COMMONWEALTH OF AUSTRALIA

DEPARTMENT OF NATIONAL DEVELOPMENT

BUREAU OF MINERAL RESOURCES, GEOLOGY AND GEOPHYSICS

Record No. 1969 /27

Mellong Well

Petrological Study of (A.O.G) No.1

Sydney Basin N.S.WI

by

S.J. Mayne

The information contained in this report has been obtained by the Department of National Development as part of the policy of the Commonwealth Government to assist in the exploration· and development of mineral resources. It may not be published in any form or use in 11 company prospectus or statement without the permission in writing of the Director, Bure~u of Mineral Resources, Geology and Geophysics.

Record No. 1969 /27

Petrological Study of Mellong No.1 Well (A.O.G)

Sydney Basin N.S.W.

by

S.J. Mayne

The information contained in this report has been obtained by the Department of N~tional Development as part of the policy of the Commonwealth Government to assist in the exploration and development of mineral resources. It may not be published in any form or use in a company prospectus or statement without the permission in writing of the Director, Bureau of Mineral Resources, Geology and Geophysics.

,. ,

RECORDS NO. 1969/21

PEI'ROLOGICAL STUDY OF MELLONG (A.O.G.) NO. I WELL

SYDNEY BASIN, NEW SOUTH WALES

by

S.J. MAYNE

,.

PErROLooICAL STUDY OF MELLONG (A.O.G.) NO. I WELL SYDNEY BASIN, NEW SOUTH WALES

GENERAL INFORMATION

G&)LooY

UNIT Me 1

UNITS Me 2-7

UNIT Me 2

UNIT Me 3

UNIT Me 4

UNIT Me 5 UNIT Me 6

UNIT Me 7 UNIT Me 8

T ABLE OF CONTENTS

Provenance and Environment

Comparison with Mt. llirwin

Comparison with Grose River District

Palaeontology

Permo-Triassic Boundary

Summary

References

Appendix

TEXT FIGURES

FIGURE 1: Summary of Petrological Results

FIGURE 2: Comparison of B. M.R. units with company interpretation

FIGURE 3: Comparison of Grose River, Mellong and Mt. Murwin

PLATES

Page

1

2-13 ~

3-5 3

3

4

4

4-5

5 5-6

6-7

7-8

8-9

9 9-10

10

10-11

12-13

PLATE 1A: Petrographic Well Log O' - 1700' (End of Report)

PLATE 1B: Petrographic Well Log 1700' - 2970' (End of Report)

MELLONG. No.1 WELL

Summary ·of PetrologicQ'·" Results

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Fig.1

B.MR Petroleum' explorofion. Fsbtuory 9 ro accompany Record x AUS-I-69

,-

GENERAL INFORMATION

Well Data

Well Name ani Number:

Operating Company:

Location:

Date Drilled:

Elevation:

Total Depth:

Rig Type:

Logs Run:

Hydrocarbon Shows:

Water Testing:

Mellong No. 1

Australian Oil and Gas Corporation

Latitude 330 00'25" South

Longitude 150041' 36" East

3 miles south-east of the Township of

Putty, in the County of Hunter.

1 :250,000 Sheet Singleton 'j .). 9

, . . ...

196-3/64

Ground 1146' a.s.l.

Collar 1149' a.s.l.

2970' Percussion.

Gamma-r a3. Resistivity and Self­

Potential logs were run by the N.S.W.

Department of Mines.

Two gas shows, too small to be measured

by the standard equipment, were detected

between 1830' - 1836' and 2045' - 2050'.

Water was encountered at several

horizons (see p.2, 4, 5,).

Summary of Major Reference

penetrated:

The well was drilled in the period 20.11.1963 - 29:2.1964, and

Triassic ( 0' - 370' ( 370' - 2480'

Permian 2480' - 2970'

(Hawkesbury Sandstone) (Narrabeen Group)

("Upper Coal Measures")

The well was located on the crest of a small closed anticline with a north­

south trending axis, in the Sydney Basin. It was drilled in the hope of finding

commercial quantities of gas in a dominantly sand sequence of the Narrabeen

Group. These sandstones were mostly "tight", but evidence of porosity and ,

perm~abili ty was afforded by at least seven water horizons and two gas horizons .•

New isopach data obtained show that the Narrabeen thins to the north and. north­

west.

The presence of white tuffaceous shales in the uppermost "Upper

Coal Measures" resemble occurrences near Newcastle and Burr ago rang. These beds

ma3 prove to be good marker beds for the "Upper Coal Measures" in the Sydney Basin.

The Company did not attempt a correlation with the defined units of

other areas.

Cuttings I

Coresl

2.

Material Available for Stud.Y . .

0' to 2910' (total depth) at 10' intervals.

Nil.

Methods Used

All samples were examined with a low-power binocular microscope,

and thin sections were made from chosen intervals and examined under a

petrological microscope. Eight units were distinguished on lithological

characteristics and on log features.

Pettijohn's classification of sedimentary rocks (1951) was used.

GEOLOGY

The uppermost rocks penetrated by the well are a distinctive

sandstone 360'deep. They cannot be subdivided readily, and so constitute

a single major unit, Me 1.

Unit Me 1

Characteristicsl This unit extends from the surface to 360' and apart from a

thin sil ty l~er at about 285' consists of ortho quartzite. The quartz grains

are subangular to angular, Qolourless,dominantly medium-grained but ranging

from very fine to coarse. Crystal faces are often present. Graphite is

alw~s present but varies from rare to common.

The orthoquartzite occurs in two types, the common or normal

Hawkesbury Sandstone, and a dark brown ferruginous variety.

(a) The normal orthoquartzite consists of rather closely

packed quartz grains with occasional feldspars (including

plagioclase and microcline), chert liths, white mica, and

kaolin as an interstitial cement.

Whi teand colourless pebbles of quartz up to 15 mm occur

spor adic ally.

(b) The ferruginous orthoquartzite shows a disrupted framework

of irregular quartz grains, many of which are shattered

by a sub-parallel system of cra:cks. Limonite (goethite)

occupies the interstices, opening up m~ of the cracks in

the quartz grains, and constituting up to 3~ of the total

rock. There are a few feldspar grains and flakes of white

mica.

This ferruginous sandstone occurs as bands in the normal

sandstone.

Fresh water flowed at 100 gph from the very bottom of Me 1.

,.

3.

Major Unit Me 2 to Me 1

This sequence is 2120' thick, extending from 360' to 2480'. It

consists of sandstone» and siltstone and shale: the pelitic grades dominate

in both the upper and IO'l'ler horizons, whilst the sandstone predominates in

the middle horizons.

The sandstone, which falls in the category of protoquartzite,

contains a distinctive component of grains of coloured che;rt, especially green

and reddish brown, which mc\y be up to 15 mm in size. Chert gravel is more

common in the lower levels than in the higher.

The pelitic rocks are mostly sandy Siltstone, sometimes verging

on the very-fine-sandstone border, but also include the so-called "chocolate"

or "red" shales frequently found elsewhere in the upper Narrabeen sequence.

Siderite occurs throughout this sequence: sometimes it is

coarse enough to be seen by thenaked eye, and often it is partly altered to

limonite.

Unit Me 2

Characteristics: This unit is 210' thick, extending from 370' to 580'. It

consists of 5~ siltstone interlaminated with 43% quartz greywacke. The

siltstone ranges in, colour from "red" or "chocolate" to brown and pale grey.

It is probably mottled as some chips show irregular colour boundaries. It

consists of kaolin, illite, limonitized siderite, traces of chert and from 10%

to 15% angular quartz and feldspar grains, some small carbonaceous flakes which

at times may be in just sufficient quantity to impart a slight fissility, and

occasional small grains of zircon and tourmaline.

The quartz greywacke consistf! of aboll-t 401» subangular quartz grains

and 401» rounded chert li ths, and the rest an infilling ot kaolin, illite and

limonitic siderite. There is no graphite.

Unit Me 3

Characteristics: This is an orthOquartzite 110' thick (from 580' - 690'). The

quartz is clear, colourless and medium/coarse grained at the top of the unit and

fine to medium grained at the bottom. There is a cement of white kaolin and \

siderite, and sporadic quartz gravel up to 10 mm, but no chert or graphite.

Unit Me 4 Characteristics: This sequenoe is 140' thick (from 690' - 830') and consists

{I

of interlaminated fine siltstone like that in Me 2, sandy siltstone and very

subordinate protoquartzite. The sandy siltstone consists of a fairly equi­

granula,.r mosaic of somewhat irregularly-shaped grains of quartz and feldspar,

with illite, siderite, zircon, tourmaline and a few small ohert grains.

Fresh water is recorded as having flowed at 600 gph from 595'

in Me 3, ani at 150 gph from 785' in Me 4.

Unit Me 5

Characteristics: This unit is 1~010' thick, extending from 830' to 1840'. It

is essentially a sandstone unit, with a spa,.rse development of very thin and

widely separated siltstone l~ers. The gamma ray log supports the identification

of this sequence of rocks as a unit.

The sandstone samples oonsist only of disaggregated sand, indioating

a rather friable rock with little effeotive oementing material. There is a

goodly proportion, up to 30%, of multi-ooloured chert grains of all sizes up to

10 rom. It is probable that the rock is a protoquartzite~ verging on an ortho­

quartzite, with siderite qnd white kaolin binding material.

The porous and p~rmeable nature of the sandstone is further indicated

by the following records of underground water produced from the well:-

fCeSh water f'lowLt8 at 800 gph from 960' - 970' <I ? " 1,009 ' I'! 650 " 1,265' 11 300 11 1,660'

Unit Me 6

Charaoteristios: This unit is 460' thiok, extending from 1840' to 2300'. Lithologioally it is dominantly a medium-grained sandstone with thin variegated

sil tstone bands well distributed throughout. Multiooloured chert gravel is

common, and there are two very thin coal l~ers. The geop~sioal logs reveal

this unit clearly, especially the break at 2300'.

The sandstone is a medium-grained proto quartzite tending towards

subgreywacke. It oonsists of a rather tightly-fitting framework of rounded

chert and devitrified volcanio ash grains, subangular quartz and feldspars up

to 7% of the total, and fairly oommon siderite oement.

At the top of the unit there was a small gas show and another

at 2050'. Both yielded less than 500 cu. ft .. / daJ', and were the only occurrences

of ~drocarbons in the Mellong well.

At 1869' there was a small flow of water with an unusually high

sodium. .. bicarbonate content.

Unit Me 1

Characteristics: This unit is 180' thick, extending from 2300' to 2480'.

All three geophysical logs confirm its existence. Lithologically it consists

of sandstone and siltstone similar to those described above. It differs from

Me 6 by having a higher percentage of shaley members and by a markedly less

amount of multicoloured chert grains, and from Me 8 by the virtual absence of

coaly material.

Unit Me 8

The rocks below 2480' constitute a major unit which cannot

readily be subdivided.- The frequent occurrence of coal confers upon it the

designation of "Coal Measures". It is quite likely that they represent cyclical

deposits as envisaged by F.W. Booker. The upper 200' are more arenaceous than

the lower intervals and thus form a transition zone into the overlying deposits

of the Narrabeen Group.

Unit Me 8

Charaoteristicsl This unit is at least 490'thick, extending from 2480' to

total depth at 2910'. Its identity is quite clearly revealed on the wire-line

logs, which indicate a shale":'rich sequence containing coal seams and sandstone.

Unfortunately, an accurate representation of the lithology cannot be obtained

from the Cl.1ttings because of such trouble at the well as caving, mixing and

insufficient recovery. It seems reasonable to interpret the wire-line logs as

showing coal occurrences as in the following table, which also shows coal as it

is recorded in the cuttings.

Coal Seams Coal Seams 'Ii of (as interpreted from logs) (as indicated in cuttings) sample

1. 2480' 2480'

2. 2520' 2510~ - 2530' 10

3. 2540' 2510' - 2580' 20

4- 2605' 2620' - 2630' 10

5. 2650'

6.

6. 2610' - 2680' 2100' - 2130' 10% 2130' - 2150' 1r$ (cavings)

1· 2110' 2180' - 2190' 5% 8. 2195' 2800' - 2820"' 1~

9. 2815' 2820' - 2880' trace 2910' 2920' 3ato

10. 2935~ 2940' - 2970' 1r$

The coal is mainly a hard. bituminous type, but there is no firm

evidence for its existing in other than thin seams. The occurrences at 2600' and

2610' m~ be from 5' to 10' thick. The co al is associated with black carbonaceous

shale and this material m~ in fact constitute some of the supposed coal

occurrences. Films of calcite and ankerite have been detected associated with the

coal. The other pelitic rocks present are greyish or brownish siltstones

similar to those encountered higher up the borehole. The sandstones, too, are

protoquartzites similar to those already described in unit Me 2.

Perhaps the most noteworthy rock present is a whitish-grey very

fine-grained devitrified vo~canic ash or crystal vitric tuff. The sample from

2640' - 2650' consists largely of this material, and pieces of it are fairly

Common throughout the remainder of the sequence. It is unfortunately impossible

to decide if these come from earlier-formed l~ers of ash or whether they are merely

cavings from the interval 2640' - 2650'. The rock consists of a very finEi-grained

mosaic of devitrified glass and shards with a sprinkling of fresh-looking

feldspars (? Oligoclase) and quartz. Carbonate grains are present, and a few

zircons. X-r~ examination reveals the presence of montmorillonite.

Provenance, and Environment of Deposition: The rocks encountered in the Mellong • • I '

borehole (likewise those in the Mt. Murwin borehole) were probably all deposited

during one major sedimentary episode, with no breaks of great significance. They

vary in type from shale and. mudstone to gravel beds, or sandstone with. abundant

gravel content, and these . all seem to be intimately associated. Even the cuttings

show siltstone with medium sandstone, or sandstone with large gravel pebbles in

the one small .rock fragment.

It is envisaged that during Permo-Triassic times a number of short

rapidly flowing streams descended from the. uplands enclosing the Sydney Basin

area of deposition. Loss of energy resulting from decrease in gradient brought

about the deposition of coarser material in 101'1 angle alluvial fans, levees and

deltaic structures in the basin. In riverine swamps ad'jacent to the levees and.

in the ponds and. lagoons of the del tar-areas fine-grained material settled, and

naturally such places were favourable sites for the collection of plant debris

which was later coalified.

In these deltaic areas, maintained by the vigorous inflowing

streams, there was a fairly high degree of impermanence of features, even

though the overall pattern remained over a vast length of time (from the

middle Permian to the middle Triassic). Such events as the breaching of

levees, the prograding of deltas, the blocking of distributaries on one

alluvial fan by the encroachment of a neighbouring fan, the action of waves

along a lake- (or sea- ) shore would all have combined to give the intimate

interrelationship of events and deposits to which cuttings bear witness.

The major coal-zones maJ" however be indicators of a basic process

of cyclic sedimentation, as visualized by Booker (1951).

The area of provenance is assumed to have been the nearby (60 to

80 miles) uplands of Older Palaeozoic sediments and Middle Palaeozoic igneous

intrusions which had been upraised in the Devono-Carboniferous orogenies.

Because of Mellong's comparative proximity to the western margin of the Basin

there is a higher percentage of arenaceous material in the deposits, whilst

. fine and coaly material occurs in thinner and more erratic la\Yers than in

more eastern localities. The well-known folding in the northern coalfields of

N.S.W. ma\Y well have been associated with the erosion of primary chert beds

laid down during the Permo-Carboniferous, the debris of which, transported by

turbulent streams, provided such a notable proportion of the Narrabeen sediments.

It is very likely that much of the sediments is reworked debris from till and .... outwash plains formed du~ing the Permo-Carboniferous ice-age which was, in the

Permo-Triassic, still dperative or only recently over.

There is the possibility of the. at present unknown, eastern

boundary region of the Sydney Basin having contributed materialcto the sediments

of-the Mellong Area. In particular, none of the Permian volcanoes, whose ashes

. are so widespread, has ever been located: they ma\Y have been situated in this

lost land - which. could (by invoking Continental drift) have been New Zealand.

Comparison with Mt. Mlrwin A.O.G. NO.1: The closeness of the Mt. Mlrwin

section to that of Mellong invites a comparison between them. There is a

considerable stratigraphic Similarity, as can be seen from Plate 3.

~ .. ' ,

, ,

,', ":'., I

" ,

, ' , '

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..... "

. ~ ..

. . ... ;! '. ~ .

.' , ""

. .." : ........ '\' " ,I"

.. . '. ' .. - '-, . Fig,2

" . .. , . ,(- .. . . " COMPARISON OF B.M.R. UNITS

: ' , WITH ..

COMPANY INT£RPRETATION , .'

"

B.M.R. UNITS BOUNDARY COMPANY AiO.G.', DEPTHS

, , ; MAJOR MINOR -(ft.)

, FORMATION GROUP' A'GE

"

, " J , ,-HAwKESBURY, I "

Me, , Me I " SANDSTONE -,', .. , , , ,

" .. , ' I

360 \ I I '" ! " " .. , '

" \ L,', :

Me2 ',' . i" " .. z "

" ... ;., U 581 w " -' " w - en

, ,

Me3 ,', en , , m . i .. ~' .

Me2 " ,. <t ..

; « -.... - 690 ", I a:: " " a:: M e7 .. -

I-;;", I a:: " l, '" Me4 " , . ,~. , "

, -- <t " " , ' -,

830' .,,'.\ - Z "

, Me5

2375 1840

, ,,' --..

'" " CJ)-.. , --. w MeG

I -- .. a:: -I-- ' W

.-

" .J ::> .. 2300" I- CJ) Z CJ) <{ <t , , « w' -Me7 U :E ~ !; "

Il:: 2480 w

L1J \ .. - Z ~ Q.,

Me8 Mee <{ 0 , U : ,

2970 B,M.R, Petroleum Explorotlon, Februaryl969 !o accompony Record1969/27 X AUS-I-70

8. Me 1 corresponds with MM 1 (both are Hawkesbury Sandstone)

Me 2, 3, 4 " " MM2 and MM3

Me 5 " " MM4

Me6 ani 7 " MM5

Me8 " " MM 6, 7, 8. (Newcastle Coal Measures)

The major unit Me 2 - 7 is 2120' thick, and the equivalent major unit MM 2 - 5

is 2215' thick.

The stratigraphic differences are:

(a) Me 2,3:~ 4.·tu'.e clearly distinguishable, whereas MM2 and 3

are distinguished on statistical grounds only. Me 2 is

thinner than MM2 + MM 3.

(b) Me 5 on the other hand is thicker than MM 4.

(c) The arrangement of coal seams is different, but this mqy

be more apparent than real, as Me is based on log-data,

whilst MM is based merely on cuttings samples.

Li thologically, Me 1 differs from MM 1 only in containing graphite.

This mineral is w~dely distributed in the Hawkesbury Sandstone and its apparent

absence from MM 1 is probably only fort~itous.

"Red Beds" are· more pronounoed in Me 2 ani 4· than in MM 2 - 3.

Coloured chert pebbles and grains are, if any thing, more abundant

in Mellong than in Mt. Murwin, and the former is distinctly more arenaoeous than

the latter.

Devitrified voloanio ash is a more proI!linent component of the

lithology of Me 8 than of the equivalent beds MM 6 - 7 - 8.

Comparison with the Grose River Distriot I The beds of the Narrabeen Group at

Mellong also resemble closely those of the Narrabeen Group at Grose River, as

desoribed by Crook (1956). The Grose River sequenoe is as follows:

Hawkesbury Sandstone

Burralow Formation

Grose Sandstone

450' thiok (including the Tabarag

Sandstone Member, 80' thick and 130' above

the base of the Burralow). Grey shale and

red-brown ol~stone.

700' thiok composed of massive labile to

sub-labile sandstone with some beds of

shale and siltstone

Caley Formation

9. 150' thiok of sub-labile sandstone,

silty mudstone and shale.

It may be seen (Pl. 3) that Me 3 corresponds to the Tabarag

Sandstone MeP,lber of the Burralow Formation, and that Me 2 and Me 4 correspond

to the overlying and underly~ng shaley zones of the Formation. Me 5 is the

muoh thicker equivalent of the Grose Sandstone and Me 6 and Me 7 are the muoh

thioker equivalent of the Caley Form~tion.

It is reasonably oertain, therefore, that the Narrabeen Group

of the Sydney Basin is divisible into three formations (the Caley, Grose aqd

Burralow) rather than into two (the Clifton Sub-Group and the Gosford

Formation) as in the eastern part of the Basin.

Palaeontologya Palaeontologioally, there is little material available.

Dr. E. Kemp has examined a few cuttings for spores and has reported (personal

oommun~oation) that:

(i) the interval 2840' - 2850' contains spores diagnos~tio

of the palynologioal unit P3b - 4 of Evans. Within this

unit Evans inoluded the Newoastle and Tomago Coal Measures

am the Mulbring Siltstone. The type of spore suggested

a depositional site olose to the site of growth of the

parent plants.

(ii) P4 type l;Ipores w.ere also tound in the intervals 2580' -

2590'; 2510' - 2520'; 2460' - 2470'.

(iii) The interval 2360' - 2370' yielded forms whioh, if the

outtings were not oavings from higher levels, suggest

the inComing of Triassio elements.

(lv) From the interval 2510' - 2520' there oomes a shred of

evidenoe, in the form of an aori taroh alga, that braokish

water :i,.nfluenoes may have penetrated as far as the

Mellong region at the very olose of the Permian.

The Perm-Triassio Boundarya The Company ohose to place this boundary at 2480'

on the Ii thologioal grounds that here was the virtual end. of the Coal Measures.

/'

I I i 1

; .i

Fig 3

GROSE RIVER MELLONG ·MT MURWIN

Mel . .' ::.': MM I HAWKESBURY

w z

UJ 0 (/J .... o (/J a:: a (!) ~ ,

(/J

.... ,. '.' ...

f-:.-_-.-:- ------

Me2

• . . . . --'--::-=~:--- 1-:-:,...,.......,....-1 ~ ..... : •.• :.;.: •.. : TABARAG, .:.::: .:-: •.•••.• Me3

SANPSTONE

'::-.':;~: :".::';~-::" M 4 _,_._. _______ ._._. e ::'°:°,';. . .... ~

• 0° •• :

• : '; .: : : • °0 .: :. " ." .. ' '. '.' . . :.... :.::::<.:' . ', .....

• " '0 • .. '.' : " : ',' .:.: ; : '. ' .. : .. ~ .. ~ :. <, : ....

',' " . • '0 •• :

: ~ : .. :: :.' ~ ••••••• 0. '0.·· ., • .• !.

: ..... :.:.:; Me5

1 '.\\:::./ . : " . :.:. ~ . ; 0

1• '. '0' : ....... " .

CALEV FORMATION ~~:'.~f~ ~ . en _.-

. . ~ UJ •• . o . 0: • ., .

(!)...J:l '-_ X ~ en •• .... 0 ~ JU::E _

. '-

'- ' ~- .......

.i .

. 1··· . '.' .; o. '0' ••••• I,

I" ••• ... , · .... :.::': ".: .: "0

..... ~:'~ ; : : :. . ..••...• i'. :~: :'.: Me6 . , •• 0

0

.. :: .. ~.o ,,-.,~

'0 " •

" .------.. .-- .-:'-MeS -. ..

MM2

::: : .... :..'. MM3 ,'.', ' .. ,0.' ;

' .. ~ .. ' . · .. . · " ... ' • "0· • · " .' . · ... "

• .: 0" :','

' ..

· ... • ,0 " · . ~ : : .. ' ....

:. ',', .. : . ~ " .. . ... · .. ' ' . . .... . · ... .

· " '. ~:: ..

0° ,'- •• ' •

~~~,'. · ... . . .... :":', .-:--- . . . · . : :: ~ . ... ~. '.:: : :. ':' : -. -r-: · .' . :. "'-'

MM4

MM5

•. _ MM6-6 .- . . '- ""T

8. M..R. Pelroleum ExploroilonJ:'ehruory 1969 To (Jccompony Record 1969/2"

lLJ ..J .... VI ~ U

~ z

t

z UJ w m ~ a:: a:: ~

z

!

" ...J <X 0 U

VI W 0: :l en· <X w ::E

X AUS-I-71

. , .

10.

Rocks with lower Triassic affinities occur at 2370' and of

definite upper Permian age at 2460'.

The palynological unit Tr1 a which succeeds P4 in other localities

is now considered to be of uppermost Permian age. It is likely that the

Mellong unit Me 7 includes this palynological unit Tr1a, and that the Permo­

Triassic boundary there lies at about 2400'.

The Permo-Triassic boundary at Mellong, as at Mt. Murwin, appears • .< - - ••

to be undistinguished by ~ noteworthy lithological feature and to be well

above the younge"st coal ·seam of the Newcastle Coal Measures.

Summary: The section consists of 27~O' of sediments that appear to be all of

non-marine origin, although there is a suggestion of a slight brackish-water

influence at 2510'. It is postulated that all the sediments represent the

accumulations of the varied micro-environments of a deltaic plain, over which

slight amounts of volcanic ash settled from time to time.

I

Eight units have been separated out on litho1ogical and geophysical

grounds, but there is no reason to doubt the essential conformity of the

sediments of these units which range in time from the upper Permian to the

middle Triassic.

There is a strong stratigraphic resemblance petween the beds at

~llong and those at Mt. Mui'win and in ~he Grose River District. The Narrabeen

Group units in particular can be arranged in the same three formations as exist

at Grose River.

The somewhat scanty information afforded by spores indicates that

the Permo-Triassic boundary is at 2400', some 80' above the horizon commonly

chosen, i.e. the upper limit end of the significantly large coal horizons.

AUSTRALIAN OIL AND GAS CORPORATION,

BOOKER, F. VI 0'

References

1964 Mellong No. 1 Well, Sydney BaSin,

N.S.W. Final Report.

1957 Studies in Permian Sedimentation

in the Sydney Basin. N.S.W. Dept.

of Mines Tech. Reports,vol. 5

1957·

11.

CROOK, K.W.A.,

PEl'TIJOHN, F ..J. .• ,

1956 The Stratigraphy and Petrology

of the Narrabeen Group in the

Grose River District.

1957

Jour. and Proc. Roy. Soc. N.S.W.

Vol. 90, Part II, 1956.

Sedimentary Roc~,New York,

Harper.

12.

APPENDIX·

Pa~nology of Cuttings from Mellong (A.O.G.) NO.1 Well,

Sydney Basin, N.S.W.

Cuttings from five intervals were examinEd by Dr. E. Kemp

(B.M.R.) who recovered the following forms:

1. From interval 2840' - 2850':

Dalhuntyispora parvi thola (very well preserved, ;common)

Cirratriradites sp.

Acanthotriletes cf. filiformis II terete angulatus

Leiotriletes directus

Punctatispori tes sp.

Parasacci tes sp. (rare)

Gnetaceaepollenites sinuosus

Striatopodooarpidites of. pantii

cf. Fimbraesporites sp.

Taeniaesporites sp. (Triassic form, m~ be oaving contaminant)

Dalhuntyispora parvithola and Gnetaoeaepollenites sinuosus are diagnostic of

palynologioal unit P3b-4 of Evans.

2. From interval 2580' - 2590':

Protohaploxypinus limpidus

Leiotriletes direotus

Acanthotriletes sp.

3. From interval 2510' - 2520':

Striatopodocarpites oancellatus

Protohaploxypinus limpidus

Vitreisporites pallidus

Marsupipollenites triradiatus

Microbaoulispora sp. indet.

Lophotriletes sp.

4. From interval 2460' - 2470':

Striatopodooarpites oanoellatus II sp.

Falcisporites sp. (a Triassio form)

13. Protohaplo~inus limpidus

II sp.

:. Vitreisporites palUdus

Lophotriletes sp.

Apiculatisporis filifo~~s

Veryhachium sp. (a 'non-freshwat!=lr acritarch alga)

5. From interval 2)60' - 2310' s"

Falcisporites ap.

? Taeni"aesporites ap.

Reticuloidosporites sp. indet.

Leiotriletes direotus

WELL NAME,No. MellongNolBore ELEVATION (A.SU SAMPLE STORAGE

OPERA.TING Co. \USTRALIAN OIL&CASCORP.LTD.: Ground Level 1146; fl. :BM.R.,Canberra PETROGRAPH Ie WELL LO G

WELL LOCATION .C~lla~ Dalum,1149'nsl.ft

Lal.: 330 00'?1" .S .• Long.: 1 S0041' 36" E.. Ba sin SYDNEY BASI.:.

S I a Ie IIE'I/ "O~'I'I! W AL.ES

Te n e men t No .. P.E.L.No. 103,N.S.W.Minp.3 Dept.

1250.000 Sheel No.S 1/56-5

200

000

1200

1300

1400

1500

1600

I , I

I I t-t !

t I

I r

.. M R ".fro/,um Exploratio" Ja"uary /966.

HYDROCARBON SYMBOLS

~ Show of all

e Trace of all

.tJ:. Show of QOs

-0 Trace of Oos

o Fluorescenc,

MISCELLANEOUS

Intervol ond Num ber

of Formation T.~t

No sample available

tram int.rval

'00

Geology by.

ZOO fI

DESCRIPTIONS OF

CUTTI N G S

Description ® reter!; to litnolotjllcol

palfern@ 01 correspondrnQ depth)

PALl VtLLOW .. ME1)IUM·'.AIN[D SANDSToNt

WITH CL[Alit SU .... MGULA .. QUA'RTZ IN

WHITE IiI~T1!Il\.5I'A1!SE hlUSCOVITE ANl>

IOlIAl'HITE.l>151'ns[]) ltDUN:PEl> _1I.TZ

• TIIl~"K' OF MOW .. F'(1tWUGINOU,

SANDSTONE

• ... OWN ,,,TS'Tg,,,, -NIT" &1try MOTTLIMe;

"ALE ""LLOW M(~IIJM TO '1"[" '''''INI' cauAIT1 SAM'D5ToN£ WITIo4 WMr1"r ([ .. , .. T.

3,5 AS A.O~C

.. A' ... .ao-vll'

4 AS AJI,ovE

ME llONG (A,O.G.) No 1

S.J.Moyne

[JiJhon oxide

EJVO!CaniC5

o

,-::r .'

'.'

.. ,."

1°,,°6' 1 BreCCia to conolomerot. LITHOLOGICAL SYMBOLS

E2J ....... Quortz sand ,Iondstone ~ Cool

~t~~~ ~- Siltstone ---1 '-'-'I } ~ - - Snole ond mudstone '-~'- Cloystone

{ ~ , c , Calcirudite

E2i9 Llm.stone ____

~ ~ ~ ~ Calcorenit.

~ Dolomlt. ~ Calcilutite ~ ~~

DESCRIPTION

OF

INTERPRETED

LITHOLOGY

Rock Nome

(attrr Prttljohn ,1957)

OIITHOQUARTZ ITE l'ALE BUFF.MlJ)lUhI'GRAINE\),

"RAINS SUIII\NGULAR,SOMC WITH C1l'fS'Al '1'(15. LENSES OF CMltSER 5A~ /'til> IIOIII6l£l) "I.I.tIlTZ

PEpLE5 II' TO "mm. IHTERSTITIAl WHITE C.LAY OCCASIONAL CllAINS OF FELlISMR SHREOS of WHITt hllCA AND RAU BLEBS 6,. GRAPHITE. I~RE'ULAR U"oNIT[-IIICH MilliS •

I .. TIIl.CDDI:P 5ILTaTON£ AND NOTOQYA1tTZIT'1

702 .... TIIE XQUEIICE IS SILTSTONE 302" . . I'IIOTO ....... TZITE T .. JlLTSTONE CONSISTS ., ISZ ..... RTZ,S2 r£LIIIM. IN A MATRIX", li:AOLU ... S'W'CIT£. CA_ACEOUS rU"(I:5, SlKRITE UAN.,,,. TO LltrAONtTI, AIQ) aA"£ 11.'OMS. THI .... crrOQUA.T&ITC COIIIlfiTS "~"_,,,~.~ __ • ...., ~~,::l=~<"nT .... U.

-nt~ SILTSTONE AMP PIlOTO ....... TZ,ITI" AS A"'V[, TIll 5A_ SlL T5TOOl[ _ ..... E"e"'UANULAI. _$~I~ ... ...,A"RTJ, NG nL»,p,A. "RAINS"" TO -Ii ..... , ",,""Ttl IIMaITE/UMOHITf, ~ .... c.MfaT Z.Iyt,COM NO TOUlilMALUIE

"ROToaUAltT'1ITE WITH IlL T,ToN' .... RTINU

""OTOQ."AIlT~IT •• A5 AaOVl, WITH NICH CO,.ToN"T t:'F 01'01» AIiP •• AV[l·IIZfP I;IIA"'S tlf Co\'OURl"'D c,HE1I:T.

BM.R. UNITS

z o ;::: !!, a: u

'" .., o

W Z 0 .-(J) Q

Z « tn

Plale

lA

Q.

:> 0 .., a: ", ", . ..

U

o

0::: (/')

z

<

X AUS -1- 60A

•

FO S S I LS

'900

3000

00

00

00 !

! i

8.M.R p,frol.um E,cplorofton Jonuory 1968.

DES C R I PTI 0 N S 0 F

CUTTIN GS

Descrlpflon ® refers to IIfholo91COI

POflern@ 01 corresDondlnc;J depth)

4 MEDIUM-_RAIN(D QUARTZ CHERT SANDSTONE

........ ilL TSTOOI[ WITH "'Uhl'" SANDSTONr

n.;A(..[ 011 COAL WITH SMiIT"( 'ILTn'ONE ... ,...

ME»"J'" SAUSTDNE.

COAL.

COAL

WMIf!$H "o~('''M'' ASif

C..E ..... I.IlO~1'4 AO"LAC,tl. c~eus 5ttAt.1

COAL.

'INTEIltL""'IMATtD $.AMJ"( "LTSTC",'/

"IM£ ...... pM('pt\J1'IA ~D:!ioTON[J "I.("'t,

ANP (.A~NAc.[I1I1~. 5HAL£i, C_AL

AIIID "'" .. TI'>" "."'ANle A ....

..... ·.it ... ·x:.

.. '!-'

DESCRIPTION

OF

INTERPRETED

LITHOLOGY

IIiTEItIl[DDED 'ItOTOQUAItTZITE AND SILtSTONE

1151 OF THIS SUUENCE CONSISTS OF PROTOQUA"T:t In: (AS A1!OIIE)

IS Z CON 51 5TS or GR£Y-BaOWN SILTSTONE {fI5 ~CNI:) WITH OCCIlSIOtIAL COALY

PARTIN,S.

,OZ Dr THIS SEQUENCE COI/SISTS Dr acy O,.TE:N CARAOHACCOUS IILTSTON[

40l COOISISTS OF PIIIQTOQUARTZITE (liS

.-.:>vc) WIT1-I NO (""RSE CHERT (;I/\'N5 .

II EN T I TlV[ success ... , IW COAL,

CII~AC[OIl5 SIL TST_ All'

PtlOT04llUAilT ZITf ; SOMf PAU: artY D£v,T"'rl£JI VOLCANIC '"'Sit

B.M.R. UNITS

QJ

o

&oJ ... ..

u

z ~

~ 0:: I.J.J

a.

XAU5-1-60B