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The geological history of Mars can be broadly classified into many epochs, but the following are the three major ones: Noachian epoch (named after Noachis Terra): Formation of the oldest extant surfaces of Mars, 3.8 billion years ago to 3.5 billion years ago. Noachian age surfaces are scarred by many large impact craters.
Jupiter and Saturn have several large moons, such as Io, Europa, Ganymede and Titan, which may have originated from discs around each giant planet in much the same way that the planets formed from the disc around the Sun. [88] [89] [90] This origin is indicated by the large sizes of the moons and their proximity to the planet. These attributes ...
This article discusses how rocks are formed. There are also articles on physical rock formations, rock layerings , and the formal naming of geologic formations. Terrestrial rocks are formed by three main mechanisms: Sedimentary rocks are formed through the gradual accumulation of sediments: for example, sand on a beach or mud on a river bed. As ...
Analysis indicates that Kuiper belt objects are composed of a mixture of rock and a variety of ices such as water, methane, and ammonia. The temperature of the belt is only about 50 K, [88] so many compounds that would be gaseous closer to the Sun remain solid. The densities and rock–ice fractions are known for only a small number of objects ...
Some of the moons of Jupiter, Saturn, and Uranus are believed to have formed from smaller, circumplanetary analogs of the protoplanetary disks. [18] [19] The formation of planets and moons in geometrically thin, gas- and dust-rich disks is the reason why the planets are arranged in an ecliptic plane. Tens of millions of years after the ...
The name of the rock is then determined based on the types of minerals present. Schists are foliated rocks that are primarily composed of lamellar minerals such as micas. A gneiss has visible bands of differing lightness, with a common example being the granite gneiss. Other varieties of foliated rock include slates, phyllites, and mylonite.
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 itself.
The composition of Mars covers the branch of the geology of Mars that describes the make-up of the planet Mars. "Hottah" rock outcrop on Mars – ancient streambed [1] [2] [3] viewed by the Curiosity Rover (September 12, 2012, white balanced) (raw, close-up, 3-D version). Abundant iron compounds are responsible for the bright brownish-red ...