Authors / CoAuthors
Roach, I.C. | McQueen, K.G. | Brown, M.C.
Abstract
The Monaro Volcanic Province in southeastern New South Wales is an Early to Middle Tertiary intraplate volcanic province of lava field style, similar to the Newer Volcanic Province of southwestern Victoria. The lava pile is dominated by nepheline basanite, alkali olivine basalt and transitional basalt with minor olivine tholeiite and nepheline hawaiite. Olivine nephelinite lavas occur near the top of the lava pile. The lavas are interbedded with Tertiary sediments and hyaloclastites, some of which have formed in lakes, probably developed by lava damming the pre-basaltic drainage. Thick weathering profiles, in some cases bauxitic, are developed on many of the flows in the lava pile, suggesting long breaks between eruptions at particular sites. This is consistent with sporadic eruplions from widely scattered vents. Most known eruption sites in the province are represented by volcanic plugs of aphanitic to coarse-grained nepheline basanite, olivine nephelinite, nepheline hawaiite and alkali olivine basalt. Fractionated varieties of these rocks also occur together with minor feldspar-rich and titanian augite-rich cumulates. The predominant plug type is aphanitic to fine-grained nepheline basanite, containing mantle xenoliths and/or kaersutite amphibole. Basement fractures have had a major influence on the position of volcanic centres. Plugs are concentrated along two northwest trending linear zones: the Bemboka Zone in the north; and the Berridale-Towamba Zone in the south. The Berridale Fault-Towamba Lineament is a major crustal feature of the region. Other basement structures, including north-northeast-trending faults , appear to have controlled some eruption centres away from the two major zones.
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document
eCat Id
81405
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Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
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Keywords
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- GA PublicationJournal
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- NSW
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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- Published_External
Publication Date
1994-01-01T00:00:00
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unknown
Topic Category
geoscientificInformation
Series Information
AGSO Journal of Australian Geology and Geophysics 15:3:381-394
Lineage
Unknown
Parent Information
Extents
[-37.2, -35.8, 148.5, 149.5]
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Spatial Resolution
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