Darling Scarp, Perth, Swan River estuary. Image Science and Analysis Laboratory, NASA

Darling Scarp, Perth, taken from Kelmscott.

The Darling Scarp (known earlier as Darling Range) is a low escarpment running North-South to the East of Perth, Western Australia. ImageMetadata File history File links STS097-712-37. ... ImageMetadata File history File links STS097-712-37. ... ImageMetadata File history File links Download high resolution version (864x648, 119 KB) Darling range taken from Kelmscott. ... ImageMetadata File history File links Download high resolution version (864x648, 119 KB) Darling range taken from Kelmscott. ... In geology, an escarpment is a transition zone between different physiogeographic provinces that involves an elevation differential, often involving high cliffs. ... Perth is the state capital and most populous city of Western Australia. ... Motto: Cygnis Insignis (Distinguished by its swans) Nickname: Wildflower State Other Australian states and territories Capital Perth Government Governor Premier Const. ...

History

The original inscriptions from maps of the 1830's show "General Darlings Range"; later it became Darling Range, and only in the late twentieth century did it become known as the Darling Scarp. In the late twentieth century it was still being named the Darling Ranges, despite common understanding of it being an escarpment. Also there was a tendency to identify the locations on or behind the scarp as being in or on 'Perth Hills' or 'The Hills'.

Early traverses were by explorers of the 1830's and the most commonly known is that of Ensign Dale, who appears to have gone from the Guildford location, to the south side of Greenmount Hill and up through the Helena Valley. Guildford, Western Australia Guildford was established in 1829 on the Swan River, being sited near a permiment fresh water supply. ... Greenmount, Western Australia Can refer to - Greenmount Hill, Greenmount a Locality in Mundaring, Western Australia Shire, and also to Greenmount National Park. ...

Geology

The Darling escarpment is an ancient fault-line, which separates the younger sedimentary rocks of the Perth Basin from the ancient cratonic interior of the continent. Old fault exposed by roadcut near Harrisburg, Pennsylvania. ... A craton is an old and stable part of the continental crust that has survived the merging and splitting of continents and supercontinents for at least 500 million years. ...

The Darling Fault separates the Phanerozoic aged sediments to its west from the Yilgarn Craton to the east. It is concealed by sediments, but is located by geophysical data. The Darling Fault is over 1,000km long and has a downthrow of up to 15 kilometres, with the west side down.

The Archaean granites and gneisses of the Yilgarn Craton form the high ground of the Perth Hills and can be observed in several road cuts immediately before the pumping station of the Golden Pipeline. The Archean is a geologic eon; it is a somewhat antiquated term for the time span between 2500 million years before the present and 3800 million years before the present. ... Quarrying granite for the Mormon Temple, Utah Territory. ... Gneiss Gneiss is a common and widely distributed type of rock formed by high grade regional metamorphic processes from preexisting formations that were originally either igneous or sedimentary rocks. ... The Yilgarn Craton is a craton which constitutes the bulk of the Western Australian land mass. ...

The sediments of the Perth Basin are Tertiary and Quaternary in age immediately below Perth and include coquina, travertine and sandy limestones with abundant shelly material. Perth is sited on a set of sand dunes formed during the Pliocene-Pleistocene during the last Ice Age. Categories: Stub ... Travertine A carving in travertine Travertine, a natural stone, is a white concretionary form of calcium carbonate that is usually hard and semicrystalline. ... Variations in CO2, temperature and dust from the Vostok ice core over the last 400 000 years For the animated movie, see Ice Age (movie). ...

Offshore, the sand dune system and surficial deposits transition into a system of partly eroded limestones and sandy limestones. These form a series of drowned cuestas which today form submerged reefs. Cuestas in geology are ridges formed by gently tilted hard rock layers. ...

Climate effects

Often the Bureau of Metereology identify different weather for 'the hills' in comparison to that of the Swan Coastal Plain Swan Coastal Plain Swan Coast Plain from Darling Scarp The geographic feature that lies directly west of the Darling Scarp, and which contains the Swan River as it travels west to the Indian Ocean. ...

Also, in traditionally hot summers, strong easterly winds travelling across the scarp have presented serious issues for planes using the Perth Airport due to the alignment of the runways. A documented accident in 1999 involving wind shear from the scarp is at the Perth Airport article. Perth Airport (IATA: PER, ICAO: YPPH) is an Australian domestic and international airport located in Belmont, Western Australia and is the main airport servicing Perth, Western Australia. ...

Landuse conflict

The Darling escarpment has had over the last hundred years been exploited for stone quarries, Forestry and Bauxite Mining. Extensive timber railways and timber mills and the supporting communities existed along the escarpment due to the high quality jarrah forests. The El Chino Mine located near Silver City, New Mexico is an open-pit copper mine This article is about mineral extraction. ... A decidous beech forest in Slovenia. ... It has been suggested that this article or section be merged with Lumber. ... Binomial name Eucalyptus marginata Donn ex Sm. ...

Water supply

In the early twentieth century, most of the main rivers flowing off the escarpment had mainly been utilised for dams for water supply.

The scarp also defines the easternmost limit of the various aquifers present in the Perth Basin sediments, most notably the Southwest Yarraadee Aquifer. The scarp forms adivide between the hypersaline groundwaters typical of the Yilgarn Craton basement from the fresh groundwaters of the Perth Basin. Some dams along the scarp are contaminated by seepage of saline water from the granite into the base of the dam's water column and must be periodically flushed to preserve water quality. An aquifer is an underground layer of water-bearing permeable rock, or permeable mixtures of unconsolidated materials (gravel, sand, silt, or clay) (see also groundwater). ...

Rock quarries

Also in the early to mid-twentieth century numbers of rock quarries existed on the edge of the escarpment - visible and affecting both the aesthetics and the environment of the escarpment.

In the area where the Helena River emerges from its valley to the sandplain, there are still four quarries evident, despite being unused for fifty years or more. The Helena River is a tributary of the Swan River, Western Australia Location It rises in country east of Mount Dale and moves to the north west to Mundaring Weir, where it is dammed. ...

• Bluestone (1850's name), later known as Greenmount Quarry (1850's to 1920's), at Greenmount Hill west side.
• Mountain Quarry (sometimes Boya Quarry), south of Greenmount Hill, which ceased operation in 1963.
• Fremantle Harbour Works Quarry (sometimes, C. Y. O'Connor's Mole Reconstruction Quarry, and later known as the Public Works Quarry), now Hudman Road Quarry at edge of Darlington-Boya localities border, operated from the 1900's to the 1930's.
• Statham Quarry at Gooseberry Hill at northern edge of the Zig Zag formation.

There have also been visible quarries on the scarp in the Gosnells and Herne Hill areas. Location of Fremantle, Western Australia Fremantle (32°03′15″S, 115°44′53″E) is a city located within the Perth metropolitan area on Australias western coast, at the mouth of the Swan River, 19 kilometres southwest of Perths Central Business District. ... kick my ass OConnor (1842–March 10, 1902) was an Irish engineer. ... Darlington, Western Australia A locality in the Shire of Mundaring, on the Darling Scarp, and north of the Helena River. ... The City of Gosnells is a Local Government Area of Western Australia. ...

Legislative restrictions upon such developments were initiated in the late twentieth century to prevent further visible scars on the western face of the scarp.

Bauxite mining

In the late twentieth century, the proving of bauxite deposits correlating to the extensive Jarrah Forests saw wide ranging protests against the proposals to mine the forests. Subspecies subsp. ...

The lengthy process of protest forced the government and miners to check their original proposals, and wide ranging processes to guard segments of the Jarrah Forests from mining ensued.

Dieback and fire

Also in the late twentieth century, dieback effecting Jarrah timber in particular infected large tracts of the forest. Currently only the restriction of vehicle access has proved effective in slowing the spread of this disease. This gained greater acceptance and publicity through the decision to allow Rally Australia to operate along services roads provided that the vehicles had a thorough wash including the under carriage at the end of each stage. Binomial name Phytophthora cinnamomi Rands Phytophthora cinnamomi is a soil-borne water mould that produces an infection which causes a condition in plants called root rot or dieback. infects the roots by zoospores entering the root behind the root tip. ...

In late 2004, the largest bushfire in the Northern Jarrah Forest for at least 100 years has created significant issues for the forest as well. As a result of this fire intensity the Government increase the volume of controlled burns along the entire escarpment to reduce the build up of flammable materials.

Current activity

The escarpment is currently the site of a number of approved mines of bauxite (or Aluminium ore), which are mined by the company Alcoa along with others. The bauxite mines (and rehabilitated areas after mining) have erased all the evidence of the networks of the timber railways. Bauxite with penny Bauxite (pebbly) Bauxite is a naturally occurring, heterogeneous material composed primarily of one or more aluminium hydroxide minerals, plus various mixtures of silica, iron oxide, titania, aluminium silicates, and other impurities in minor or trace amounts. ... Alcoa NYSE: AA is the world’s leading producer of primary and fabricated aluminum, and alumina with operations in 43 countries. ...

The future

The potential for further landuse conflict exists in the presence of unrelinquished mining leases over large tracts of the escarpment; plans by Governmental operations in Forest reserves; water authority sensitivity towards access to its water catchment areas; bushfire control measures; and demands for further intensification of urbanization on the escarpment.

Darling Range National Park

A network of reserves of crown lands on the escarpment have been connected into a national park to maintain and conserve parts of the escarpment.

In most cases the reserves or parks had individual names prior to being incorporated into the larger park, for example the Serpentine National Park, John Forrest National Park and the Greenmount National Park Serpentine is a national park in Western Australia (Australia), 52 km southeast of Perth. ... John Forrest is a national park in Western Australia (Australia), 24 km east of Perth. ... Greenmount is a national park in Western Australia (Australia), 22 km east of Perth. ...

Bibliography

• Engineering Geology of the Precambrian Rocks of the Darling Scarp

External links

• Hydrology of the Perth Basin
• Serpentine National Park
• Darling Scarp Walk, bushwalk