A report on the foraminiferal biostratigraphy of three boreholes Stavely 1, 11 and 14

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1 report on the foraminiferal biostratigraphy of three boreholes Stavely 1, 11 and 14 1 SSOCITE PROFESSOR STEPHEN J. GLLGHER School of Earth Sciences, The University of Melbourne, Victoria 3010, ustralia sjgall@unimelb.edu.au INTRODUCTION This is a report on the outcome of foraminiferal micropalaeontological analyses of twelve samples from three bores Stavely-1, -11 and 14. Ten of these samples were chemically disaggregated and wet sieved using a 63 µm sieve by Geoscience ustralia (Stavely-11 and -14). Two additional samples (Stavely-1) were processed by similar techniques at the University of Melbourne. The age and possible lithostratigraphic units (using the Gallagher and Gourley, 2007 nomenclature) of these samples is listed in Table 1, further detailed foraminiferal data can be found in Tables 2, 3 and 4. CODE BORE DEPTH (m) GE Zone STVELY-11 GTS2012 age (Ma) Probable Lithostratigraphic units STV Late Miocene to Pliocene <5.72 Loxton-Parilla Sand STV Late Miocene to Pliocene <5.72 Bookpurnong Beds STV Late Miocene to Pliocene <5.72 Bookpurnong Beds STV Middle Miocene M Murray Supergroup Ettrick Formation STV11 65 Early Miocene Murray Supergroup Geera Clay? STVELY STV14 92 Late Miocene to Pliocene <5.72 Loxton-Parilla Sand STV Likely to be Late Miocene <5.72 Bookpurnong Beds STV Early Miocene M Murray Supergroup Upper Mannum Formation STV Early Miocene M Murray Supergroup Upper Mannum Formation STV ?? Murray Supergroup Geera Clay? STVELY-14 STV1 73 Early Miocene M STV1 141 Early Miocene? Heytesbury Group Heytesbury Group Gellibrand Marl Gellibrand Marl Table 1: summary of the foraminiferal biostratigraphy of the Stavely samples analysed, note the foraminiferal zones are international zones and their chronology follows the GTS2012 Timescale (Gradstein et al., 2012).

2 2 The biostratigraphic scheme and the lithostratigraphic nomenclature used in the report are shown in Figure 1. Figure 1. Foraminiferal biostratigraphy and lithostratigraphy of the Murray Basin adapted from Gourley and Gallagher (2007) converted to the Gradstein et al. (2012) timescale.

3 STVELY-1 foraminiferal biostratigraphy 3 Foraminifera and bryozoans are abundant in the two Otway Basin samples analysed. STV1 141 m diverse inner to middle shelf benthic foraminiferal assemblage is present including: Globocassidulina subglobosa, cibicidids, bolivinids and Eponides repandus. Planktic foraminifera are rare with only Globigerina bulloides present. In the absence of diagnostic planktic foraminifers, two particular benthic foraminifera allow a possible age assignment: Wadella globiformis and Pararotalia mackayi. These taxa are common and co-occur typically in the Early Miocene strata (Gourley, 2005) and rarely co-occur in Middle Miocene strata. ge: Early Miocene Unit: Probably the Gellibrand Marl in the Heytesbury Group. STV1 73m Planktic and benthic foraminifera are abundant in this sample. Thirty species of inner to middle shelf (plus some outer shelf) benthic foraminiferal species are present including: Notorotalia spp., G. subglobosa, Lenticulina spp., Cibicides spp. and nomalinoides macroglabra. Pararotalia mackayi is present in the absence of Wadella globiformis. Larger benthic foraminifera are common and include: mphistegina lessoni, Operculina victoriensis, Planorbulinella larvata and Lepidocyclina howchini. The planktic foraminiferal fauna is typified by an assemblage of Miocene forms such as Globigerinoides trilobus, G. ruber, Globoturborotalia woodi woodi and G. woodi connecta. Specifically the presence of G. trilobus and G. ruber with the larger benthic foraminifer L. howchini in the absence of the Orbulina bioseries points to an Early Miocene M4 zonal age with a biochronological age range of to Ma. ge: Early Miocene M4 ( Ma) Unit: Probably the Gellibrand Marl in the Heytesbury Group.

4 STVELY-11 foraminiferal biostratigraphy Foraminifera vary in abundance in the five Murray Basin samples studied. 4 STV11 65 m The oldest sample analysed is a shallow marine sediment dominated by micaceous and pyritic material with minor glauconite. Foraminifera are extremely rare and include single specimens of planktic foraminifera: Globoturborotalia woodi woodi and G. woodi connecta. The presence of these taxa and the samples stratigraphic association of the overlying Middle Miocene sample at 43.32, suggests it is probably Early Miocene. ge: Early Miocene Unit: Probably the?geera Clay in the Murray Supergroup. STV m This sample yields a high diversity of marine bioclast types including abundant bryozoans. Foraminifera are abundant including eighteen species of benthic and six species of planktics. Benthic forms include middle to outer shelf taxa such as: Cibicidoides perforatus, Eponides lornensis, Lenticulina spp. and nomalinoides macroglabra. The planktic assemblage includes the key Middle Miocene M5 zonal age taxa Orbulina suturalis and Praeorbulina glomerosus curva in the absence of Orbulina universa ( Ma). ge: Middle Miocene, M5 zone ( Ma). Unit: Probably the Ettrick Formation in the Murray Supergroup. STV m This is a glauconite-dominated sample with bryozoans and abundant bivalves. Inner shelf benthic foraminifera are abundant in the absence of planktic foraminifera. The assemblage is dominated by Elphidium spp. Cibicides spp. and Bolivina spp. with lesser Discorbis spp. and

5 Glabratellina spp. and Cellanthus craticulatum. Inner shelf facies with Elphidium spp. with minor planktic forms is typical of the Late Miocene Bookpurnong Beds (Gourley, 2005). 5 ge: Late Miocene to Pliocene Unit: Probably the Bookpurnong Beds. STV m This is a mollusc bioclast dominated sample with rounded coarse quartz grains. Inner shelf benthic foraminifera are abundant in the absence of planktic foraminifera. The assemblage is dominated by Elphidium spp. and Notorotalia spp. with minor mmonia beccarii. mmonia beccarii first appears in southeast ustralia in the Late Miocene and it ranges to the present (Gourley, 2005). In the Murray Basin is occurs in small amounts in the Bookpurnong Beds and becomes abundant near the base of the overlying Loxton-Parilla Sands. Thus it is likely that this sample is from the Late Miocene Bookpurnong Beds. ge: Late Miocene to Pliocene Unit: Probably the Bookpurnong Beds. STV m This sample lacks foraminifera yet contains glauconite. Thus it is likely to be a very shallow marine unit such as the Loxton-Parilla Sand as it immediately overlies the Bookpurnong Beds Barren ge: Post Late Miocene? Unit: Probably the Loxton-Parilla Sands.

6 STVELY-14 foraminiferal biostratigraphy Foraminifera vary in abundance in the five Murray Basin samples studied. STV m The oldest sample analysed is a shallow marine sediment with dolomitised bioclasts (foraminifera and ostracods) minor glauconite. 6 Foraminifera are extremely rare and poorly preserved. ge:? Unit: Probably the?geera Clay in the Murray Supergroup. STV m Bryozoans, molluscs and sponge spicules dominate this sample. Benthic and planktic foraminifera are abundant in this sample. Middle to outer shelf benthic foraminifera dominate including: Globocassidulina subglobosa,. macroglabra and Sphaeroidina bulloides. The planktic foraminiferal assemblage is typified by Miocene forms such as Globigerinoides trilobus, G. bisphaericus, G. ruber, Globoquadryina dehiscens, Globoturborotalia woodi woodi and G. woodi connecta in the absence of the Orbulina bioseries. This suggests an Early Miocene M4 zonal age with a biochronological age range of to Ma. ge: Early Miocene M4 ( Ma) Unit: Probably Upper Mannum Formation in the Murray Supergroup. STV m Bryozoans, molluscs and sponge spicules dominate this sample. Similar to the underlying sample benthic and planktic foraminifera are abundant in this sample. Middle to outer shelf benthic foraminifera dominate including: Cibicides spp., Notorotalia spp., Globocassidulina

7 7 subglobosa,. macroglabra, Eponides spp. and Sphaeroidina bulloides with minor larger benthic forms such as Operculina victoriensis. The planktic foraminiferal assemblage is similar to the underlying Early Miocene sample however it includes the addition of the taxon Praeorbulina sicana in the absence of Orbulina suturalis or P. glomerosus indicating an upper Early Miocene M5 zonal age with a biochronological age range of to Ma. ge: Early Miocene M5 zone ( Ma) Unit: Probably Upper Mannum Formation in the Murray Supergroup. STV m This is a bryozoan, echinoderm spine and mollusc dominated sample. Inner shelf benthic foraminifera are common in the absence of planktic foraminifera. The assemblage is dominated by Elphidium spp. Notorotalia spp. and Cellanthus craticulatum. Inner shelf facies with Elphidium spp. with minor planktic forms is typical of the Late Miocene Bookpurnong Beds (Gourley, 2005). ge: Late Miocene to Pliocene Unit: Probably the Bookpurnong Beds. STV14 92 m This sample contains glauconite, echinoderm fragments and abundant ferruginous concretions. Shallow water innermost shelf foraminifera dominate in the absence of planktic forms. Elphidium spp., mmonia beccarii and Discorbis dimidiatus are abundant with lesser amounts of Notorotalia spp. and Cibicides spp. In the Murray Basin D. dimidiatus is present only near the base of the Loxton-Parilla Sands (Gourley, 2005) where. beccarii also dominates. This suggests that this sample has a Late Miocene or younger age. ge: Late Miocene to Pliocene Unit: Probably the Loxton-Parilla Sands.

8 REFERENCES ND BIBLIOGRPHY BROWN C.M. & STEPHENSON.E Murray Basin subsurface stratigraphic database. Bureau of 8 Mineral Resources Report, 262. BROWN C.M. & STEPHENSON.E Geology of the Murray Basin. BMR Bulletin 235, GLLGHER, S.J., and GOURLEY, T.L Revised Oligo-Miocene stratigraphy of the Murray Basin, southeast ustralia. ustralian Journal of Earth Sciences v. 54: p GOURLEY T.G Stratigraphy and palaeoenvironmental evolution of Oligocene to Pliocene marine strata in the Murray Basin, Victoria, southeast ustralia. Unpublished PhD Thesis, The University of Melbourne, Melbourne, GOURLEY T.L., and GLLGHER, SJ., 2004, Foraminiferal biofacies of the Miocene warm to cool climatic transition in the Port Phillip Basin, southeastern ustralia: Journal of Foraminiferal Research, v. 34, p GRDSTEIN, F. M., OGG, J. G., SCHMITZ, M. D., OGG, G. M., The Geologic Time Scale Elsevier. HOLDGTE G.R. & GLLGHER S.J Tertiary a period of transition to marine basin environments. In: Birch, W. D. ed., Geology of Victoria, pp GS (Victoria Division), Melbourne. LUKSIK J.J. & JMES N.P Lithostratigraphic revision and correlation of the Oligo-Miocene Murray Supergroup, western Murray Basin, South ustralia. ustralian Journal of Earth Sciences 45,

9 Table 2 STVELY-1 FORMINIFER STVELY 1 STV1 STV1 FORMINIFER depth BIOCLSTS Bryozoans Echinoid spines/fragments = abundant Foraminifera C = common Sponge spicules R = rare Crab claws = present Gastropods Ostracod BENTHIC ROTLIIDE INDET BENTH ROT nomalinoides macroglabra Bolivina spp. Cassidulinoides spp. Cibicides spp. Cibicides pseudoconvexus Discorbinella spp. Discorbis spp. Elphidium spp. Eponides repandus Fissurina spp. Glabratellina spp. Globocassidulina subglobosa Heronallenia spp. Heronallenia parri Lagenid Notorotalia spp. Pararotalia mackayi Planodiscorbis spp. Siphonina australis Uvigerina spp. Wadella globiformis mphistegina lessoni strononion spp. Cibicides vortex Cibicidoides spp. Discorbinella scopos Lenticulina spp. Lepidocyclina howchini Nonionella spp. Operculina victoriensis Planorbulinella larvata Polymorphinid Sphaeroidina bulloides Trifarina spp. MILIOLID FORMINIFER Triloculina spp. Spirrilina spp. Quinqueloculina spp. GGLUTINTED FORMINIFER Dorothia minima Gaudryina spp. Indet. agglut. PLNKTONIC (GLOBIGERINCEE) Globigerina bulloides bulloides Globigerinoides ruber Globigerinoides trilobus trilobus Globoquadryina altispira Globoquadryina dehiscens Globoturborotalia woodi connecta Globoturborotalia woodi woodi

10 Table 3 STVELY-11 FORMINIFER STVELY 11 STV11 STV11 STV11 STV11 STV11 FORMINIFER depth LITHICS Pyrite Micaceous Glauconite R Ferrugenous concretions Rounded Quartz grains BIOCLSTS Charcoal/Wood R Fish teeth R = abundant Foraminifera R C 0 C = common Mollusc undiff R R = rare Brachiopod = present Bryozoans 0 = barren Coral Echinoid spines/fragments Gastropods Ostracod Scaphopod Sponge spicules Bivalve BENTHIC ROTLIIDE nomalinoides macroglabra strononion spp. Cerobertina spp. Cibicides spp. Cibicidoides perforatus Discorbinella scopos Discorbis spp. Eponides lornensis Fissurina spp. Lenticulina spp. Notorotalia spp. C Polymorphinid Pullenia quinqueloba Siphonina australis Sphaeroidina bulloides Baggina spp. Bolivina spp. C Cellanthus craticulatum Cibicidoides spp. Discorbinella bertheloti Elphidium spp. Eponides repandus Glabratellina spp. Heronallenia spp. Lagenid Nonionella spp. mmonia beccarii Trifarina spp. MILIOLID FORMINIFER Pyrgo spp. Triloculina spp. Spirrilina spp. GGLUTINTED FORMINIFER Dorothia minima Textularia spp. PLNKTONIC (GLOBIGERINCEE) Globoturborotalia woodi connecta Globoturborotalia woodi woodi Globigerina bulloides bulloides Globigerina spp. Globigerinoides conglobatus Globigerinoides trilobus trilobus Praeorbulina glomerosus curva Orbulina suturalis R R

11 Table 4 STVELY-14 FORMINIFER STVELY 14 STV14 STV14 STV14 STV14 STV14 FORMINIFER depth LITHICS Glauconite R Ferrugenous concretions Rounded Quartz grains Dolomitised bioclasts R BIOCLSTS Foraminifera R C C Ostracod R = abundant Bivalve C = common Bryozoans R = rare Mollusc undiff = present Sponge spicules Echinoid spines/fragments BENTHIC ROTLIIDE INDET BENTH ROT R nomalinoides macroglabra strononion spp. Bolivina spp. Cassidulina spp. Cibicides spp. Cibicides vortex Cibicidoides spp. Discorbinella bertheloti Fissurina spp. Glabratellina spp. Globocassidulina subglobosa Heterolepa spp. Lagenid Notorotalia spp. Polymorphinid Siphonina australis Sphaeroidina bulloides Cellanthus craticulatum Cibicides pseudoconvexus Elphidium spp. Eponides lornensis Eponides repandus Heronallenia spp. Lenticulina spp. Operculina victoriensis Planodiscorbis spp. Trifarina spp. Uvigerina spp. Discorbis spp. mmonia beccarii Discorbis dimidiatus MILIOLID FORMINIFER Spirrilina spp. GGLUTINTED FORMINIFER Dorothia minima PLNKTONIC (GLOBIGERINCEE) Dentoglobigerina sp. Globigerina bulloides bulloides Globigerinoides bisphericus Globigerinoides ruber Globigerinoides trilobus trilobus Globoquadryina dehiscens Globoturborotalia woodi woodi Praeorbulina sicana