Last edited by Vutaur
Friday, July 31, 2020 | History

3 edition of Early Archean basement in the Canadian Shield found in the catalog.

Early Archean basement in the Canadian Shield

W. R. A. Baragar

Early Archean basement in the Canadian Shield

a review of the evidence

by W. R. A. Baragar

  • 225 Want to read
  • 14 Currently reading

Published by Geological Survey of Canada : available from Printing and Publishing Supply and Services Canada in Ottawa .
Written in English

    Places:
  • Canadian Shield.
    • Subjects:
    • Geology, Stratigraphic -- Archaean.,
    • Geology -- Canadian Shield.

    • Edition Notes

      StatementW. R. A. Baragar, J. C. McGlynn.
      SeriesPaper - Geological Survey of Canada ; 76-14, Paper (Geological Survey of Canada) ;, 76-14.
      ContributionsMcGlynn, J. C., joint author.
      Classifications
      LC ClassificationsQE185 .A42 No. 76-14, QE653 .A42 No. 76-14
      The Physical Object
      Pagination21 cm. :
      Number of Pages21
      ID Numbers
      Open LibraryOL4295398M
      LC Control Number78323396

      Middle Archean to GA Early Archean to GA The divisions above are based upon key events in Earth history. For example, the onset of banded iron formations or BIFs. We’ll talk more about these next time. Incidentally, here are a couple of really nice diagrams from summary publications looking at the Canadian Shield. Precambrian - Precambrian - Precambrian geology: By international agreement, Precambrian time is divided into the Archean Eon (occurring between roughly billion years ago and billion years ago) and Proterozoic Eon (occurring between billion and million years ago). After the Precambrian, geologic time intervals are commonly subdivided on the basis of the fossil record.

      The Precambrian basement underlying the Williston Basin can be divided into three geological provinces (Green et al., ). The Archean Wyoming and Superior Provinces are cratonic masses. Precambrian - Precambrian - Greenstones and granites: Greenstone-granite belts such as those of the Archean continued to form in the Proterozoic, albeit in greatly reduced amounts. They are characterized by abundant volcanic rocks that include pillowed subaqueous basalt flows and subaerial and subaqueous volcaniclastic rocks. Magnesian komatiites are for the most part absent, however.

      Tectonic accretion of the northwestern Canadian Shield took place from Late Archean through Middle Proterozoic as oceanic lithosphere was consumed and terranes were amalgamated into the Slave craton by about Ga, and later, exotic terranes (e.g., Hottah terrane) were accreted to the western margin of the Slave craton between about Archean granitic rocks along the southern Bear–Slave boundary fall into three age groups: the oldest are Ma old intrusive tonalites and granodiorites that form the basement to the Yellowknife.


Share this book
You might also like
Report upon the paleontology of the province of Ontario

Report upon the paleontology of the province of Ontario

Price index numbers for current cost accounting

Price index numbers for current cost accounting

The Autobiography of an Unkown Indian

The Autobiography of an Unkown Indian

Insects as human food

Insects as human food

Femmes Et Metiers

Femmes Et Metiers

Catalogue of the ... collection of old porcelain, formed by the Right Honourable the late Earl of Dudley, ...

Catalogue of the ... collection of old porcelain, formed by the Right Honourable the late Earl of Dudley, ...

Amendment to transportation Act, 1920.

Amendment to transportation Act, 1920.

The last dying words, speech, and genuine confession of three malefactors, who were executed at Tyburn, near York, on Saturday the 13th of April, 1793

The last dying words, speech, and genuine confession of three malefactors, who were executed at Tyburn, near York, on Saturday the 13th of April, 1793

first thousand Penguins

first thousand Penguins

RACER # 3697203

RACER # 3697203

Channeling

Channeling

Ora tokai keno

Ora tokai keno

Jewish life in modern Britain

Jewish life in modern Britain

Early Archean basement in the Canadian Shield by W. R. A. Baragar Download PDF EPUB FB2

Get this from a library. Early Archean basement in the Canadian Shield: a review of the evidence. [W R A Baragar; J C McGlynn]. Early and Middle Archean rocks (greater than Ma) occur in the exposed parts of the Slave, Superior and Wyoming provinces.

The northern extension of the Wyoming craton into southern Alberta is indicated by a U-Pb zircon age of + 22/ from a basement core. The Archean Eon (/ ɑːr ˈ k iː ə n / ar-KEE-ən, also spelled Archaean or Archæan) is one of the four geologic eons of Earth's history, occurring (4 to Gya).During the Archean, the Earth's crust had cooled enough to allow the formation of continents and the beginning of life on Earth.

Early Archaean Basement on the Canadian Shield: A Review of the Evidence: Geol. Surv. Canada Paper, 7G (), p. 21 Bhatia, M.R. Bhatia Plate tectonics and geochemical composition of sandstonesAuthor: Richard W. Ojakangas.

SIMS, "Boundary between Archean greenstone and gneiss terranes in northern Wisconsin and Michigan", Selected Studies of Archean Gneisses and Lower Proterozoic Rocks, Southern Canadian Shield, G.

Morey, Gilbert N. Hanson. Greenstone belts are zones of variably metamorphosed mafic to ultramafic volcanic sequences with associated sedimentary rocks that occur within Archaean and Proterozoic cratons between granite and gneiss bodies.

The name comes from the green hue imparted by the colour of the metamorphic minerals within the mafic rocks: the typical green minerals are chlorite, actinolite, and other green. The diatreme is believed to have transported, from a deep crustal source, fragments of a previously unrecognized basement gneiss of early Archean age into m.

Metallogeny of Archaean-Proterozoic Boundaries Early proterozoic tectonics and metallogeny of the lake huron region of the Canadian shield Author links open overlay panel S.M.

Roscoe a K.D. Card. "Tonalitic gneiss of early Archean age from northern Michigan", Selected Studies of Archean Gneisses and Lower Proterozoic Rocks, Southern Canadian Shield. the crystalline basement of the continent, are exposed at the earth's surface in an area of about two million square miles in the Canadian Shield and in smaller areas of the Cordilleran and Appalachian mountain belts.

Elsewhere, the basement is buried beneath layers of sedimentary rock, as shown on Plate I (found after Chapter 20). Our informa. Archean surface crystalline rocks of the Canadian Shield differ chemically from those of Proterozoic age. The younger rocks are higher in K 2 O, TiO 2, U, and Th and lower in Na 2 O, Cr, Ni, and possibly MgO and CaO.

This may be a secondary result of vertical chemical zoning of the crust as a result of metamorphism accompanied by anatectic melting. The Slave Craton is an Archaean craton in the north-western Canadian Shield, in Northwest Territories and Slave Craton includes the Ga-old Acasta Gneiss which is one of the oldest dated rocks on Earth.

Covering aboutkm 2 (, sq mi), it is a relatively small but well-exposed craton dominated by ~– Ga (billion years-old) greenstones and turbidite. The main Archean elements of the Canadian Shield, the Slave, Rae, Hearne, and Superior cratons variously formed during the Eo- to Neoarchean, and each preserves rich Neoarchean to early Paleoproterozoic deformation and metamorphic cratons amalgamated during the latter part of the Paleoproterozoic to form the Laurentian component of supercontinent Nuna.

The Canadian Shield. A large area of Precambrian (Archean) basement rocks that make up the exposed core of North America and shows at the surface mostly across Canada and the northern United States.

Lasted from the early Archean until the beginning of the Proterozoic Eon. New and published apatite U-Pb, 40Ar/39Ar K-feldspar MDD, apatite fission-track, and zircon/apatite (U-Th)/He data from ≥ Ga crystalline basement rocks across the Canadian Shield (e.g. Except for the Alberta segment, the Snowbird tectonic zone was not the site of an Early Proterozoic plate margin.

We suggest that the geometry of the Archean–Early Proterozoic boundary in the western Canadian Shield represents a jagged continental margin, composed of a pair of reentrants defined by rifted and transform segments.

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.

Precambrian Research, 20 () Elsevier Science Publishers B.V., Amsterdam -- Printed in The Netherlands ARCHEAN CHEMICAL WEATHERING AT THREE LOCALITIES ON THE CANADIAN SHIELD MIKKEL SCHAU and JOHN B. HENDERSON Geological Survey of Canada, Booth Street, Ottawa, Ontario KIA OE4 (Canada) ABSTRACT Schau, M.

and. A shield is a large area of exposed Precambrian crystalline igneous and high-grade metamorphic rocks that form tectonically stable areas.

These rocks are older than million years and sometimes date back 2 to billion years. [citation needed] They have been little affected by tectonic events following the end of the Precambrian, and are relatively flat regions where mountain building.

Intracratonic indentation of the Archean Slave Province into the Early Proterozoic Thelon Tectonic Zone of the Churchill Province, northwestern Canadian Shield. John B.

Henderson, Peter H. McGrath, Reginald J. Theriault, and, Otto van Breemen. However, the U-Pb ages and Hf isotope systematics of xenocrystic zircons brought to the surface in lamproite diatremes from three Proterozoic outcrop areas of the craton suggest the widespread presence of unexposed Archean basement, with zircon age populations of – Ma and – Ma and Hf model ages of to ca.

Ga or older.The Canadian shield is divided into several provinces on the basis of a. fossil content. b. structural trends and age dates. c. the composition of the basement rocks.

d. sedimentary structures such as cross-bedding and paleocurrent directions.The Canadian Shield or Bouclier canadien (French), also called the Laurentian Plateau, is a large area of exposed Precambrian igneous and high-grade metamorphic rocks (geological shield) that forms the ancient geological core of the North American continent (the North American Craton or Laurentia).

Glaciation has left the area only a thin layer of soil, through which the composition of igneous.