Term
| Seismic waves refract allowing geophysicists to calculate |
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Definition
| variations in the thickness of the earth's crust |
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Term
| continental crust is ______ near the surface; ______ with depth |
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Definition
| felsic near the surface, mafic with depth |
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Term
| Oceanic Crust is _____ near the surface and __________ at depth |
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Definition
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Term
| what is mohoroicic (moho) discontinuity |
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Definition
| seperates both oceanic and continental crust from mantle |
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Term
| oceanic crust is thick/thin and shallow/dense? |
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Definition
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Term
| is the core solid or liquid and why? |
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Definition
| liquid because s-waves can't go through it |
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Term
| The Earth is also known as The Blue Planet |
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Definition
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Term
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Definition
| area of ocean that extends from continent. it is rather shallow. |
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Term
| the mid-ocean ridge is marked by |
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Definition
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Term
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Definition
| between the shore and the more steeply dipping continental slope |
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Term
| oceanic ridge or mid-ocean ridge is elevated with a rift valley down the middle |
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Definition
| the further you get from the ridge the deeper the ocean gets - marked by earthquakes |
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Term
| active continental margin develops |
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Definition
| at the leading edge of a continental plate where oceanic lithosphere is subducted |
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Term
| passive continental margins |
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Definition
| are within a plate rather than at a plate boundary, and they lack the volcanic and seismic activity found at active continental margins. |
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Term
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Definition
| upper most igneous unit of ocean floor |
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Term
| most sediment on the deep seafloor is pelagic. what does pelagic mean |
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Definition
| it means that the sediment settled from suspension far from land |
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Term
| pelagic sediment is further characterized as pelagic clay and ooze. pelagic clay is |
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Definition
| brown or red and is composed of clay-sized particles from the continents or oceanic islands. |
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Term
| pelagic ooze is made up mostly of tiny shells of marine organisms. where is it found |
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Definition
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Term
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Definition
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Term
| oceanic currents are driven by |
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Definition
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Term
| surface winds blow from _____ pressure to ______ pressure |
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Definition
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Term
| oceanic crust is composed of basalt and gabbro and is generated continuously at |
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Definition
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Term
| oceanic crust is consumed at |
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Definition
| subduction ones and thus most of it is recycled a small amount is found in mountain ranges on land |
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Term
| the oceanic crust found in mountain ranges on land where emplaced by |
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Definition
| moving along large fractures called thrust faults |
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Term
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Definition
| preserved slivers of oceanic crust, along with part of the underlying upper mantle |
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Term
| an ideal ophiolite consists of |
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Definition
| rocks of the upper oceanic crust, esp. pillow lava and sheet lava flows underlain by a sheeted dike complex |
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Term
| a complete ophiolite consists of |
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Definition
| deep-sea sedimentary rocks underlain by rocks of the oceanic crust and upper mantle |
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Term
| sampling and drilling at oceanic ridges reveal that oceanic crust is indeed made up of pillow lava and sheet lava flows underlain by a sheeted dike complex, just as predicted from studies of |
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Definition
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Term
| oceanic crust is made of gabbro and the upper mantle is made up of |
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Definition
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Term
| oceanic crust is made of gabbro and the upper mantle is made up of |
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Definition
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Term
| the true geologic margin of a continent is where |
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Definition
| granitic continental crust changes to basalt and gabbro oceanic crust |
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Term
| basalt is fine grained due to rapid cooling and it is |
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Definition
| grey to black it is an extrusive volcanic rock |
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Term
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Definition
| large particles at the bottom small on top |
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Term
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Definition
| large particles at the bottom small on top |
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Term
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Definition
| it is an orientation of horizontal line drawn on the surface |
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Term
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Definition
| it is the degree angle to which it has been tipped |
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Term
| when a rock varies in strike and dip it is alled a |
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Definition
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Term
| a fold can be divided in half on its |
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Definition
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Term
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Definition
| a general term encompassing all changes in the shape or volume of rocks |
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Term
| how does rock deformation occur |
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Definition
| rocks may be crumpled into folds or fractured as a result of stress, which results from force applied to a given area of rock |
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Term
| if the intensity of the stress is greater than the rock's internal strength, the rock undergoes strain, what is strain |
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Definition
| deformation caused by stress |
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Term
| stress comes in three types what are they |
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Definition
| compression, tension and shear |
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Term
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Definition
| rocks or any other object are squeezed or compressed by forces directed toward one another along the same line |
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Term
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Definition
| results from forces acting along the same line, but in opposite directions |
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Term
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Definition
| forces act parallel to one another but in opposite directions |
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Term
| _____ and ______ describe the orientation of rock layers with respect to a horizontal plane |
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Definition
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Term
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Definition
| direction of a line formed by the intersection of a horizontal plane and an inclined plane |
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Term
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Definition
| a measure of an inclined plane's deviation from horizontal, so it must be measured at right angles to strike direction |
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Term
| geologic structures are types of |
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Definition
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Term
| folded rock layers, geologic structures known as folds |
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Definition
| planar features are crumpled and bent |
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Term
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Definition
| a simple bend or flexure in otherwise horizontal or uniformly dipping rock layers |
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Term
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Definition
| a simple bend or flexure in otherwise horizontal or uniformly dipping rock layers |
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