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Shag Rock (Houtman Abrolhos)
Shag Rock is a small rocky island in the Wallabi Group of the Houtman Abrolhos. Geography It is located at ,Gazetteer of Australia (1996). Belconnen, ACT: Australian Surveying and Land Information Group. about east of West Wallabi Island.Australia 1:100000 Topographic Survey, Map sheet 1641 (Edition 1): Wallabi Its nearest neighbour is Plover Island, about away. The island has an area of about , and a maximum elevation of . It is uninhabited, 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 thick, and is of Quaternary origin. Reef that formed during the Eemian Stage (about 125,000 years ago) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indian Ocean
The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by the Southern Ocean or Antarctica, depending on the definition in use. Along its core, the Indian Ocean has some large marginal or regional seas such as the Arabian Sea, Laccadive Sea, Bay of Bengal, and Andaman Sea. Etymology The Indian Ocean has been known by its present name since at least 1515 when the Latin form ''Oceanus Orientalis Indicus'' ("Indian Eastern Ocean") is attested, named after Indian subcontinent, India, which projects into it. It was earlier known as the ''Eastern Ocean'', a term that was still in use during the mid-18th century (see map), as opposed to the ''Western Ocean'' (Atlantic Ocean, Atlantic) before the Pacific Ocean, Pacific was surmised. Conversely, Ming treasure voyages, Chinese explorers in the Indian Oce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcrete
Caliche () is a sedimentary rock, a hardened natural cement of calcium carbonate that binds other materials—such as gravel, sand, clay, and silt. It occurs worldwide, in aridisol and mollisol soil orders—generally in arid or semiarid regions, including in central and western Australia, in the Kalahari Desert, in the High Plains of the western United States, in the Sonoran Desert, Chihuahuan Desert and Mojave Desert of North America, and in eastern Saudi Arabia at Al-Hasa. Caliche is also known as calcrete or kankar (in India). It belongs to the duricrusts. The term ''caliche'' is Spanish and is originally from the Latin ''calx'', meaning lime. Caliche is generally light-colored, but can range from white to light pink to reddish-brown, depending on the impurities present. It generally occurs on or near the surface, but can be found in deeper subsoil deposits, as well. Layers vary from a few inches to feet thick, and multiple layers can exist in a single location. A caliche lay ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitraria Billardierei
''Nitraria billardierei'', commonly known as nitre bush or dillon bush, is a perennial shrub native to Australia. It is often found in saline areas or other areas which have been disturbed. This species produces flowers predominantly in spring, with small ovoid or oblong fruit (drupe) that are purple, red or golden. The fruit are edible, said to taste like salty grapes. They were eaten, sometimes whole, including the stone, by indigenous Australians such as the Wemba-Wemba. Fruit can also be made into jam or dried and stored. It is a broad and low shrub, up to high and 4 m wide. Nitre bush is found across all mainland states of Australia. The plant's spread and germination in areas of heavy clay soil is assisted by the fruit's consumption by emu The emu () (''Dromaius novaehollandiae'') is the second-tallest living bird after its ratite relative the ostrich. It is endemic to Australia where it is the largest native bird and the only extant member of the genus ''D ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atriplex Cinerea
''Atriplex cinerea'', commonly known as grey saltbush, coast saltbush, barilla or ''truganini'', is a plant species in the family Amaranthaceae. It occurs in sheltered coastal areas and around salt lakes in the Australian states of Western Australia, South Australia, Tasmania, Victoria and New South Wales. The Latin specific name ''cinerea'' means "ashy". ''Atriplex cinerea'' has a chromosome number 2n=54, indicating the species is hexaploid as the base number in ''Atriplex'' is 9. Description ''Atriplex cinerea'' is a prostrate to erect, heavily branched, leafy shrub growing up to 1.8m high and up to 2.5 m wide. Stems are initially ridged and angular, becoming woody with age. The leaves are elliptic to oblong. 40 mm long, 15 mm wide. Petioles are 1–3 mm. Leaves alternate and are silver or grey-green in colour. The plant is covered with bladderlike hairs. The species is monoecious or dioecious. The male flowers in purple globular clusters (but look yellow when ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tecticornia Halocnemoides
''Tecticornia halocnemoides'', commonly known as shrubby samphire or grey glasswort,* is a species of succulent, salt tolerant plant endemic to Australia. It grows as a spreading or erect shrub up to fifty centimetres high. It was first published as ''Arthrocnemum halocnemoides'' in 1845, but transferred into ''Halosarcia'' in 1980, and into ''Tecticornia ''Tecticornia'' is a genus of succulent, salt tolerant plants largely endemic to Australia. Taxa in the genus are commonly referred to as samphires. In 2007, the genus ''Halosarcia'', along with three other Australian genera (''Pachycornia'', ' ...'' in 2007. It is a highly variable species, with five published subspecies, some of which are themselves highly variable. These are ''T. halocnemoides'' subsp. ''halocnemoides'', ''T. halocnemoides'' subsp. ''caudata'', ''T. halocnemoides'' subsp. ''longispicata'', ''T. halocnemoides'' subsp. ''catenulata'' and ''T. halocnemoides'' subsp. ''tenuis''. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eemian Stage
The Eemian (also called the last interglacial, Sangamonian Stage, Ipswichian, Mikulin, Kaydaky, penultimate,NOAA - Penultimate Interglacial Period http://www.ncdc.noaa.gov/global-warming/penultimate-interglacial-period Valdivia or Riss-Würm) was the interglacial period which began about 130,000 years ago at the end of the Penultimate Glacial Period and ended about 115,000 years ago at the beginning of the Last Glacial Period. It corresponds to Marine Isotope Stage 5e. Although sometimes referred to as the "last interglacial" (in the "most recent previous" sense of "last"), it was the second-to-latest interglacial period of the current Ice Age, the most recent being the Holocene which extends to the present day (having followed the last glacial period). The prevailing Eemian climate was, on average, around 1 to 2 degrees Celsius (1.8 to 3.6 Fahrenheit) warmer than that of the Holocene. During the Eemian, the proportion of in the atmosphere was about 280 parts per million. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quaternary
The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans from 2.58 million years ago to the present. The Quaternary Period is divided into two epochs: the Pleistocene (2.58 million years ago to 11.7 thousand years ago) and the Holocene (11.7 thousand years ago to today, although a third epoch, the Anthropocene, has been proposed but is not yet officially recognised by the ICS). The Quaternary Period is typically defined by the cyclic growth and decay of continental ice sheets related to the Milankovitch cycles and the associated climate and environmental changes that they caused. Research history In 1759 Giovanni Arduino proposed that the geological strata of northern Italy could be divided into four successive formations or "orders" ( it, quattro ordini). The term "quaternary" was introduced by Jules Desnoye ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limestone
Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms when these minerals precipitate out of water containing dissolved calcium. This can take place through both biological and nonbiological processes, though biological processes, such as the accumulation of corals and shells in the sea, have likely been more important for the last 540 million years. Limestone often contains fossils which provide scientists with information on ancient environments and on the evolution of life. About 20% to 25% of sedimentary rock is carbonate rock, and most of this is limestone. The remaining carbonate rock is mostly dolomite, a closely related rock, which contains a high percentage of the mineral dolomite, . ''Magnesian limestone'' is an obsolete and poorly-defined term used variously for dolomite, for limes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coral
Corals are marine invertebrates within the class Anthozoa of the phylum Cnidaria. They typically form compact colonies of many identical individual polyps. Coral species include the important reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton. A coral "group" is a colony of very many genetically identical polyps. Each polyp is a sac-like animal typically only a few millimeters in diameter and a few centimeters in height. A set of tentacles surround a central mouth opening. Each polyp excretes an exoskeleton near the base. Over many generations, the colony thus creates a skeleton characteristic of the species which can measure up to several meters in size. Individual colonies grow by asexual reproduction of polyps. Corals also breed sexually by spawning: polyps of the same species release gametes simultaneously overnight, often around a full moon. Fertilized eggs form planulae, a mobile early form of the coral polyp which, when m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wallabi Limestone
Wallabi Limestone is the name given to the dense calcretised, limestone platform that underlies the Wallabi Group of the Houtman Abrolhos, an archipelago off the coast of Western Australia. This platform, which arises abruptly from a flat shelf, is about 40 metres thick, and is of marine biogenic origin, having originated as a coral reef. It reached its maximum size during the Eemian Stage (about 125,000 years ago), when sea levels were higher than at present. The subsequent fall in sea level resulted in the reef becoming emergent in places, thus forming the basement of the group's "central platform" islands, namely West Wallabi Island, East Wallabi Island and North Island. References See also *List of types of limestone This is a list of types of limestone arranged according to location. It includes both formal stratigraphic unit names and less formal designations. Africa Egypt *Tura limestone, used for the Great Pyramid casing stones *Mokattam limestone; Gr ... Limesto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Western Australia
Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to the south, the Northern Territory to the north-east, and South Australia to the south-east. Western Australia is Australia's largest state, with a total land area of . It is the second-largest country subdivision in the world, surpassed only by Russia's Sakha Republic. the state has 2.76 million inhabitants percent of the national total. The vast majority (92 percent) live in the south-west corner; 79 percent of the population lives in the Perth area, leaving the remainder of the state sparsely populated. The first Europeans to visit Western Australia belonged to the Dutch Dirk Hartog expedition, who visited the Western Australian coast in 1616. The first permanent European colony of Western Australia occurred following the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North Island (Houtman Abrolhos)
North Island is the northernmost island in the Houtman Abrolhos, a coral reef archipelago in the Indian Ocean off the coast of Mid West Western Australia. Located about 14 km (9 mi) from the nearest island group, it is one of the largest islands in the Houtman Abrolhos, and one of the few to support dune systems. It has relatively diverse flora dominated by chenopod shrubs and fauna that includes the introduced tammar wallaby, around seven species of reptile, and about 15 resident bird species. First recorded and surveyed in 1840, North Island has been a seasonal camp for western rock lobster fishermen since the beginning of the 20th century, and this remains the principal focus of human activity on the island. There is also a small amount of tourism, though for the most part it is reserved as conservation habitat for vegetation communities and rare birds. History Discovery The earliest recorded sighting of North Island occurred in May 1840, during the third survey ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
