scholarly journals Acado-Baltic Volcanism in Eastern North America and Western Europe: Implications for Cambrian Tectonism

10.4138/1609 ◽  
1986 ◽  
Vol 22 (3) ◽  
Author(s):  
John D. Greenough ◽  
V. S. Papezik
Keyword(s):  
North America ◽  
Western Europe ◽  
Eastern North America

Review of the Devonian camerate crinoid Bogotacrinus scheibei Schmidt from Colombia

1987 ◽  
Vol 61 (4) ◽  
pp. 750-757 ◽  
Author(s):  
George C. Mcintosh
Keyword(s):  
North America ◽  
Western Europe ◽  
Lower Devonian ◽  
Appalachian Basin ◽  
Upper Devonian ◽  
Eastern North America ◽  
Late Devonian ◽  
Early Devonian ◽  
Lower Upper

Two recently collected specimens of Bogotacrinus scheibei Schmidt, 1937, from the Devonian (Emsian–Eifelian) Floresta Formation of Colombia reveal that Bogotacrinus is a dicyclic camerate crinoid genus closely related to Pterinocrinus Goldring, 1923 (Lower–Upper Devonian of eastern North America and western Europe), and Ampurocrinus McIntosh, 1981 (Lower Devonian of Bolivia). The new diplobathrid camerate crinoid family Pterinocrinidae, characterized by species with low conical dicyclic cups and rami composed of compound, bipinnulate brachials, is herein proposed to accommodate these three genera. This family originated in western Europe and migrated into the Malvinokaffric and southern Eastern Americas Realms during the Early Devonian and into the northeastern Appalachian Basin by the Late Devonian.

Precise U–Pb zircon dates from the Avalon Terrane in Newfoundland

1988 ◽  
Vol 25 (3) ◽  
pp. 442-453 ◽  
Author(s):  
T. E. Krogh ◽  
D. F. Strong ◽  
S. J. O'Brien ◽  
V. S. Papezik
Keyword(s):  
North America ◽  
High Precision ◽  
Western Europe ◽  
Main Group ◽  
Eastern North America ◽  
Broad Area ◽  
Separate Event ◽  
Pan African ◽  
Intrusive Rocks ◽  
Group Flow

The following new U–Pb dates are provided for zircons from volcanic and intrusive rocks of the Avalon Terrane of Newfoundland: Burin Group ophiolite (Wandsworth pegmatitic gabbro), [Formula: see text]; Marystown Group ash-flow tuff, [Formula: see text]; Rock Harbour Group rhyolite clast in conglomerate, [Formula: see text]; Harbour Main Group ash-flow tuff, [Formula: see text]; Harbour Main Group flow-banded rhyolite, [Formula: see text]; porphyritic rhyolite plug intruding Harbour Main Group, 632 ± 2 Ma; Holyrood Granite, [Formula: see text]; rhyolite dyke, Harbour Main Group, [Formula: see text]; and welded ash-flow tuff, "Grand Beach porphyry," [Formula: see text]. All of the dated zircons are simple, single-age populations with no trace of inheritance. These dates confirm that the ophiolitic Burin Group represents an older and separate event that correlates precisely with the Bou Azzer ophiolite of Morocco and that the Rock Harbour Group does not represent continental volcanism that preceded that event. The Rock Harbour, Marystown, and Harbour Main groups and the Holyrood Granite (632–608 Ma) are all part of the younger 650–550 Ma pulse of Pan-African orogenesis that affected a broad area extending through Africa, Asia, western Europe, southern England and Wales, and eastern North America. However, a shortage of high-precision dates throughout these terranes precludes very exact correlations and thus very exact interpretations in terms of specific tectonic or magmatic events. Although these dates require some revisions in the stratigraphy of the Newfoundland Avalon Terrane, they do not support suggestions that the Avalon Terrane comprises a "collage of suspect terranes." The age of the Grand Beach porphyry (394 Ma) places it squarely with the Acadian granites of the Appalachians and removes it from consideration as part of the Marystown Group.

scholarly journals Differing histories of Eocene angiosperm diversity in eastern North America and western Europe: dependence on paleogeography

1992 ◽  
Vol 6 ◽  
pp. 105-105
Author(s):  
Norman O. Frederiksen
Keyword(s):  
North America ◽  
Western Europe ◽  
Environmental Heterogeneity ◽  
Gulf Coast ◽  
Middle Eocene ◽  
Late Eocene ◽  
Middle Part ◽  
Eastern North America ◽  
Climatic Fluctuations ◽  
Angiosperm Pollen

Studies of Eocene angiosperm pollen floras in eastern North America (my work, especially in the eastern Gulf Coast) and western Europe (Boulter, Krutzsch) have shown significant differences in floral diversities between the two regions: in western Europe, maximum diversity was in the early Eocene and it decreased thereafter, in eastern North America, maximum diversity was in the middle part of the middle Eocene. The hypothesis presented here is that paleogeography was an important control on the diversity histories in the two regions: eastern North America was part of a large terrestrial landmass, whereas the terrestrial depositional basins of western Europe were on islands or peninsulas surrounded by the sea. Migrations between eastern and western North America were relatively easy, but migrations within what is now western Europe involved island-hopping, which explains distinct diachroneity of some angiosperm first appearances among different basins there. Western European basins were in contact with a large land mass during late Paleocene time but became isolated and smaller during the middle to late Eocene marine transgression. These changes resulted in decreased genetic exchange and increased probabilities of extinction due to (1) greater competition among species because of a reduced number of niches and (2) presence of small, isolated species populations, leading to local variations in extinctions, which probably explain the observed diachronism of taxon last appearances in different areas of Europe. Terrestrial climatic cooling in western Europe may be linked to decreasing contact between the NW European Tertiary Basin and the warm Tethys Seaway during the middle and late Eocene. In short, some combination of low environmental heterogeneity, geographic isolation, and long-term climatic deterioration probably caused the decrease in angiosperm diversity during the middle and late Eocene in western Europe.Several factors encouraged increasing or stable diversity in eastern North America but were far less effective in western Europe: (1) Eastern North America underwent greater climatic fluctuations during the Eocene (thus, immigration of taxa with different climatic preferences took place at different times), whereas the islands and peninsulas of western Europe had more uniform, maritime climates. (2) Evolution and immigration of r-selected taxa in eastern North America were favored by distinct dry seasons at certain times during the Eocene and by repeated marine transgressions and regressions that created opportunities for evolution and immigration of r-selected plants on and to freshly exposed coastal plain. In contrast, the predominantly maritime climates of western Europe in the early and middle Eocene favored K-selected plants, which had fewer possibilities for evolution and which had greater difficulty in migrating because island-hopping taxa are mainly r-selected. (3) “Arcto-Tertiary” taxa adapted to cooler climates lived and evolved in the uplands of the Appalachian Mountains, whereas western Europe was relatively flat in the Eocene –another example of its relative lack of environmental heterogeneity.

scholarly journals Hairy St. John’s-wort (Hypericum hirsutum L.) in the Toronto Area, New to North America

2011 ◽  
Vol 125 (3) ◽  
pp. 248
Author(s):  
Paul A. Heydon ◽  
Gavin C. Miller ◽  
Michael J. Oldham
Keyword(s):  
North America ◽  
Western Europe ◽  
Western China ◽  
Eastern North America ◽  
St John’S Wort ◽  
St John's Wort ◽  
Natural Range

Hairy St. John’s-wort (Hypericum hirsutum L.) is newly reported for Canada and North America based on two collections from the Toronto, Ontario, area. This perennial Eurasian herb has a large natural range from western Europe to western China. It grows in moist successional, edge, and meadow habitats. It should be looked for in such habitats elsewhere in eastern North America.

First record of Euscelidius variegatus (Hemiptera: Cicadellidae) in eastern North America

2019 ◽  
Vol 151 (5) ◽  
pp. 648-650
Author(s):  
Jean-Philippe Parent ◽  
Lori Bittner ◽  
Joel H. Kits
Keyword(s):  
North America ◽  
Vitis Vinifera ◽  
Western Europe ◽  
First Record ◽  
Eastern North America ◽  
Western North America ◽  
Euscelidius Variegatus

AbstractEuscelidius variegatus (Kirschbaum) (Hemiptera: Cicadellidae) is a leafhopper known to vector phytoplasmas in cultivated vines (Vitis vinifera Linnaeus (Vitaceae)) of western Europe. Its occurrence has been recorded in western North America more than 60 years ago, but so far not in eastern North America, including Canada. In the last 15 years, three specimens have been found in Ontario near and around vineyards. Here we report the first record of E. variegatus in Canada and eastern North America.

scholarly journals Dynamical Systems Theory Sheds New Light on Compound Climate Extremes in Europe and Eastern North America

2020 ◽  
Author(s):  
Flavio Pons ◽  
Paolo De Luca ◽  
Gabriele Messori ◽  
Davide Faranda
Keyword(s):  
Dynamical Systems ◽  
North America ◽  
Systems Theory ◽  
Western Europe ◽  
Climate Extremes ◽  
Dynamical Systems Theory ◽  
Dependence Structure ◽  
Eastern North America ◽  
Geographical Regions ◽  
North Western

<p>We propose a novel approach to the study of compound extremes, grounded in dynamical systems theory. Specifically, we present the co-recurrence ratio (α), which elucidates the dependence structure between maps by quantifying their joint recurrences. This approach is applied to daily climate extremes, derived from the ERA-Interim reanalysis over the 1979-2018 period. The analysis focuses on concurrent (i.e. same-day) wet (total precipitation) and windy (10m wind gusts) extremes in Europe and concurrent cold (2m temperature) extremes in Eastern North America and wet extremes in Europe. Results for wet and windy extremes in Europe, which we use as a test-bed for our methodology, show that α peaks during boreal winter. High αvalues correspond to wet and windy extremes in north-western Europe, and to large-scale conditions resembling the positive phase of the North Atlantic Oscillation (NAO). This confirms earlier findings which link the positive NAO to a heightened frequency of extra-tropical cyclones impacting north-western Europe, resulting in frequent wet and windy extremes. For the Eastern North America-Europe case, α extremes once again reflect concurrent climate extremes -- in this case cold extremes over North America and wet extremes over Europe. Our analysis provides detailed spatial information on regional hotspots for these compound extreme occurrences, and encapsulates information on their spatial footprint which is typically not included in a conventional co-occurrence analysis. We conclude that α successfully characterises compound extremes by reflecting the evolution of the associated meteorological maps. This approach is entirely general, and may be applied to different types of compound extremes and geographical regions.</p>

Early Devonian conodonts from Prince of Wales Island, southeastern Alaska

1984 ◽  
Vol 21 (12) ◽  
pp. 1415-1425 ◽  
Author(s):  
Norman M. Savage ◽  
George E. Gehrels
Keyword(s):  
North America ◽  
Western Europe ◽  
Central And Eastern Europe ◽  
Eastern North America ◽  
Small Islands ◽  
Early Devonian ◽  
Northern Half ◽  
Eastern Australia ◽  
Southern Half ◽  
Devonian Age

Early Devonian conodonts from 11 localities on Prince of Wales Island and adjacent small islands, southeastern Alaska, include Pandorinellina optima (Moskalenko), Pandorinellina exigua philipi (Klapper), Pandorinellina exigua exigua (Philip), Pandorinellina? boucoti (Klapper), Pelekysgnathus serratus Jentzsch, Pelekysgnathus cf. P. klamathensis Savage, Pelekysgnathus n. sp., Eognathodus sulcatus sulcatus Philip, Eognathodus sulcatus kindlei Lane and Ormiston, Eognathodus sulcatus n. ssp. A, Eognathodus sulcatus n. ssp. B, Ozarkodina eberleini Savage, Kimognathus alexeii Mashkova, Kimognathus n. sp. A, and Kimognathus n. sp. B. The occurrences indicate that Lower Devonian deposits are widespread on Prince of Wales Island. On Wadleigh Island, Zlichovian, and probably older, deposits underlie Eifelian beds of the Wadleigh Limestone, previously thought to include limestone only of Middle and Late Devonian age. The Early Devonian faunas of this part of southeastern Alaska contain species characteristic of Cordilleran North America. There are strong affinities with Nevada, eastern Australia, and central Asia, but lesser affinities with central and eastern Europe. Affinities with eastern North America and western Europe are relatively weak. Regional variations in conodont color alteration indices suggest that the southern half of Prince of Wales Island has a different post-Devonian thermal history from the northern half.

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