Authors / CoAuthors
Gibson, D.L. | Magee, J.W. | Lawrie, K.C. | Halas, L.
Abstract
Neotectonic faulting and uplift has previously been described from field evidence in higher relief erosional areas in far northwest NSW. In this study, airborne electromagnetics (AEM) and high resolution LiDAR datasets were used to identify buried neotectonic features in the Lower Darling Floodplain and adjacent lowlands. The AEM data (acquired over an area of 7,500 sq km and validated by 100 new boreholes) reveal that the top surface of the ?Late Pliocene to Pleistocene Blanchetown Clay, a widespread lacustrine fine grained unit deposited in palaeo Lake Bungunnia, has an undulating to sharply offset surface. Gridding of closely spaced points on AEM flight line sections suggests that it has been affected by local warping and faulting, as well as regional tilting due to basin subsidence or margin uplift. Local relief reaches 20m, with small highs and lows apparently controlled by networks of closely spaced intersecting faults that are mostly expressed as warps in the near surface. Across the entire area, the top of the Blanchetown Clay varies in elevation from 20 to 80 m AHD. Some of the up-warped areas are associated with local landscape highs, but most structures have no apparent surface expression. However, the Darling River and its anabranches (Talyawalka, Charlie Stones and Tandou Creeks, and the Great Darling Anabranch) follow zones of local structural lows, and some of the interpreted faults are echoed by linear river reaches and terrace edges interpreted from LiDAR DEM and satellite imagery. Geomorphic mapping and dating of scroll-bar sediments suggest that the main course of flow of the Darling River system has previously flipped between two preferred courses (the modern Darling, and a course following Talyawalka Creek/Tandou Creek/Redbank Creek/Great Darling Anabranch). This newly discovered structural control explains why the Lower Darling channel has apparently not migrated across the entire floodplain.
Product Type
nonGeographicDataset
eCat Id
74801
Contact for the resource
Custodian
Point of contact
Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
ACT
2601
Australia
Keywords
-
- External PublicationAbstract
- ( Theme )
-
- deformation
- ( Theme )
-
- geomorphology
- Australian and New Zealand Standard Research Classification (ANZSRC)
-
- Earth Sciences
-
- Published_Internal
Publication Date
2012-10-25T00:00:00
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.