Evidence and timing of crustal extension versus shortening in the early tectonothermal evolution of a Proterozoic continental rift sequence at Broken Hill, Australia

Low-pressure (P) high-temperature (T) metamorphism previously attributed to crustal thickening accompanying nappe emplacement in the Paleoproterozoic Willyama Supergroup at Broken Hill is reinterpreted as a response to crustal extension (D1) and bimodal magmatism commencing circa 1700 Ma. D1 deformation occurred under amphibolite-granulite facies conditions, producing layer-parallel fabrics (S1) and metapelitic mineral assemblages in which andalusite dominated over sillimanite. Crustal extension ceased soon after 1640 Ma to be followed by crustal thickening, higher-pressure metamorphism, and northeast vergent recumbent folding (D2) attendant on inversion of the original D1 extensional structures. D2 recumbent folding has previously gone unrecognized but probably peaked around 1600 Ma before further amphibolite facies metamorphism between 1600 and 1590 Ma accompanying upright folding and northwest directed thrust faulting (D3). In the light of this revised tectonothermal history, geodynamic models erected to explain elevated thermal gradients and low-P-high-T granulite facies metamorphism in tectonically thickened crust may not be as relevant to Broken Hill as once thought. Above average crustal temperatures and low-P-high-T metamorphism in the Willyama Supergroup more likely occurred in response to voluminous magmatic intrusion accompanying crustal thinning, mantle upwelling and emplacement and unroofing of midcrustal rocks along a major detachment surface. A second major structural and/or stratigraphic break in the Willyama Supergroup is indicated by the absence of D1 fabrics from the uppermost part of the sequence.

Simple

Identification info

Date (Publication)
2004-01-01T00:00:00
Citation identifier
Geoscience Australia Persistent Identifier/https://pid.geoscience.gov.au/dataset/ga/71093

Citation identifier
Digital Object Identifier/http://dx.doi.org/10.1029/2003TC001552

Cited responsible party
Role Organisation / Individual Name Details
Author

Gibson, G.M.

 1
Author

Peljo, M.

 2
Author

Chamberlain, T.

 3
Point of contact
Role Organisation / Individual Name Details
Custodian

MNHD
Owner

Commonwealth of Australia (Geoscience Australia)
Custodian

Commonwealth of Australia (Geoscience Australia)

 Voice
Topic category
  • Geoscientific information

Extent

N
S
E
W


Maintenance and update frequency
Unknown
Keywords

  • External Publication

  • Scientific Journal Paper

Keywords

  • AU-NSW

Australian and New Zealand Standard Research Classification (ANZSRC)

  • Earth Sciences

Keywords

  • Published_External

Resource constraints

Title

Creative Commons Attribution 4.0 International Licence

Alternate title

CC-BY

Edition

4.0

Website

http://creativecommons.org/licenses/

Access constraints
License
Use constraints
License

Resource constraints

Title

Australian Government Security ClassificationSystem

Edition date
2018-11-01T00:00:00
Website

https://www.protectivesecurity.gov.au/Pages/default.aspx

Classification
Unclassified
Language
English
Character encoding
UTF8

Distribution Information

Distributor contact
Role Organisation / Individual Name Details
Distributor

Commonwealth of Australia (Geoscience Australia)

 Voice
OnLine resource

Link to Publication

Link to Publication

Resource lineage

Statement

Unknown

Hierarchy level
Non geographic dataset
Other

External Publication

Description

Source data not available.

Metadata constraints

Title

Australian Government Security ClassificationSystem

Edition date
2018-11-01T00:00:00
Website

https://www.protectivesecurity.gov.au/Pages/default.aspx

Classification
Unclassified

Metadata

Metadata identifier
urn:uuid/a05f7892-f9b5-7506-e044-00144fdd4fa6

Title

GeoNetwork UUID

Language
English
Character encoding
UTF8
Contact
Role Organisation / Individual Name Details
Point of contact

Commonwealth of Australia (Geoscience Australia)

 Voice

Type of resource

Resource scope
Document
Name

nonGeographicDataset

Alternative metadata reference

Title

Geoscience Australia - short identifier for metadata record with

uuid

Citation identifier
eCatId/71093

Metadata linkage

https://ecat.ga.gov.au/geonetwork/srv/eng/catalog.search#/metadata/a05f7892-f9b5-7506-e044-00144fdd4fa6

Date info (Revision)
2018-04-22T08:44:53
Date info (Creation)
2010-09-30T00:00:00

Metadata standard

Title

AU/NZS ISO 19115-1:2014

Metadata standard

Title

ISO 19115-1:2014

Metadata standard

Title

ISO 19115-3

Title

Geoscience Australia Community Metadata Profile of ISO 19115-1:2014

Edition

Version 2.0, September 2018

Citation identifier
https://pid.geoscience.gov.au/dataset/ga/122551

 
 

Spatial extent

N
S
E
W



Provided by

Access to the portal

Associated resources

Not available