Oceanic crust is the uppermost layer of the oceanic portion of a tectonic plate. The crust overlies the solidified and uppermost layer of the mantle. The crust and the solid mantle layer together comprise oceanic lithosphere.
Oceanic crust is the result of erupted mantle material originating from below the plate, cooled and in most instances, modified chemically by seawater. This occurs mostly at mid-ocean ridges, but also at scattered hotspots, and also in rare but powerful occurrences known as flood basalt eruptions. It is primarily composed of mafic rocks, or sima, which is rich in iron and magnesium. It is thinner than continental crust, or sial, generally less than 10 kilometers thick; however it is denser, having a mean density of about 2.9 grams per cubic centimeter as opposed to continental crust which has a density of about 2.7 grams per cubic centimeter.
Although a complete section of oceanic crust has not yet been drilled, geologists have several pieces of evidence that help them understand the ocean floor. Estimations of composition are based on analyses of ophiolites (sections of oceanic crust that are preserved on the continents), comparisons of the seismic structure of the oceanic crust with laboratory determinations of seismic velocities in known rock types, and samples recovered from the ocean floor by submersibles, dredging (especially from ridge crests and fracture zones) and drilling. Oceanic crust is significantly simpler than continental crust and generally can be divided in three layers.
It’s what’s inside that counts ... Outwardly they were very righteous ... When they gave money to the poor they made sure everyone could hear the coins dropping into the plate. The Queen Mary was the largest ship to cross the oceans when launched in 1936 ... It turns out that the 3/4” steel plate which formed the stacks had all but corroded away ... .
When the Big One hits, the first thing Washington residents notice may not be the ground shaking but their phone issuing a warning ... The alerts will also warn of potentially damaging earthquakes that are more likely to occur sooner, on one of two dozen crustal faults in the Puget Sound region alone, or deeper slips on the underlying ocean plate ... ....
The researchers term the mechanism a "subduction pulley" where the weight of the subducting portion that dives beneath another tectonic plate, pulls on the drifting ocean plate and tears apart the weak microcontinent sections in an early phase of potentially significant damage.
Everyone needs a hug from time to time, and now new drone footage suggests that even whales enjoy a cuddle ...North Atlantic right whales ... Two other species of right whales exist ... Right whales are baleen whales, feeding on copepods (tiny crustaceans) by straining huge volumes of ocean water through their baleen plates, which act like a sieve. Source ... .
Indonesia's Mount Sinabung volcano erupted on Friday but, despite a massive column of smoke and ash, no evacuation order has been made ... Read more ... It sits on the "Ring of Fire", a belt of tectonic plate boundaries circling the PacificOcean where frequent seismic activity occurs. Follow us on Facebook, Twitter and Instagram to stay connected ....
It’s like, “imagine you’re in a cafe in Paris, and you eat a tuna sandwich, and it’s really wonderful.” And then he talks about, “think about if you had to orchestrate how that sandwich got to your plate? Like you would have to be in the ocean ...
BROOKLAWN — The OceanCity HighSchool baseball team made one comeback Saturday afternoon ... Ocean City (4-2) is ranked No ... Ocean City trailed 3-1 when it came to the plate for its final at-bat in the bottom of the seventh inning ... The Rams sent 11 hitters to the plate, took advantage of four Ocean City walks and scored six runs.
7 OceanCity 5. Ocean City made one comeback Saturday afternoon ... Ocean City (4-2) is ranked No ... Ocean City trailed 3-1 when it came to the plate for its final at-bat in the bottom of the seventh inning ... The Rams sent 11 hitters to the plate, took advantage of four Ocean City walks and scored six runs ... Nunan started for Ocean City.
But new research has concluded they are part of a geological upheaval hundreds of millions of years ago, when the collision of the Earth's tectonic plates thrust fragments of the floor and rocks of a now-vanished ocean up through the surface, where they remain to this day.
But new research has concluded they are part of a geological upheaval hundreds of millions of years ago, when the collision of the Earth’s tectonic plates thrust fragments of the floor and rocks of a now-vanished ocean up through the surface, where they remain to this day.
You may have read about, or may have seen it on the news, about an island of trash floating in the PacificOcean that is the size of Texas, or even larger ... The recent pandemic has led to skyrocketing of single-use plastic plates and dinnerware, so we have plastic everywhere and a large percent of it ends up in the ocean ... As reported in DeZeen, Feb ... .