Authors / CoAuthors
Wang, L. | Chopping, R. | Duan, J.
Abstract
Geoscience Australia (GA) and the Geological Surveys of Queensland (GSQ) and NSW (GSNSW) are undertaking a multi-year, multi-disciplinary collaborative project with the aim of characterising the largely unexplored southern Thomson Oregon region (Figure 1). As part of this, a number of precompetitive geophysical datasets have been acquired or are planned to be acquired within the southern Thomson region. These datasets will support an improved understanding of the: - thickness and nature of cover; - geology obscured by recent sedimentary cover or regolith; and, - mineral systems potential of the region. Magnetotellurics is a passive geophysical technique which records the earth's natural time-varying electrical and magnetic fields to provide a measure of the subsurface conductivity/resistivity (these two physical properties are related as resistivity is the inverse of conductivity). The frequencies of magnetic and electrical sources recorded provide different depth information - audiomagnetotellurics (AMT) which records higher frequency data and images shallower electrical structure, while broadband MT (BBMT) records lower frequencies that image relatively deeper electrical structure. Although the depth of investigation of the technique varies according to the local resistivity structure, in general AMT images the shallowest upper crust only (14 km depth) and BBMT images the crust (~60 km depth). For the southern Thomson region, BBMT was acquired along 2 long and one shorter transect to provide pictures of the entire crust of the region, while AMT was acquired along shorter and higher-resolution lines to provide knowledge of the cover of the region. Within this document we detail the acquisition, processing and analysis of the MT data, and present preliminary resistivity models. These data, their analyses and models are released as underpinning datasets to support future geophysical analyses and geological interpretation. Accordingly, this report focuses primarily on the core geophysical aspects from acquisition through to preliminary modelling.
Product Type
document
eCat Id
90086
Contact for the resource
Custodian
Collaborator
Collaborator
Point of contact
Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
ACT
2601
Australia
Digital Object Identifier
Keywords
- Australian and New Zealand Standard Research Classification (ANZSRC)
-
- Magnetism and Palaeomagnetism
- ( {1} )
-
- HVC_144686
- ( {1} )
-
- GA Publication
- ( Theme )
-
- magneto-tellurics
- ( {1} )
-
- Published_External
Publication Date
2017-03-07T11:00:00
Creation Date
2016-01-01T00:00:00
Security Constraints
Legal Constraints
Status
Purpose
Maintenance Information
notPlanned
Topic Category
geoscientificInformation
Series Information
Record 2017/003
Lineage
Product is derived from geophysical data acquired in 2014-2015. Analyses in product conducted by Geoscience Australia personnel, as described in the product.
Parent Information
Extents
[-31, -27.5, 143.8, 147]
Reference System
Spatial Resolution
Service Information
Associations
Source Information
Data acquired by geophsyical contractors, 2014-2015. 143.8 147 -31 -27.5