GEOL 306 Lecture 7: Class 7_ January 30
7 Feb 2018
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Could be considered as one more or less continuous volcano. Totally spreading rate: slow (2-5 cm/yr), intermediate (5- Plates are pulled apart so lava intrudes to fill in space. Very difficult to study (deep), mor eruptions never directly witnessed. 75,000 rise > 1 km above sea floor. Due to different amount of heat and magma. Ophiolite: section of earth"s oceanic lithosphere uplifted and exposed above sea level. Found in cyprus, new guinea, california, oman. Magma chamber beneath ridge at <1 to 6 km below seaflor. Gabbro: basalt that did not reach surface, cooled slowly, crystallized entirely. Dike: subsurface igneous body that is tabular in shape and cuts across bedding or foliation of older rock. Through which it has intruded, subvertical typically. When reaching surface, lava forms pillow lavas. Pillow lavas are commonly 1 meter in diameter, result from submarine eruption. Never caught in progress yet at mid-ocean ridges. To deep, too difficult to predict when.
