Authors / CoAuthors
Wilford, J.R.
Abstract
The combined analysis of airborne electromagnetics (AEM), airborne gamma-ray spectrometry (AGRS), magnetics and a digital elevation model with ground-based calibration, has enable construction of a 3D architectural and landscape evolution model of valley fill deposits around the township of Jamestown in South Australia. The valley fill sediments consist of traction, suspension and debris-flow deposits that range in age (optically stimulated luminescence OSL dating) from 102 ka (±12) to the present day. A sediment isopach map generated from the AEM dataset reveals the 3D structure of the valley-fill deposits. The sediments are up to 40 m thick within asymmetrical valleys and are the result of colluvial fan, floodplain and sheet-wash processes. The sediments fine upwards with a higher proportion of coarser bed load deposits toward the base and fine sand, silt and clay towards the top of the sequence. A strong linear correlation between airborne K response and soil texture allowed the percentage of surface silt to be modelled over the depositional landforms. The sediments are thought to have been derived by a combination of aeolian dust accessions, and weathering and erosion of bedrock materials within the catchment. Older drainage lines reflected in the distribution of relatively closely spaced and well connected 'magnetic channels' differ markedly from present day streams that are largely ephemeral and interrupted. This is thought to reflect a change in local hydrology and associated geomorphic processes from relatively high to lower energy conditions as the valley alluviated. These hydrological changes are likely to be associated with a drying climate, lower recharge and runoff.
Product Type
nonGeographicDataset
eCat Id
68546
Contact for the resource
Resource provider
Point of contact
Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
ACT
2601
Australia
Point of contact
- Contact instructions
- MEG
Keywords
-
- External Publication
- ( Theme )
-
- 3D model
- ( Theme )
-
- DEM
- ( Theme )
-
- drainage
- ( Theme )
-
- geomorphology
- ( Theme )
-
- regolith
-
- AU-SA
- Australian and New Zealand Standard Research Classification (ANZSRC)
-
- Earth Sciences
-
- Published_Internal
Publication Date
2009-01-19T00:00:00
Creation Date
Security Constraints
Legal Constraints
Status
Purpose
Maintenance Information
unknown
Topic Category
geoscientificInformation
Series Information
Lineage
Unknown
Parent Information
Extents
Reference System
Spatial Resolution
Service Information
Associations
Downloads and Links
Source Information
Source data not available.