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Walker Volcanics STRATNO: 19240
Current: Yes Rank: Formation, beds Status: Formal State(s): ACT , NSW
Category: Unknown or process pending Usage: Defined Definition Card: No
Originator: Entry date: 01-JAN-88Last Update: 20-AUG-18
Replaced by: Previously known as:
Description: Green to purple dacite ignimbrite and bedded tuff, minor andesite, volcaniclastic sediment and limestone; calcareous and tuffaceous shale and siltstone
Comments: Canberra & Michelago 1:100k sheet areas. Equivalent to, but not yet formally included in, the Douro Group [2012].
Geological province: Lachlan Orogen
Type state: ACTReference section type: outcrop section
Maximum thickness: 1500mMinimum thickness:
Unit Age Event: eruption
Top of unit -
Minimum age: Wenlock Ma: % from base of biozone: Age method:
Maximum age: Ma: % from base of biozone: Age method:
Base of unit -
Minimum age: Ma: % from base of biozone: Age method:
Maximum age: Early Silurian Ma: % from base of biozone: Age method:

Stratigraphic Hierarchy (current units only) Rank Status

Chemical Hierarchy (current units only) Rank Status


Related units: Relationship: Contact Type:
Tarpaulin Creek Ashstone Member overlies Walker Volcanics
First Reference:
REFID: 36441 Owen, M., Wyborn, D., Blythe, P., 1979, Brindabella, New South Wales and Australian Capital Territory, 1:100 000 geological series map. Sheet 8627, 1st edition., Bureau of Mineral Resources, Australia, 1v, Map

Definition Reference:
REFID: 42820 Abell, R.S., 1991, Geology of the Canberra 1:100 000 Sheet area, New South Wales and Australian Capital Territory, Bureau of Mineral Resources, Australia. Bulletin, 233, 116p

Use on maps:
REFID: 36441 Owen, M., Wyborn, D., Blythe, P., 1979, Brindabella, New South Wales and Australian Capital Territory, 1:100 000 geological series map. Sheet 8627, 1st edition., Bureau of Mineral Resources, Australia, 1v, Map
REFID: 36633 Henderson, G.A.M., Matveev, G., 1980, Geology of Canberra, Queanbeyan, and Environs, 1:50 000 geological series map. 1st edition., Bureau of Mineral Resources, Australia, 1v
REFID: 42497 Duff, B.A., Ward, P., Crook, K.A.W., Rickard, M.J., 1985, Tasman Orogen Profile 5 - Wagga Wagga-Batemans Bay, New South Wales., Geological Survey of New South Wales, 1v, Map
REFID: 42726 Chappell, B.W., English, P.M., King, P.L., White, A.J.R., Wyborn, D., 1991, Granites and related rocks of the Lachlan Fold Belt (1:1 250 000 scale map)., Bureau of Mineral Resources, Australia, 1v, map
REFID: 42727 Abell, R.S., 1992, Canberra 1:100 000 scale geological map sheet 8727. 1st edition., Bureau of Mineral Resources, Australia, 1v, map
REFID: 44092 Wyborn, D., Owen, M., Wyborn, L., 1990, Geology of the Kosciusko National Park (1:250 000 scale map), Bureau of Mineral Resources, Australia, 1v, map
REFID: 60078 Owen, M., Wyborn, D., Wyborn, L., 1982, Kosciusko National Park and Environs, New South Wales, 1:250 000 Geological Special, Preliminary edition, Bureau of Mineral Resources, Geology and Geophysics, 1v, Map


Full Bibliographic Details (ordered by usage, publication year)

REFID: 42820 Abell, R.S. 1991 Geology of the Canberra 1:100 000 Sheet area, New South Wales and Australian Capital Territory Bureau of Mineral Resources, Australia. Bulletin 233 116p
Usage: Defined (p26) Min age from reference: Early Silurian Comments: Of Hawkins Volcanic Suite.
REFID: 45147 Owen, M. , Wyborn, D. 1979 Geology and geochemistry of the Tantangara and Brindabella 1:100 000 Sheet areas, New South Wales and Australian Capital Territory. Bureau of Mineral Resources, Australia. Bulletin 204
Usage: Defined (M144) Min age from reference: late Wenlockian Max age from reference: late Wenlockian Comments:
REFID: 41356 Owen, M. , Senior, D. , Owen, J. , Hodgson, J. 1988 Geological monuments in the Australian Capital Territory. Australian Heritage Commission 1v
Usage: Fully described (p18) Comments:
REFID: 22857 Scheibner, E. , Basden, H. (ed.) 1998 Geology of New South Wales - Synthesis. Volume 2 Geological Evolution. Geological Survey of New South Wales. Memoir (Geology) 13(2) 666pp
Usage: Described (p176, p462 App.1 Tb.A1.6) Min age from reference: Wenlockian Max age from reference: Wenlockian Comments: Of the Hawkins Suite. Massive and banded dacitic ignimbrite; minor interbedded lenses of fossiliferous limestone and shale. Max. thickness: 1.5km. See also p464 App.1,Tb.A1.6.
REFID: 43159 Wyborn, D. 1993 Palaeozoic Felsic Volcanism in the Canberra District Australian Geological Survey Organisation. Record 1993/68 13p
Usage: Described (Fig.2p4,p9.) Comments:
REFID: 42421 Johnston, P.A. 1991 Systematics and ontogeny of a new bivalve, Umburra cinefacta, from the Silurian of Australia: implications for pteriomorphian evolution. Alcheringa 15(4) p293-319
Usage: Described (p294) Min age from reference: Wenlockian late Comments:
REFID: 37728 Henderson, G.A.M. 1981 Geology of Canberra, Queanbeyan, and environs. Notes to accompany the 1980 1:50 000 geological map. Bureau of Mineral Resources, Australia 1v
Usage: Described (Table 2) Comments:
REFID: 22768 Scheibner, E. , Basden, H. (ed.) 1998 Part 6(16). Silurian-Middle Devonian. In: Geology of New South Wales - Synthesis. Geological Survey of New South Wales. Memoir (Geology) 13(2) p140-189
Usage: Briefly described (p176) Comments:
REFID: 42727 Abell, R.S. 1992 Canberra 1:100 000 scale geological map sheet 8727. 1st edition. Bureau of Mineral Resources, Australia 1v map
Usage: Briefly described (map legend) Min age from reference: Wenlock Max age from reference: Wenlock Comments: Of Hawkins Volcanic Suite. Purple and greenish-grey dacitic ignimbrite. Disconformably underlies Mount Painter Volcanics; intruded by Federal Golf Course Tonalite. BMR map symbol: Smw. Geol. Prov: Canberra Block.
REFID: 42726 Chappell, B.W. , English, P.M. , King, P.L. , White, A.J.R. , Wyborn, D. 1991 Granites and related rocks of the Lachlan Fold Belt (1:1 250 000 scale map). Bureau of Mineral Resources, Australia 1v map
Usage: Briefly described (map legend) Min age from reference: Silurian Comments:
REFID: 44092 Wyborn, D. , Owen, M. , Wyborn, L. 1990 Geology of the Kosciusko National Park (1:250 000 scale map) Bureau of Mineral Resources, Australia 1v map
Usage: Briefly described (map legend) Min age from reference: Late Silurian Max age from reference: Early Silurian Comments: Sv2
REFID: 42497 Duff, B.A. , Ward, P. , Crook, K.A.W. , Rickard, M.J. 1985 Tasman Orogen Profile 5 - Wagga Wagga-Batemans Bay, New South Wales. Geological Survey of New South Wales 1v Map
Usage: Briefly described (Map Legend) Min age from reference: Wenlockian Max age from reference: Wenlockian Comments:
REFID: 49013 Strusz, D.L. 1982 Size distribution statistics, Wenlock brachiopods from Canberra, Australia. Bureau of Mineral Resources, Australia, Report 237(MF183)
Usage: Briefly described (p1) Comments:
REFID: 36441 Owen, M. , Wyborn, D. , Blythe, P. 1979 Brindabella, New South Wales and Australian Capital Territory, 1:100 000 geological series map. Sheet 8627, 1st edition. Bureau of Mineral Resources, Australia 1v Map
Usage: Briefly described (map legend) Min age from reference: Wenlockian Max age from reference: Wenlockian Comments: Extrusive. Green to purple dacite ignimbrite and bedded tuff, minor andesite, volcaniclastic sediment and limestone. Underlies Tarpaulin Creek Ashstone Member (Uriarra Volcanics). BMR map code: Svw.
REFID: 68592 Thomas, O.D. , Pogson, D.J. 2012 Goulburn 1:250 000 geological sheet SI/55-12 2nd Edition Explanatory notes Geological Survey of New South Wales 69p, chart and CD
Usage: Mentioned (p428, p443, p457) Min age from reference: Silurian Max age from reference: Silurian Comments: Owen and Wyborn (1979). Equivalent to, but not yet formally included in, the Douro Group.
REFID: 63083 Sandford, A.C. , Holloway, D.J. 2006 Early Silurian phacopide trilobites from central Victoria, Australia Memoirs of Museum Victoria 63(2) p215-255
Usage: Mentioned (p218) Comments: In Canberra area. Includes a fossil fauna of scutellids, illaenids, harpetids, cheirurids and staurocephalids.
REFID: 60989 Percival, I.G. , Wright, A.J. 2005 A New Early Silurian Species of Trimerella (Brachipoda: Craniata) from the Orange District, New South Wales Proceedings of the Linnean Society of New South Wales 126 p111-120
Usage: Mentioned (p111) Comments: Canberra area. Includes an uncommon Silurian trimerellide brachiopod.
REFID: 24248 Strusz, D.L. 2002 Brachiopods of the Orders Protorthida and Orthida from the Silurian of the Yass Syncline, southern New South Wales Alcheringa 26 (1) p49-86
Usage: Mentioned (p67, p72 Tb. 4) Comments:
REFID: 13996 Pickett, J.W. , Burrow, C.J. , Holloway, D.J. , Munson, T.J. , Percival, I.G. , Rickards, R.B. , Sherwin, L. , Simpson, A.J. , Strusz, D.L. , Turner, S. , Wright, A.J. 2000 Silurian palaeobiogeography of Australia Association of Australasian Palaeontologists, Memoir 23 127-165
Usage: Mentioned (p141, p143-145) Min age from reference: Silurian Max age from reference: Silurian Comments: NW of Canberra. Late Wenlock. Hosts a new pteriomorph, Umburra cinefacta; has its own monotypic family. Bivalve taxa distribution Table. Hosts a diverse late Wenlock trilobite fauna. Biogeographic affinities.
REFID: 43481 Lewis, G.B. , Abell, R.S. 1994 Geology of Canberra Field Trip Guide AGSO Field Trip Guide 1 16
Usage: Mentioned (3) Comments:
REFID: 42994 Strusz, D.L. 1990 Catalogue of Type, Figured and Cited specimens in the Commonwealth Palaeontological Collection -- BRACHIOPODA. Bureau of Mineral Resources, Australia, Report 298 289pp
Usage: Mentioned (p5) Comments:
REFID: 47037 Strusz, D.L. 1984 Brachiopods from the Silurian of Fyshwick, Canberra, Australia. BMR Journal of Australian Geology and Geophysics 9(2) p107-19
Usage: Mentioned (p107) Comments:
REFID: 39975 Strusz, D.L. 1984 Brachiopods of the Yarralumla Formation (Ludlovian), Canberra, Australia. Alcheringa 8(2) p123-150
Usage: Mentioned (p123) Comments:
REFID: 60078 Owen, M. , Wyborn, D. , Wyborn, L. 1982 Kosciusko National Park and Environs, New South Wales, 1:250 000 Geological Special, Preliminary edition Bureau of Mineral Resources, Geology and Geophysics 1v Map
Usage: Mentioned (Map Legend) Min age from reference: Silurian Max age from reference: Silurian Comments:
REFID: 47032 Strusz, D.L. 1982 On Australina Clarke - and its junior synonyms Lissatrypa, Lissatrypoidea, and Tyrothyris (Silurian-Devonian brachiopoda). BMR Journal of Australian Geology and Geophysics 7(1) p73-77
Usage: Mentioned (Fig.1) Comments:
REFID: 38035 Wyborn, D. , Owen, M. , Compston, W. , McDougall, I. 1982 The Laidlaw Volcanics; a Late Silurian point on the geological time scale. Earth and Planetary Science Letters 59(1) p90-100
Usage: Mentioned (p92) Comments:
REFID: 37752 Strusz, D.L. 1982 Wenlock brachiopods from Canberra. Alcheringa 6(2) p105-142
Usage: Mentioned (p105) Comments:
REFID: 36633 Henderson, G.A.M. , Matveev, G. 1980 Geology of Canberra, Queanbeyan, and Environs, 1:50 000 geological series map. 1st edition. Bureau of Mineral Resources, Australia 1v
Usage: Mentioned (Map legend) Min age from reference: Middle Silurian Max age from reference: Middle Silurian Comments:
REFID: 37013 Strusz, D.L. 1980 The Encrinuridae and related trilobite families, with a description of Silurian species from southeastern Australia. Palaeontographica, Abteilung A A 168 p1-68
Usage: Mentioned (p13) Comments:

Bibliographic references returned: 29 This data is subject to Geoscience Australia's disclaimer and copyright statements.