Were Jurassic tholeiitic lavas originally widespread in southeastern Canada?: a test of the broad terrane hypothesis

1999 ◽  
Vol 36 (9) ◽  
pp. 1509-1516 ◽  
Author(s):  
Georgia Pe-Piper ◽  
David JW Piper
Keyword(s):  
Atlantic Canada ◽  
Large Area ◽  
Grand Banks ◽  
Type Section ◽  
The North ◽  
Geochemical Variations ◽  
Competing Models ◽  
Uplift And Erosion ◽  
Newark Basin ◽  
Fundy Basin

Two competing models have been proposed for Early Jurassic magmatism on the eastern North American margin. The "broad terrane" hypothesis argues that tholeiitic lavas were extruded over a large area and later eroded. Alternatively, the lavas were extruded only in the basins in which they now outcrop. We compare the stratigraphy and geochemistry of the tholeiitic lavas and dykes from Atlantic Canada with those of the type section of the Newark basin and use this correlation to test these two models. The earliest high-Ti quartz tholeiites in the type section are represented by lavas in the Fundy basin (North Mountain Basalt), Scotian basin, and eastern Grand Banks and by the Shelburne and Ministers Island dykes. Spatial and temporal geochemical variations in the North Mountain Basalt are mirrored by the Shelburne dyke, strengthening the case that the two were geochemically related. Basalts in Grand Manan Island, on the footwall of the Grand Manan fault that bounds the Fundy basin, are geochemically similar to the lowest North Mountain Basalt flow. These observations suggest that the earliest basalt flows were originally more extensive and have become restricted by later uplift and erosion. However, younger magmas in the Newark basin are represented only by the Caraquet, Anticosti, and Avalon dykes in Atlantic Canada, and corresponding lavas were never deposited in the Fundy basin or eastern Grand Banks. Thus, Jurassic tholeiitic lava distribution lies in between the predictions of the "broad terrane" and the "restricted basin" models.

Foraminiferal distribution and sedimentary facies on the Grand Banks of Newfoundland

1969 ◽  
Vol 6 (3) ◽  
pp. 475-487 ◽  
Author(s):  
B. K. Sen Gupta ◽  
R. M. McMullen
Keyword(s):  
Sedimentary Facies ◽  
Abundant Species ◽  
Large Area ◽  
Grand Banks ◽  
The North ◽  
Gravel Size ◽  
Labrador Current ◽  
Seaward Edge ◽  
Total Ratio ◽  
North Western

The southern part of the Grand Banks can be divided into three sedimentary regions. The north western region is dominated by gravel-size material; this is probably a reworked glacial sediment and its limit may indicate the seaward edge of the Quaternary ice sheet. The other regions are both dominated by sand-size pro-glacial material reworked in post-glacial times. The southwestern region includes a large area of finer sediment, which shows the highest density of foraminiferal tests. Dominant lineations indicate the probable influence of the Labrador Current and the Gulf Stream in the distribution of sediments.On the Tail of the Bank, an inverse relationship is commonly present between the density of the benthonic tests and the grain-size of the sediment. Of the 88 species present in the benthonic assemblage, 31 occur in 30% or more of the stations and only 5 occur in more than 90% of the stations. Islandiella islandica (Nørvang) is the most abundant species. The distribution of the living/total ratio in the benthonic Foraminifera is erratic, but particular areas of significantly high or low ratios may be related to different rates of sedimentation. The distribution of the planktonic assemblage, dominated by Globigerina pachyderma (Ehrenberg), is apparently controlled mainly by the movement of the Labrador Current waters. The percentage of planktonic tests in the total foraminiferal population decreases sharply on the shallow plateau, inward from the edge of the Bank.

OFFSHORE WIND ENERGY IN ATLANTIC CANADA - COMPARING THE INNER SHELF GEOLOGY WITH THAT OF THE NORTH SEA AND UNITED STATES ATLANTIC COAST

2020 ◽  
Author(s):  
Jordan Eamer ◽  
◽  
John Shaw ◽  
Edward L. King ◽  
Kevin Mackillop ◽  
...  
Keyword(s):  
United States ◽  
Wind Energy ◽  
North Sea ◽  
Atlantic Coast ◽  
Offshore Wind ◽  
Atlantic Canada ◽  
Offshore Wind Energy ◽  
Inner Shelf ◽  
The North ◽  
The North Sea

New Evidence of the Late Neopleistocene Peopling of the Lower Ob Valley

2021 ◽  
Vol 49 (1) ◽  
pp. 9-20
Author(s):  
I. D. Zolnikov ◽  
A. A. Anoikin ◽  
E. A. Filatov ◽  
A. V. Vybornov ◽  
A. V. Vasiliev ◽  
...  
Keyword(s):  
Upper Paleolithic ◽  
The Arctic ◽  
Northern Eurasia ◽  
West Siberian Plain ◽  
Faunal Remains ◽  
Human Occupation ◽  
Large Area ◽  
Paleolithic Site ◽  
The North ◽  
Available Information

This study focuses on the early human occupation of the arctic part of the West Siberian Plain and introduces the finds at the Paleolithic site Kushevat (Shuryshkarsky District, Yamal-Nenets Autonomous Okrug), discovered in 2020. Geological and geomorphological characteristics of the Lower Ob region are provided, the chronology of the key Middle and Late Neopleistocene sequences is assessed, and criteria underlying the search for Paleolithic sites in the area are outlined. We describe the discovery and excavations at Kushevat, its stratigraphy and its faunal remains. On the basis of correlation with neighboring key Late Neopleistocene sections with a representative series of absolute dates, the age of the site is estimated at cal 50–35 ka BP. Results of a traceological study of a possibly human-modified reindeer antler are provided. Findings at Kushevat and the available information on the early peopling of northern Eurasia suggest that the boundary of the inhabited part of that region must be shifted ~200 km to the north. The Ob, therefore, is one of the last major Siberian rivers where traces of the Early Upper Paleolithic culture have been found. The discovery of a stratified site in its lower stretch is a milestone in the Paleolithic studies in the region. A large area over which faunal remains are distributed, and the presence of lithics among the surface finds, suggest that Kushevat is a highly prospective site for future archaeological studies of the early stages in the human peopling of the region.

Ordovician rocks in the Eastcan et al. Freydis B-87 and other wells in offshore Atlantic Canada

1984 ◽  
Vol 21 (7) ◽  
pp. 864-868 ◽  
Author(s):  
W. A. M. Jenkins
Keyword(s):  
Late Ordovician ◽  
Atlantic Canada ◽  
Grand Banks ◽  
Exploratory Wells

Acritarchs and Chitinozoa from the lower 1300 ft (400 m) of the Eastcan et al. Freydis B-87 well, Labrador Shelf, indicate that these strata accumulated in a marine setting during Late Ordovician time. Five or more other exploratory wells on the Labrador Shelf and the Grand Banks of Newfoundland also have encountered Ordovician rocks.

Vowel raising in Basaa: a synchronic chain shift

Phonology ◽  
1996 ◽  
Vol 13 (2) ◽  
pp. 239-267 ◽  
Author(s):  
Deborah Schlindwein Schmidt
Keyword(s):  
Phonological Representation ◽  
Large Area ◽  
Bantu Languages ◽  
North East ◽  
The North ◽  
Equatorial Africa ◽  
Verb Forms ◽  
Vowel Raising

Like many of the zone A Bantu languages of western equatorial Africa, Basaa, which is spoken over a large area to the north-east and east of Douala, Cameroon, shows an inventory of seven surface vowels (Guthrie 1953). The Basaa forms cited in this article, all of which are found in the comprehensive Dictionnaire Basaa-Français (Lemb & de Gastines 1973), are transcribed using the vowel symbols in (1):These vowel symbols differ from those used by Guthrie only in that the hooks are eliminated from underneath his [i] and [u] and the dots are eliminated from underneath his [???] and [???]. I assume for these vowels the characteristics indicated in (1), where non-parenthesised feature specifications are a property of surface phonological representation and parenthesised feature specifications are default phonetic values. Following Hyman's (1988) analysis of Esimbi, another Cameroonian language containing these vowels in its inventory, I take [E] and [ɔ] to be low.The verb roots in (2) contain instances of each of the seven surface vowels of Basaa:Though bare verb roots may surface unsuffixed, suffixal extensions may also be added to give applied, passive, habitual, direct causative, indirect causative, simultaneous, associative, possessive, reversive, reflexive, stative and nominalised forms. Of interest to us is the vowel raising induced within the verb root when certain of these suffixal extensions are added. In (3) we see the CVC verb forms of (2) along with their corresponding applied and indirect causative forms:Other suffixal extensions that induce raising are the passive, direct causative, simultaneous, reversive and stative extensions. For example, these other suffixal extensions attach to /ten/, one of the verb roots in (3), to give [tina], [tinis], [tinha], [tinil] and [tiní], respectively.

scholarly journals Morphology and distribution of the freshwater mussel Diplodon granosus, a rare and poorly understood species

2020 ◽  
Vol 50 (1) ◽  
pp. 44-53 ◽  
Author(s):  
Igor Christo MIYAHIRA ◽  
Maria Cristina Dreher MANSUR ◽  
Daniel Mansur PIMPÃO ◽  
Sheyla Regina Marques COUCEIRO ◽  
Sonia Barbosa dos SANTOS
Keyword(s):  
South America ◽  
Freshwater Mussels ◽  
Freshwater Mussel ◽  
Wide Distribution ◽  
Large Area ◽  
The North ◽  
Coastal Rivers ◽  
The Status ◽  
Long Time

ABSTRACT Diplodon granosus was one of the first freshwater mussels to be described for South America. However, the status of the species was confusing for a long time, receiving different taxonomic treatments. In this paper, we redescribe the shell, with new data on the soft parts and information on the distribution and conservation of D. granosus, a rarely recorded species. The shell is thin, not inflated; the macrosculpture is composed only by granules that cover the whole shell, not forming bars; the microsculpture comprises short spikes. In the soft parts we highlight the few, weak and irregularly distributed lamellar connections of the outer demibranch and some features of the stomach, such as the distally enlarged minor typhlosole. There are records of D. granosus over a large area of South America, from Guiana to Argentina. However, most of these records are related to other species and the distribution of D. granosus is restricted to the north of South America in the basins of the Amazonas and Orinoco rivers, and coastal rivers in between. Despite this wide distribution, the species occurs in specific habitats, mainly streams (igarapés), resulting in an extremely fragmented occurrence. Thus, any disturbance to these habitats can threat this freshwater mussel.

scholarly journals Modelling the spread and connectivity of waterborne marine pathogens: the case of PaV1 in the Caribbean

2014 ◽  
Vol 72 (suppl_1) ◽  
pp. i139-i146 ◽  
Author(s):  
Andrew S. Kough ◽  
Claire B. Paris ◽  
Donald C. Behringer ◽  
Mark J. Butler
Keyword(s):  
Field Experiments ◽  
Significant Risk ◽  
Large Area ◽  
Larval Stages ◽  
The North ◽  
Risk Of Mortality ◽  
Rapid Spread ◽  
Waterborne Transmission ◽  
Juvenile Stages ◽  
The Caribbean

AbstractThe PaV1 virus infects spiny lobsters (Panulirus argus) throughout most of the Caribbean, where its prevalence in adult lobsters can reach 17% and where it poses a significant risk of mortality for juveniles. Recent studies indicate that vertical transmission of the virus is unlikely and PaV1 has not been identified in the phyllosoma larval stages. Yet, the pathogen appears subclinically in post-larvae collected near the coast, suggesting that lobster post-larvae may harbour the virus and perhaps have aided in the dispersal of the pathogen. Laboratory and field experiments also confirm the waterborne transmission of the virus to post-larval and early benthic juvenile stages, but its viability in the water column may be limited to a few days. Here, we coupled Lagrangian modelling with a flexible matrix model of waterborne and post-larval-based pathogen dispersal in the Caribbean to investigate how a large area with complex hydrology influences the theoretical spread of disease. Our results indicate that if the virus is waterborne and only viable for a few days, then it is unlikely to impact both the Eastern and Northwestern Caribbean, which are separated by dispersal barriers. However, if PaV1 can be transported between locations by infected post-larvae, then the entire Caribbean becomes linked by pathogen dispersal with higher viral prevalence in the North. We identify possible regions from which pathogens are most likely to spread, and highlight Caribbean locations that function as dispersal “gateways” that could facilitate the rapid spread of pathogens into otherwise isolated areas.

scholarly journals The Icelandic Low as a Predictor of the Gulf Stream North Wall Position

2016 ◽  
Vol 46 (3) ◽  
pp. 817-826 ◽  
Author(s):  
Alejandra Sanchez-Franks ◽  
Sultan Hameed ◽  
Robert E. Wilson
Keyword(s):  
Gulf Stream ◽  
Southern Oscillation ◽  
Time Lags ◽  
Grand Banks ◽  
The North ◽  
Cape Hatteras ◽  
Pressure Anomaly ◽  
Icelandic Low ◽  
North Wall ◽  
Wall Position

AbstractThe Gulf Stream’s north wall east of Cape Hatteras marks the abrupt change in velocity and water properties between the slope sea to the north and the Gulf Stream itself. An index of the north wall position constructed by Taylor and Stephens, called Gulf Stream north wall (GSNW), is analyzed in terms of interannual changes in the Icelandic low (IL) pressure anomaly and longitudinal displacement. Sea surface temperature (SST) composites suggest that when IL pressure is anomalously low, there are lower temperatures in the Labrador Sea and south of the Grand Banks. Two years later, warm SST anomalies are seen over the Northern Recirculation Gyre and a northward shift in the GSNW occurs. Similar changes in SSTs occur during winters in which the IL is anomalously west, resulting in a northward displacement of the GSNW 3 years later. Although time lags of 2 and 3 years between the IL and the GSNW are used in the calculations, it is shown that lags with respect to each atmospheric variable are statistically significant at the 5% level over a range of years. Utilizing the appropriate time lags between the GSNW index and the IL pressure and longitude, as well as the Southern Oscillation index, a regression prediction scheme is developed for forecasting the GSNW with a lead time of 1 year. This scheme, which uses only prior information, was used to forecast the GSNW from 1994 to 2015. The correlation between the observed and forecasted values for 1994–2014 was 0.60, significant at the 1% level. The predicted value for 2015 indicates a small northward shift of the GSNW from its 2014 position.

Observations nouvelles sur la stratigraphie du Jurassique de la region de Kandreho (Madagascar)

1963 ◽  
Vol S7-V (6) ◽  
pp. 969-979 ◽  
Author(s):  
Jean Blaison
Keyword(s):  
Type Section ◽  
The North

Abstract The cuestas along the Ikahavo coast, north of Tsilanarano, are designated as the type section for the Madagascar Jurassic. The transgressive marine Toarcian overlies the Isalo sandstone unconformably and is more extensive than previously thought. The thickness of the Aalenian is decreased due to the increased importance of the Toarcian. The Bathonian was located more to the north at Beranonorambe. Three ammonite species are described, Phymatoceras collignoni n. sp. (middle Toarcian), Sonninia (Sherbonites) aff. adicra, and Micromphalites (?) sp. (middle-upper Bathonian). Astarte baueri n. sp. is described from the Bouleiceras-Protogrammoceras zone.

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