Significance of clinopyroxene compositions from the Cudgegong Volcanics and Toolamanang Volcanics: Cudgegong-Mudgee district, NSW, Australia

1985 ◽  
Vol 49 (353) ◽  
pp. 591-599 ◽  
Author(s):  
J. W. Pemberton ◽  
R. Offler
Keyword(s):  
New South ◽  
New South Wales ◽  
Structural Formula ◽  
Primary Phase ◽  
Late Ordovician ◽  
Parent Magma ◽  
Calc Alkaline ◽  
South Wales ◽  
Stratigraphic Position ◽  
Altered Basalt

SynopisClinopyroxene phenocrysts and groundmass crystals are relict phases in altered basalt and basaltic andesite lavas, and arenites of the Cudgegong Volcanics and Toolamanang Volcanics, Cudgegong-Mudgee district, New South Wales. Petrography, field relationships and clinopyroxene compositions indicate that basaltic blocks in the latter unit are reworked from the Cudgegong Volcanics. Clinopyroxene phenocrysts show a restricted compositional range and minor Feenrichment from core to rim, features considered indicative of a calc-alkaline parent magma. It is proposed that the Cudgegong Volcanics crystallized under hydrous conditions, at least in the later stages, with rising fO2 resulting in a Fe-Ti oxide crystallizing as a primary phase. The clinopyroxenes are considered to have crystallized at moderate (5–6 kbar) and falling pressures and at minimum temperatures in the range 900 to 1000°C. Coupled substitutions affecting the “other” components in the clinopyroxene structural formula indicate that the ivAl-viFe3+, ivAl-viAl and ivAl-viTi4+ couples are important. The Sofala Volcanics, south of the study area, and the Cudgegong Volcanics are similar in age, petrography and stratigraphic position, and contain relict clinopyroxenes which are chemically similar. This suggests that the units are laterally equivalent and adds further evidence to the proposal that an oceanic island arc system was active in central western New South Wales during the Late Ordovician.

The first well-preserved radiolarians from the Ordovician of Australia

1986 ◽  
Vol 60 (1) ◽  
pp. 145-157 ◽  
Author(s):  
B. D. Webby ◽  
W. M. Blom
Keyword(s):  
New Species ◽  
Debris Flows ◽  
New South ◽  
New South Wales ◽  
Late Ordovician ◽  
Siliceous Sponge ◽  
Radiolarian Assemblage ◽  
South Wales ◽  
Limestone Breccia

Late Ordovician radiolarians are described from allochthonous limestone breccia deposits of the graptolitic Malongulli Formation of central New South Wales. Included among the forms are the new ‘palaeoactinommid’ genus Kalimnasphaera with new species K. maculosa, the new entactiniid species, Entactinia subulata, and the new anakrusid species, Auliela taplowensis. A number of other entactiniids and the first recorded Ordovician ‘rotasphaerids’ are placed in open nomenclature. Graptolite faunas of the Malongulli Formation indicate that the deposits range in age from the Eastonian Zone of Dicranograptus hians kirki to the Bolindian Zone of Climacograptus uncinatus, that is, from latest Caradoc to early or middle Ashgill in age. This is only the second known well-preserved radiolarian assemblage to be illustrated from Late Ordovician (late Caradoc–Ashgill) successions, and the earliest known from Australia. The radiolarians typically occur in tabularly shaped, laminated lime-mudstone clasts with an abundance of siliceous sponge remains. These clasts appear to be formed from peri-platform ooze of the ‘deeper-water’ slope facies, which became incorporated in debris flows moving into the adjoining basin.

Middle and Late Ordovician magmatic evolution of the Macquarie Arc, Lachlan Orogen, New South Wales

2007 ◽  
Vol 54 (2-3) ◽  
pp. 181-214 ◽  
Author(s):  
A. J. Crawford ◽  
S. Meffre ◽  
R. J. Squire ◽  
L. M. Barron ◽  
T. J. Falloon
Keyword(s):  
New South ◽  
New South Wales ◽  
Late Ordovician ◽  
Magmatic Evolution ◽  
South Wales ◽  
Lachlan Orogen

Late Ordovician nautiloids from central New South Wales, Australia

1985 ◽  
Vol 9 (2) ◽  
pp. 143-157 ◽  
Author(s):  
Bryan Stait ◽  
Barry D. Webby ◽  
Ian G. Percival
Keyword(s):  
New South ◽  
New South Wales ◽  
Late Ordovician ◽  
South Wales

Trilobites of the suborder Illaenina from the Silurian of north Queensland, Australia

2016 ◽  
Vol 90 (3) ◽  
pp. 433-471 ◽  
Author(s):  
David J. Holloway ◽  
Philip D. Lane
Keyword(s):  
New South ◽  
New South Wales ◽  
Late Ordovician ◽  
Junior Synonym ◽  
South Wales ◽  
Senior Synonym

AbstractThe trilobite fauna of the middle Silurian (Telychian to possibly earliest Sheinwoodian) Tomcat Creek limestone in the Broken River Province of north Queensland is dominated by the suborder Illaenina, including illaenimorphs (Illaeninae and Bumastinae) and members of the Scutelluidae. Scutelluidae are most diverse, with eight genera, of whichDolabrapex,Iotoryx,Perizostra, andQuintoniaare new.Perizostrais the first scutelluid with a cephalon that may be described as of phacomorph appearance. Illaenimorphs are represented by three genera, includingOpsypharus, which is regarded as a senior synonym ofParacybantyxbut distinct fromFailleanawith which it has been placed in synonymy by some authors. Thirteen species are new:Cybantyx?ergodes,Opsypharus pandanensis,Australoscutellum talenti,Dolabrapex acomus,Illaenoscutellum psephos,Iotoryx clarksoni,Japonoscutellum mawsonae,J. drakton,J. fractum,Kosovopeltis avita,Perizostra campbelli,Quintonia arata, andQ. pavo. A species ofStenopariais placed in open nomenclature. The species ofAustraloscutellum,Illaenoscutellum, and possiblyKosovopeltisare the oldest known representatives of those genera. These genera andJaponoscutellumare also common in faunas from limestones of Wenlock to Ludlow age in central western New South Wales, reflecting the similarity in lithofacies. The monotypic Late Ordovician genusCraigheadia, which has been regarded as a scutelluid, belongs to the Lichidae and is probably a junior synonym ofLeiolichas.

Ordovician sponge spicules from New South Wales, Australia

1993 ◽  
Vol 67 (1) ◽  
pp. 28-41 ◽  
Author(s):  
B. D. Webby ◽  
J. Trotter
Keyword(s):  
Debris Flows ◽  
New South ◽  
New South Wales ◽  
Late Ordovician ◽  
New Genera ◽  
Siliceous Sponge ◽  
Upper Cambrian ◽  
South Wales ◽  
Sponge Spicules ◽  
First Time

An abundant, varied, and well-preserved assemblage of discrete sponge spicules of late Ordovician age is described from the Malongulli Formation of central New South Wales. It is associated with one of the most diverse Ordovician siliceous sponge faunas known. The assemblage occurs in allochthonous limestone blocks within breccia deposits of a predominantly graptolitic and spiculitic siltstone succession, and is composed mainly of hexactinellid spicule types. Included are a number of distinctive forms, recognized as new taxa—Silicunculus bengtsoni, Kometia cruciformis, Chelispongia prima, and Pseudolancicula exigua. All are new genera except Silicunculus Bengtson, 1986, which was previously described from the upper Cambrian of Queensland. The problematical Anomaloides reticulatus Ulrich, 1878, is reported for the first time from Australia. A wide variety of other diagnostic, but more generalized, spicule types also occurs, including stauractines, pinnular and nonpinnular pentactines and hexactines, ornamented oxyhexasters and echinhexasters, clavules, anchorate root-tufts, and uncinates. The pinnular pentactines may be assigned to the form genus Palaeorubus Ishiga (in Ishiga et al., 1987), interpreted incorrectly by Ishiga as a radiolarian. The sponges, discrete spicules, and radiolarians of these limestone clasts were transported in debris flows to a basinal setting from peri-platform oozes that formed on the flanks of the shallow offshore island-arc platform of the Molong High.

Beidellitic montmorillonite from Swansea, New South Wales

Clay Minerals ◽  
1971 ◽  
Vol 9 (1) ◽  
pp. 107-123 ◽  
Author(s):  
J. D. Hamilton
Keyword(s):  
Coal Seam ◽  
Infrared Absorption ◽  
New South ◽  
New South Wales ◽  
Structural Formula ◽  
X Ray ◽  
South Wales ◽  
Heat Treated ◽  
Saturated Form ◽  
Image Position

AbstractThe minus 1μm fraction of an argillized vitric tuff, overlying the Wallarah Coal Seam near Swansea, N.S.W. is a nearly monomineralic (95%+) expandite clay, which hydrates and reacts to glycerol and heat treatments like montmorillonite. Results of X-ray, differential thermal, thermogravimetric and infrared absorption analyses confirm the general montmorillonoid character of the mineral, but chemical data indicate that much of its structure charge arises from substitutions in the tetrahedral zones of the lattice, as in beidellite rather than montmorillonite. The structural fOrmula deduced for the Ca++-saturated form of the minus 0.1μm clay is:The distinctive behaviours of the heat-treated NH4+- and Li+-saturated structures also suggest that the mineral is a 'beidellitic montmorillonite' rather than a montmorillonite.

Conodonts of Caradocian (Late Ordovician) age from the Cliefden Caves Limestone, southeastern Australia

1990 ◽  
Vol 64 (5) ◽  
pp. 821-831 ◽  
Author(s):  
Norman M. Savage
Keyword(s):  
New Species ◽  
North America ◽  
Southeast Asia ◽  
New South ◽  
New South Wales ◽  
Late Ordovician ◽  
Eastern Siberia ◽  
Southeastern Australia ◽  
South Wales ◽  
Eastern Australia

New species of Aphelognathus, Belodina, Taoqupognathus, and Yaoxianognathus have been identified in the Late Ordovician Cliefden Caves Limestone Group in central-western New South Wales, Australia. Of the Aphelognathus species, Aphelognathus percivali n. sp. and A. webbyi n. sp. occur in the basal Gleesons Limestone Member and A. packhami n. sp. and A. stevensi n. sp. occur 30 m higher in the Wyoming Limestone Member. It seems likely from the similarity of several of the elements that A. packhami is closely related to A. percivali, and A. stevensi to A. webbyi. Yaoxianognathus wrighti n. sp. occurs in the Gleesons Limestone Member but not in the Wyoming Limestone Member. Belodina confluens, Belodina hillae n. sp., Belodina n. sp., Panderodus gracilis, Taoqupognathus philipi n. sp., and Phragmodus? tunguskaensis occur at both horizons. The conodonts suggest a middle to late Caradocian (mid-Shermanian to mid-Edenian) age for the lowest part of the Cliefden Caves Limestone. The occurrence in southeastern Australia of the forms Taoqupognathus, Yaoxianognathus, and Phragmodus? tunguskaensis suggest affinities to coeval faunas in China and eastern Siberia. The four new species of Aphelognathus are distinct from known species in the Late Ordovician of North America and Europe but they may help characterize a paleobiogeographic region that includes eastern Australia and southeast Asia.

Plagiogranites in the Coolac ophiolite suite, New South Wales, Australia

1983 ◽  
Vol 120 (1) ◽  
pp. 1-20 ◽  
Author(s):  
P. M. Ashley ◽  
B. J. Franklin ◽  
A. S. Ray
Keyword(s):  
Late Stage ◽  
New South ◽  
New South Wales ◽  
Chemical Data ◽  
Calc Alkaline ◽  
Tholeiitic Magma ◽  
South Wales ◽  
Ophiolite Suite ◽  
Oceanic Plagiogranite

SummaryPlagiogranites occur mainly as intrusive bodies and tectonic inclusions within mafic and ultramafic members of the Coolac ophiolite suite. Quartz diorites and trondhjemites appear to represent localized late-stage felsic differentiates of subalkaline tholeiitic magma, with their formation dominantly controlled by fractionation of hornblende and plagioclase. Albitites are interpreted as altered equivalents of quartz diorites and trondhjemites. Chemical data, while emphasizing the similarity of these rocks to ‘oceanic plagiogranite', also indicate that variation in the latter may be broader than previously defined. The Coolac rocks show less marked Fe-enrichment, higher Ni and Cr, and lower Y and Zr than many ophiolitic plagiogranites. These data are consistent with weak calc-alkaline tendencies demonstrated in the Coolac ophiolite suite.

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