An acid deposition perspective for northeastern Alberta and northern Saskatchewan

1982 ◽  
Vol 18 (1-3) ◽  
pp. 413-419 ◽  
Author(s):  
S. R. Shewchuk
1986 ◽  
Vol 23 (9) ◽  
pp. 1433-1437 ◽  
Author(s):  
C. D. Frost ◽  
R. A. Burwash

To determine the extent of reworked Archean crust in the western Churchill Province, we have examined Sm–Nd crustal residence ages of basement cores in southern Alberta and southwestern Saskatchewan along with crustal residence ages calculated for other Sm–Nd data available from the Churchill Province. The deep drill hole samples from the Interior Platform give Sm–Nd crustal residence ages that average 2.8 Ga. Granulites from northeastern Alberta and composite gneisses from northern Saskatchewan also provide Archean crustal residence ages. These data demonstrate that the presence of reworked Archean crust in the western Churchill Province is more widespread than has been confirmed previously. We suggest that Sm–Nd crustal residence ages are valuable estimates of crust formation times, especially in orogenic areas where other isotope systems have been disturbed.


2016 ◽  
Vol 146 ◽  
pp. 300-310 ◽  
Author(s):  
Colin J. Whitfield ◽  
Aidan C. Mowat ◽  
Kenneth A. Scott ◽  
Shaun A. Watmough

Author(s):  
Kyle T. Thornham ◽  
R. Jay Stipes ◽  
Randolph L. Grayson

Dogwood anthracnose, caused by Discula destructiva (1), is another new catastrophic tree disease that has ravaged natural populations of the flowering dogwood (Cornus florida) in the Appalachians over the past 15 years, and the epidemic is prognosticated to continue (2). An estimated 9.5 million acres have been affected, primarily in the Appalachian Mountains, from VA southwards, alone, and an estimated 50% of all dogwoods in PA have been killed. Since acid deposition has been linked experimentally with disease induction, and since the disease incidence and severity are more pronounced at higher elevations where lower pH precipitation events occur, we investigated the effect of acidic foliar sprays on moiphologic changes in the foliar cuticle and trichomes (3), the initial sites of infection and foci of Discula sporulation.


Author(s):  
James S. Webber

INTRODUCTION“Acid rain” and “acid deposition” are terms no longer confined to the lexicon of atmospheric scientists and 1imnologists. Public awareness of and concern over this phenomenon, particularly as it affects acid-sensitive regions of North America, have increased dramatically in the last five years. Temperate ecosystems are suffering from decreased pH caused by acid deposition. Human health may be directly affected by respirable sulfates and by the increased solubility of toxic trace metals in acidified waters. Even man's monuments are deteriorating as airborne acids etch metal and stone features.Sulfates account for about two thirds of airborne acids with wet and dry deposition contributing equally to acids reaching surface waters or ground. The industrial Midwest is widely assumed to be the source of most sulfates reaching the acid-sensitive Northeast since S02 emitted as a byproduct of coal combustion in the Midwest dwarfs S02 emitted from all sources in the Northeast.


1987 ◽  
Vol 22 (4) ◽  
pp. 559-569 ◽  
Author(s):  
Thomas P. Hynes ◽  
Randy M. Schmidt ◽  
Tim Meadley ◽  
Neill A. Thompson

Abstract Data are provided on the release of 5 radionuclides, 17 metals and 7 major ions from a uranium mining operation in northern Saskatchewan. The downstream concentration of these contaminants is documented, and the point of “no discernible impact” is determined. Sediments in a downstream lake are monitored for uranium and molybdenum, and the post-release fate of these metals is discussed.


1984 ◽  
Vol 21 (10) ◽  
pp. 1082-1097 ◽  
Author(s):  
S. L. Fumerton ◽  
M. R. Stauffer ◽  
J. F. Lewry

The Early Proterozoic Wathaman batholith, in northern Saskatchewan and Manitoba, is a 900 km long, megacrystic granite–granodiorite intrusion that straddles the junction between ensialic miogeoclinal and probably ensimatic eugeoclinal–island-arc terranes of the "Trans-Hudson Orogen," of the western Churchill Province. Although the largest Precambrian batholith known, it is, apart from marginal complexities, remarkably homogeneous throughout and, unlike comparably sized and situated Phanerozoic batholiths, shows no evidence of multiple intrusion, nor does it have comagmatic early mafic phases. However, it may be considered as just one phase of a larger batholithic belt that also includes numerous smaller plutons. Taken as a whole the composite batholithic belt is similar in many aspects to Mesozoic Pacific rim batholithic belts, and like them probably was emplaced during plate collision.The batholith is affected by pervasive internal deformation, is bounded on the northwest by major blastomylonite zones, and is transected internally by splaying shear zones. It is a mid- to late-synkinematic Hudsonian intrusion, emplaced within a markedly compressional, crustal regime. On the basis of petrological, geochemical, and isotopic criteria the batholith is an "I-type" intrusion, but the origin of the magma and the emplacement mechanisms are still unresolved problems.


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