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The oldest dated rocks formed on Earth, as an aggregate of minerals that have not been subsequently broken down by erosion or melted, are more than 4 billion years old, formed during the Hadean Eon of Earth's geological history, and mark the start of the Archean Eon, which is defined to start with the formation of the oldest intact rocks on Earth.
A rock formation is an isolated, scenic, or spectacular surface rock outcrop. Rock formations are usually the result of weathering and erosion sculpting the existing rock. The term rock formation can also refer to specific sedimentary strata or other rock unit in stratigraphic and petrologic studies.
Fossils may be found either associated with a geological formation or at a single geographic site. Geological formations consist of rock that was deposited during a specific period of time. They usually extend for large areas, and sometimes there are different important sites in which the same formation is exposed.
Metamorphic rocks are typically found in areas of mountain building. Rock can also form in the absence of a substantial pressure gradient as material that condensed from a protoplanetary disk, without ever undergoing any transformations in the interior of a large object such as a planet or moon. Astrophysicists classify this as a fourth type of ...
Metamorphic rocks are formed by subjecting any rock type—sedimentary rock, igneous rock or another older metamorphic rock—to different temperature and pressure conditions than those in which the original rock was formed. This process is called metamorphism, meaning to "change in form". The result is a profound change in physical properties ...
Slate – Metamorphic rock - A low grade metamorphic rock formed from shale or silt; Suevite – Rock consisting partly of melted material formed during an impact event – A rock formed by partial melting during a meteorite impact; Talc carbonate – A metamorphosed ultramafic rock with talc as an essential constituent; similar to a serpentinite
Onaping Fallback Breccia, polished slab, 15 by 23 cm (6 by 9 in) The Sudbury basin formed as a result of an impact into the Nuna supercontinent from a large impactor body approximately 10–15 km (6.2–9.3 mi) in diameter that occurred 1.849 billion years ago [2] in the Paleoproterozoic era.
Shaanxi tiankeng cluster, discovered in 2016, it is one of the largest in the world comprising forty-nine sinkholes and more than fifty funnels ranging from 50–100 metres in diameter. South China Karst, World Heritage Site; Stone Forest; Xiaozhai Tiankeng, also known as the Heavenly Pit, is the world's largest sinkhole. [3]