Outcrop in the context of "Steppe eagle"

The Acropolis of Athens (Ancient Greek: ἡ Ἀκρόπολις τῶν Ἀθηνῶν, romanized: hē Akropolis tōn Athēnōn; Modern Greek: Ακρόπολη Αθηνών, romanized: Akrópoli Athinón) is an ancient citadel located on a rocky outcrop above the city of Athens, Greece, and contains the remains of several ancient buildings of great architectural and historical significance, the most famous being the Parthenon. The word Acropolis is from Greek ἄκρον (akron) 'highest point, extremity' and πόλις (polis) 'city'. The term acropolis is generic and there are many other acropoleis in Greece. During ancient times the Acropolis of Athens was also more properly known as Cecropia, after the legendary serpent-man Cecrops, the supposed first Athenian king.

While there is evidence that the hill was inhabited as early as the 4th millennium BC, it was Pericles (c. 495–429 BC) in the fifth century BC who coordinated the construction of the buildings whose present remains are the site's most important ones, including the Parthenon, the Propylaea, the Erechtheion and the Temple of Athena Nike. The Parthenon and the other buildings were seriously damaged during the 1687 siege by the Venetians during the Morean War when gunpowder being stored by the Turkish rulers in the Parthenon was hit by a Venetian bombardment and exploded.

Pedra Branca (European Portuguese: [ˈpɛðɾɐ ˈβɾɐ̃kɐ]), also known as Batu Putih (Malay: [batu puteh]), is an outlying island and the easternmost point of Singapore. The name of the island, which is Portuguese for "white rock", refers to whitish guano deposited on the rock. The island consists of a small outcrop of granite rocks with an area of about 8,560 square metres (92,100 sq ft) at low tide. During the low water spring tide it measures, at its longest, 137 metres (449 ft) and has an average width of 60 metres (200 ft). Pedra Branca is situated at 1°19′48″N 104°24′27″E / 1.33000°N 104.40750°E / 1.33000; 104.40750, where the Singapore Strait meets the South China Sea, and so is considered a maritime landmark of the eastern entrance of the Singapore Strait.

There are two maritime features near Pedra Branca. Middle Rocks, under the sovereignty of Malaysia, consists of two clusters of small rocks about 250 metres (820 ft) apart situated 0.6 nautical miles (1.1 km; 0.7 mi) south of Pedra Branca. South Ledge, which is 2.2 nautical miles (4.1 km; 2.5 mi) to the south-south-west of Pedra Branca, is a rock formation visible only at low-tide.

The internal structure of Earth is the layers of the planet Earth, excluding its atmosphere and hydrosphere. The structure consists of an outer silicate solid crust, a highly viscous asthenosphere, and solid mantle, a liquid outer core whose flow generates the Earth's magnetic field, and a solid inner core.

Scientific understanding of the internal structure of Earth is based on observations of topography and bathymetry, observations of rock in outcrop, samples brought to the surface from greater depths by volcanoes or volcanic activity, analysis of the seismic waves that pass through Earth, measurements of the gravitational and magnetic fields of Earth, and experiments with crystalline solids at pressures and temperatures characteristic of Earth's deep interior.

The Dresser Formation is a Paleoarchean geologic formation that outcrops as a generally circular ring of hills in the North Pole Dome area of the East Pilbara Terrane of the Pilbara Craton of Western Australia. This formation is one of many formations that comprise the Warrawoona Group, which is the lowermost of four groups that comprise the Pilbara Supergroup. The Dresser Formation is part of the Panorama greenstone belt that surrounds and outcrops around the intrusive North Pole Monzogranite. Dresser Formation consists of metamorphosed, blue, black, and white bedded chert; pillow basalt; carbonate rocks; minor felsic volcaniclastic sandstone and conglomerate; hydrothermal barite; evaporites; and stromatolites. The lowermost of three stratigraphic units that comprise the Dresser Formation contains some of the Earth's earliest commonly accepted evidence of life such as morphologically diverse stromatolites, microbially induced sedimentary structures, putative organic microfossils, and biologically fractionated carbon and sulfur isotopic data.

In geology, basement and crystalline basement are crystalline rocks lying above the mantle and beneath all other rocks and sediments. They are sometimes exposed at the surface, but often they are buried under miles of rock and sediment. The basement rocks lie below a sedimentary platform or cover, or more generally any rock below sedimentary rocks or sedimentary basins that are metamorphic or igneous in origin. In the same way, the sediments or sedimentary rocks on top of the basement can be called a "cover" or "sedimentary cover".

Basement rock consists of continental crustal rock which has been modified several times through tectonic events including deformation, metamorphism, deposition, partial melting and magmatism.

Methane clathrate (CH₄·5.75H₂O) or (4CH₄·23H₂O), also called methane hydrate, hydromethane, methane ice, fire ice, natural gas hydrate, or gas hydrate, is a solid clathrate compound (more specifically, a clathrate hydrate) in which a large amount of methane is trapped within a crystal structure of water, forming a solid similar to ice. Originally thought to occur only in the outer regions of the Solar System, where temperatures are low and water ice is common, significant deposits of methane clathrate have been found under sediments on the ocean floors of the Earth (around 1100 m below the sea level). Methane hydrate is formed when hydrogen-bonded water and methane gas come into contact at high pressures and low temperatures in oceans.

Methane clathrates are common constituents of the shallow marine geosphere and they occur in deep sedimentary structures and form outcrops on the ocean floor. Methane hydrates are believed to form by the precipitation or crystallisation of methane migrating from deep along geological faults. Precipitation occurs when the methane comes in contact with water within the sea bed subject to temperature and pressure. In 2008, research on Antarctic Vostok Station and EPICA Dome C ice cores revealed that methane clathrates were also present in deep Antarctic ice cores and record a history of atmospheric methane concentrations, dating to 800,000 years ago. The ice-core methane clathrate record is a primary source of data for global warming research, along with oxygen and carbon dioxide.

The lithology of a rock unit is a description of its physical characteristics visible at outcrop, in hand or core samples, or with low magnification microscopy. Physical characteristics include colour, texture, grain size, and composition. Lithology may refer to either a detailed description of these characteristics, or a summary of the gross physical character of a rock. Examples of lithologies in the second sense include sandstone, slate, basalt, or limestone.

Lithology is the basis of subdividing rock sequences into individual lithostratigraphic units for the purposes of mapping and correlation between areas. In certain applications, such as site investigations, lithology is described using a standard terminology such as in the European geotechnical standard Eurocode 7.

Long Ya Men or Longyamen (simplified Chinese: 龙牙门; traditional Chinese: 龍牙門; pinyin: lóngyámén; Malay: Batu Berlayar) or Dragon's Teeth Gate, is the name that Chinese explorer Wang Dayuan recorded for Batu Belayar, a craggy granite outcrop that formerly stood at the gateway to Keppel Harbour in Singapore. In his description, "The strait runs between the two hills of the Temasek (Chinese: 單馬錫; pinyin: Dānmǎxī; Pe̍h-ōe-jī: Tan-má-sek or Chinese: 淡馬錫; pinyin: Dànmǎxī; Pe̍h-ōe-jī: Tām-má-sek) natives which looked like a dragon's teeth." From there, the name Long Ya Men or Dragon Teeth's Gate was born.

The rocky outcrop served as a navigational aid to ancient mariners sailing through the swift waters of the narrow channel, but was subsequently destroyed by the British in 1848 to widen the channel for larger vessels to sail through. In 2005, a symbolic replica was erected by the Singapore government near its original site to mark the role it played in Singapore's maritime history.