Uluru (Ayers Rock) - Northern Territory, Australia
Posted by: Groundspeak Premium Member Metro2
S 25° 20.560 E 131° 01.285
52J E 703438 N 7195571
Quick Description: Uluru is an inselberg, literally "island mountain".
Location: Northern Territory, Australia
Date Posted: 12/2/2013 8:18:29 AM
Waymark Code: WMJM3W
Published By: Groundspeak Premium Member RakeInTheCache
Views: 11

Long Description:
Uluru is also known as Ayers Rock. It is a sandstone formation with an elevation of 863 m (2,831 ft).
This Wikipedia article (visit link) discusses the geologic significance:

"Uluru is one of Australia's most recognisable natural landmarks. The sandstone formation stands 348 m (1,142 ft) high, rising 863 m (2,831 ft) above sea level, with most of its bulk lying underground, and has a total circumference of 9.4 km (5.8 mi). Both Uluru and the nearby Kata Tjuta formation have great cultural significance for the A?angu people, the traditional inhabitants of the area, who lead walking tours to inform visitors about the local flora and fauna, bush foods and the Aboriginal dreamtime stories of the area.

Uluru is notable for appearing to change colour at different times of the day and year, most notably glowing red at dawn and sunset.

Kata Tjuta, also called Mount Olga or The Olgas, lies 25 km (16 mi) west of Uluru. Special viewing areas with road access and parking have been constructed to give tourists the best views of both sites at dawn and dusk.


Uluru rock formations
Panorama from the top of Uluru, showing a typical gullyUluru is an inselberg, literally "island mountain". An inselberg is a prominent isolated residual knob or hill that rises abruptly from and is surrounded by extensive and relatively flat erosion lowlands in a hot, dry region. Uluru is also often referred to as a monolith, although this is a somewhat ambiguous term that is generally avoided by geologists. The remarkable feature of Uluru is its homogeneity and lack of jointing and parting at bedding surfaces, leading to the lack of development of scree slopes and soil. These characteristics led to its survival, while the surrounding rocks were eroded. For the purpose of mapping and describing the geological history of the area, geologists refer to the rock strata making up Uluru as the Mutitjulu Arkose, and it is one of many sedimentary formations filling the Amadeus Basin.

Composition

Uluru is dominantly composed of coarse-grained arkose (a type of sandstone characterized by an abundance of feldspar) and some conglomerate.[6][9] Average composition is 50% feldspar, 25–35% quartz and up to 25% rock fragments; most feldspar is K-feldspar with only minor plagioclase as subrounded grains and highly altered inclusions within K-feldspar.[6] The grains are typically 2–4 millimetres (0.079–0.16 in) in diameter, and are angular to subangular; the finer sandstone is well sorted, with sorting decreasing with increasing grain size. The rock fragments include subrounded basalt, invariably replaced to various degrees by chlorite and epidote. The minerals present suggest derivation from a predominantly granite source, similar to the Musgrave Block exposed to the south. When relatively fresh, the rock has a grey colour, but weathering of iron-bearing minerals by the process of oxidation gives the outer surface layer of rock a red-brown rusty colour. Features related to deposition of the sediment include cross-bedding and ripples, analysis of which indicated deposition from broad shallow high energy fluvial channels and sheet flooding, typical of alluvial fans.


Rain water flows off Uluru along channels marked by dark algae, forming small ponds at the baseAge and origin[edit]The Mutitjulu Arkose is believed to be of about the same age as the conglomerate at Kata Tjuta, and to have a similar origin despite the rock type being different, but it is younger than the rocks exposed to the east at Mount Conner, and unrelated to them. The strata at Uluru are nearly vertical, dipping to the south west at 85°, and have an exposed thickness of at least 2,400 m (7,900 ft). The strata dip below the surrounding plain and no doubt extend well beyond Uluru in the subsurface, but the extent is not known.

The rock was originally sand, deposited as part of an extensive alluvial fan that extended out from the ancestors of the Musgrave, Mann and Petermann Ranges to the south and west, but separate from a nearby fan that deposited the sand, pebbles and cobbles that now make up Kata Tjuta.

The similar mineral composition of the Mutitjulu Arkose and the granite ranges to the south is now explained. The ancestors of the ranges to the south were once much larger than the eroded remnants we see today. They were thrust up during a mountain building episode referred to as the Petermann Orogeny that took place in late Neoproterozoic to early Cambrian times (550-530 Ma), and thus the Mutitjulu Arkose is believed to have been deposited at about the same time.

The arkose sandstone which makes up the formation is composed of grains that show little sorting based on grain size, exhibit very little rounding and the feldspars in the rock are relatively fresh in appearance. This lack of sorting and grain rounding is typical of arkosic sandstones and is indicative of relatively rapid erosion from the granites of the growing mountains to the south. The layers of sand were nearly horizontal when deposited, but were tilted to their near vertical position during a later episode of mountain building, possibly the Alice Springs Orogeny of Palaeozoic age (400-300 Ma)."
Waymark is confirmed to be publicly accessible: yes

Parking Coordinates: N 25° 20.587 W 131° 01.275

Access fee (In local currency): 25.00

Requires a high clearance vehicle to visit.: no

Requires 4x4 vehicle to visit.: no

Public Transport available: no

Website reference: [Web Link]

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Recent Visits/Logs:
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denben visited Uluru (Ayers Rock) - Northern Territory, Australia 11/14/2014 denben visited it
quiet1_au visited Uluru (Ayers Rock) - Northern Territory, Australia 9/23/2014 quiet1_au visited it
ROSS1957 visited Uluru (Ayers Rock) - Northern Territory, Australia 1/17/2014 ROSS1957 visited it
netdust visited Uluru (Ayers Rock) - Northern Territory, Australia 2/6/2007 netdust visited it
Metro2 visited Uluru (Ayers Rock) - Northern Territory, Australia 10/1/1986 Metro2 visited it

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