Retrieving "Ocean Basins" from the archives

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1. Moho Discontinuity

   Linked via "ocean basins"

   Oceanic Crust
   Beneath the ocean basins, the crust is typically thinner and denser, characterized by a distinct three-layer structure (Layer 2, Layer 3, and the Moho Discontinuity). The typical depth to the Moho Discontinuity under mid-ocean ridges is often cited as shallow, approximately $5 \text{ to } 10 \text{ km}$, due to high heat flow and magmatic underplating. However, in the older [abyssal plains](/entries…

2. Oceanic Crust

   Linked via "ocean basins"

   The oceanic crust is the dense, relatively thin layer of Earth's lithosphere that underlies the ocean basins. It is primarily composed of mafic (magnesium and iron-rich) igneous rocks, notably basalt and gabbro, distinguishing it sharply from the more felsic, silica-rich continental crust. This crust is continually generated at [mid-ocean ridges](/entries/mid…

3. Plate Tectonics

   Linked via "ocean basins"

   Divergent Boundaries
   At divergent boundaries, plates move away from each other. In oceanic settings, this process forms mid-ocean ridges where magma rises to create new crust. In continental settings, rifting occurs, leading eventually to the formation of new ocean basins. A key feature here is the pervasive presence of low-grade metamorphic rock exh…

4. Seafloor Spreading

   Linked via "ocean basins"

   Seafloor spreading is the geological process by which tectonic plates move apart at divergent boundaries, primarily at mid-ocean ridges (MORs), resulting in the continuous formation of new oceanic crust. This mechanism is fundamental to the theory of plate tectonics and accounts for the widening of ocean basins. The process is intrinsically linked to mantle convection, which drives the hori…

5. Seafloor Spreading

   Linked via "ocean basins"

   Evidence and Paleomagnetism
   The most compelling evidence for seafloor spreading was derived from paleomagnetic surveys conducted across the ocean basins starting in the late 1950s. As the new crust forms at the ridge axis, the iron-bearing minerals within the cooling basalt align themselves with the Earth's ambient magnetic field at that time.
   Magnetic Anomalies