40Ar/39Ar dating of micas from the East Kemptville tin deposit, Yarmouth County, Nova Scotia

1985 ◽  
Vol 22 (10) ◽  
pp. 1546-1548 ◽  
Author(s):  
M. Zentilli ◽  
P. H. Reynolds
Keyword(s):  
Nova Scotia ◽  
North America ◽  
Iberian Peninsula ◽  
South Mountain Batholith ◽  
Northwest Africa ◽  
Acadian Orogeny ◽  
Tin Deposit

The East Kemptville tin deposit in Nova Scotia, the largest known tin deposit in North America, lies in a greisen zone within the Davis Lake Pluton, generally considered to be part of the Devonian South Mountain Batholith. Our dating of micas from within the deposit suggests that the greisenization process that accompanied mineralization took place about 295 ± 5 Ma ago, that is, ca. 60 Ma after the emplacement of the batholith.Hydrothermal alteration–mineralization activity in southern Nova Scotia coincided with extensive shearing and tectonism throughout the Hercynian orogen. The East Kemptville deposit appears to be approximately coeval with similar mineralization in southwest England, the Iberian peninsula, and northwest Africa and much younger than the Devonian Acadian orogeny.

Fuscopannaria ignobilis. [Descriptions of Fungi and Bacteria].

2013 ◽  
Author(s):  
P. F. Cannon
Keyword(s):  
North America ◽  
Iberian Peninsula ◽  
Geographical Distribution ◽  
Conservation Status ◽  
Deciduous Trees ◽  
Epiphytic Lichen ◽  
Northwest Africa ◽  
Closed Canopy

Abstract A description is provided for Fuscopannaria ignobilis, a widespread epiphytic lichen-forming fungus, usually found on deciduous trees, but sometimes also on evergreens, occurring on both closed canopy forests and open areas, away from the sea and often at higher altitudes in the Iberian Peninsula. Some information on its dispersal and transmission and conservation status is given, along with details of its geographical distribution (Africa (Kenya, northwest Africa), North America (USA), Europe (Croatia, France, Greece, Italy, Montenegro, Norway, Portugal, Slovenia, Spain, UK)).

Petrology of the South Mountain Batholith, Nova Scotia

1975 ◽  
Vol 12 (7) ◽  
pp. 1209-1218 ◽  
Author(s):  
C. B. McKenzie ◽  
D. B. Clarke
Keyword(s):  
Nova Scotia ◽  
Fractional Crystallization ◽  
Lower Crust ◽  
Granitic Rocks ◽  
The South ◽  
South Mountain Batholith ◽  
Partial Fusion ◽  
Acadian Orogeny

Approximately one-third of western Nova Scotia is underlain by granitic rocks of the South Mountain batholith. The pi u ton is an epizonal complex of granodiorite, adamellite and alaskite which was emplaced after the folding and metamorphic events of the Acadian orogeny. Chemical and petrographic data suggest that the rocks comprise a single comagmatic suite related by the fractional crystallization of biotite and plagioclase. The magma for the batholith may have been produced by partial fusion of the lower crust, or through a hybridization of mantle and crustal melts.

Geochronological evidence for multiple tectono-thermal overprinting events in the East Kemptville muscovite–topaz leucogranite, Yarmouth County, Nova Scotia, Canada

1991 ◽  
Vol 28 (2) ◽  
pp. 209-224 ◽  
Author(s):  
D. J. Kontak ◽  
R. F. Cormier
Keyword(s):  
Nova Scotia ◽  
North America ◽  
Low Temperature ◽  
Thermal Activity ◽  
Geochronological Data ◽  
Step Heating ◽  
Meguma Terrane ◽  
Tin Deposit ◽  
Incremental Step ◽  
Geochronological Evidence

The East Kemptville muscovite–topaz leucogranite, located in Yarmouth County, Nova Scotia, Canada, is host rock to the only producing primary tin deposit in North America (56 Mt, 0.165% Sn). Previous geochronological studies include (i) Rb–Sr whole-rock analyses of the quartz–topaz greisens, which indicated a date of 337 ± 5 Ma, and (ii) 40Ar/39Ar analyses of greisen muscovite, which indicated apparent plateau dates of ca. 300 Ma. However, the pervasive development of deformational fabrics at East Kemptville suggests that both the Rb–Sr whole-rock and 40Ar/39Ar muscovite ages are at best minimum estimates for the inferred time of mineralization. In the present study, Rb–Sr whole-rock and mineral (muscovite, plagioclase, K-feldspar) analyses and 40Ar/39Ar incremental-step heating of a muscovite separate indicate the following: (i) diffusion of Sr on the whole-rock scale terminated at 344 ± 5 Ma (11 point isochron date), coincident with closure of muscovite to intracrystalline diffusion of Ar (apparent plateau date of 338 ± 2 Ma) and (ii) internal reequilibration of Sr among muscovite, feldspar, and whole rock varied considerably such that Rb–Sr whole rock – muscovite pairs give dates of 361–311 Ma (mean = 330 Ma, n = 7), whereas whole rock – plagioclase – K-feldspar give dates of 276–240 Ma (mean = 254 Ma, n = 7). This younger thermal event is reflected in apparent dates of 269–286 Ma for the low-temperature steps of the 40Ar/39Ar muscovite age spectrum.Collectively the data indicate that the East Kemptville area either cooled slowly over a protracted period of time (ca. 100 Ma) or experienced episodic tectono-thermal activity at ca. 344, 330, and 254 Ma. Examination of previously published geochronological data for the southern Meguma Terrane indicates that these aforementioned ages broadly coincide with earlier documented magmatic or tectono-thermal events (e.g., intrusion of Wedgeport Pluton at 315 Ma). Inferences by some workers of mid-Carboniferous magmatism in the Meguma Terrane are, however, not supported by the present study.

Syn-Acadian emplacement model for the South Mountain batholith, Meguma Terrane, Nova Scotia: Magnetic fabric and structural analyses

1997 ◽  
Vol 109 (10) ◽  
pp. 1279-1293 ◽  
Author(s):  
Keith Benn ◽  
Richard J. Horne ◽  
Daniel J. Kontak ◽  
Geoffrey S. Pignotta ◽  
Neil G. Evans
Keyword(s):  
Nova Scotia ◽  
Magnetic Fabric ◽  
The South ◽  
South Mountain Batholith ◽  
Meguma Terrane

CHAETOCNEMA CONCINNA (MARSHAM, 1802), A EUROPEAN FLEA BEETLE INTRODUCED IN NORTH AMERICA (COLEOPTERA: CHRYSOMELIDAE: ALTICINAE)

1990 ◽  
Vol 122 (4) ◽  
pp. 647-650
Author(s):  
Laurent Lesage
Keyword(s):  
Nova Scotia ◽  
North America ◽  
Prince Edward Island ◽  
Host Plants ◽  
Flea Beetle ◽  
Collection Data ◽  
First Time

AbstractChaetocnema concinna (Marsham, 1802), a European flea beetle, is reported for the first time from Canada. Preliminary collection data indicate that it may feed on the same host plants as in Europe. It has been collected to date in Prince Edward Island, Nova Scotia, and Maine.

PREDATION BY INSECTS AND SPIDERS INHABITING COLONIAL WEBS OF HYPHANTRIA CUNEA

1972 ◽  
Vol 104 (8) ◽  
pp. 1197-1207 ◽  
Author(s):  
R. F. Morris
Keyword(s):  
Population Dynamics ◽  
Nova Scotia ◽  
North America ◽  
Population Density ◽  
New Brunswick ◽  
Numerical Response ◽  
Initial Number ◽  
Hyphantria Cunea ◽  
The North ◽  
The Mean

AbstractThe number of predators inhabiting nests of Hyphantria cunea Drury was recorded annually for 13 years in four areas in New Brunswick and two areas on the coast of Nova Scotia. The most common groups were the pentatomids and spiders, which sometimes reproduced within the nests, but the mean number per nest was low in relation to the number of H. cunea larvae in the colonies. The rate of predation on fifth-instar larvae was low. Small or timid predators appeared to prey largely on moribund larvae or small saprophagans during the principal defoliating instars of H. cunea.No relationship could be detected between the number of larvae reaching the fifth instar and the number of predators in the colony; nor could any functional or numerical response of the predators to either the initial number of larvae per colony or the population density of colonies be found. It is concluded that the influence of the nest-inhabiting predators is small and relatively stable, and may be treated as a constant in the development of models to explain the population dynamics of H. cunea.H. cunea is a pest in parts of Europe and Asia, where it has been accidentally introduced from North America. The introduction to other continents of the North American predator, Podisus maculiventiis (Say), is discussed briefly.

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.

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