GENERAL GEOLOGY

Detailed explanation-1: -Hydrothermal Metamorphism (Fig. 8.3): typically occurs along mid-ocean ridge spreading centers where heated seawater percolates through hot, fractured basalt. Chemical reactions between the heated seawater and basalt result in metamorphism of the basalt.

Detailed explanation-2: -Mid-ocean ridges occur along divergent plate boundaries, where new ocean floor is created as the Earth’s tectonic plates spread apart. As the plates separate, molten rock rises to the seafloor, producing enormous volcanic eruptions of basalt.

Detailed explanation-3: -Because the ridge is the site of focused volcanic activity, seawater circulates actively to cool the new crust. This heated water reacts with the volcanic rock, dissolving out metals and depositing them around seafloor hot springs.

Detailed explanation-4: -Mid-ocean ridges are considered the planet’s largest magmatic system. At divergent plate boundaries, magma is generated by decompression melting of upwelling mantle. Melts are focused as they ascend through the upper mantle and lower crust and collect beneath the ridge axis in elongate melt lenses.

Detailed explanation-5: -What causes mid-ocean ridges to form? Mid-ocean ridges form at divergent plate boundaries, where seafloor spreading leads to the production of new ocean crust. This new crust is formed due to igneous intrusions and extrusions as magma either cools beneath the Earth’s surface or erupts as lava above the Earth’s surface.