The Biogeographic History of Iceland – The North Atlantic Land Bridge Revisited

2011 ◽  
pp. 647-668 ◽  
Author(s):  
Thomas Denk ◽  
Friðgeir Grímsson ◽  
Reinhard Zetter ◽  
Leifur A. Símonarson
Keyword(s):  
North Atlantic ◽  
Land Bridge ◽  
The North ◽  
Biogeographic History ◽  
History Of ◽  
The North Atlantic

scholarly journals Historical biogeography of Acer L. (Sapindaceae): genetic evidence for Out-of-Asia hypothesis with multiple dispersals to North America and Europe

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jian Gao ◽  
Pei-Chun Liao ◽  
Bing-Hong Huang ◽  
Tao Yu ◽  
Yu-Yang Zhang ◽  
...  
Keyword(s):  
Northern Hemisphere ◽  
North Atlantic ◽  
Multiple Sources ◽  
Land Bridge ◽  
The North ◽  
Biogeographic History ◽  
Modern Species ◽  
History Of ◽  
Nuclear Its ◽  
Inference Methods

AbstractBiogeography is the study of where, when, and how modern species evolved and diversified. Acer L. (maple) is one of the most diverse and widespread genera in the Northern Hemisphere. It comprises 124–156 species in the world, approximately 80% species of Acer are native in Asia. The current diversity center of Acer is not congruent with the distribution of the oldest fossils of the genus. Therefore, we herein used 84 species and subspecies to reconstruct the phylogeny and investigate the biogeographic history of Acer using nuclear ITS and three cpDNA fragments (psbA-trnH spacer, rpl16 intron, and trnL-trnF spacer) with maximum likelihood, maximum parsimony, and Bayesian inference methods. The analyses showed that the current diversity center and the origin center of Acer is Asia. Additionally, the North American and Euro-Mediterranean species originated from multiple sources from Asia via the North Atlantic Land Bridge and the Bering Land Bridge, and intercontinental migration has mainly occurred since the Miocene. This study not only provides a novel insight of the origin and dispersal routes of Acer but also exemplifies how past climatic changes affect the diversification-rates of Northern Hemisphere forest trees.

TERTIARY LAND BRIDGES AND THEIR CLIMATE: BACKDROP FOR DEVELOPMENT OF THE PRESENT CANADIAN INSECT FAUNA

1980 ◽  
Vol 112 (11) ◽  
pp. 1089-1103 ◽  
Author(s):  
John V. Matthews
Keyword(s):  
North Atlantic ◽  
Coniferous Forest ◽  
Late Eocene ◽  
Land Bridge ◽  
Insect Fauna ◽  
The North ◽  
Late Tertiary ◽  
Tropical Conditions ◽  
History Of ◽  
The North Atlantic

AbstractStudies of Quaternary age Coleoptera fossils from North America and Europe plus recent analyses of insect fossils from late Tertiary (Miocene and Pliocene) sites in northern Canada, Alaska, and eastern Siberia show that many of the species composing the present Canadian insect fauna probably evolved during the Tertiary. Thus the history of Tertiary land bridge links between North American and adjacent continents is pertinent for a discussion of the present Canadian insect fauna.Movement of lithosphere plates has contributed directly to the emergence and foundering of Tertiary land bridges in three key areas: Beringia, the North Atlantic, and Middle America.A land bridge probably connected Siberia and Alaska in the Beringian region for most of the Tertiary. During the Eocene its climate was such as to allow exchange of tropical to subtropical adapted plants and animals. Paleobotanical evidence suggests that the Beringian area never supported the type of mixed-mesophytic forests called for by the Arcto-Tertiary concept. By the mid-Miocene much of the region north of 65° was probably a rich coniferous forest. Lowland tundra undoubtedly exited on the fringes of Beringia as early as the Pliocene.Two and possibly three land bridges connected Greenland and Northern Europe during the Tertiary. The DeGeer bridge joined northern Greenland and Norway prior to the opening of the Greenland Sea in the late Eocene – Early Oligocene. The Greenland-Faeroes bridge was never more than a causeway along the route of the submerged ridge now occupied by Iceland. However it persisted longer, possibly existing as a chain of islands as late as the Miocene. A third land bridge may have connected Labrador and Rockall Bank near England during the Paleocene and early Eocene. The climatic history of the North Atlantic region is poorly known, but apparently sites as far north as Ellesmere Island were warm enough during the Paleocene to support subtropical to warm temperate mammalian faunas.For most of the Tertiary the middle American region remained isolated from South America. Changes in movements of several lithosphere plates created conditions appropriate for north-south island dispersal as early as the Miocene but a true land connection, the existing isthmus, did not form until the Pliocene. Paleontological evidence suggests that tropical conditions were not prevalent there until after that event.

The Metasomatized Mantle beneath the North Atlantic Craton: Insights from Peridotite Xenoliths of the Chidliak Kimberlite Province (NE Canada)

2019 ◽  
Vol 60 (10) ◽  
pp. 1991-2024 ◽  
Author(s):  
M G Kopylova ◽  
E Tso ◽  
F Ma ◽  
J Liu ◽  
D G Pearson
Keyword(s):  
North Atlantic ◽  
Thermal State ◽  
Mineral Chemistry ◽  
Mantle Metasomatism ◽  
Labrador Sea ◽  
The North ◽  
Rock Types ◽  
History Of ◽  
The North Atlantic ◽  
North Atlantic Craton

Abstract We studied the petrography, mineralogy, thermobarometry and whole-rock chemistry of 120 peridotite and pyroxenite xenoliths collected from the 156–138 Ma Chidliak kimberlite province (Southern Baffin Island). Xenoliths from pipes CH-1, -6, -7 and -44 are divided into two garnet-bearing series, dunites–harzburgites–lherzolites and wehrlites–olivine pyroxenites. Both series show widely varying textures, from coarse to sheared, and textures of late formation of garnet and clinopyroxene. Some samples from the lherzolite series may contain spinel, whereas wehrlites may contain ilmenite. In CH-6, rare coarse samples of the lherzolite and wehrlite series were derived from P = 2·8 to 5·6 GPa, whereas predominant sheared and coarse samples of the lherzolite series coexist at P = 5·6–7·5 GPa. Kimberlites CH-1, -7, -44 sample mainly the deeper mantle, at P = 5·0–7·5 GPa, represented by coarse and sheared lherzolite and wehrlite series. The bulk of the pressure–temperature arrays defines a thermal state compatible with 35–39 mW m–2 surface heat flow, but a significant thermal disequilibrium was evident in the large isobaric thermal scatter, especially at depth, and in the low thermal gradients uncharacteristic of conduction. The whole-rock Si and Mg contents of the Chidliak xenoliths and their mineral chemistry reflect initial high levels of melt depletion typical of cratonic mantle and subsequent refertilization in Ca and Al. Unlike the more orthopyroxene-rich mantle of many other cratons, the Chidliak mantle is rich (∼83 vol%) in forsteritic olivine. We assign this to silicate–carbonate metasomatism, which triggered wehrlitization of the mantle. The Chidliak mantle resembles the Greenlandic part of the North Atlantic Craton, suggesting the former contiguous nature of their lithosphere before subsequent rifting into separate continental fragments. Another, more recent type of mantle metasomatism, which affected the Chidliak mantle, is characterized by elevated Ti in pyroxenes and garnet typical of all rock types from CH-1, -7 and -44. These metasomatic samples are largely absent from the CH-6 xenolith suite. The Ti imprint is most intense in xenoliths derived from depths equivalent to 5·5–6·5 GPa where it is associated with higher strain, the presence of sheared samples of the lherzolite series and higher temperatures varying isobarically by up to 200 °C. The horizontal scale of the thermal-metasomatic imprint is more ambiguous and could be as regional as tens of kilometers or as local as <1 km. The time-scale of this metasomatism relates to a conductive length-scale and could be as short as <1 Myr, shortly predating kimberlite formation. A complex protracted metasomatic history of the North Atlantic Craton reconstructed from Chidliak xenoliths matches emplacement patterns of deep CO2-rich and Ti-rich magmatism around the Labrador Sea prior to the craton rifting. The metasomatism may have played a pivotal role in thinning the North Atlantic Craton lithosphere adjacent to the Labrador Sea from ∼240 km in the Jurassic to ∼65 km in the Paleogene.

scholarly journals First monk seal from the Southern Hemisphere rewrites the evolutionary history of true seals

2020 ◽  
Vol 287 (1938) ◽  
pp. 20202318
Author(s):  
James P. Rule ◽  
Justin W. Adams ◽  
Felix G. Marx ◽  
Alistair R. Evans ◽  
Alan J. D. Tennyson ◽  
...  
Keyword(s):  
Southern Hemisphere ◽  
North Atlantic ◽  
Marine Mammals ◽  
Evolutionary History ◽  
Major Change ◽  
The North ◽  
History Of ◽  
Entire History ◽  
The North Atlantic ◽  
Monk Seals

Living true seals (phocids) are the most widely dispersed semi-aquatic marine mammals, and comprise geographically separate northern (phocine) and southern (monachine) groups. Both are thought to have evolved in the North Atlantic, with only two monachine lineages—elephant seals and lobodontins—subsequently crossing the equator. The third and most basal monachine tribe, the monk seals, have hitherto been interpreted as exclusively northern and (sub)tropical throughout their entire history. Here, we describe a new species of extinct monk seal from the Pliocene of New Zealand, the first of its kind from the Southern Hemisphere, based on one of the best-preserved and richest samples of seal fossils worldwide. This unanticipated discovery reveals that all three monachine tribes once coexisted south of the equator, and forces a profound revision of their evolutionary history: rather than primarily diversifying in the North Atlantic, monachines largely evolved in the Southern Hemisphere, and from this southern cradle later reinvaded the north. Our results suggest that true seals crossed the equator over eight times in their history. Overall, they more than double the age of the north–south dichotomy characterizing living true seals and confirms a surprisingly recent major change in southern phocid diversity.

A connected history of political economy in Asia and Europe, ca 1750–1914

2020 ◽  
pp. 1-2
Author(s):  
Alessandro Stanziani
Keyword(s):  
Political Economy ◽  
Ottoman Empire ◽  
North Atlantic ◽  
Western Europe ◽  
Economic Thought ◽  
The North ◽  
History Of ◽  
The North Atlantic ◽  
History Of Political Economy ◽  
Political Economic

The history of political-economic thought has been built up over the centuries with a uniform focus on European and North American thinkers. Intellectuals beyond the North Atlantic have been largely understood as the passive recipients of already formed economic categories and arguments. This view has often been accepted not only by scholars and observers in Europe but also in many other places such as Russia, India, China, Japan, and the Ottoman Empire. In this regard, the articles included in this collection explicitly differentiate from this diffusionist approach (“born in Western Europe, then flowed everywhere else”).

Second reply to the comment by Romero and Kannada on “Genetic analysis of 16th-century whale bones prompts a revision of the impact of Basque whaling on right and bowhead whales in the western North Atlantic”Appears in Can. J. Zool. 84(7): 1059–1065.

2008 ◽  
Vol 86 (1) ◽  
pp. 76-79 ◽  
Author(s):  
Jeff W. Higdon
Keyword(s):  
Genetic Analysis ◽  
North Atlantic ◽  
16Th Century ◽  
Bowhead Whales ◽  
Potential Value ◽  
The North ◽  
The Pacific ◽  
History Of ◽  
The North Atlantic ◽  
The Impact

The comments by A. Romero and S. Kannada (2006. Can. J. Zool. 84: 1059–1065) provide a brief summary of North Atlantic whaling history as a critique of T. Rastogi et al. (2004. Can. J. Zool. 82: 1647–1654) . However, they fall far short of providing an accurate review of whaling history in this region. The authors present a number of factual errors, misuse several key sources, and make significant omissions, ultimately defeating the purpose of providing information to biologists, managers, and historians. In this comment I highlight the mistakes in their representation of the history of North Atlantic whaling for bowhead whales ( Balaena mysticetus L., 1758). There are unacceptable errors for most nations covered, and for American whaling in particular. The authors assert that over 30 000 bowhead whales were landed by Yankee whalers in the North Atlantic when the vast majority were in fact taken on the Pacific grounds. Although a summary of whaling history is an admirable goal and of potential value, it is unfortunate that the authors missed such an opportunity by failing to adequately research this topic, failing to include important citations, and by including sources that do not provide the information indicated. Providing a whaling summary with such errors and omissions only adds further confusion to an already confusing theme.

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