Zobrazeno 1 - 10
of 16
pro vyhledávání: '"Thomas E. Krogh"'
Publikováno v:
Canadian Journal of Earth Sciences. 48:205-245
The Pikwitonei Granulite Domain located at the northwestern margin of the Superior Province is one of the largest Neoarchean high-grade terranes in the world, with well-preserved granulite metamorphic assemblages preserved in a variety of lithologies
Autor:
David F.HessD.F. Hess, Robert E.JohnsonR.E. Johnson, Peter S. Dahl, Thomas E. Krogh, Sandra L. Kamo, Thomas B. Hanley
Publikováno v:
Canadian Journal of Earth Sciences. 48:161-185
The Middle Mountain Metamorphic Domain of the Montana Metasedimentary Terrane, northwestern Wyoming Craton, within the northwestern Tobacco Root Mountains, mainly comprises migmatized tonalitic gneiss interlayered with amphibolitic (hornblende) gneis
Publikováno v:
Canadian Journal of Earth Sciences. 48:441-472
Reconstructing tectonic histories involving continental collision, subduction, and exhumation at plate-tectonic rates of ∼1 cm/year, requires precise U–Pb zircon geochronology. The Western Gneiss Region has exceptional exposures of high-pressure
Publikováno v:
Canadian Journal of Earth Sciences. 48:325-346
The U–Pb geochronology of three granitoid plutons and three granitic pegmatite dykes, largely from the Thompson Nickel Belt located along the northwestern Superior craton margin, was investigated to place constraints on the timing of felsic magmati
Publikováno v:
Precambrian Research. 167:201-212
The easternmost Grenville Province behaved in a structurally distinct manner from the remainder of the eastern Grenville Province (EGP) during Grenvillian orogenesis (1085–985 Ma). Geochronological, structural and geophysical data are used to demon
Publikováno v:
Precambrian Research. 165:61-95
This study is a fascinating example, from the eastern Grenville Province, of unraveling the triple challenges inherent in the geochronological investigation of any multi-orogenic region, namely inheritance, emplacement and subsequent metamorphism. Th
Publikováno v:
Canadian Journal of Earth Sciences. 39:831-843
Four UPb dating sites straddling the Grenville front on the Labrador coast were investigated. Sites 1 and 2 exhibit complex intrusive, deformational, and metamorphic histories and were studied in detail, whereas two simpler outcrops (sites 3 and 4)
Autor:
Thomas E. Krogh, Charles F. Gower
Publikováno v:
Canadian Journal of Earth Sciences. 39:795-829
The geological evolution of the eastern Grenville Province can be subdivided into three stages. During the first stage, namely pre-Labradorian (> 1710 Ma) and Labradorian (17101600 Ma) events, a continental-marginal basin was created and subsequent
Autor:
Thomas E. Krogh, Donald W. Davis
Publikováno v:
Chemical Geology. 172:41-58
Zircons from two Archean samples, a 2732-Ma trondhjemite and a 2728-Ma dacite, both from the western Superior province, were washed in hydrofluoric acid (HF) at moderate temperatures. Zircon residues and HF wash solutions were analyzed for U/Pb isoto
Publikováno v:
Precambrian Research. 89:25-45
In the southwestern Grenville Province, the Central Gneiss Belt consists of a belt of parautochthonous rocks in the north and a collage of allochthonous lithotectonic domains in the south. Near Pointe-au-Baril, Ontario, the allochthon-parautochthon b