Shag Rock (Houtman Abrolhos)

Infobox Island
name = Shag Rock


image caption =
locator

map_custom = no
location = Indian Ocean, off the coast of Western Australia
coordinates = coord|28|28|33|S|113|42|44|E|display=inline,title|type:isle
archipelago = Houtman Abrolhos
area = 0.1 hectares
length = 50 metres (160 ft)
width = 20 metres (70 ft)
coastline =
highest mount =
elevation = 3 metres (10 ft)
country = Australia
country admin divisions title = State
country admin divisions = Western Australia
population = nil
additional info =

Shag Rock is a small rocky island in the Wallabi Group of the Houtman Abrolhos.

Geography

It is located at coord|28|28|33|S|113|42|44|E|display=inline,Gazetteer of Australia (1996). Belconnen, ACT: Australian Surveying and Land Information Group.] Gazetteer of Australia | name = Shag Rock | id = 280455] about 1.5 kilometres east of West Wallabi Island.Australia 1:100000 Topographic Survey, Map sheet 1641 (Edition 1): Wallabi] Its nearest neighbour is Plover Island, about 700 metres away. The island has an area of about 0.1 hectares, and a maximum elevation of three metres (10 ft). It is uninhabitated, and devoid of human infrastructure.

This island should not be confused with the rocky island that lies to the west of North Island. The latter has no gazetted name, but is informally known as "Shag Rock".

Geology and physiography

Shag Rock is essentially an outcrop of Wallabi Limestone, a dense calcretised, coral limestone platform that underlies the entire Wallabi Group. This platform, which arises abruptly from a flat shelf, is about 40 metres thick, and is of Quaternary origin. Reef that formed during the Eemian interglacial (about 125,000 years ago), when sea levels were higher than at present, are now emergent in places, and constitute the basement of the group's "central platform" islands, of which Shag Island is one.cite book | author = Collins, Lindsay B.; Zhu, Zhong Rong; Wyrwoll, Karl-Heinz | year = 1998 | chapter = Late Tertiary-Quaternary Geological Evolution of the Houtman Abrolhos Carbonate Platforms, Northern Perth Basin | editor = Purcell, R. and Purcell, P. (eds) | title = The sedimentary basins of Western Australia | volume = 2 | pages = 647-663 | location = Perth, Western Australia | publisher = Petroleum Exploration Society of Australia | chapterurl = http://espace.lis.curtin.edu.au/archive/00000155/ | accessdate = 2008-05-02] cite book | author = Collins, Lindsay B.; Zhu, Zhong Rong; Wyrwoll, Karl-Heinz | year = 2004 | chapter = Geology of the Houtman Abrolhos Islands | pages = 811–834 | title = Geology and hydrogeology of carbonate islands (Developments in Sedimentology 54) | editor = Vacher, Leonard and Quinn, Terrence (eds) | publisher = Elsevier Science]

Flora

About half of the island, including most of its centre, is rock with no vegetation cover. A very small area just south of the centre is vegetated by "Tecticornia halocnemoides" (Shrubby Samphire). The remainder of the island, predominantly the northern third and a patch in the south west, is vegetated by "Atriplex cinerea" (Grey Saltbush), "Nitraria billardierei" (Nitre Bush) and "Pittosporum phylliraeoides" (Weeping Pittosporum).cite journal | first = Judith M. | last = Harvey | year = 2001 | title = A flora and vegetation survey of the islands of the Houtman Abrolhos, Western Australia | journal = CALMScience | volume = 3 | issue = 4 | pages = 521–623 Data also available in cite paper | author = McCrea, Jo (ed.) | title = Inventory of the Land Conservation Values of the Houtman Abrolhos Islands | month = October | year = 2003 | edition = Fisheries Management Paper No. 151 | id = ISSN|0819-4327 | publisher = Department of Fisheries, Government of Western Australia | url = http://www.fish.wa.gov.au/docs/mp/mp151/index.php?0508 | accessdate = 2008-02-02]

References