Abstract

In a reconstructed supercontinent assembly at ~0.9 Ga, the Grenville orogen extends from Scandinavia through North America and Antarctica to Australia. Part of it, the 2000 km long Grenville Province, exposed in the southeastern Canadian Shield, is large enough to allow a comprehensive view of its tectonic character. It has an orogen-parallel zonation: older, reworked crust, representing Archaean and Palaeoproterozoic orogens exposed in adjacent parts of the shield, is restricted to its northwest side; supracrustal and plutonic rocks of Grenvillian age (~1.3-0.95 Ga) are limited to the southeastern half. The latter lie on or within late Palaeoproterozoic and earlier Mesoproterozoic crust, which is the deformed, temporal equivalent of terranes that form a substantial part of the buried North American craton south of the shield. A pre-Grenvillian period of quiescence at ~1.5 Ga may have followed an earlier continental assembly. Grenvillian calc-alkaline igneous rocks, limited in volume and distribution, represent arc accretion that terminated with ocean closure by ~1.2 Ga. New crust was added after continent-continent collision and attendant crustal thickening by emplacement of large gabbro-anorthosite massifs of mantle origin, associated with, and in part responsible for, granitoid magma derived from the lower crust. This magmatism, beginning at ~1.18 Ga, was accompanied or followed by high-grade metamorphism, except in parts of the Grenvillian supracrustal terranes, and by low-angle, thrust-sense, ductile deformation directed toward the north and northwest. Ductile followed by brittle extensional deformation between 1.05 and 1.0 Ga, along with terminal thrust-uplift along the northwest margin of the orogen, represent the closing stages of tectonic activity, leading to unroofing and cooling by ~0.9 Ga. There is little evidence in the Grenville Province for supercontinent break-up until ~600 Ma.
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Product Type/Sub Type

nonGeographicDataset

Constraints

Creative Commons Attribution 4.0 International Licence

IP Owner

Commonwealth of Australia (Geoscience Australia)

Author(s)

Date (publication)

1995-01-01T00:00:00

Product Type

nonGeographicDataset

Topic Category

geoscientificInformation

GA Catalogue Number

81418 Product http://www.ga.gov.au/metadata-gateway/metadata/record/81418/

Keywords

GA Publication
Journal
Earth Sciences

Resource Language

English

Resource Character Set

utf8

Resource Security Classification

unclassified

Lineage

Unknown

Digital Transfer Options

onLine

Distributor

Role
distributor
Organisation Name
Commonwealth of Australia (Geoscience Australia)
City
Canberra
Administrative Area
ACT
Postal Code
2601
Country
Australia
Email Address

Source Description

Source data not available.

Metadata File Identifier

fae9173a-7167-71e4-e044-00144fdd4fa6

Metadata Standard Name

ANZLIC Metadata Profile: An Australian/New Zealand Profile of AS/NZS ISO 19115:2005, Geographic information - Metadata

Metadata Standard Version

1.1

METADATA SECURITY CLASSIFICATION

unclassified

Metadata Contact

Role
pointOfContact
Organisation Name
Commonwealth of Australia (Geoscience Australia)
City
Canberra
Administrative Area
ACT
Postal Code
2601
Country
Australia
Email Address
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