What is a morb?

What is a morb?

An abbreviation for Mid Ocean Ridge Basalt. Said of basalts that form by 15 to 30 percent partial melting of the upper mantle at depths of 50 to 80 kilometers below the mid ocean spreading ridges.

What is e morb and N morb?

Abstract. At present, MORB is the most detailed basanitoid, can be divided into two categories, N-MORB and E-MORB. It is generally considered that both N-MORB and OIB are independent end-members from depleted and enriched mantle-derived rocks, while E-MORB is the result of mixing N-MORB with OIB.

What is OIB geology?

Ocean island basalt (OIB) is a volcanic rock, usually basaltic in composition, erupted in oceans away from tectonic plate boundaries. … Mantle plume conduits may drift slowly, but Earth’s tectonic plates drift more rapidly relative to mantle plumes.

How is morb produced?

MORB are generated by massive melting events that mix melts derived from depleted mantle and relatively enriched ‘plums’ of recycled materials, while the smaller degrees of melting typical of ocean island basalts are capable of extracting more of the ‘plums. ‘

Is MORB a word?

Mid-ocean ridge basalt.

Are mid-ocean ridges?

Mid-ocean ridges occur along divergent plate boundaries, where new ocean floor is created as the Earth’s tectonic plates spread apart. … Two well-studied mid-ocean ridges within the global system are the Mid-Atlantic Ridge and the East Pacific Rise.

What terms describe mid-ocean ridge basalt?

they are referred to as mid-ocean-ridge basalt (MORB). They are subalkaline tholeiites that contain olivine in the norm and less than 0.25 percent potash. The chemistry suggests that MORB was generated from a mantle that was depleted of volatile elements (e.g., lanthanum [La], cerium [Ce], sodium, and potassium) in a

What is mid oceanic ridge basalt?

Mid-ocean ridge basalt (commonly referred to as MORB) is a variety of submarine basalt erupted, in response to sea floor spreading, along the entire length of the Earth’s mid-ocean ridge system (some 65 000 km in length).

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What is HIMU geology?

HIMU is geochemical jargon for high-, with being defined as = (238U/204Pb)t = 0 [Houtermans, 1953; Zindler and Hart, 1986]. Although 238U/204Pb ratios change significantly with time, is defined as the present-day (i.e., zero-age, t = 0) 238U/204Pb ratio by convention.

Where is basalt found?

It is found all over Earth, but especially under the oceans and in other areas where Earth’s crust is thin. It formed in the Isle Royale-Keweenaw region because of the Midcontinent Rift. Most of Earth’s surface is basalt lava, but basalt makes up only a small fraction of continents.

How does ocean island basalt form?

If mantle plumes are sourced by the LLSVPs, these plumes may convey primitive and subducted material to the shallow mantle where they are melted to generate OIB melts. Ocean island basalts result from melting hot, buoyantly upwelling mantle beneath the world’s ocean basins.

Where are Morbs created?

mid-ocean ridges The oceanic crust (made of basalts) is formed on mid-ocean ridges. MORB = Mid-Ocean Ridge Basalt. This is the main site of volcanic activity on Earth, and the most abundant igneous rock!

What rocks are located at mid-ocean ridges?

Igneous rock is formed by the cooling and crystallization of molten magma at volcanoes and mid-ocean ridges, where new crust is generated. Examples of igneous rock are basalt, granite, and andesite (Fig. 7.57 A).

What will happen to the seafloor when the plates are drifting?

As tectonic plates slowly move away from each other, heat from the mantle’s convection currents makes the crust more plastic and less dense. The less-dense material rises, often forming a mountain or elevated area of the seafloor. Eventually, the crust cracks.

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What does got the Morbs mean?

Got the Morbs: Use of this 1880 phrase indicated temporary melancholy. Half-Rats: Partially intoxicated.

How do ridges form?

A mid-ocean ridge or mid-oceanic ridge is an underwater mountain range, formed by plate tectonics. This uplifting of the ocean floor occurs when convection currents rise in the mantle beneath the oceanic crust and create magma where two tectonic plates meet at a divergent boundary.

Where did the geologist discovered mid-ocean ridge?

It is now called the Mid-Ocean Ridge. In 1953, American physicists Maurice Ewing (1906-1974) and Bruce Heezen (1924-1977) discovered that through this underwater mountain range ran a deep canyon. In some places the canyon, called the Great Global Rift, came very close to land.

What is the border between two tectonic plates called?

boundary The border between two tectonic plates is called a boundary. All the tectonic plates are constantly moving very slowly around the planet, but in many different directions.

What type of boundary is the Mid-Atlantic Ridge?

divergent boundaries Perhaps the best known of the divergent boundaries is the Mid-Atlantic Ridge. This submerged mountain range, which extends from the Arctic Ocean to beyond the southern tip of Africa, is but one segment of the global mid-ocean ridge system that encircles the Earth.

What observation has been made about the age of the basalt?

What observation has been made about the age of basalt that forms mid ocean ridge? Basalt an ignasious rock formed at mid ocean ridges is younger than all other rock away from it.

What type of tectonic plate boundary created the Mid-Atlantic Ridge?

divergent The Mid-Atlantic Ridge is a mid-ocean ridge (a divergent or constructive plate boundary) located along the floor of the Atlantic Ocean, and part of the longest mountain range in the world.

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What is crest of Mid Oceanic ridge?

The mid-ocean ridge is a continuous chain of volcanoes on the ocean floor where lava erupts and the crust of the Earth is created. Nearly every day, somewhere on the crest of the mid-ocean ridge, there is likely to be an eruption of lava or an intrusion of magma that builds the ocean crust.

How were the mid-ocean ridges discovered?

However, as surveys of the ocean floor continued around the world, it was discovered that every ocean contains parts of the mid-ocean ridge system. The German Meteor expedition traced the mid-ocean ridge from the South Atlantic into the Indian Ocean early in the twentieth century.

What type of rock is basalt?

Basalt is a hard, black volcanic rock. Basalt is the most common rock type in the Earth’s crust. Depending on how it is erupted, basalt can be hard and massive (Figure 1) or crumbly and full of bubbles (Figure 2).

What is the northern hemisphere reference line?

Most OIB’s lie along a common trend sometimes called the Northern Hemisphere Reference line, (NHRL). Why Northern Hemisphere? Because some of the southern hemisphere OIB islands are not only more potassic but have a higher 207 and 208 relative to 204, compared to northern hemisphere rocks.