Test your basic knowledge |

Subject : science
Instructions:
  • Answer 50 questions in 15 minutes.
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  • Match each statement with the correct term.
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This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.
1. The difference between the expected strength of the Earth's main field at a certain location and the actual measure strength of the magnetic field at that location. Places where the field strength is stronger that expected are positive anomalies - an






2. Along much of the perimeter of the Pacific Ocean - the ocean floor reaches astounding depths of 8-12km. These areas define elongate troughs - and they border volcanic arcs - the curving chains of active volcanoes.






3. An ultramafic rock with large grains. intrusive - phaneritic igneous rock.






4. A reference to the pattern structure of a mineral. A material in which atoms are fixed in an orderly pattern - a crystalline solid.






5. Mineral crystal formation type; from directly from a vapor - occurs around volcanic vents or around geysers. At such locations - volcanic gases or steam enter the atmosphere and cool - so certain elements cannot remain in gaseous form.






6. Lava flowing on dry land cools more slowly that lava erupting underwater.






7. Fluid basaltic lava extruded from crustal fractures called fissures.






8. Rocks which develop when hot molten rock cools and freezes solid.






9. Deeper sublayer of the mantle - depth of 660km to 2900km.






10. Two different minerals which have the same composition but have different crystal structures.






11. Type of lava flow; the most viscous of any lava flow because it is the most silicic and the coolest in nature. Tends to accumulate in a lava dome above the vent or in short and bulbous flows 1 to 2 km long.






12. The angle between the direction that a compass needle points at a given location and the direction of the 'true' (geographic) north. Through this process - the magnetic poles never stray more than 15 degrees of latitude from the geographic pole.






13. The speed of the movements of the plates with respect to the speed of the other plates' movements. Absolute plate velocity is a measure of the movement of any plates relative to a fixed point in the mantle.






14. Active hot-spot volcanoes commonly occur at the end of a chain of dead volcanoes.






15. Chemical precipitates; salt deposits formed as a consequence of evaporation. Examples - rock salt and gypsum.






16. Soil section below the A-horizon; a soil level that has undergone substantial leaching but has not yet mixed with organic material. Because it lacks organic materials - this horizon tends to be lighter than the A-horizon. Part of the zone of leaching






17. Places with particularly voluminous quantities of magma erupting or intruding.






18. A naturally occurring solid - formed by geologic processes - has a crystalline structure and a definable chemical composition - and is generally inorganic.






19. Physical property of a mineral; refers to the way a mineral surface scatters light. Metallic versus non-metallic in nature.






20. Type of igneous rock composition; composed of dark silicates and calcium-rich feldspar - referred to as mafic (magnesium and iron). Make up the ocean floor/volcanic islands.






21. Sedimentary rock composed of clay.






22. In addition to islands that rise above sea level - seamounts have been detected (isolated submarine mountains) - once volcanoes but no longer erupt.






23. A plate boundary at which two plates move toward one another so that one plate sinks beneath the other. Subduction zones; Engage the sinking process known as subduction - between plates - consuming old oceanic lithosphere due to high density. Can sim






24. Cause of melting; the variation in temperature with depth is expressed in the geotherm; because pressure prevents melting - a decrease in pressure can permit melting. Specifically - if the pressure affecting hot mantle rock decreases while the temper






25. Natural bond connecting rocks; mineral material that precipitates from water and fills the space between grains.






26. Rocks whose crystals interlock with each other.






27. During the final stages of cooling - lava flows contract and may fracture into roughly hexagonal columns.






28. The intrusion of numerous plutons in a region - produces a vast composite body that may be several hundred kilometers long and over 100km wide; an immense body of igneous rock.






29. Distinguishing feature of magma; Because not all minerals melt by the same amount under given conditions - and because chemical reactions take place during melting - the magma that forms as a rock begins to melt does not have the same composition as






30. Heat from an intense surface fire bakes and expands the outer layer of the rock. On cooling - the layer contracts - causing the outer part of the rock spall - or break off in sheet-like pieces.






31. Biochemical sedimentary rock; it's made from cryptocrystalline quartz. Examples - flint and jasper.






32. Type of sedimentary soil/rock; Calcite in a pedocal soil accumulates in the B-horizon and may cement soil together - creating this solid mass.






33. Mineral class; consist of metal cations bonded by oxygen anions. Examples - hematite and magnetite. Some contain a relatively high proportion of metal atoms - and thus are ore minerals.






34. Times when the Earth's magnetic field flips from normal to reversed polarity - or vice versa. When the Earth has reversed polarity - the south magnetic pole lies near the north geographic pole - and the north magnetic pole lies near the south geograp






35. A sediment-filled depression; in an area where the lithosphere has subsided.






36. A process occurring when the sea level rises - the coast migrates inland. Through this - an extensive layer of beach forms.






37. Perhaps the cause for the large igneous provinces; formations within the mantle - plumes that bring up vastly more hot asthenosphere than normal plumes.






38. A fine spray of lava instantly freezes to form fine particles of glass.






39. Chemical weathering during Which minerals dissolve into water.






40. After sand has lost its feldspar composition due to weathering over time - sediment composed entirely of quartz grains gets buried and lithified to form this type of rock.






41. When silt and clay accumulate in the flat areas bordering a stream - lagoon - or delta - the silt when lithified becomes this type of sediment. And the mud - when lithified - becomes another type of sediment - also known as shale.






42. Similar to ripples - but are much larger. Small ripples often form on the surface of these structures.






43. Rock made by the freezing of magma underground - after it has pushed its way (intruded) into preexisting rock of the crust.






44. Inorganic limestone; rock composed of crystalline calcium carbonate formed by chemical precipitation.






45. Low-viscosity (basaltic) lava flows out of a volcano easily - whereas high-viscosity (andesitic and rhyolitic) lava can clog and build pressure within a volcano. Basaltic eruptions are typically effusive and produce shield volcanoes - whereas rhyolit






46. The shape of the sea floor surface. Investigation of the sea-floor revealed the presence of several important features: mid-ocean ridges - deep-ocean trenches - seamount chains - and fracture zones.






47. Materials that easily transform into gas at the relatively low temperatures found at the Earth's surface.






48. An exposure of bedrock.






49. Type of volcanic eruption; takes place when water gains access to the hot rock around the magma chamber and suddenly transforms into steam - a pyroclastic eruption involving the reaction of water with magma.






50. Process where new divergent boundaries form when a continent splits and separates into two continents.