Authors / CoAuthors
Magee, J. | Brodie, R.S. | Halas, L.
Abstract
Groundwater resources have been investigated in Pliocene aquifers in the Lower Darling Valley (LDV) near Menindee, N.S.W. Multiple lines of evidence indicate that modern aquifer recharge is episodic and occurs by lateral leakage from incised channels during high-magnitude floods. Minimal modern recharge occurs away from the incised channels. The LDV Quaternary fluvial sequence consists of scroll-plain tracts of different ages incised into higher, older and more featureless floodplains, which were also originally deposited by lateral-migration fluvial phases. Optically-stimulated luminescence (OSL) and radiocarbon dating has been used to date periods of scroll-plain activity. The youngest, now inactive, scroll-plain phase associated with the modern Darling River, was active in the period 7-2 ka. A previous anabranch scroll-plain phase has Last Glacial Maximum dates around 17-22 ka. Older less distinct scroll-plain tracts are associated with the anabranch system (~30ka) and the Darling River tract (~45-50 ka). The oldest dates of 85 ka and >150 ka come from lateral-migration sediments, that lack visible scroll-plain traces and lie beneath the higher floodplain. This chronologic sequence suggests regular recurrence of ~5 ka lateral-migration episodes separated by ~10 ka periods of quiescence. The active lateral-migration phases, with deeply scoured channels, clean coarse channel and point-bar sands and probably higher stream-flow discharges are tacitly associated with enhanced palaeorecharge episodes. The Pliocene Calivil Formation in the Larloona Palaeochannel is located 4-10 km east of the modern Darling channel and is isolated from modern recharge. However it retains relatively low salinity groundwater, which has radiocarbon ages that range from 11.9 to 16.2 ka (calibrated to numeric ages). These groundwater ages correspond with a main episode of palaeorecharge relating to the lateral-migration phase in the nearby Talyawalka anabranch of the Darling River which was active between 17 and 22 ka. The slightly younger groundwater age reflects minor contributions of more recent waters since the main palaeorecharge event. In this way, palaeorecharge episodes can be linked to the interpreted depositional history that implicitly includes the role of neotectonics.
Product Type
nonGeographicDataset
eCat Id
75743
Contact for the resource
Custodian
Owner
Custodian
Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
ACT
2601
Australia
Keywords
-
- External PublicationAbstract
- Australian and New Zealand Standard Research Classification (ANZSRC)
-
- Geology
-
- Published_Internal
Publication Date
2013-01-01T00:00:00
Creation Date
Security Constraints
Legal Constraints
Special, MOU, etc.
Access - restricted
Use - license
Status
Purpose
Maintenance Information
notPlanned
Topic Category
geoscientificInformation
Series Information
Lineage
Abstract prepared for submission to the International Association of Hydrogeologists (IAH).
Parent Information
Extents
Reference System
Spatial Resolution
Service Information
Associations
Downloads and Links
Source Information
Source data not available.