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Surface of Earth, showing higher elevations in red. Geomorphology (from Ancient Greek γῆ (gê) 'earth' μορφή (morphḗ) 'form' and λόγος 'study') [2] is the scientific study of the origin and evolution of topographic and bathymetric features generated by physical, chemical or biological processes operating at or near Earth's surface.
Landforms together make up a given terrain, and their arrangement in the landscape is known as topography. Landforms include hills , mountains , canyons , and valleys , as well as shoreline features such as bays , peninsulas , and seas , [ 3 ] including submerged features such as mid-ocean ridges , volcanoes , and the great ocean basins .
Some of this object's mass merged with Earth, significantly altering its internal composition, and a portion was ejected into space. Some of the material survived to form the orbiting Moon. Outgassing and volcanic activity produced the primordial atmosphere. Condensing water vapor, augmented by ice delivered from comets, produced the oceans. [15]
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
Land is often defined as the solid, dry surface of Earth. [1] The word land may also collectively refer the collective natural resources of Earth, [2] including its land cover, rivers, shallow lakes, its biosphere, the lowest layer of the atmosphere (troposphere), groundwater reserves, and the physical results of human activity on land, such as architecture and agriculture. [3]
Earth is rounded into an ellipsoid with a circumference of about 40,000 km. It is the densest planet in the Solar System. Of the four rocky planets, it is the largest and most massive. Earth is about eight light-minutes away from the Sun and orbits it, taking a year (about 365.25 days) to complete one revolution.
Solidified lava flow in Hawaii Sedimentary layers in Badlands National Park, South Dakota Metamorphic rock, Nunavut, Canada. Geology (from Ancient Greek γῆ (gê) 'earth' and λoγία () 'study of, discourse') [1] [2] is a branch of natural science concerned with the Earth and other astronomical objects, the rocks of which they are composed, and the processes by which they change over time. [3]
The earliest Earth crust probably forms similarly out of similar material. On Earth the pluvial period starts, in which the Earth's crust cools enough to let oceans form. c. 4,404 Ma – First known mineral, found at Jack Hills in Western Australia. Detrital zircons show presence of a solid crust and liquid water.