Carydium supply models for the origin of heterodont and taxodont hinges. Anamorphic and other evidence suggests that both are iterative types, and fundamental differences between them may be few. Hence, their preeminence as diagnostic criteria among higher taxa is diminished.

Key Role of the North Pacific Oscillation–West Pacific Pattern in Generating the Extreme 2013/14 North American Winter

2015 ◽  
Vol 28 (20) ◽  
pp. 8109-8117 ◽  
Author(s):  
Stephen Baxter ◽  
Sumant Nigam
Keyword(s):  
North America ◽  
North American ◽  
North Pacific ◽  
Eastern North America ◽  
North Pacific Oscillation ◽  
Winter Climate ◽  
West Pacific ◽  
The North ◽  
The Tropics ◽  
The North Pacific

Abstract The 2013/14 boreal winter (December 2013–February 2014) brought extended periods of anomalously cold weather to central and eastern North America. The authors show that a leading pattern of extratropical variability, whose sea level pressure footprint is the North Pacific Oscillation (NPO) and circulation footprint the West Pacific (WP) teleconnection—together, the NPO–WP—exhibited extreme and persistent amplitude in this winter. Reconstruction of the 850-hPa temperature, 200-hPa geopotential height, and precipitation reveals that the NPO–WP was the leading contributor to the winter climate anomaly over large swaths of North America. This analysis, furthermore, indicates that NPO–WP variability explains the most variance of monthly winter temperature over central-eastern North America since, at least, 1979. Analysis of the NPO–WP related thermal advection provides physical insight on the generation of the cold temperature anomalies over North America. Although NPO–WP’s origin and development remain to be elucidated, its concurrent links to tropical SSTs are tenuous. These findings suggest that notable winter climate anomalies in the Pacific–North American sector need not originate, directly, from the tropics. More broadly, the attribution of the severe 2013/14 winter to the flexing of an extratropical variability pattern is cautionary given the propensity to implicate the tropics, following several decades of focus on El Niño–Southern Oscillation and its regional and far-field impacts.

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