Although the Mid Atlantic Ridge is mostly an underwater feature portions of it

Although the mid atlantic ridge is mostly an

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- Although the Mid-Atlantic Ridge is mostly an underwater feature, portions of it have enough elevation to extend above sea level. - The ridge is a slow spreading center and has an average spreading rate of about 2.5 centimetres (0.98 in) per year and forms an ocean trench about the size of the Grand Canyon.
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General classification and sub-classification of igneous rocks Categories of rocks - Felsic (most silica rich) o Granite (coarse-grained) - Intermediate o Diorite (coarse-grained) o Andesite (fine-grained) - Mafic o Gabbro (coarse-grained) o Basalt (fine-grained) - Ultra-mafic (most Fe+magnesium rich) o Peridotite (coarse-grained, typically subcrustal) The major elements and minerals that make up the crust, mantle and Earth as a whole Earths mass - Comprises of: iron (32%), oxygen (30%), silicon (15%), magnesium (14%) - The remaining of Earth’s mass consists of the remaining 88 elements Elements in Earth’s crust – all approximate amounts - 47% oxygen - 28% silicon - 8% aluminum - 5% iron - 4% calcium - 3% sodium - 3% potassium - 2% magnesium Earth’s mantle - Upper mantle o Inner zone: plastic flowing rock o Outer zone: rigid rock - Elements in the mantle: o 45% oxygen o 22% silicon o 23% magnesium o Iron. Aluminum, calcium, sodium, potassium o These elements are all bound together in the form of silicate rocks
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Earth’s materials -
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