Marine Geology Phần 10 potx

landslide a rapid downhill movement of earth materials triggered by earth￾quakes and severe weather

Langmuir circulation near-surface alternating vortices aligned down￾wind, generated by the interaction of waves and mean shear currents

Laurasia (lure-AY-zha) a northern supercontinent of Paleozoic time, con￾sisting of North America, Europe, and Asia

Laurentia (lure-IN-tia) an ancient North American continent

lava molten magma that flows out onto the surface

limestone a sedimentary rock composed of calcium carbonate that is

secreted from seawater by invertebrates and whose skeletons compose

the bulk of deposits

lithosphere (LI-tha-sfir) the rocky outer layer of the mantle that includes

the terrestrial and oceanic crusts; the lithosphere circulates between

Earth’s surface and mantle by convection currents

lithospheric plate a segment of the lithosphere, the upper-layer plate of the

mantle, involved in the interaction of other plates in tectonic activity

lysocline the ocean depth below which the rate of dissolution just exceeds

the rate of deposition of the dead shells of calcareous organisms

magma a molten rock material generated within Earth and that is the con￾stituent of igneous rocks

magnetic field reversal a reversal of the north-south polarity of Earth’s

magnetic poles

magnetometer a devise used to measure the intensity and direction of the

magnetic field

manganese nodule a cobble-shaped ore on the deep-sea floor, which is

rich in manganese and iron

mantle the part of a planet below the crust and above the core, composed

of dense rocks that might be in convective flow

massive sulfides sulfide metals deposited from hydrothermal solutions

megaplume a large volume of mineral-rich warm water above an oceanic

rift

Mesozoic (MEH-zeh-ZOE-ik) literally the period of middle life, referring

to a period between 250 and 65 million years ago

metamorphism (me-teh-MORE-fi-zem) recrystallization of previous

igneous, metamorphic, and sedimentary rocks created under extreme

temperatures and pressures without melting

meteorite a metallic or stony celestial body that enters Earth’s atmosphere

and impacts onto the surface

microplate a small block of ocean crust surrounded by major plates

Mid-Atlantic Ridge the seafloor-spreading ridge that marks the exten￾sional edge of the North and South American plates to the west and the

Eurasian and African plates to the east

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Marine Geology

midocean ridge a submarine ridge along a divergent plate boundary

where a new ocean floor is created by the upwelling of mantle material

Mohorovicic discontinuity/Moho (MOE-HOE) the boundary between

the crust and mantle discovered by Andrija Mohorovicic

mollusk (MAH-lusc) a large group of invertebrates, including snails, clams,

squids, and extinct ammonites, characterized by an internal and external

shell surrounding the body

natural selection the process by which evolution selects species for survival

or extinction depending on the environment

nontransform fault small offsets with overlapping ridge tips at faults that

offset the Mid-Atlantic Ridge

nuée ardente (NU-ay ARE-don) an avalanche of glowing clouds of ash

and pyroclastics

olivine (AH-leh-vene) a green, iron-magnesium silicate common in intru￾sive and volcanic rocks

ophiolite (oh-FI-ah-lite) oceanic crust thrust upon continents by plate tec￾tonics

ore body the accumulation of metal-bearing ores where the hot

hydrothermal water moving upward toward the surface mixes with cold

sea water penetrating downward

orogeny (oh-RAH-ja-nee) an episode of mountain building by tectonic

activity

outgassing the loss of gas from within a planet as opposed to degassing, the

loss of gas from meteorites

overthrust a thrust fault in which one segment of crust overrides another

segment for a great distance

oxidation the chemical combination of oxygen with other elements

pahoehoe (pah-HOE-ay-hoe-ay) a Hawaiian term for ropy basalt lava

paleomagnetism the study of Earth’s magnetic field, including the posi￾tion and polarity of the poles in the past

paleontology (pay-lee-on-TAH-logy) the study of ancient life-forms,

based on the fossil record of plants and animals

Paleozoic (PAY-lee-eh-ZOE-ic) the period of ancient life, between 540

and 250 million years ago

Pangaea (pan-GEE-a) a Paleozoic supercontinent that included all the

lands of the Earth

Panthalassa (pan-THE-lass-ah) the global ocean that surrounded Pangaea

peridotite the most common ultramafic rock type in Earth’s mantle

period a division of geologic time longer than an epoch and included in an

era

photosynthesis the process by which plants form carbohydrates from car￾bon dioxide, water, and sunlight

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glossary