Authors / CoAuthors
Blewett, R.S. | Czarnota, K. | Henson, P.A.
Abstract
The NNW-trending tectonic grain of the Eastern Yilgarn Craton (EYC) was established as a result of predominantly ENE-directed extension (D1 and D3) and E(ENE)-W(WSW) (D2, D4) to NE-SW directed (D5) contraction. The result has been a succession of NNW-striking co-planar, but temporally discrete, fabric elements that can be difficult to reliably interpret at any single location. Despite this, many past workers interpreted the NNW-striking fabric as the result of only one deformation event, and used it as a marker for correlating structural events across the region. In order to unravel the complexity, this paper presents a new six-fold (D1 to D6) deformation nomenclature based on >10000 new mesoscale structural observations including their kinematic analysis and cross cutting relationships. These mesoscale data were referenced with regional 3D map patterns, stratigraphic-magmatic-metallogenic considerations, and deep seismic reflection images. This integrated geodynamic-architectural approach is applicable to solving structural-event histories in other coplanar poly-deformed terrains. Gold mineralisation occurred during the first five events, but was particularly vigorous from D3 onwards. The D3 event marked the most profound change in the tectonic evolution of the EYC, with changes in greenstones, granites and tectonic mode (lithospheric extension and core complexes), with the first significant gold deposited within extensional shear zones that dissected the crust. Later contraction (D4) was imposed at a high angle to the previously established anisotropic architecture. The outcome was the creation of a new dynamic permeability framework which resulted in gold mineralisation during NNW-striking sinistral strike-slip faulting and associated thrusting. A further stress switch (D5) further modified the architecture resulting in N- to NNE-striking dextral strike-slip faulting, and the final period of gold mineralisation before late-stage extension (D6).
Product Type
nonGeographicDataset
eCat Id
68826
Contact for the resource
Custodian
Point of contact
Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
ACT
2601
Australia
Keywords
-
- External Publication
- ( Theme )
-
- structural geology
- ( Theme )
-
- mineral deposits
- ( Theme )
-
- pmd*CRC
-
- AU-WA
- Australian and New Zealand Standard Research Classification (ANZSRC)
-
- Earth Sciences
-
- Published_Internal
Publication Date
2009-04-20T00:00:00
Creation Date
Security Constraints
Legal Constraints
Status
Purpose
Maintenance Information
unknown
Topic Category
geoscientificInformation
Series Information
Lineage
Unknown
Parent Information
Extents
[-32.0, -26.0, 120.0, 126.0]
Reference System
Spatial Resolution
Service Information
Associations
Downloads and Links
Source Information
Source data not available.