| Title | Proposals for time classification and correlation of precambrian rocks and events in Canada and adjacent areas of the Canadian Shield part 1 : a time classification of precambrian rocks and
events |
| Download | Downloads |
| |
| Licence | Please note the adoption of the Open Government Licence - Canada
supersedes any previous licences. |
| Author | Stockwell, C H |
| Source | Geological Survey of Canada, Paper no. 80-19, 1982, 135 pages (6 sheets), https://doi.org/10.4095/109353  Open Access |
| Year | 1982 |
| Publisher | Geological Survey of Canada |
| Document | serial |
| Lang. | English |
| Maps | Publication contains 4 maps |
| Map Info. | geological, 1:10,000,000 |
| Media | paper; on-line; digital |
| Related | This publication is related to Proposals for time
classification and correlation of precambrian rocks and events in Canada and adjacent areas of the Canadian Shield, part 2: a provisional standard for correlating precambrian rocks |
| File format | pdf |
| Province | British Columbia; Alberta; Saskatchewan; Manitoba; Ontario; Quebec; New Brunswick; Nova Scotia; Prince Edward Island; Newfoundland and Labrador; Northwest Territories; Yukon; Nunavut; Canada |
| NTS | 1; 2; 3; 10; 11; 12; 13; 14; 15; 16; 20; 21; 22; 23; 24; 25; 26; 27; 28; 29; 30; 31; 32; 33; 34; 35; 36; 37; 38; 39; 40; 41; 42; 43; 44; 45; 46; 47; 48; 49; 52; 53; 54; 55; 56; 57; 58; 59; 62; 63; 64; 65;
66; 67; 68; 69; 72; 73; 74; 75; 76; 77; 78; 79; 82; 83; 84; 85; 86; 87; 88; 89; 92; 93; 94; 95; 96; 97; 98; 99; 102; 103; 104; 105; 106; 107; 114O; 114P; 115; 116; 117; 120; 340; 560 |
| Subjects | geochronology; geological time scale; Precambrian |
| Released | 1982 03 01; 2016 03 11 |
| Abstract | Precambrian time is subdivided on the basis of periods of orogenic activity as displayed mainly in the Canadian Shield. Commonly each orogeny is followed unconformably by the deposition of sedimentary
and volcanic rocks. The time boundaries chosen are natural ones that separate basement from unconformably overlying rocks. To achieve this, boundaries between time units are drawn at the close of the last orogeny of the basement and are defined in
type regions which serve as standards r or reference. Isotopie age determinations are used to date, as accurately as possible, the geologically defined time boundaries in type regions but present estimates may be revised as more information becomes
available. Isotopie ages are also used for arranging the several tirne units in chronological order, for placing sedimentary and volcanic rock and anorogenic intrusions into their appropriate time units, and for long range correlation. All
Precambrian time is divided into two main units called the Archean and Proterozoic with the boundary between them defined by the close of the Kenoran Orogeny presently estimated at about 2500 Ma. The Archean is divided into four informal units, the
oldest ending about 3400-3500 Ma ago. The Proterozoic is divided into three formal units called the Aphebian, the H elikian, and the Hadrynian with boundaries between them defined, respectively, by the close of the Hudsonian Orogeny at about 1750 Ma
and by the close of the Grenvillian Orogeny at about 1000 Ma. Each of the se Proterozoic units is further divided into two or three time units, mostly informal. |
| GEOSCAN ID | 109353 |
|
|