Bombo Headland Quarry Geological Site | NSW Environment & Heritage

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Bombo Headland Quarry Geological Site

Item details

Name of item: Bombo Headland Quarry Geological Site
Other name/s: Bombo Quarry
Type of item: Landscape
Group/Collection: Landscape - Natural
Category: Geological site or area
Location: Lat: -34.6515752778 Long: 150.8622035780
Primary address: Princes Highway, Bombo, NSW 2533
Parish: Kiama
County: Camden
Local govt. area: Kiama
Local Aboriginal Land Council: Illawarra
Property description
Lot/Volume CodeLot/Volume NumberSection NumberPlan/Folio CodePlan/Folio Number
LOT1 DP1030989
PART LOT2 DP598759
PART LOT1 DP744712
All addresses
Street AddressSuburb/townLGAParishCountyType
Princes HighwayBomboKiamaKiamaCamdenPrimary Address

Owner/s

Organisation NameOwner CategoryDate Ownership Updated
Department of Planning and InfrastructureState Government 
Sydney WaterState Government29 Mar 99

Statement of significance:

Bombo Headland Quarry Geological site is of research/technical significance in the numerous dykes which cut the Permian Bombo Latite. One of the dykes is geologically unique and contains an abundant xenoliths which represent material brought up to the earth's mantle, about 80 kilometres below the surface of Eastern Australia. The mineral assemblages including apatite, amphibole, pyroxene, spinel and ilmenite , and the range of compositions are unique and are not represented anywhere else in the world. The Bombo Latite Member is also of international scientific significance in providing one of a number of samples upon which the concept and limits of Kiaman Magnetic Interval were defined. Like rocks of Permian age throughout the world, the latite shows a reversed polarity (at the time of its extrusion the North and South magnetic poles were reversed). This interval, named after Kiama, has been used for intercontinental palaeomagnetic correlation of Late Palaeozoic rock sequences. The area is of high educational value. In addition the area is scenically attractive and has considerable potential for recreational and tourist use. (Wass1979) (Percival)
Date significance updated: 06 Aug 12
Note: The State Heritage Inventory provides information about heritage items listed by local and State government agencies. The State Heritage Inventory is continually being updated by local and State agencies as new information becomes available. Read the OEH copyright and disclaimer.

Description

Physical description: Two units of the Late Permian Gerringong volcanic facies are exposed on Bombo Headland. The Kiama Sandstone member forms a narrow wave-cut platform and adjacent vertical cliff face around the south-eastern extremity of the quarry. To the north the sandstone dips below sea level and is overlain by about 20m of porphyritic basalt, termed Bombo Latite member. The contact between the two units is well-exposed in the cliff section at the eastern end of the section of the two points comprising the headland. The red-brown colour (due to oxidisation of haematite) of the sandstone contrasts markedly with the grey-black latite, which displays spectacular columnar jointing elsewhere in the quarry. Isolated columns 5-5 meters in height stand adjacent to the coast between the north and south parts of the quarry; just to the north the sea wall exposes cross sections of the columns 1-2.5 metres in diameter, resulting in a 'Giants Causeway' appearance.

Petrographic descriptions of the latite emphasise its conspicuous porphyritic texture; large labradorite to andesine phenocrysts with minor clinopyroxene are set in a groundmass of feldspar microlites with interstital chlorite and iron oxide. The latite is commonly vesicular. Agglomerates or volcanic beccias are developed in some areas of the quarry, e.g. the south-western portion near the access road. This lithology is readily distinguished from the latite by its chaotic appearance and light-coloured matrix.

A capping of cream-coloured weathered latite, still retaining the characteristic porphyritic texture, may be studied at the top of the northern and western quarry faces. This sharpley-defined zone of surface weathering and soil formation overlies relatively fresh rock exhibiting columnar jointing.

The Bombo Latite Member was subsequently intruded by at least five basaltic (monchiquite) dykes of probable tertiary age which flowed around and between the columns of latite often taking 90 degree changes in direction. Early workers (Jaquet 1905 & Harper 1915) mapped and described these dykes but subsequent development of the quarry provided further exposures and obliterated others. Today dykes are mainly in the northern half of the quarry but at least one extends across the floor of the excavation in the vicinity of the isolated columnar stacks. They are of interest due to their inclusions of xenoliths and xenocrysts, which are believed to represent fragments of the earth's mantle incorporated in magmas originating from within that zone. Sussmilch (1905) described xenoliths of hypersthene gabbro, augite peridotite, enstatite peridotite and pyroxenite occurring as rounded fragments and boulders embedded in the monchiquite. From a deeper level of what was probably the same dyke, Wilshire & Binns (1961) recorded hornblendite and glimmerite as the dominant xenoliths. Present exposures of most of the other dykes appear to lack macroscopically visible xenoliths (Percival).
Current use: Geological site
Former use: Quarry

History

Historical notes: In 1979 a nomination was received from the Geological Society of Australia (NSW Division) for the Bombo Quarry. The importance of the geological features was brought to the Heritage Council's attention by Dr Suzanne Wass of Macquarie University's School of Earth Sciences. The quarry was owned by the Metropolitan Water, Sewerage and Drainage Board and it was proposed that a pollution control plant be constructed on the floor of the disused quarry.

Following site inspections and lengthy consultations between the Metropolitan Water, Sewerage and Drainage Board, NSW Heritage Council, NSW Planning Commission and other key agencies a Permanent Conservation Order was placed over the site in 1983. It was transferred onto the State Heritage Register in 1999.

Historic themes

Australian theme (abbrev)New South Wales themeLocal theme
1. Environment-Tracing the evolution of a continent's special environments Environment - naturally evolved-Activities associated with the physical surroundings that support human life and influence or shape human cultures. (none)-
3. Economy-Developing local, regional and national economies Environment - cultural landscape-Activities associated with the interactions between humans, human societies and the shaping of their physical surroundings (none)-
3. Economy-Developing local, regional and national economies Science-Activities associated with systematic observations, experiments and processes for the explanation of observable phenomena (none)-

Procedures /Exemptions

Section of actDescriptionTitleCommentsAction date
57(2)Exemption to allow workStandard Exemptions SCHEDULE OF STANDARD EXEMPTIONS
HERITAGE ACT 1977
Notice of Order Under Section 57 (2) of the Heritage Act 1977

I, the Minister for Planning, pursuant to subsection 57(2) of the Heritage Act 1977, on the recommendation of the Heritage Council of New South Wales, do by this Order:

1. revoke the Schedule of Exemptions to subsection 57(1) of the Heritage Act made under subsection 57(2) and published in the Government Gazette on 22 February 2008; and

2. grant standard exemptions from subsection 57(1) of the Heritage Act 1977, described in the Schedule attached.

FRANK SARTOR
Minister for Planning
Sydney, 11 July 2008

To view the schedule click on the Standard Exemptions for Works Requiring Heritage Council Approval link below.
Sep 5 2008

PDF Standard exemptions for works requiring Heritage Council approval

Listings

Heritage ListingListing TitleListing NumberGazette DateGazette NumberGazette Page
Heritage Act - State Heritage Register 0017702 Apr 99 271546
Heritage Act - Permanent Conservation Order - former 0017708 Jul 83 963162
Regional Environmental PlanIllawarra REP No.1 11 Apr 86   
Local Environmental Plan 199619 Jul 96 0874241
Register of the National Estate  26 Mar 95   

References, internet links & images

TypeAuthorYearTitleInternet Links
Tourism 2007Bombo Headland Quarry Geological Site View detail
TourismAttraction Homepage2007Bombo Headland Quarry Geological Site View detail

Note: internet links may be to web pages, documents or images.

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(Click on thumbnail for full size image and image details)

Data source

The information for this entry comes from the following source:
Name: Heritage Office
Database number: 5045194
File number: S90/07292 & HC 30270


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