Tectonic control of Tertiary deposition in the StreathamDeep-Lead System in western Victoria

M. RAIBER* AND J. A. WEBB

Environmental Geosciences, La Trobe University, Bundoora, Vic. 3086, Australia.

The mainly sub-basaltic paleodrainage of the Streatham Deep-Lead System covers 42500 km2

between the West Victorian Uplands and the Otway Basin, from which it is separated by a subsurfacegranite ridge. Five main tributaries flowed southwards into a series of grabens that host up to 140 m offluvial coal-bearing sediments (Yaloak/Calivil Formation). The grabens were probably initiallyconnected to the ocean (Otway Basin) through a western outlet; in the Eocene, the outlet shiftedeastwards. Accumulation of the deep-lead sediments in the central grabens was controlled bysynsedimentary subsidence along reactivated north-northwest Paleozoic and east-northeastCretaceous faults. Fault movement occurred in the mid-Late Paleocene in the western depocentre,and Eocene in the central and eastern depocentres, and correlates well with tectonic activity in theeastern part of the Otway Basin. Following an Early Oligocene hiatus, fluvial sedimentation andsyndepositional faulting recommenced from the Late Oligocene to Late Miocene/Pliocene,concomitant with sediment deposition and faulting in deep leads to the north of the divide. A finalperiod of compressional faulting in the latest Miocene– Early Pliocene uplifted some sections of theStreatham Deep-Lead System, before it was almost entirely covered by basalt lavas.

KEY WORDS: deep lead, landscape evolution, Otway Basin, palynology, Streatham Deep-Lead System,tectonic activity, Tertiary, West Victorian Uplands.

INTRODUCTION

During the Early – mid-Tertiary, over large areas of

southeastern Australia a series of river systems, flowing

both north and south of the drainage divide, deposited

fluvial sediments in valleys eroded into the Paleozoic

basement. In western Victoria, these sediments were

sealed by the Newer Volcanic basalts erupted during

the Plio-Pleistocene, and are often referred to as

(sub-basaltic) deep leads or sub-basaltic gravels

(Canavan 1988).

With the first discovery of gold in deep-lead sedi-

ments in western Victoria in 1854 (Krause 1874), the

deep leads gained economic significance, and some

yielded large quantities of gold. Although more than

150 years have elapsed since the onset of gold mining in

western Victoria, exploration for gold in the deep leads

continues. More recently, deep-lead groundwater has

been utilised as a resource, and the potential for the

deep-lead sediments to help define the landscape evolu-

tion of the region has been realised. Taken together,

these factors have contributed to a growing scientific

interest in the deep leads.

Since the first landmark study on the deep leads

of Victoria, in which Hunter (1909) presented maps

and cross-sections for numerous deep leads, many

authors have investigated the north- and south-flowing

systems (Canavan 1988; Macumber 1991; Cayley &

McDonald 1995; Hughes & Carey 2002; Taylor et al.

2000; Cayley & Taylor 2001). A key concern of recent

studies (Bishop & Li 1997; Carey & Hughes 1997; Hill

1999; Hughes et al. 1998; Taylor & Gentle 2002; Holdgate

et al. 2004, 2006) is the timing of the entrenchment and

deposition in the context of the landscape evolution of

the West Victorian Uplands.

In the current study, we focus on one of the most

widespread and complex deep leads of western Victoria

(Figure 1), herein named the Streatham Deep-Lead

System, and previously known as the Kornong Graben

(Bradley et al. 1994) and Streatham Sub-basin (Holdgate

et al. 2004, 2006). This paleodrainage system has been

extensively drilled as part of groundwater investiga-

tions conducted by the Rural Water Commission (Nolan

et al. 1990) and mineral exploration surveys. The

resultant knowledge of the stratigraphic record, in

conjunction with airborne geophysical images, allows

a detailed examination of the relationship between

sediment accumulation in the deep lead, Tertiary

tectonic activity and the landscape evolution of western

Victoria.

GEOLOGICAL SETTING

The Streatham Deep-Lead System (Figure 2a, b) overlies

Cambrian basement of the St Arnaud Group turbidites

in the east and, in the west the Moornambool

Metamorphic Complex, a 15 km wide high-strain zone

*Corresponding author: mraiber@students.latrobe.edu.au.

Australian Journal of Earth Sciences (2008) 55, (493 – 508)

ISSN 0812-0099 print/ISSN 1440-0952 online � 2008 Geological Society of Australia

DOI: 10.1080/08120090801888610

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characterised by schist, quartzite and amphibolite

(VandenBerg et al. 2000). The Moyston Fault

(Figure 2a) was long thought to be the boundary

between the Lachlan and Delamerian Fold Belts, but

recent research indicates that this orogenic boundary is

located further east (Miller et al. 2005). The Delamerian

Fold Belt was cratonised in the Cambrian, while the

Lachlan Fold Belt was cratonised later, between the Late

Ordovician and the Middle Devonian (Cayley & Taylor

2001; Moore 2002).

During the Late Silurian to Early Carboniferous,

I-type plutons of granitic or granodioritic composition

(VandenBerg et al. 2000) were intruded, including the

Dundonnell Granite and the Illoura Granodiorite

(Figure 2a, b).

Following the Early to mid-Paleozoic tectonic and

intrusive activity, a long period of stability followed

during the Late Paleozoic and Mesozoic (Cayley &

Taylor 2001), and an extensive paleoplain formed, which

dates back to at least the Triassic (Hughes et al. 1998).

Despite considerable modification, landscape remnants

of the paleoplain may still exist (Ollier & Pain 1994;

Cayley & McDonald 1995), such as the summits of

Langi Ghiran, Mt Cole, Mt Buangor and Mt Ararat

(Figure 2a, b).

During tectonism in the Late Jurassic to Early

Cretaceous, the basement was segmented along north-

northwest faults (Foster & Gleadow 1992; Moore 2002)

and the West Victorian Uplands were upwarped in the

Cretaceous. The current landscape configuration is a

result of the stripping of the uplifted paleoplain during

two major cycles of erosion and deposition dating

back to the Late Cretaceous and continuing through

the Cenozoic (Cayley & Taylor 2001; Hughes & Carey

2002).

The older of these depositional sequences, the White

Hills Gravel, occurs in elevated landscape positions on

hill tops and valley flanks, as ferruginised conglomer-

ates mainly composed of reef quartz interbedded with

sand lenses. These mature sediments were deposited in

a high-energy fluvial environment and are remnants of

once-broader valley-floor deposits (Cayley & McDonald

1995; Hughes et al. 1998; Cayley & Taylor 2001; Hughes &

Carey 2002). Using U – Pb SHRIMP dating of zircons, a

maximum Late Cretaceous age has been inferred for the

White Hills Gravel (Birch et al. 2007).

The second cycle of erosion and deposition began

with uplift and valley incision in the Paleocene (Hughes

et al. 1998). Sediments deposited in these valleys are mid-

Paleocene to Late Miocene in age, and form the sub-

basaltic deep leads, including the Streatham system,

which have been incised into and lie topographically

50 – 100 m below the White Hills Gravel.

During the Oligocene and Miocene, numerous mar-

ine transgressions occurred in the Otway Basin, but

most of them reached only the southern margin of the

Streatham Deep-Lead System, where a thin section of

marine strata accumulated (Nolan et al. 1990). In the

latest Miocene, a major transgression covered much of

southern Victoria; as the sea retreated, a series of

strandlines, the latest Miocene – Early Pliocene Doro-

dong Sands, were deposited (Paine et al. 2004; Wallace

et al. 2005).

The Newer Volcanic basalts erupted across western

Victoria in several phases during the Late Miocene to

Quaternary (Bennetts et al. 2003; Joyce 2003). The

earliest flow covering the sediments of the Streatham

Deep-Lead System southeast of Ararat has been dated at

6.07 + 0.11 Ma (Webb et al. 1998). Most eruptions

occurred at 3 – 1 Ma (Price et al. 1997), but the youngest

lava flows in the study area are younger than 1 Ma, as

suggested by their well-preserved flow features with

little or no soil cover (Joyce 2003). The lava flows created

a flat to gently undulating plain with a disrupted

Figure 1 Location of Streatham

Deep-Lead System and adjacent

sedimentary basins and uplands.

494 M. Raiber and J. A. Webb

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Figure 2 (a) Paleozoic basement units underlying the Streatham Deep-Lead System. Note the granites along the southern

margin. Modified from VandenBerg et al. (2000). (b) Basement contour map.

Tectonic control of Tertiary deposition 495

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drainage that bears no relationship to the underlying

deep-lead system.

METHODS

To investigate the Streatham Deep-Lead System, bore

log records of more than 300 exploration, groundwater

and stratigraphic bores were compiled and analysed

from well-completion reports, mining records and

electronic databases. Where the deep-lead sediments

are covered by valley-filling basalts, their extent can

often be mapped using the first derivative of the

aeromagnetic intensity, because the increased thickness

of the basalts in the paleovalleys and/or the existence of

a maghemite/ferricrete layer on top of the deep-lead

sediments gives an enhanced magnetic response

(Holdgate et al. 2006). Palynological ages for the deep-

lead strata (Table 1) were compiled from previous

studies and supplemented by nine additional determina-

tions by A. D. Partridge (Appendix 1) conducted on chip

samples sourced from the Department of Primary

Industries Core Library.

A Digital Elevation Model (DEM) from the NASA

shuttle radar topography mission was combined with

high-resolution airborne geophysical images (radio-

metrics, aeromagnetics and gravity) using Global Map-

per and MapInfo to map the basement geology,

particularly the orientation of lineaments and locations

of granites, as well as the extent of the Newer Volcanics.

All data were incorporated into a set of geological maps

and cross-sections, using the AGD 66 datum, and from

this information, a conceptual model for the evolution

and the structural controls of the Streatham Deep-Lead

System has been developed.

STREATHAM DEEP-LEAD SYSTEM

The Streatham Deep-Lead System extends over an area

of more than 2500 km2 south of the West Victorian

Uplands and southeast of the Grampians, and comprises

three parts: a branched headwater system, a central

deep with three depocentres, and two southern outlets.

Headwater system

The widely branched headwater tributary system con-

sists of five major arms (Figure 3). From west to east,

these are the Mt William Deep Lead, the gold-rich Langi

Logan or Main Hopkins Lead southeast of Ararat, the Mt

Cole Lead (named herein) starting from northwest of

Beaufort, the Mt. Emu Lead (named herein) to the

southeast of Beaufort (this lead is separated from the

north-flowing Madame Hopkins Lead by a low pass) and

the Mt Bute Lead (named herein) to the east (its

eastwards extent is uncertain due to a lack of strati-

graphic bores). The Mt Cole and Mt Emu Leads, which

have in general low-relief headwaters (about 300 m

AHD), are 410 km wide, whereas the Mt William and

Langi Logan Leads, which have headwaters rising to

more than 500 m AHD, are 52.5 km wide; here the

Tertiary rivers were more deeply incised into the

Paleozoic bedrock. The tributary leads extend

25 – 30 km from their headwaters in the foothills of the

outcropping Paleozoic basement rocks to the point

where they merge into the central section of the deep-

lead system.

For limited areas in the headwaters, where the

tributary leads branch out onto the Paleozoic bedrock,

the deep-lead sediments are uncapped or covered by a

veneer of Quaternary sediments (Figure 4a). South-

wards, they are covered by 30 – 110 m of basalts.

The thickness of the deep-lead sediments in the

headwaters varies considerably. In the wider Mt Cole

and Mt Emu Leads, the sediments are generally thin (a

few metres to about 30 m: Figure 3) with a steady

downvalley increase in thickness. In the narrower Mt

William and Langi Logan Leads, the thickness of the

sediments is far more variable, and it does not always

thicken in a downvalley direction; the sediment thick-

nesses may suddenly increase from a few metres to

more than 45 m (Figure 3), probably as a result of

syndepositional fault-bounded subsidence (discussed

further below).

Upstream, the basal sediments mainly consist of

coarse gravel and boulders and contain a significant

proportion of reworked White Hills Gravel quartz

cobbles (Cayley & McDonald 1995) overlain by thin

layers of clay or sandy clay (Figure 5). With increasing

distance downstream, the gravels become progressively

thinner and are often covered by sands, clays and coal

with fining-upwards trends.

The Mt Emu Lead sediments contain Late Oligocene

to Late Miocene palynofloras (bores 46853, 54474, 62734:

Figure 4a, b; Table 1), and an upper age limit for the

sediments of the Langi Longan Lead is given by the age

of the oldest basalt covering this lead southeast of

Ararat (Late Miocene, 6.07+ 0.11 Ma: Webb et al. 1998).

No additional dates could be obtained from the head-

waters deep-lead sediments due to the lack of available

cores or the absence of datable material in the cores.

Central depocentres

An isopach map of the sediments filling the central

part of the Streatham Deep-Lead System underneath

the basalt (Figure 3) shows the existence of three

depocentres, with sediment thicknesses reaching up to

140 m. Superposition of mapped faults (Figure 6)

shows that these depocentres are fault-bounded gra-

bens, and represent major structural depressions

evident on the top-of-basement structure contour map

(Figure 2b). The western and eastern boundaries of all

depocentres coincide with the location of reactivated

north-northwest-oriented Paleozoic faults. A series of

east-northeast-trending faults have also contributed to

the formation of the grabens, as shown by an analysis

of aeromagnetic and gravity images and the DEM

(Figure 6). These east-northeast faults represent exten-

sions of faults with this orientation mapped by

Holdgate et al. (2006) throughout the central highlands

using the Shuttle Radar topographic imagery.

The composition of the deep-lead sediments in the

depocentres varies spatially (Figure 5). In the western

depocentre (Figures 3, 5), gravels are absent or confined

496 M. Raiber and J. A. Webb

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Table

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Tectonic control of Tertiary deposition 497

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to thin layers while sands, ligneous clays and coal

dominate. In the central depocentre, up to 15 fining-

upwards cycles can be identified (Figure 5). These

fining-upwards cycles and the coaly lithology indicate

that the deposition of these sediments occurred in a

floodplain environment with repeated periods of flood-

ing and drying.

The overall transformation from very coarse-

grained fluvial sediments in the headwaters of the

deep leads to finer-grained sediments deposited in a

swampy environment downstream marks a change

from high-energy transport in a dominantly braided

river system in the steeper upper reaches to low-energy

transport across a floodplain in the central section of

the deep-lead system.

Palynological age determinations show that deposi-

tion in the central depocentres took place over a time

interval of more than 50 million years, from mid – Late

Paleocene to Middle – Late Miocene (Morgan 1990;

Stanley 1987, 1988, 1990; this study; Table 1; Appendix

1). The oldest sediments (mid – Late Paleocene) are

*80 m thick and located in the western depocentre

(Figures 4a, 5; Table 1). Ages from the 140 m of

sediments in the central depocentre range from Early

Eocene to Late Miocene, with most of the sediments

deposited during the Eocene. In the eastern depocentre

Figure 3 Isopach map of the Yaloak/Calivil Formation in the Streatham Deep-Lead System. Also shown are the limits of the

Late Oligocene/Early Miocene and Late Miocene transgressions in this area.

498 M. Raiber and J. A. Webb

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Figure 4 (a – c) Cross-sections through the Streatham Deep-Lead System. See Figure 3 for location of sections.

Tectonic control of Tertiary deposition 499

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(Figure 4a; Table 1) there is a narrow range of Eocene

ages. Thus, the major phase of sediment accumulation

in the central depocentres occurred during the Paleo-

cene and Eocene. This was probably followed by a

period of non-deposition in the Early Oligocene, and

then accumulation of a thin sequence of sediments from

the mid-Miocene to Pliocene, at much the same time as

deposition in the headwater deep leads (Late Oligocene

to Late Miocene).

These ages indicate that Paleocene to Eocene sedi-

ment accumulation was restricted to the three central

depocentres by syndepositional subsidence (Figures 3,

4a), and suggest that at this time the headwaters deep

leads functioned only as transport pathways for the

sediment supply from the Western Uplands. After a

probable Early Oligocene hiatus in deposition, accumu-

lation of sediments was more widespread in the

Miocene, possibly due to broad downwarping of the

Streatham Deep-Lead System.

Outlets and position of the coastline

The headwaters of the Streatham Deep-Lead System are

well constrained by bore logs and airborne geophysical

images, but the outlet to the sea, connecting the

deep-lead system to the Otway Basin, has proved

difficult to locate. There are two possible positions, one

in the west and one in the east (Figures 3, 4c). The

eastern outlet was located in a small basement depres-

sion between the Dundonnell Granite and the Illoura

Granodiorite (Figure 2a, b) (Stanley 1992), which are

part of a massive basement ridge separating the deep-

lead system from the Otway Basin (Figure 4b). Despite

extensive drilling, the exact position of the break

through this granite ridge could not be located (D. R.

Stanley pers. comm. 2005). However, this is the only

location throughout the deep lead where Late Oligocene

to Early Miocene marine sediments (Gellibrand Marl)

are found (Figure 3).

A second location where the Streatham Deep-Lead

System flowed into the sea was identified by this study,

incised into the Paleozoic bedrock to the west of Lake

Bolac (Figures 2b, 4c), where up to 40 m of deep-lead

sediments were intersected during a mineral explora-

tion survey (Stuart-Smith & Black 1999). A lack of core

samples from these sediments meant that no palynolo-

gical ages could be obtained, so the age of these

sediments is uncertain, but this outlet was probably

active only during the early history of the deep lead

(discussed further below).

Figure 5 Lithological sections in selected bores throughout the Streatham Deep-Lead System, showing the spatial variability

of the deep-lead sediments. The locations of the sections and those bores sampled for palynology are shown on the inset map.

NV, Newer Volcanic basalts; Y/C, Yaloak/Calivil Formation undifferentiated; Y, Yaloak Formation; C, Calivil Formation.

500 M. Raiber and J. A. Webb

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The near-absence of Early to Middle Tertiary marine

strata through the central section of the Streatham

Deep-Lead System, despite the numerous transgressions

of this age in the Otway Basin, shows that there was a

sufficient continuous supply of clastic sediments from

the highlands to the north to ensure that despite the

continuing subsidence (see below), the floor of the

paleovalley did not fall below sea-level.

Stratigraphic nomenclature

Deep-lead sediments in Victoria are generally assigned

to the Calivil Formation (Figure 7), which was intro-

duced by Macumber (1973) for Late Eocene to Late

Miocene sediments of the Avoca and Loddon deep leads

north of the continental drainage divide, and has also

been applied to deep leads south of the divide (Cayley &

Taylor 2001; Holdgate et al. 2006). The Late Oligocene –

Late Miocene/Pliocene sediments which occur through-

out the Streatham Deep-Lead System are separated from

the older strata by a short phase of non-deposition

during the Early Oligocene, and are best identified as

Calivil Formation (Figure 7).

The Paleocene – Eocene sediments confined to the

central depocentres of the Streatham Deep Lead System

were initially referred to the Eastern View Formation

by Mann et al. (1992) (Figure 7). This unit was erected in

the adjacent northeastern Otway Basin for non-marine

sediments (sands, silts and coals) of Paleocene to Eocene

age, locally extending into the Oligocene (Abele et al.

1988). The Streatham sediments also resemble the

Yaloak Formation, which occurs in downfaulted basins

to the east (Lal Lal Basin and Ballan Graben: Holdgate &

Gallagher 2003), and has a similar coaly composition

and age range (Figure 7). The tectonic setting of the

Streatham Deep-Lead System is closer to the onshore

Lal Lal Basin/Ballan Graben than the Otway Basin,

which is much larger and extends offshore. Therefore,

the Paleocene – Eocene sediments of the Streatham

Deep-Lead System are here assigned to the Yaloak

Formation.

DEPOSITIONAL AND TECTONIC HISTORY

The palynological dating and structural analysis show

that the evolution of the Streatham Deep-Lead System

took place in several phases, resulting in the formation

of a complicated graben system (Figure 4a, b).

Initial development of the landscape(mid-Cretaceous –earliest Paleocene)

The Western Victorian Uplands may have been initially

uplifted in the mid-Cretaceous (Ollier & Joyce 1986;

Joyce 1992) at the same time as the Southeastern

Uplands (Foster & Gleadow 1992; Joyce & Webb 2003).

Substantial erosion formed an extensive, broad valley

system that was partly infilled by the White Hills Gravel

in the latest Cretaceous to earliest Paleocene (Figure 8).

Figure 6 Location of the major faults that determined sediment accumulation in the depocentres of the Streatham Deep-Lead

System (mapped from DEM, airborne geophysics and VandenBerg et al. 2000). Additional faults are present, but their

locations are unconstrained and hence not shown.

Tectonic control of Tertiary deposition 501

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The absence of Upper Cretaceous to Lower Paleocene

sediments equivalent to the White Hills Gravel at the

base of the Streatham Deep-Lead System sediments

indicates that the White Hills Gravel was restricted to

upstream positions closer to the uplands.

Mid – Late Paleocene sedimentation

After the deposition of the White Hills Gravel, the

landscape was most likely uplifted in the Early Paleo-

cene, and the White Hills Gravel incised and partly

removed, leaving only disconnected remnants on valley

flanks and hill tops (Hughes et al. 1998). During the mid

to Late Paleocene, *80 m of Yaloak Formation sedi-

ments (Figure 3) were deposited in the western depo-

centre of the Streatham Deep-Lead System (Figure 8) by

a river system with an extensive floodplain (as sug-

gested by the fining-upwards cycles with coal). Syn-

depositional subsidence of at least 40 m was controlled

by the Moyston and Westermere Faults (the latter

named herein) (Figures 4a, 7) and a set of unnamed

east-northeast faults. The river system probably entered

the sea through a gap between the basement outcrops of

Glenthompson Sandstone and Grampians Group west of

Lake Bolac (Figures 2a, b, 3, 4c), connecting the

Streatham Deep-Lead System to the Otway Basin.

Although the sediments deposited in this outlet are

undated, the exclusively Paleocene ages of the strata in

the western depocentre make it likely that the outlet

was active during the Paleocene. To the east of this

outlet, a granite ridge separated the deep lead from the

ocean, and Yaloak/Calivil Formation sediments are

absent to the south of this ridge.

At the end of the Paleocene, movement on the

Moyston and Westermere Faults stopped, and deposi-

tion in this part of the basin ceased.

Early – Late Eocene sedimentation

During the Early Eocene to mid – Late Eocene, up to

140 m of Yaloak Formation sediments were deposited in

the central and eastern depocentres (Figures 3, 4a, 8).

Palynological ages (Figures 4a, b, 5; Table 1) show that

the main period of syndepositional subsidence occurred

during the Early Eocene. Deposition in the central

depocentre was controlled by the Tara (named herein)

and Concongella Faults and a set of east-northeast faults

with a maximum vertical displacement of *140 m. The

faults along the margins of the eastern depocentre are

difficult to identify in the aeromagnetic images and

the DEM, due to the strong overriding magnetic

signature and topographic expression of the Dorodong

Sand strandlines, which cover the deep-lead sediments

in this part of the system (Figure 4a).

Figure 7 Stratigraphy of the Streatham Deep-Lead System, and regional correlations. Age scale does not apply to Paleozoic

basement.

502 M. Raiber and J. A. Webb

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From the Eocene onwards, the river system of the

Streatham Deep Lead entered the ocean (Otway Basin)

through a new outlet east of Mt Fyans (Figures 3, 4c),

located in a topographic low between the basement

highs of the Dundonnell Granite and Illoura Granodior-

ite (Figures 2a, b, 4c). The eastwards change in the site of

the outlet accompanied the eastwards shift in the area of

subsidence within the central depocentres of the deep-

lead system.

Late Oligocene– Late Miocene sedimentation

Following a depositional hiatus in the Early Oligocene,

sedimentation recommenced in the Late Oligocene to

Early Miocene, when the sea transgressed sufficiently

northwards that the coastline reached and overtopped

the granite ridge forming the southern margin of the

Streatham Deep-Lead System (Figure 3). A thin se-

quence of Gellibrand Marl accumulated over a small

area north and northeast of the eastern outlet. At the

same time, a *30 m-thick sheet of fluvial sediments

(Calivil Formation) was deposited throughout the Strea-

tham system, perhaps due to a broad downwarping

(Figure 8). In addition, there was localised syndeposi-

tional fault-related subsidence, causing a substantial

variation in sediment thicknesses deposited at this time

in the headwaters deep leads (Figure 3).

Latest Miocene to Early Pliocene marinetransgression and eruption of Newer Volcanics

In the latest Miocene, the most extensive of the Tertiary

transgressions in southeastern Australia covered the

southern and central part of the Streatham system. As

the sea retreated in the Early Pliocene, the strandline

sediments of the Dorodong Sands were deposited and

covered the deep-lead sediments throughout the system

(Figures 3, 8).

Localised subsidence appears to have occurred in the

central depocentre at this time, where a sequence of

70 m of Dorodong Sands was intersected in groundwater

bore 110097 (Figures 4b, 8). Due to the lack of dateable

material, it was not possible to obtain an age for these

sediments, but the absence of coal and the uniform fine

sand lithology indicates that this is a sequence of

downfaulted strandline Dorodong Sands rather than

fluvial deep-lead sediments. Subsidence in this areally

constricted depocentre was probably controlled by the

Coongee and Concongella Faults (Figure 6).

Following the regression in the Early Pliocene but

prior to the eruption of Newer Volcanic basalts, a period

of compressional block faulting caused extensive uplift

and displacement of the Dorodong Sands strandlines

throughout western Victoria (Paine et al. 2004). In the

area southwest of Lake Bolac (Figure 3), a basement

block overlain by Dorodong Sands and a narrow belt of

Yaloak Formation was uplifted (Figure 8), and erosion

partially or completely removed the Dorodong Sands.

The first relatively limited eruptions of basalt lavas

occurred during the Late Miocene close to the head-

waters of the deep-lead system. Plio-Pleistocene erup-

tions of the Newer Volcanics (mostly between 3 and

1 Ma) covered the Dorodong Sands and the Yaloak/

Calivil Formation throughout most of the system,

disrupting the drainage and levelling out existing

topographic lows, including those formed by the

Pliocene block faulting. This resulted in reduced relief

and lower gradients between the stream headwaters in

the Western Uplands and the southern plain. As a result,

the streams that became established across the surface

Figure 8 Diagrammatic represen-

tation of regional landscape evo-

lution and the depositional phases

in the western depocentre and

central depocentre; section-lines

run from headwaters to ocean

outlet in each area.

Tectonic control of Tertiary deposition 503

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of the basalt have only shallow valleys and thin fluvial

sediments.

DISCUSSION

Structural trends and Tertiary tectonism acrosswestern Victoria

Early Tertiary fault movement, probably related to the

Australia – Antarctica breakup, was widespread across

western Victoria; minor overall north – south extension

reactivated pre-existing faults to form localised grabens

that received Paleocene – Eocene sediments. Fault activ-

ity in the Streatham Deep-Lead System has similar

timing and structural trends to that in the eastern

Otway Basin.

In the Port Campbell Embayment and Colac Trough,

located to the south and southeast of the Streatham

Deep-Lead System (Figure 1), thick sequences of Wan-

gerrip Group were deposited unconformably on the Late

Cretaceous Sherbrook Group during the Paleocene to

Early Eocene, due to subsidence controlled by faulting

(Cooper 1995; Edwards et al. 1996). Syndepositional

graben formation also occurred in the Tyrendarra

Embayment during the Paleocene to Early Eocene

(Perincek & Cockshell 1995).

The major north-northwest-trending lineaments

across the Streatham Deep-Lead System (e.g. Moyston,

Coongee and Concongella Faults) can be traced south on

aeromagnetic and gravity images from the Western

Volcanic Plain into the eastern part of the Otway

Basin, where these reactivated Paleozoic structures also

control sediment accumulation (Moore 2002). East-

northeast-trending lineaments, such as the Colac

Monocline and the Bambra Fault, can be identified on

gravity images across the northern margin of the Port

Campbell Embayment and the Colac Trough. These

lineaments run parallel to the main rift axis between

Antarctica and Australia (Edwards et al. 1996), which

developed during the mid-Cretaceous (Moore 2002), and

also correspond to the east-northeast structural trends

observed throughout the Streatham Deep-Lead System

and the Western Uplands.

The Tertiary deep-lead systems north of the drainage

divide (e.g. Loddon – Ballarat system) are cross-cut by

east-northeast-trending faults (Holdgate et al. 2006) that

can be traced southwestwards using the airborne

geophysical images and the DEM into the Streatham

Deep-Lead System, where they represent the northern

and southern edges of the major depocentres and also

cross-cut the headwaters deep leads. The east-northeast

faulting north of the divide was coeval with the Late

Eocene to Miocene sedimentation in both these deep

leads (Canavan 1988; Holdgate et al. 2006) and the

headwaters deep leads south of the divide, but was later

than the Paleocene – Eocene activity in the central

depocentres of the Streatham Deep-Lead System.

Early Pliocene syndepositional downfaulting of

Dorodong Sands occurred contemporaneously in the

Hamilton Graben west of the study area (Paine et al.

2004), and in the central depocentre of the Streatham

Deep-Lead System (Figure 8).

CONCLUSIONS

The mainly sub-basaltic Streatham Deep-Lead System

covers *2500 km2 and consists of five major tributaries,

which fuse into a central section with three major

depocentres. Fluvial coal-bearing sediments of the

Yaloak Formation were deposited in the depocentres as

a series of fining-upwards cycles. The western depocen-

tre received *80 m of sediments from the mid to Late

Paleocene, whereas the central and eastern depocentres

accumulated up to 140 m of Eocene to Late Miocene

strata. Sediment accumulation was controlled by sub-

sidence along north-northwest- and east-northeast-

trending, reactivated Paleozoic and Cretaceous faults.

Syndepositional faulting with a similar orientation and

timing also occurred in the Otway Basin to the south.

In the Paleocene, the river system of the Streatham

Deep Lead flowed into the ocean (Otway Basin) through

a western outlet; in the Eocene, the outlet shifted

eastwards along with the locus of sedimentation, to a

location between two basement highs east of Mt Fyans.

Following a short hiatus in the Early Oligocene,

fluvial sedimentation and syndepositional faulting re-

commenced from the Late Oligocene to Late Miocene/

Pliocene, depositing the *30 m thick Calivil Formation

throughout the deep-lead system, perhaps due to a broad

downwarping. Sediment deposition and faulting oc-

curred at the same time in the north-flowing deep leads

in central and northern Victoria.

A period of latest Miocene to Early Pliocene fault

subsidence affected the central depocentre, followed by

widespread compressional block faulting across western

Victoria in the Early Pliocene. The deep-lead sediments

were then covered by basalts, mostly erupted in the Plio-

Pleistocene.

ACKNOWLEDGEMENTS

We would like to acknowledge the financial assistance of

the Glenelg Hopkins Catchment Management Authority

and the Australian Institute of Nuclear Science and

Engineering. We also wish to thank the Department of

Primary Industries Victoria for providing bore log re-

cords and airborne geophysical images and granting

access to the core library, as well as Sinclair Knight Mertz

for supplying bore log records. The authors wish to thank

Darren Bennetts and Matthew Edwards for their com-

ments on the draft manuscript and journal reviewers

David Taylor and Guy Holdgate for their suggestions,

which helped to improve the quality of the manuscript.

REFERENCES

ABELE C., GLOE C. S., HOCKING J. B., HOLDGATE G., KENLEY P. R.,

LAWRENCE C. R., RIPPER D., THRELFALL W. F. & BOLGER P. F. 1988.

Tertiary. In: Douglas J. G. & Ferguson J. A. eds. Geology of

Victoria, pp. 251 – 350. Geological Society of Australia, Victorian

Division, Melbourne.

BENNETTS D. A., WEBB J. A. & GRAY C. M. 2003. Distribution of Plio-

Pleistocene basalts and regolith around Hamilton, western

Victoria, and their relationship to groundwater recharge and

discharge. In: Roach I. C. ed. Advances in Regolith, pp. 11 – 15.

Cooperative Research Centre for Landscape Environments and

Mineral Exploration, Bentley.

504 M. Raiber and J. A. Webb

Downloaded By: [La Trobe University Library] At: 03:59 21 October 2008

BIRCH W. D., BARRON L. M., MAGEE C. & SUTHERLAND F. L. 2007. Gold-

and diamond-bearing White Hills Gravel, St Arnaud district,

Victoria: age and provenance based on U – Pb dating of zircon

and rutile. Australian Journal of Earth Sciences 54, 609 – 628.

BISHOP P. & LI S. 1997. Sub-basaltic deep-lead systems and gold

exploration at Ballarat, Australia. Australian Journal of Earth

Sciences 44, 253 – 264.

BRADLEY J., STANLEY D., MANN B., CHAPLIN H. & FOLEY G. 1994.

Ballarat Hydrogeological Map (1:250 000 scale) Murray Basin

Hydrogeological Map Series. Australian Geological Survey

Organisation, Canberra.

CANAVAN F. 1988. Deep lead gold deposits of Victoria. Geological

Survey of Victoria Bulletin 62.

CAREY S. P. & HUGHES M. J. 1997. Three generations of gold-bearing

fluvial systems at Ararat, Victoria. Geological Society of Aus-

tralia Abstracts 47, 4.

CAYLEY R. A. & MCDONALD P. A. 1995. Beaufort 1:100 000 map

geological report. Geological Survey of Victoria Report 104.

CAYLEY R. A. & TAYLOR D. H. 2001. Ararat 1:100 000 map geological

report. Geological Survey of Victoria Report 115.

COOPER G. T. 1995. Seismic structure and extensional development of

the eastern Otway Basin – Torquay Embayment. APEA Journal

35, 436 – 450.

EDWARDS J., LEONARD J. G., PETTIFER G. R. & MCDONALD P. A. 1996.

Colac 1:250 000 map geological report. Geological Survey of

Victoria Report 98.

FOSTER D. A. & GLEADOW A. J. W. 1992. Reactivated tectonic

boundaries and implications for the reconstruction of south-

eastern Australia and northern Victoria Land, Antarctica.

Geology 20, 267 – 270.

HILL S. M. 1999. Mesozoic regolith and palaeolandscape features in

southeastern Australia: significance for interpretations of denu-

dation and highland evolution. Australian Journal of Earth

Sciences 46, 217 – 232.

HOLDGATE G. R., CUNNINGHAM K. A., WALLACE M. W.,

GALLAGHER S. J. & MOORE D. H. 2004. Tertiary ‘deep lead’

palaeoriver systems and their relationship to basin evolution,

Victoria. In: Boult P. J., Johns D. R. & Lang S. C. eds. Eastern

Australasian Basin Symposium 2, pp. 707 – 724. Petroleum

Exploration Society of Australia Special Publication.

HOLDGATE G. R. & GALLAGHER S. J. 2003. Chapter 10: Tertiary. In:

Birch W. D. ed. Geology of Victoria, pp. 289 – 335. Geological

Society of Australia Special Publication 23.

HOLDGATE G. R., WALLACE M. W., GALLAGHER S. J., WITTEN R. B.,

STATS B. & WAGSTAFF B. E. 2006. Cenozoic fault control on ‘deep

lead’ palaeoriver systems, Central Highlands, Victoria. Austra-

lian Journal of Earth Sciences 53, 445 – 468.

HUGHES M. J. & CAREY S. P. 2002. Palaeodrainage development of the

West Victorian Uplands, Victoria, Australia. In: Victoria Under-

cover: Benalla 2002. Conference Proceedings and Field Guide:

Collaborative Geoscience in Northern Victoria, pp. 155 – 159.

CSIRO Publishing, Collingwood.

HUGHES M. J., KOTSONIS A. & CAREY S. P. 1998. Cainozoic weathering

and its economic significance in Victoria. Australian Institute of

Geoscientists Bulletin 24, 135 – 148.

HUNTER S. B. 1909. The deep leads of Victoria. Geological Survey of

Victoria Memoir 7.

JOYCE E. B. 1992. The West Victorian Uplands of southeastern

Australia: origin and history. Earth Surface Processes and

Landforms 17, 407 – 418.

JOYCE E. B. 2003. Western Volcanic Plains, Victoria. In: Roach I. C.

ed. Advances in Regolith, p. 5. Cooperative Research Centre for

Landscape Environments and Mineral Exploration, Bentley.

JOYCE E. B. & WEBB J. A. 2003. Chapter 18: Geomorphology. In:

Birch W. D. ed. Geology of Victoria, pp. 553 – 562. Geological

Society of Australia Special Publication 23.

KRAUSE F. M. 1874. Geological Survey of Ararat. Geological Survey of

Victoria Progress Report 2, 93 – 98.

MACUMBER P. G. 1973. Progress report on the groundwater survey of

the Avoca and Loddon valleys. In: Groundwater Investigation

Program Report 1972, p. 7. Department of Mines Victoria.

MACUMBER P. G. 1991. Interaction between groundwater and surface

systems in northern Victoria. Department of Conservation and

Environment, Melbourne.

MANN B. S., STANLEY D. A., BOLGER P. F. & NOLAN J. 1992.

Groundwater processes in the basalt plains of

southwestern Victoria. Geological Survey of Australia Abstracts

32, 259 – 260.

MILLER J. McL., PHILLIPS D., WILSON C. J. L. & DUGDALE L. J. 2005.

Evolution of a reworked orogenic zone: the boundary

between the Delamerian and Lachlan Fold Belts,

southeastern Australia. Australian Journal of Earth Sciences

52, 921 – 940.

MOORE D. H. 2002. Basement basin relationships in the Otway Basin,

Victoria, Australia. Victorian Initiative for Minerals and Petro-

leum Report 78.

MORGAN R. 1990. Palynology of nineteen samples from the Basalt

Plains and Riverine Plains Victoria, Australia. Geological Survey

of Victoria Report 1990/24 (unpubl.).

NOLAN J., STANLEY D., WIJESEKERA N. & MANN B. 1990. Basalt plains

hydrogeological investigation progress report no. 1. Rural

Water Commission, Victoria, Investigation Branch Report 1990/

1 (unpubl.).

OLLIER C. D. & JOYCE E. B. 1986. Regolith terrain units of the

Hamilton 1:100 000 sheet, western Victoria. Bureau of Mineral

Resources Record 1986/33.

OLLIER C. D. & PAIN C. F. 1994. Landscape evolution and tectonics in

southeastern Australia. AGSO Journal of Australian Geology &

Geophysics 15, 335 – 345.

PAINE M. D., BENNETTS D. A., WEBB J. A. & MORAND V. J. 2004.

Nature and extent of Pliocene strandlines in southwestern

Victoria and their application to late Neogene tectonics.

Australian Journal of Earth Sciences 51, 407 – 422.

PERINCEK D. & COCKSHELL C. D. 1995. The Otway Basin: Early

Cretaceous rifting to Neogene inversion. APEA Journal 35,

451 – 466.

PRICE R. C., GRAY C. M. & FREY F. A. 1997. Strontium isotopic and

trace element heterogeneity in the plains basalts of the Newer

Volcanic Province, Victoria, Australia. Geochimica et Cosmochi-

mica Acta 61, 171 – 192.

STANLEY D.R. 1987. Well completion report: Geelengla 10. Rural

Water Commission, Victoria, Investigation Branch Report 1987/

48 (unpubl.).

STANLEY D. R. 1988. Well completion report; Dunnawalla 9, GC 13:

lignite potential of the northern margin of the Otway Basin.

Rural Water Commission, Victoria, Investigation Branch Report

1988/9 (unpubl.).

STANLEY D. R. 1990. Well Completion report Kornong 1 and 2. Rural

Water Commission, Victoria, Investigation Branch Report 1990/

26 (unpubl.).

STANLEY D. R. 1992. Groundwater usage and resource potential along

the northern margin of the Basalt Plains, western Victoria.

Rural Water Commission, Victoria, Investigation Branch Report

1992/6 (unpubl.).

STUART-SMITH P. & BLACK L. P. 1999. Willaura, Sheet 7422, Victoria,

1:100 000 Map Geological Report. Australian Geological Survey

Organisation Record 1999/38.

TAYLOR D. H. & GENTLE L. V. 2002. Evolution of deep-lead

palaeodrainages and gold exploration at Ballarat, Australia.

Australian Journal of Earth Sciences 49, 869 – 878.

TAYLOR D. H., WOHLT K. E., SIMONS B. A., MAHER S., MORAND V. J. &

SAPURMAS P. 2000. Creswick 1:100 000 map area geological report.

Geological Survey of Victoria Report 117.

VANDENBERG A. H. M., WILLMAN C. E., MAHER S., SIMONS B. A.,

CAYLEY R. A., TAYLOR D. H., MORAND V. J., MOORE D. H. &

RADOJKOVIC A. 2000. The Tasman Fold Belt System in Victoria.

Geological Survey of Victoria Special Publication.

WALLACE M. W., DICKINSON J. A., MOORE D. H. & SANDIFORD M. 2005.

Late Neogene strandlines of southern Victoria: a unique record

of eustasy and tectonics in southeast Australia. Australian

Journal of Earth Sciences 52, 279 – 297.

WEBB A. W., OSBORNE C. R., TAYLOR D. H. & CAYLEY R. A. 1998.

K – Ar geochronology of Newer Volcanics on the Ballarat 1:250

000 map sheet. Geological Survey of Victoria Report 1998/10

(unpubl.).

Received 9 February 2007; accepted 16 November 2007

Tectonic control of Tertiary deposition 505

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Bore-ID

Sample depth (m)

Parupa/

87762

144 – 145

Kornong/72649 Dunnawalla

9

71.5 – 72.8

Caramballuc

North 54474

92 – 94

Enuc/

62734

105

Baangal/

46853a

66 – 68 &

76 – 78

80 – 81.5 122 – 123 142.8 – 145

Spores

Baculatisporites disconformis – – – – – – X –

Baculatisporites sp. nov. – – – – – – 1.0% –

Baculatisporites spp. 1.0% 1.9% 0.6% 0.6% 1.0% – – –

Clavifera triplex 0.3% – – 1.3% – – – –

Cyathidites paleospora – – – – – – 28.0% X

Cyathidites porospora – – – – – – X –

Cyathidites splendens – – X X – – – –

Cyathidites spp. 7.7% – – – – – – –

Cyathidites spp. (large) – – 2.5% – – – – –

Cyathidites spp. (small) – 3.1% 3.1% 8.4% 1.5% – – –

Foveotriletes balteus 0.3% – – – – – – –

Foraminisporis bifurcatus – – – – – – ? –

Gleicheniidites circinidites 1.0% – 0.6% 0.6% – – 4.0% –

Ischyosporites gremius 1.3% X – X – – X –

Ischyosporites irregularis sp. nov. – – – – 1.5% – – –

Laevigatosporites major – 2.5% 0.6% X 1.0% – 3.5% –

Laevigatosporites ovatus 1.0% 0.6% 4.9% 2.6% 3.0% X 0.5% –

Matonisporites ornamentalis – X – – 0.5% – 0.5% –

Peromonolites densus – – – – X – – –

Peromonolites vellosus 0.3% – – – – – – –

Polypodiaceoisporites tumulatus – – – – – – X –

Polypodiisporites spp. 0.3% 4.3% – – 1.0% – 1.0% –

Ricciaesporites sp. – – – – – – X –

Rugulatisporites cowrensis – – – – – – 0.5% –

Trilete spores indet. – 0.6% – – 0.5% – – –

Tripunctisporis maastrichtiensis – – – X X – – –

Stereisporites australis – – – – – – 1.0% –

Rugulatisporites mallatus X – – – – – – –

Trilete spores indet. – – – – – – 0.5% –

Verrucosisporites kopukuensis 0.3% 1.2% X 0.6% 1.0% –

Total spores: 13.5% 14.3% 12.3% 14.2% 10.9% 51% 40.5% –

Gymnosperm pollen

Araucariacites australis 1.0% – 1.2% 1.9% – – 1.0% –

Dilwynites granulatus 11.3% – 1.9% 3.9% – – – –

Darcycarpites australiensis – 3.1% – – 5.4% – 2.0% –

Dilwynites tuberculatus 1.6% – 5.6% 0.6% – – – –

Lygistepollenites balmei 0.3% – – – – – – –

Lygistepollenites florinii 6.1% 7.5% 9.9% 3.9% 1.0% 0.5% 1.5% –

Microcachryidites antarcticus 0.6% – 1.2% 0.6% 1.0% – – –

Parvisaccites catastus – 0.6% – – – – – –

Phyllocladidites mawsonii 0.6% 9.9% – – X 1.4% – –

Phyllocladidites verrucosus X – – – – – – –

Podocarpidites spp. 40.0% 9.9% 29.6% 23.2% 12.4% – 3.5% –

Trichotomosulcites subgranulatus 6.1% 2.5% 0.6% 1.3% X – – –

Total gymnosperm pollen: 67.7% 33.5% 50.0% 35.5% 19.8% 1.9% 8.5% –

Angiosperm pollen

Banksieaeidites arcuatus – – – – – 0.5% – –

Banksieaeidites elongatus – – – – – 0.5% 0.5% –

Banksieaeidites minimus – – – – – – 5.5% –

Beaureaidites elanansiformis – – – – – 0.5% – –

Bysmapollis emaciatus – 0.6% – – – – – –

Bysmapollis minimus – – – – X – – –

Chenopodipollis chenopodiaceoides – – – – – – X –

(continued)

APPENDIX 1: SPECIES LIST OF STREATHAM DEEP-LEAD SEDIMENTS

A. D. Partridge (Biostrata Pty Ltd: AlanPartridge@access.net.au)

506 M. Raiber and J. A. Webb

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APPENDIX 1 (Continued)

Bore-ID

Sample depth (m)

Parupa/

87762

144 – 145

Kornong/72649 Dunnawalla

9

71.5 – 72.8

Caramballuc

North 54474

92 – 94

Enuc/

62734

105

Baangal/

46853a

66 – 68 &

76 – 78

80 – 81.5 122 – 123 142.8 – 145

Cupanieidites orthoteichus – – – – 0.5% – – –

Dicotetradites clavatus 0.3% 0.6% 4.3% 0.6% – – – –

Ericipites crassiexinus – 0.6% – – – – – –

Ericipites scabratus 0.6% – 3.1% 12.9% 0.5% 0.9% 0.5% X

Gambierina edwardsii 0.3% – – – – – – –

Gambierina rudata 0.3% – – – – – – –

Gyropollis psilatus – – – – – – 0.5% –

Haloragacidites amolosus – – – – – – 0.5% –

Haloragacidites haloragoides – – – – – – 5.5% X

Haloragacidites harrisii X 3.7% 1.2% 2.6% 2.5% 55.9% 10.0% X

Ilexpollenites anguloclavatus – – – – – 0.9% – –

Ilexpollenites spp. 0.6% – 1.2% X – – – –

Liliacidites sp. – – – – – – X –

Lymingtonia sp. – X – – – – – –

Malvacipollis robustus sp. nov. – X – – – – – –

Malvacipollis subtilis X 3.1% – X – 0.9% – –

Micrantheum spinysporis – – – – – X – –

Milfordia homeopunctata – – – – – – X –

Milfordia incertus – – – – – – 13.5% X

Myrtaceidites eucalyptoides – – – – – – 0.5% –

Myrtaceidites parvus/mesonesus – – – – – – 0.5% –

Nothofagidites asperus – – – – X – – –

Nothofagidites brachyspinulous – 0.6% – – 0.5% – – –

Nothofagidites deminutus – 0.6% – – 11.4% 2.3% – –

Nothofagidites emarcidus/heterus 1.0% 28.6% X 1.9% 44.1% 18.3% X –

Nothofagidites endurus 0.6% – – – – – – –

Nothofagidites falcatus – 3.1% – – 1.5% 0.5% 0.5% –

Nothofagidites flemingii X 1.2% X 0.6% – X – –

Nothofagidites goniatus – 0.6% – – – – – –

Nothofagidites vansteenisii – X – – 1.0% 0.5% – –

Periporopollenites demarcatus – 2.5% 1.2% – 2.5% 1.9% – –

Periporopollenites plyoratus 2.9% – – 1.3% X – – –

Periporopollenites vesicus – 1.2% – – – – – –

Polyporina reticulata – – – – – – – X

Polycolpites langstonii X – – – – – – –

Proteacidites spp. 9.0% 1.9% 13.6% 24.5% 2.0% 3.3% X –

Proteacidites annularis ? – – – – 1.4% – –

Proteacidites differentipolus – – – X – – – –

Proteacidites grandis – – 1.9% 1.9% – – – –

Proteacidites obscurus – – – – – 0.5% – –

Proteacidites pseudomoides – – 1.9% X – – – –

Proteacidites rectomarginis – – – – – 6.1% – –

Proteacidites stipplatus – – – – – X – –

Proteacidites sp. cf. P.rectus – – – X – – – –

Proteacidites tenuiexinus – – X X – – – –

Proteacidites truncatus – – – – – – X –

Proteacidites (Hakeidites) sp. – – – – – – 9.5% –

Pseudowinterapollis couperi – – – – – – X –

Santalumidites cainozoicus – X – – 0.5% – – –

Stephanocolpites oblatus – – – – – – X –

Striasyncolpites laxus – – – – – – X –

Tetracolporites multistrixus sp.nov. X – – – – – – –

Tetracolporites verrucosus ? – – – – – – –

Tricolpate and Tricolpate pollen undiff. 0.6% 2.5% 8.0% 2.6% – 1.9% 2.0% –

Tricolpites phillipsii 0.6% – – 1.3% – – – –

Tricolpites simatus – – – – X – – –

Tricolpites thomasii – – – – X – – –

Tricolporate pollen undiff. – – – – 1.0% – – –

Tricolporites adelaidensis 0.3% – 0.6% X – 0.5% – –

Tricolorites leuros – X – – 0.5% 0.9% – –

(continued)

Tectonic control of Tertiary deposition 507

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APPENDIX 1 (Continued)

Bore-ID

Sample depth (m)

Parupa/

87762

144 – 145

Kornong/72649 Dunnawalla

9

71.5 – 72.8

Caramballuc

North 54474

92 – 94

Enuc/

62734

105

Baangal/

46853a

66 – 68 &

76 – 78

80 – 81.5 122 – 123 142.8 – 145

Tricolporites marginatus sp. nov. X – X – – – – –

Tricolporites microreticulatus – – – X – – – –

Tricolporites sphaerica 1.0% 0.60% 0.60% – – – – –

Triporopollenites ambiguus – – – X 0.5% – – –

Triporopollenites spp. 0.3% – – – – – – –

Tubulifloridites antipodica – – – – – – 0.5% –

Total angiosperm pollen: 18.7% 52.2% 37.7% 50.3% 69.3% 98.1% 51.0% –

Total spore – pollen count: 310 161 162 155 202 213 200 –

Other palynomorphs

Fungal germlins – – – – – 0.7% – –

Fungal fruiting bodies – – 1.2% – – – – –

Fungal spores & hyphae 1.9% – 5.2% 1.9% 4.2% 27.2% 1.0% –

Botryococcus braunii – – – – – – 3.3% –

Brazilea sp. – – – – – – X –

Gelasinicysta vangellii – – – – – – 0.5% X

Gelasinicysta sp. 4 – – – – – – X –

Lecaniella sp. 8 – – – – – – X –

Tertaporina sp. – – – – – – – X

Indeterminate palynomorphs – – – – 3.7% 1.0% – –

Total other palynomorphs 1.9% 0% 6.4% 1.9% 7.9% 28.9% 4.8% –

Total other palynomorphs count: 6 0 11 3 17 85 10 –

Grand total count: 316 161 173 158 219 298 210 –

aLimited palynomorph assemblage in bore Baangal/46853 does not allow accurate determinations, but similarity of the assemblage to

that recorded from Enuc/62734 at 105 m indicates that these two samples are probably the same age.

508 M. Raiber and J. A. Webb

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