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Ferrocement or ferro-cement [1] is a system of construction using reinforced mortar [2] or plaster (lime or cement, sand, and water) applied over an "armature" of metal mesh, woven, expanded metal, or metal-fibers, and closely spaced thin steel rods such as rebar. The metal commonly used is iron or some type of steel, and the mesh is made with ...
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.
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]
Initially, Earth was molten due to extreme volcanism and frequent collisions with other bodies. Eventually, the outer layer of the planet cooled to form a solid crust when water began accumulating in the atmosphere. The Moon formed soon afterwards, possibly as a result of the impact of a planetoid with Earth.
Anthropic rock is rock that is made, modified and moved by humans.Concrete is the most widely known example of this. [1] The new category has been proposed to recognise that human-made rocks are likely to last for long periods of Earth's future geological time, and will be important in humanity's long-term future.
An axe made of iron, dating from the Swedish Iron Age The earliest iron objects found in Europe date from the 3rd millennium BC, and are assigned to the Yamnaya culture and Catacomb culture . [ 49 ] [ 50 ] Eastern Europe, especially the Cis-Ural region, shows the highest concentration of early and middle Bronze Age iron objects in western ...
Made of iron and nickel, the hot, solid sphere is about 70% the size of the moon. Recent research suggested this dense center reversed its spin, and now, scientists have also found evidence that ...
Although theories that resulted from the heightened interest in the Earth's composition were often manipulated to support the concept of the Deluge, a genuine outcome was a greater interest in the makeup of the Earth. Due to the strength of Christian beliefs during the 17th century, the theory of the origin of the Earth that was most widely ...