Mapping the disruption of source magnetization depth estimates by near-surface magnetisations  

Authors / CoAuthors

Foss, C. | Hope, J.

Abstract

<div>Near-surface magnetizations are ubiquitous across many areas of Australia and complicate reliable estimation of depth to deeper magnetizations. We have selected four test areas in which we use equivalent source dipoles to represent and quantify the near-surface magnetizations. We present a synthetic modelling study that demonstrates that field variations from the near-surface magnetizations substantially degrade estimation of depth to a magnetization 500 metres below the modelled sensor elevation and that these problems persist even for anomalies with significantly higher amplitudes. However, preferential attenuation of the fields from near surface magnetizations by upward continuation proved quite effective in improving estimation of depth to those magnetizations.</div> This Abstract was submitted/presented at the 2023 Australasian Exploration Geoscience Conference (AEGC) 13-18 March (https://2023.aegc.com.au/)

Product Type

document

eCat Id

147451

Contact for the resource

Keywords

( Project )

• EFTF – Exploring for the Future

( Project )

• Australia’s Resources Framework

( Project )

• Darling-Curnamona-Delamerian

• near-surface

• Magnetics

• depth estimates

theme.ANZRC Fields of Research.rdf

• Applied geophysicsMagnetism and palaeomagnetism

• Published_External

Publication Date

2023-07-19T21:59:29

Creation Date

2022-12-02T05:00:00

Security Constraints

Australian Government Security Classification System    

Classification - unclassified

Legal Constraints

Creative Commons Attribution 4.0 International Licence    

Use - license otherRestrictions

Status

completed

Purpose

This abstract discusses the results of synthetic modelling to test the effect of near-surface or surface magnetic bodies on obtaining depth to top of magnetic sources for deeper bodies of interest. We have developed an equivalent source dipole model to help quantify magnetic field variations due to near-surface magnetizations. We have inverted measured magnetic field variations over near-surface magnetizations to which we have added synthetic model magnetic fields and show that the magnetic fields due to the near-surface magnetizations significantly degrade estimation of depth to those lower magnetizations. However, upward continuation appears to provide an effective means to attenuate the fields from the near-surface magnetizations and improve estimation of depth to deeper magnetizations.

Maintenance Information

asNeeded

Topic Category

geoscientificInformation

Series Information

Australasian Exploration Geoscience Conference (AEGC), Brisbane, 13-18 March 2023 4th AEGC conference

Lineage

<div>Extended abstract submitted for Australasian Exploration Geoscience Conference, Brisbane 2023 for a poster presentation. </div><div><br></div><div>This work forms part of the magnetic depth estimation collaboration between CSIRO and Geoscience Australia, as part of the Australian Resources Framework project in Geoscience Australia's Exploring for the Future program. Depth estimates derived from this collaboration are intended to be stored in Geoscience Australia's Estimates of Geological and Geophysical Surfaces database, the national repository of depth estimate data points.</div>

Parent Information

Extents

[-44.00, -9.00, 112.00, 154.00]

Reference System

Spatial Resolution

Service Information

Associations

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Link to Conference Page  

Link to Conference Paper (Zenodo)  

Link to Dropbox (full-paper_145.pdf)  

Download Poster (pptx) [5.5 MB]  

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