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Both were also used to "harden" the cutting edge of tools such as the Egyptians using copper and bronze points for working soft stone including quarrying blocks and making rock-cut architecture. During the copper age, the ancient Chinese invented fired bricks as early as 4400BC. In Chengtoushan, fired bricks were used as flooring for houses. [16]
An earth sheltered house in Switzerland (Peter Vetsch) An earth shelter, also called an earth house, earth-bermed house, earth-sheltered house, [1] earth-covered house, or underground house, is a structure (usually a house) with earth against the walls and/or on the roof, or that is entirely buried underground.
The first eon in Earth's history, the Hadean, begins with the Earth's formation and is followed by the Archean eon at 3.8 Ga. [2]: 145 The oldest rocks found on Earth date to about 4.0 Ga, and the oldest detrital zircon crystals in rocks to about 4.4 Ga, [34] [35] [36] soon after the formation of the Earth's crust and the Earth
The geological history of Earth follows the major geological events in Earth's past based on the geologic time scale, a system of chronological measurement based on the study of the planet's rock layers (stratigraphy). Earth formed about 4.54 billion years ago by accretion from the solar nebula, a disk-shaped mass of dust and gas left over from ...
During the 17th century, both religious and scientific speculation about the Earth's origin further propelled interest in the Earth and brought about more systematic identification techniques of the Earth's strata. [9] The Earth's strata can be defined as horizontal layers of rock having approximately the same composition throughout. [10]
At one extreme, an earth sheltered dwelling is completely underground, with perhaps an open courtyard to provide air and light. An earth house may be set into a slope, with windows or door openings in one or more of its sides, or the building may be on ground level, but with earth mounded against the walls, and perhaps with an earth roof. [49]
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.
The eon's lower boundary or starting point of 4,031±3 million years ago is officially recognized by the International Commission on Stratigraphy, [1] which is the age of the oldest known intact rock formations on Earth. Evidence of rocks from the preceding Hadean Eon are therefore restricted by definition to non-rock and non-terrestrial ...