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596 Matching questions

  1. positive gravity anomaly
  2. mafic
  3. schistose
  4. crater
  5. volcanic breccia
  6. shear strength
  7. water table
  8. sedimentary structure
  9. sheet joints
  10. isotopic dating
  11. concretion
  12. calcite
  13. radioactive decay
  14. ground water
  15. compressive stress
  16. terminus
  17. stalagmite
  18. sedimentary breccia
  19. gaining stream
  20. fault-block mountain range
  21. stream channel
  22. creep
  23. drumlin
  24. frost action
  25. rigid zone
  26. earthy luster
  27. geologic cross section
  28. sea cliff
  29. columnar structure (columnar jointing)
  30. Aftershock
  31. organic sedimentary rock
  32. tensional stress
  33. chill zone
  34. butte
  35. Prearchean (Hadean) Eon
  36. contour current
  37. arête
  38. magnetite
  39. ion
  40. bed load
  41. gabbro
  42. clay mineral group
  43. tsunami (seismic sea wave)
  44. U-shaped valley
  45. hinge line
  46. glassy (vitreous) luster
  47. strip mine
  48. mechanical weathering
  49. plateau basalts
  50. mantle plume
  51. scientific method
  52. downcutting
  53. seismic reflection
  54. seamount
  55. plagioclase feldspar
  56. headward erosion
  57. crystal settling
  58. sheetwash
  59. meander
  60. well
  61. nucleus
  62. Cenozoic Era
  63. bedding
  64. epicenter
  65. atomic number
  66. brittle
  67. fracture
  68. sheet silicate structure
  69. rectangular pattern
  70. syncline
  71. kettle
  72. eon
  73. barrier reef
  74. terrigenous sediment
  75. plate tectonics
  76. speleothem
  77. environment of deposition
  78. tectonic forces
  79. receding glacier
  80. negative magnetic anomaly
  81. oil field
  82. dendritic pattern
  83. flood plain
  84. barchan
  85. elastic rebound theory
  86. crystal form
  87. ripple mark
  88. P wave
  89. solution
  90. metamorphism
  91. beach
  92. vein
  93. heat flow
  94. convergent plate boundary
  95. sandstone
  96. dike
  97. clay
  98. strike-slip fault
  99. proton
  100. suspect terrane
  101. cross-cutting relationship
  102. equilibrium line
  103. geode
  104. surf
  105. talus
  106. differential weathering
  107. rip current
  108. stream velocity
  109. drawdown
  110. divide
  111. continental slope
  112. landslide
  113. braided stream
  114. matrix
  115. flank eruption
  116. ultramafic rock
  117. atoll
  118. superposed stream
  119. Andesite
  120. permeability
  121. gravity meter
  122. wave-cut platform
  123. limb
  124. Precambrian shield
  125. flow
  126. coastal straightening
  127. sediment
  128. gravel
  129. data
  130. trellis pattern
  131. angular unconformity
  132. differentiation
  133. streak
  134. inclusion
  135. fossil assemblage
  136. intrusion (intrusive structure)
  137. sand dune
  138. seismic refraction
  139. crevasse
  140. gneissic
  141. half-life
  142. cinder cone
  143. Paleozoic Era
  144. metallic luster
  145. shearing
  146. joint
  147. Bowen's reaction series
  148. transform fault
  149. parent rock
  150. isostatic adjustment
  151. pyroxene group
  152. core
  153. B horizon (zone of accumulation)
  154. pelagic sediment
  155. quartz
  156. seismic sea wave
  157. coast
  158. positive magnetic anomaly
  159. transform plate boundary
  160. metamorphic rock
  161. rain shadow
  162. ionic bonding
  163. debris slide
  164. C horizon
  165. slide
  166. angle of dip
  167. hydrothermal rock
  168. longshore current
  169. uniformitarianism
  170. rhyolite
  171. oil shale
  172. magma
  173. electron
  174. tuff
  175. schist
  176. mudflow
  177. sill
  178. longitudinal dune (seif)
  179. oblique-slip fault
  180. circum-Pacific belt
  181. rock flour
  182. vesicle
  183. accumulation stage
  184. perched water table
  185. theory
  186. stream gradient
  187. spit
  188. geothermal gradient
  189. structural basin
  190. Mohs'
  191. heavy crude
  192. bonding
  193. nonrenewable resource
  194. luster
  195. superposition
  196. debris
  197. parabolic dune
  198. anticline
  199. regional metamorphism
  200. Quaternary Period
  201. fringing reef
  202. deposition
  203. volcanism
  204. country rock
  205. lithification
  206. frost wedging
  207. O horizon
  208. turbidity current
  209. rift valley
  210. structural dome
  211. rockfall
  212. bar
  213. zone of ablation
  214. berm
  215. dissolved load
  216. Proterozoic Eon
  217. fault
  218. left-lateral fault
  219. aseismic ridge
  220. stress
  221. losing stream
  222. geologic resources
  223. magnetic pole
  224. magmatic arc
  225. fjord
  226. conglomerate
  227. transverse dune
  228. hanging wall
  229. abyssal plain
  230. shale
  231. numerical (or absolute) age
  232. sedimentary rock
  233. marine terrace
  234. fold
  235. density
  236. texture
  237. potassium (orthoclase) feldspar
  238. marble
  239. rock cycle
  240. cirque
  241. frost heaving
  242. tillite
  243. exfoliation dome
  244. Pleistocene Epoch
  245. spring
  246. rock-basin lake (tarn)
  247. oxbow lake
  248. incised meander
  249. wavelength
  250. ice cap
  251. coarse-grained rock
  252. olivine
  253. source rock
  254. axial plane
  255. shield volcano
  256. direction of dip
  257. plutonic rock
  258. geologic map
  259. crest (of wave)
  260. alluvial fan
  261. playa lake
  262. delta
  263. basal sliding
  264. atom
  265. crustal rebound
  266. deflation
  267. lateral erosion
  268. metasomatism
  269. cross-bedding
  270. extrusive rock
  271. submarine canyon
  272. natural gas
  273. clastic sedimentary rock
  274. physical continuity
  275. unconformity
  276. feldspar group
  277. hardness
  278. breaker
  279. transportation
  280. active continental margin
  281. block
  282. arch (sea arch)
  283. hypothesis
  284. hornfels
  285. compaction
  286. mountain range
  287. isoclinal fold
  288. crystalline texture
  289. stock
  290. fossil
  291. pothole
  292. varve
  293. abyssal fan
  294. lithosphere
  295. volcanic neck
  296. isotope
  297. Phanerozoic Eon
  298. sand
  299. rock
  300. chemical sedimentary rock
  301. natural levee
  302. fracture zone
  303. laterite
  304. specific gravity
  305. body wave
  306. Ablation
  307. meander cutoff
  308. ice sheet
  309. pyroclast
  310. rotational slide (slump)
  311. erosion
  312. horn
  313. arrangement
  314. ductile
  315. major mountain belt
  316. andesite
  317. tarns
  318. intermediate
  319. atomic mass number
  320. unconfined aquifer
  321. clastic texture
  322. island arc
  323. slate
  324. silicic (felsic)
  325. oil sand
  326. subduction
  327. chert
  328. cement
  329. hydrologic cycle
  330. batholith
  331. sinkhole
  332. atomic weight
  333. formation
  334. igneous rock
  335. oil pool
  336. era
  337. chain silicate structure
  338. placer mine
  339. differential stress
  340. magnetometer
  341. volcanic dome
  342. evaporate
  343. reef
  344. plunging fold
  345. porosity
  346. correlation
  347. trough (of wave)
  348. diorite
  349. cone of depression
  350. seismograph
  351. modified Mercalli scale
  352. foliation
  353. debris fall
  354. lava flows
  355. geophysics
  356. geyser
  357. Mesozoic Era
  358. hematite
  359. A horizon (zone of leaching)
  360. alpine glaciation
  361. silicates
  362. Bajada
  363. rounding
  364. mica group
  365. vent
  366. migmatite
  367. karst topography
  368. zone of accumulation
  369. discharge
  370. crude oil
  371. reservoir rock
  372. subduction zone
  373. normal fault
  374. neutron
  375. beach face
  376. weathering
  377. isolated silicate structure
  378. advancing glacier
  379. continental glaciation
  380. contacts
  381. mesa
  382. metamorphic facies
  383. clay mineral
  384. covalent bonding
  385. original horizontality
  386. pluvial lake
  387. pumice
  388. oceanic trench
  389. coal
  390. rockslide
  391. erratic
  392. artesian well
  393. muscovite
  394. lava
  395. loam
  396. pressure release
  397. ferromagnesian mineral
  398. crystalline
  399. ophiolite
  400. negative gravity anomaly
  401. terrane (tectonostratigraphic terrane)
  402. slip face
  403. stalactite
  404. fine-grained rock
  405. passive continental margin
  406. saturated zone
  407. wave refraction
  408. gneiss
  409. Amphibole group
  410. mineral
  411. soil horizon
  412. footwall
  413. reserves
  414. stream
  415. blowout
  416. Rayleigh wave
  417. thrust fault
  418. debris avalanche
  419. open fold
  420. mud crack
  421. silica
  422. disconformity
  423. paleomagnetism
  424. divergent plate boundary
  425. moment magnitude
  426. open-pit mine
  427. surface wave
  428. caldera
  429. cleavage
  430. recrystallization
  431. magnetic reversal
  432. index fossil
  433. permafrost
  434. wave height
  435. traction
  436. biotite
  437. barrier island
  438. suspended load
  439. end moraine
  440. polar wandering
  441. crust
  442. intrusive rock
  443. quartzite
  444. slaty cleavage
  445. isotherm
  446. valley glacier
  447. petroleum
  448. seismogram
  449. shear force
  450. glacier
  451. right-lateral fault
  452. drainage basin
  453. accreted terrane
  454. cementation
  455. travel-time curve
  456. Precambrian
  457. diaper
  458. crystallization
  459. petrified wood
  460. limestone
  461. mid-oceanic ridge
  462. saltation
  463. continental rise
  464. stream terrace
  465. Mohorovicˇic´ discontinuity (Moho)
  466. convection
  467. S wave
  468. earthquake
  469. guyot
  470. equilibrium
  471. silt
  472. magnitude
  473. composite volcano (stratovolcano)
  474. chemical weathering
  475. bomb
  476. Love wave
  477. dip-slip fault
  478. residual soil
  479. ventifact
  480. solifluction
  481. playa
  482. element
  483. transported soil
  484. transform boundary
  485. moraine
  486. pediment
  487. xenolith Fragment
  488. seismic wave
  489. nonmetallic luster
  490. base level
  491. Benioff zone
  492. shear stress
  493. confining pressure
  494. granite
  495. striations
  496. sea-floor spreading
  497. stack
  498. esker
  499. framework silicate structure
  500. phyllite
  501. Curie point
  502. viscosity
  503. confined (artesian) aquifer
  504. hot spring
  505. slaty
  506. silicon-oxygen tetrahedron
  507. overturned fold
  508. depth of focus
  509. continental drift
  510. plate
  511. hydraulic action
  512. resources
  513. radial pattern
  514. epoch
  515. pillow structure (pillow basalts)
  516. fall
  517. vadose zone
  518. plateau
  519. gravitational collapse and spreading
  520. Richter scale
  521. porphyritic rock
  522. relative time
  523. exfoliation
  524. rock avalanche
  525. period
  526. elastic limit
  527. orogeny
  528. nonconformity
  529. ground moraine
  530. contact metamorphism
  531. earthflow
  532. Asthenosphere
  533. isostasy
  534. shadow zone
  535. Mediterranean-Himalayan belt
  536. flash flood
  537. ore
  538. longshore drift
  539. strike
  540. tombolo
  541. phenocryst
  542. point bar
  543. theory of glacial ages
  544. ore mineral
  545. spheroidal weathering
  546. P-wave shadow zone
  547. reverse fault
  548. Abrasion
  549. faunal succession
  550. graded bed
  551. till
  552. graded stream
  553. outwash
  554. magnetic field
  555. obsidian
  556. truncated spur
  557. pore space
  558. soil
  559. headland
  560. craton
  561. Recent (Holocene) Epoch
  562. intensity
  563. iceberg
  564. Aquifer
  565. dolomite
  566. limonite
  567. peridotite
  568. mass wasting
  569. estuary
  570. standard geologic time scale
  571. continental shelf
  572. volcano
  573. pluton
  574. basalt
  575. recumbent fold
  576. distributary
  577. strain
  578. oil trap
  579. lateral moraine
  580. mantle
  581. lateral continuity
  582. joint set
  583. bedding plane
  584. loess
  585. lithospheric delamination (or delamination)
  586. desert
  587. fold and thrust belts
  588. pyroclastic flow
  589. relief
  590. Archean Eon
  591. debris flow
  592. baymouth bar
  593. focus
  594. hanging valley
  595. drainage pattern
  596. plastic flow
  1. a A moving mass of water that develops parallel to a shoreline.
  2. b Mass wasting in which motion is taking place throughout the moving mass (flow). The common varieties are earthflow, mudflow, and debris avalanche.
  3. c Describing a substance in which the atoms are arranged in a regular, repeating, orderly pattern.
  4. d A strike-slip fault in which the block seen across the fault appears displaced to the right.
  5. e An accumulation of broken rock at the base of a cliff. (End Chapter 9)
  6. f A loss in overall volume and pore space of a rock as the particles are packed closer together by the weight of overlying material.
  7. g Various different species of fossils in a rock.
  8. h A partially filled aquifer exposed to the land surface and marked by a rising and falling water table.
  9. i The earliest Eon of Earth's history.
  10. j In mass wasting, the component of gravitational force that is parallel to an inclined surface.
  11. k Principle that geologic processes operating at present are the same processes that operated in the past. The principle is stated more succinctly as "The present is the key to the past." Also, see actualism. (End Chapter 8)
  12. l A wedge of sediment that extends from the lower part of the continental slope to the deep sea floor.
  13. m Dense, viscous petroleum that flows slowly or not at all.
  14. n Group of minerals with a sheet silicate structure.
  15. o Rock falling freely or bouncing down a cliff.
  16. p A rock that is sufficiently porous and permeable to store and transmit petroleum.
  17. q Very flat sediment-covered region of the deep-sea floor, usually at the base of the continental rise.
  18. r Boundary between two plates that are sliding past each other. (End Chapter 1)
  19. s A powder of fine fragments of rock produced by glacial abrasion.
  20. t The sequence in which minerals crystallize from a cooling basaltic magma.
  21. u A group of closely spaced mountains or parallel ridges.
  22. v A steep-sided, dome- or spine-shaped mass of volcanic rock formed from viscous lava that solidifies in or immediately above a volcanic vent.
  23. w The section of the beach exposed to wave action.
  24. x A region of Earth's outer shell beneath the lithosphere. The asthenosphere is of indeterminate thickness and behaves plastically.
  25. y The portion of the total sediment load in a stream that is carried in solution.
  26. z The sum of the weight of the subatomic particles in an average atom of an element, given in atomic mass units.
  27. aa Steplike landform found above a stream and its flood plain.
  28. ab The outer layer of rock, forming a thin skin over Earth's surface.
  29. ac Point of land along a coast.
  30. ad The low point of a wave.
  31. ae A subatomic particle that contributes mass and a single positive electrical charge to an atom.
  32. af Four-sided, pyramidal object that visually represents the four oxygen atoms surrounding a silicon atom; the basic building block of silicate minerals. Also called a silica tetrahedron or a silicon tetrahedron.
  33. ag A felsic, coarse-grained, intrusive igneous rock containing quartz and composed mostly of potassium- and sodium-rich feldspars.
  34. ah A bar of marine sediment connecting a former island or stack to the mainland.
  35. ai hardness scale Scale on which ten minerals are designated as standards of hardness.
  36. aj Great fan-shaped deposit of sediment on the deep-sea floor at the base of many submarine canyons.
  37. ak The consolidation of sediment into sedimentary rock.
  38. al A depression of the water table formed around a well when water is pumped out; it is shaped like an inverted cone.
  39. am Very slow, continuous downslope movement of soil or debris. (Begin Chapter 9)
  40. an Drainage pattern of a river and its tributaries, which resembles the branches of a tree or veins in a leaf.
  41. ao Open fissure in a glacier.
  42. ap The central zone of Earth.
  43. aq A large, long-lasting mass of ice, formed on land by the compaction and recrystallization of snow, which moves because of its own weight.
  44. ar Valuable materials of geologic origin that can be extracted from Earth.
  45. as An irregular line marking the highest level to which the winter snow cover on a glacier is lost during a melt season. (Also called snow line.)
  46. at A coarse-grained sedimentary rock (grains coarser than 2 mm) formed by the cementation of angular rubble.
  47. au Flow of water saturated debris over impermeable material.
  48. av Small earthquake that follows a main shock. (Begin Chapter 16)
  49. aw The chemical precipitation of material in the spaces between sediment grains, binding the grains together into a hard rock.
  50. ax A low ridgelike pile of till along the side of a glacier.
  51. ay Large fan-shaped pile of sediment that usually forms where a stream's velocity decreases as it emerges from a narrow canyon onto a flat plain at the foot of a mountain range.
  52. az A volcanic depression much larger than the original crater.
  53. ba A type of surface seismic wave that causes the ground to move side to side in a horizontal plane perpendicular to the direction the wave is traveling.
  54. bb Dripstone deposit of calcite that precipitate from dripping water in caves.
  55. bc Bodies of rock (e.g., rock salt) or magma that ascend within Earth's interior because they are less dense than the surrounding rock.
  56. bd The application of physical laws and principles to a study of Earth.
  57. be When pressures on a body are not of equal strength in all directions.
  58. bf The ability of a mineral to break along preferred planes.
  59. bg Molten rock, usually mostly silica. The liquid may contain dissolved gases as well as some solid minerals.
  60. bh A drainage pattern in which tributaries of a river change direction and join one another at right angles.
  61. bi A mode of transport that carries sediment downcurrent in a series of short leaps or bounces.
  62. bj A rock in which most of the mineral grains are less than one millimeter across.
  63. bk A place where water flows naturally out of rock onto the land surface.
  64. bl iron oxide that is attracted to a magnet.
  65. bm An electrically charged atom or group of atoms.
  66. bn Mineral group, all members of which are single chain silicates.
  67. bo Distance between the focus and the epicenter of an earthquake.
  68. bp Metamorphism under conditions in which high temperature is the dominant factor.
  69. bq Boulder, cobble, or pebble with flat surfaces caused by the abrasion of wind-blown sand. (End Chapter 13)
  70. br Age given in years or some other unit of time.
  71. bs Any igneous rock that forms at Earth's surface, whether it solidifies directly from a lava flow or is pyroclastic.
  72. bt Movement in which parts of a body slide relative to one another and parallel to the forces being exerted.
  73. bu Bonding due to the attraction between positively charged ions and negatively charged ions.
  74. bv Rock deposited by precipitation of ions from solution in hot water.
  75. bw A long, streamlined hill made of till.
  76. bx The ability of a rock to break along closely spaced parallel planes.
  77. by A seismometer with a recording device that produces a permanent record of Earth motion.
  78. bz The movement of eroded particles by agents such as rivers, waves, glaciers, or wind.
  79. ca A subsurface zone in which all rock openings are filled with water.
  80. cb Protons and neutrons form the nucleus of an atom. Although the nucleus occupies an extremely tiny fraction of the volume of the entire atom, practically all the mass of the atom is concentrated in the nucleus.
  81. cc A single bed with coarse grains at the bottom of the bed and progressively finer grains toward the top of the bed.
  82. cd A ridge of till piled up along the front edge of a glacier.
  83. ce Capable of being molded and bent under stress.
  84. cf Silicate minerals that are structured so that none of the oxygen atoms are shared by silica tetrahedrons.
  85. cg Volcanic activity, including the eruption of lava and rock fragments and gas explosions.
  86. ch The lowering of the water table near a pumped well.
  87. ci An arrangement of layers or beds of rock. (Begin Chapter 6)
  88. cj A small discordant pluton with an outcropping area of less than 100 square kilometers.
  89. ck Any rock that was older than and intruded by an igneous body.
  90. cl A region with low precipitation (usually defined as less than 25 cm per year).
  91. cm Resistance to flow.
  92. cn The ratio of the mass of a substance to the mass of an equal volume of water, determined at a specified temperature.
  93. co The stripping of concentric rock slabs from the outer surface of a rock mass.
  94. cp A theoretical downward limit for stream erosion of Earth's surface.
  95. cq A hard, compact, fine-grained sedimentary rock formed almost entirely of silica.
  96. cr A fine-grained, unfoliated metamorphic rock.
  97. cs Sediment composed of particles with diameter less than 1/256 mm.
  98. ct A flowing mass of sediment-laden water that is heavier than clear water and therefore flows downslope along the bottom of the sea or a lake.
  99. cu A feldspar with the formula KAlSi3O8.
  100. cv A sharp peak formed where cirques cut back into a mountain on several sides.
  101. cw Boundary between two plates that are sliding past each other.
  102. cx The rise of Earth's crust after the removal of glacial ice.
  103. cy Soil containing approximately equal amounts of sand, silt, and clay.
  104. cz A long chain (thousands of kilometers) of mountain ranges.
  105. da The total amount of a geologic material in all its deposits, discovered and undiscovered (see reserves).
  106. db A ridge of sediment, usually sand or gravel, that has been deposited in the middle or along the banks of a stream by a decrease in stream velocity.
  107. dc Land-derived sediment that has found its way to the sea floor.
  108. dd Mine in which ore is exposed at the surface in a large excavation.
  109. de A measure of an earthquake's size by its effect on people and buildings.
  110. df Fragment of rock formed by volcanic explosion.
  111. dg An area of volcanic eruptions and high heat flow above a rising mantle plume.
  112. dh A glacier confined to a valley. The ice flows from a higher to a lower elevation.
  113. di A fracture or crack in bedrock along which essentially no displacement has occurred.
  114. dj In geology, correlation usually means determining time equivalency of rock units. Rock units may be correlated within a region, a continent, and even between continents.
  115. dk A drainage pattern consisting of parallel main streams with short tributaries meeting them at right angles. (End Chapter 10)
  116. dl A very flat surface underlain by hard, mud-cracked clay.
  117. dm A line along which the temperature of rock (or other material) is the same.
  118. dn A layer of weathered, unconsolidated material on top of bedrock; often also defined as containing organic matter and being capable of supporting plant growth.
  119. do Narrow currents that flow straight out to sea in the surf zone, returning water seaward that has been pushed ashore by breaking waves.
  120. dp A theory that Earth's surface is divided into a few large, thick plates that are slowly moving and changing in size. Intense geologic activity occurs at the plate boundaries.
  121. dq A frothy volcanic glass.
  122. dr In an intrusion, the finer-grained rock adjacent to a contact with country rock.
  123. ds Any of the small ridges formed on sediment surfaces exposed to moving wind or water. The ridges form perpendicularly to the motion.
  124. dt Concept of vertical movement of sections of Earth's crust to achieve balance or equilibrium.
  125. du A large, mobile slab of rock making up part of Earth's surface.
  126. dv A stress due to a force pushing together on a body.
  127. dw The region on Earth's surface, 103° to 142° away from an earthquake epicenter, in which P waves from the earthquake are absent.
  128. dx Mineral group in which all members are double chain silicates. (Begin Chapter 2)
  129. dy A glacier covering a relatively small area of land but not restricted to a valley.
  130. dz A portion of a major mountain belt characterized by large thrust faults, stacked one upon another. Layered rock between the faults was folded when faulting was taking place.
  131. ea Mixed igneous and metamorphic rock.
  132. eb The temperature below which a material becomes magnetized.
  133. ec The top layer of soil, characterized by the downward movement of water; also called zone of leaching. (Begin Chapter 5)
  134. ed The high point of a wave.
  135. ee A major concentration of earthquakes and composite volcanoes that runs through the Mediterranean Sea, crosses the Mideast and the Himalaya, and passes through the East Indies.
  136. ef A concept suggesting that continents move over Earth's surface.
  137. eg An area where the strength of the magnetic field is greatest and where the magnetic lines of force appear to leave or enter Earth.
  138. eh The maximum amount of stress that can be applied to a body before it deforms in a permanent way by bending or breaking.
  139. ei The texture of a metamorphic rock in which minerals are separated into light and dark layers or lenses.
  140. ej The area in which S waves from the earthquake are absent.
  141. ek A stream that flows in a network of many interconnected rivulets around numerous bars.
  142. el A circular reef surrounding a deeper lagoon.
  143. em A small rock island that is an erosional remnant of a headland left behind as a wave-eroded coast retreats inland.
  144. en Fine-grained igneous rock of intermediate composition. Up to half of the rock is plagioclase feldspar with the rest being ferromagnesian minerals. (Begin Chapter 4)
  145. eo Silica-rich igneous rock or magma with a relatively high content of potassium and sodium.
  146. ep A closed depression found on land surfaces underlain by limestone.
  147. eq Rate of temperature increase associated with increasing depth beneath the surface of Earth (normally about 25°C/km).
  148. er Unsorted and unlayered rock debris carried by a glacier.
  149. es The situation in mass wasting that occurs when material free-falls or bounces down a cliff.
  150. et A luster giving a substance the appearance of unglazed pottery.
  151. eu A depression caused by the melting of a stagnant block of ice that was surrounded by sediment.
  152. ev Triangular facet where the lower end of a ridge has been eroded by glacial ice.
  153. ew A study of ancient magnetic fields.
  154. ex Crystal structure in which all four oxygen ions of a silica tetrahedron are shared by adjacent ions.
  155. ey Polygonal crack formed in very fine grained sediment as it dries.
  156. ez A map representing the geology of a given area.
  157. fa A smaller valley that terminates abruptly high above a main valley.
  158. fb A narrow, deep trough parallel to the edge of a continent or an island arc.
  159. fc Flood of very high discharge and short duration; sudden and local in extent.
  160. fd Asphalt-cemented sand deposit.
  161. fe A fine-grained deposit of wind-blown dust.
  162. ff Scale expressing intensities of earthquakes (judged on amount of damage done) in Roman numerals ranging from I to XII.
  163. fg An arrangement of interlocking crystals.
  164. fh An aquifer completely filled with pressurized water and separated from the land surface by a relatively impermeable confining bed, such as shale.
  165. fi Eon of geologic time. Includes all time following the Precambrian.
  166. fj Rock composed mostly of the remains of plants and animals.
  167. fk A meander that retains its sinuous curves as it cuts vertically downward below the level at which it originally formed.
  168. fl A term used for oxygen plus silicon.
  169. fm The quality and intensity of light reflected from the surface of a mineral.
  170. fn A steep-sided, amphitheater-like hollow carved into a mountain at the head of a glacial valley.
  171. fo The sequence in which events took place (not measured in time units).
  172. fp Broad, gently sloping cone constructed of solidified lava flows.
  173. fq A broad, gently sloping, depositional surface formed at the base of a mountain range in a dry region by the coalescing of individual alluvial fans. (Begin Chapter 13)
  174. fr Bridge of rock left above an opening eroded in a headland by waves. (Begin Chapter 14)
  175. fs A pronounced sinuous curve along a stream's course.
  176. ft Very rapid and turbulent mass wasting of debris, air, and water.
  177. fu The portion of a fracture zone between two offset segments of a mid oceanic ridge crest.
  178. fv An episode of intense deformation of the rocks in a region, generally accompanied by metamorphism and plutonic activity.
  179. fw A margin that includes a continental shelf, continental slope, and continental rise that generally extends down to an abyssal plain at a depth of about 5 kilometers.
  180. fx On minerals, extremely straight, parallel lines. (End Chapter 2)
  181. fy See tsunami.
  182. fz Any of the large crystals in porphyritic igneous rock.
  183. ga A thick shell of rock that separates Earth's crust above from the core below.
  184. gb The settling or coming to rest of transported material.
  185. gc Large angular pyroclast.
  186. gd The overlying surface of an inclined fault plane.
  187. ge Bend in layered bedrock.
  188. gf Change in direction of waves due to slowing as they enter shallow water. (End Chapter 14)
  189. gg A coarse-grained sedimentary rock (grains coarser than 2 mm) formed by the cementation of rounded gravel.
  190. gh Metamorphism coupled with the introduction of ions from an external source.
  191. gi The capacity of a rock to transmit a fluid such as water or petroleum.
  192. gj A sedimentary rock composed mostly of calcite.
  193. gk Distinct earthquake zone that begins at an oceanic trench and slopes landward and downward into Earth at an angle of about 30° to 60°.
  194. gl The grinding away of rock by friction and impact during transportation. (Begin Chapter 10)
  195. gm Line about which a fold appears to be hinged. Line of maximum curvature of a folded surface.
  196. gn Transparent or white mica that lacks iron and magnesium.
  197. go A lake formed during an earlier time of abundant rainfall.
  198. gp A plane containing all of the hinge lines of a fold.
  199. gq A lake occupying a depression caused by glacial erosion of bedrock.
  200. gr Boundary separating two plates moving away from each other.
  201. gs The bending of seismic waves as they pass from one material to another.
  202. gt Volcanic glass.
  203. gu A rock produced by metamorphism.
  204. gv Rock that has formed from (1) lithification of any type of sediment, (2) precipitation from solution, or (3) consolidation of the remains of plants or animals.
  205. gw A type of surface seismic wave that behaves like a rolling ocean wave and causes the ground to move in an elliptical path.
  206. gx Joints oriented in one direction approximately parallel to one another.
  207. gy Weight per given volume of a substance.
  208. gz Line dividing one drainage basin from another.
  209. ha The present epoch of the Quaternary Period.
  210. hb The era that followed the Precambrian and began with the appearance of complex life, as indicated by fossils.
  211. hc An intrusive structure that apparently represents magma that solidified within the throat of a volcano.
  212. hd A broad, flat-topped hill bounded by cliffs and capped with a resistant rock layer.
  213. he An epoch of the Quaternary Period characterized by several glacial ages.
  214. hf In a stream, the volume of water that flows past a given point in a unit of time.
  215. hg Metamorphic rocks that contain the same set of pressure or temperature sensitive minerals are regarded as belonging to the same facies, implying that they formed under broadly similar pressure and temperature conditions.
  216. hh Describing a rock that splits easily along nearly flat and parallel planes.
  217. hi A reverse fault in which the dip of the fault plane is at a low angle to horizontal. (End Chapter 15)
  218. hj The sliding of the sea floor beneath a continent or island arc.
  219. hk Mineral with the formula CaCO3.
  220. hl The movement of water and water vapor from the sea to the atmosphere, to the land, and back to the sea and atmosphere again.
  221. hm A coarse-grained rock composed of interlocking calcite (or dolomite) crystals.
  222. hn Drowned river mouth.
  223. ho A mound of loose sand grains heaped up by the wind.
  224. hp A rock composed of material precipitated directly from solution.
  225. hq The relative ease or difficulty with which a smooth surface of a mineral can be scratched; commonly measured by Mohs' scale.
  226. hr A submarine platform at the edge of a continent, inclined very gently seaward generally at an angle of less than 1°.
  227. hs The youngest geologic period; includes the present time.
  228. ht A type of movement that implies that a descending mass is moving downslope as a viscous fluid.
  229. hu A metamorphic rock composed of light and dark layers or lenses.
  230. hv The development of new crystals in a rock, often of the same composition as the original grains.
  231. hw A numerical scale of earthquake magnitudes.
  232. hx Fine-grained material found in the pore space between larger sediment grains.
  233. hy A type of iron oxide that has a brick-red color when powdered; Fe2O3.
  234. hz A free-falling mass of debris.
  235. ia Gradual loss of heat (per unit of surface area) from Earth's interior out into space.
  236. ib Characteristic cross-profile of a valley carved by glacial erosion.
  237. ic The total amount of space taken up by openings between sediment grains.
  238. id A substance that contains silica as part of its chemical formula.
  239. ie Downhill slope of a stream's bed or the water surface, if the stream is very large.
  240. if A stream that receives water from the zone of saturation.
  241. ig Rock formed from large pieces of volcanic rock (cinders, blocks, bombs).
  242. ih Slow-to-rapid mass wasting in which debris moves downslope as a very viscous fluid.
  243. ii of rock distinct from the igneous rock in which it is enclosed. (End Chapter 3)
  244. ij A well in which water rises above the aquifer.
  245. ik A reef attached directly to shore. (See barrier reef.)
  246. il An area underlain by one or more oil pools.
  247. im A bottom current that flows parallel to the slopes of the continental margin (along the contour rather than down the slope).
  248. in A subatomic particle that contributes mass to an atom and is electrically neutral.
  249. io The largest unit of geological time.
  250. ip A fine-grained, mafic, igneous rock composed predominantly of ferromagnesian minerals and with lesser amounts of calcium-rich plagioclase feldspar.
  251. iq A body of intrusive rock classified on the basis of size, shape, and relationship to surrounding rocks.
  252. ir Boundary surface between two different rock types or ages of rocks.
  253. is A stress due to a force pulling away on a body.
  254. it Principle that states that an original sedimentary layer extends laterally until it tapers or thins at its edges.
  255. iu A horizontal bench of rock formed beneath the surf zone as a coast retreats because of wave erosion.
  256. iv A mafic, coarse-grained igneous rock composed predominantly of ferromagnesian minerals and with lesser amounts of calcium-rich plagioclase feldspar.
  257. iw A water table separated from the main water table beneath it by a zone that is not saturated.
  258. ix Submarine ridge with which no earthquakes are associated.
  259. iy The compass direction in which the angle of dip is measured.
  260. iz A body of saturated rock or sediment through which water can move readily. (Begin Chapter 11)
  261. ja A region on the downwind side of mountains that has little or no rain because of the loss of moisture on the upwind side of the mountains.
  262. jb Rock that appears to have crystallized from magma emplaced in surrounding rock.
  263. jc Movement in which the entire glacier slides along as a single body on its base over the underlying rock.
  264. jd A sedimentary rock composed mostly of the mineral dolomite.
  265. je A means of gaining knowledge through objective procedures.
  266. jf Stress due to forces that tend to cause movement or strain parallel to the direction of the forces.
  267. jg Varying rates of weathering resulting from some rocks in an area being more resistant to weathering than others.
  268. jh An unconformity in which an erosion surface on plutonic or metamorphic rock has been covered by younger sedimentary or volcanic rock.
  269. ji Crude oil and natural gas. (Some geologists use petroleum as a synonym for oil.)
  270. jj Narrow column of hot mantle rock that rises and spreads radially outward.
  271. jk Large spindle- or lens-shaped pyroclast.
  272. jl The ability of water to pick up and move rock and sediment.
  273. jm A volcano constructed of loose rock fragments ejected from a central vent.
  274. jn Soil not formed from the local rock but from parent material brought in from some other region and deposited, usually by running water, wind, or glacial ice.
  275. jo A giant mountain range that lies under the ocean and extends around the world.
  276. jp Silica-deficient igneous rock with a relatively high content of magnesium, iron, and calcium.
  277. jq Rapid movement of debris as a coherent mass.
  278. jr Rocks, generally basalt, formed in pillow shaped masses fitting closely together; caused by underwater lava flows.
  279. js Cone-shaped mass of dripstone formed on cave floors, generally directly below a stalactite.
  280. jt Material is in equilibrium if it is adjusted to the physical and chemical conditions of its environment so that it does not change or alter with time.
  281. ju The group of processes that change rock at or near Earth's surface. (End Chapter 5)
  282. jv A tabular intrusive structure concordant with the country rock.
  283. jw In mass wasting, movement of a relatively coherent descending mass along one or more well-defined surfaces.
  284. jx Magma on Earth's surface.
  285. jy Smallest possible particle of an element that retains the properties of that element.
  286. jz A liquid mixture of naturally occurring hydrocarbons.
  287. ka The detachment of part of the mantle portion of the lithosphere beneath a mountain belt.
  288. kb A fragment of rock that is distinct from the body of igneous rock in which it is enclosed.
  289. kc V-shaped valleys that run across the continental shelf and down the continental slope.
  290. kd The vertical distance between the crest (the high point of a wave) and the trough (the low point).
  291. ke A luster that gives a substance a glazed, porcelainlike appearance.
  292. kf Stage in the evolution of major mountain belts characterized by the accumulation of great thicknesses (several kilometers) of sedimentary or volcanic rocks.
  293. kg Partly hollow, globelike body found in limestone or other cavernous rock.
  294. kh Water flowing down a slope in a layer.
  295. ki The point on Earth's surface directly above the focus of an earthquake.
  296. kj Platform of wave-deposited sediment that is flat or slopes slightly landward.
  297. kk Heavy or large sediment particles in a stream that travel near or on the stream bed.
  298. kl A naturally occurring, crystalline solid that has a specific chemical composition.
  299. km A type of iron oxide that is yellowish-brown when powdered; Fe2O3•nH2O.
  300. kn Stream that loses water to the zone of saturation.
  301. ko The general term for a slowly to very rapidly descending mass of rock or debris.
  302. kp Movement by rolling, sliding, or dragging of sediment fragments along a stream bottom.
  303. kq Material deposited by debris-laden meltwater from a glacier.
  304. kr A fingerlike ridge of sediment attached to land but extending out into open water.
  305. ks Metamorphism that takes place at considerable depth underground.
  306. kt A mine in which the valuable material is exposed at the surface by removing a strip of overburden.
  307. ku A large, rounded landform developed in a massive rock, such as granite, by the process of exfoliation.
  308. kv The removal of clay, silt, and sand particles from the land surface by wind.
  309. kw The spontaneous nuclear disintegration of certain isotopes.
  310. kx The decomposition of rock resulting from exposure to water and atmospheric gases.
  311. ky A fossil from a very short-lived species known to have existed during a specific period of geologic time.
  312. kz Rock in which most of the grains are larger than 1 millimeter (igneous) or 2 millimeters (sedimentary).
  313. la A long, narrow depression, shaped and more or less filled by a stream.
  314. lb Erosion and undercutting of stream banks caused by a stream swinging from side to side across its valley floor.
  315. lc The loss of the glacial ice or snow by melting, evaporation, or breaking off into icebergs. (Also called wastage). (Begin Chapter 12)
  316. ld Flat-topped seamount.
  317. le Major subdivision of the standard geologic time scale (e.g., Mesozoic Era).
  318. lf Outporuing of lava extruded to Earth's surface.
  319. lg Original rock before being metamorphosed.
  320. lh The concept that the ocean floor is moving away from the mid oceanic ridge and across the deep ocean basin, to disappear beneath continents and island arcs.
  321. li The water that lies beneath the ground surface, filling the cracks, crevices, and pore space of rocks.
  322. lj Sediment in a stream that is light enough in weight to remain lifted indefinitely above the bottom by water turbulence.
  323. lk A rock formed or apparently formed from solidification of magma.
  324. ll The compass direction of a line formed by the intersection of an inclined plane (such as a bedding plane) with a horizontal plane.
  325. lm A seismic wave propagated by a shearing motion, which causes rock to vibrate perpendicular to the direction of wave propagation.
  326. ln An apparent movement of the earth's poles.
  327. lo A body of rock of considerable thickness that has a recognizable unity or similarity making it distinguishable from adjacent rock units. Usually composed of one bed or several beds of sedimentary rock, although the term is also applied to units of metamorphic and igneous rock. A convenient unit for mapping, describing, or interpreting the geology of a region.
  328. lp Glacier with a positive budget, so that accumulation results in the lower edges being pushed outward and downward.
  329. lq An unconformity in which younger strata overlie an erosion surface on tilted or folded layered rock. (Begin Chapter 8)
  330. lr A deeply curved dune in a region of abundant sand. The horns point upwind and are often anchored by vegetation.
  331. ls Upper part of a glacier in which there is no plastic flow.
  332. lt Loose, solid particles that can originate by (1) weathering and erosion of preexisting rocks, (2) chemical precipitation from solution, usually in water, and (3) secretion by organisms.
  333. lu Silicate structure in which two of each tetrahedron's oxygen ions are shared with adjacent tetrahedrons, resulting in a chain of tetrahedrons.
  334. lv Rounded particles coarser than 2 mm in diameter.
  335. lw Underground accumulation of oil.
  336. lx A surface that represents missing rock strata but beds above and below that surface are parallel to one another.
  337. ly A tentative and testable theory. Usually written as an if/then statement.
  338. lz A medium-grained sedimentary rock (grains between 1/16 mm and 2 mm) formed by the cementation of sand grains.
  339. ma A mineral of commercial value.
  340. mb Shale with a high content of organic matter from which oil may be extracted by distillation.
  341. mc A resistant ridge of calcium carbonate formed on the sea floor by corals and coralline algae.
  342. md A fault with both strike-slip and dip-slip components.
  343. me A wave of energy produced by an earthquake.
  344. mf A tabular, discordant intrusive structure.
  345. mg A change in Earth's magnetic field b,etween normal polarity and reversed polarity. In normal polarity the north magnetic pole, where magnetic lines of force enter Earth, lies near the geographic North Pole. In reversed polarity the south magnetic pole, where lines of force leave Earth, lies near the geographic North Pole (the magnetic poles have exchanged positions).
  346. mh Low ridges of flood-deposited sediment formed on either side of a stream channel, which thin away from the channel.
  347. mi Iciclelike pendant of dripstone formed on cave ceilings.
  348. mj Eon of Precambrian time.
  349. mk Rapid sliding of a mass of bedrock along an inclined surface of weakness.
  350. ml A region in which the geology is markedly different from that in adjoining regions.
  351. mm That portion of a glacier with a perennial snow cover. (End of Chapter 12)
  352. mn Sediment made up of fine-grained clay and the skeletons of microscopic organisms that settle slowly down through the ocean water.
  353. mo Seismic wave that travels through Earth's interior.
  354. mp Rock with a chemical content between felsic and mafic compositions.
  355. mq The time it takes for a given amount of a radioactive isotope to be reduced by one-half.
  356. mr A valley-deepening process caused by erosion of a stream bed.
  357. ms The era that followed the Paleozoic Era and preceded the Cenozoic Era.
  358. mt The opening in Earth's surface through which a volcanic eruption takes place.
  359. mu A structure in which beds dip away from a central point.
  360. mv A reef separated from the shoreline by the deeper water of a lagoon.
  361. mw A range created by uplift along normal or vertical faults.
  362. mx At times in the past, colder climates prevailed during which significantly more of the land surface of Earth was glaciated than at present.
  363. my A rock formed from fine-grained pyroclastic particles (ash and dust).
  364. mz Sediment composed of particles with a diameter between 1/16 mm and 2 mm.
  365. na A distinctive rock sequence found in many mountain ranges on continents.
  366. nb The boundary separating the crust from the mantle beneath it (also called Moho),.
  367. nc Small shifting river channel that carries water away from the main river channel and distributes it over a delta's surface.
  368. nd A metamorphic rock characterized by coarse-grained minerals oriented approximately parallel.
  369. ne Glaciation of a mountainous area.
  370. nf A fold overturned to such an extent that the limbs are essentially horizontal.
  371. ng In mass wasting, the resistance to movement or deformation of material.
  372. nh Turbulent mixture of pyroclastics and gases flowing down the flank of a volcano.
  373. ni A feature found within sedimentary rocks, usually formed during or shortly after deposition of the sediment and before lithification.
  374. nj The vast amount of time that preceded the Paleozoic Era.
  375. nk That portion of a glacier in which ice is lost.
  376. nl Steep slope that retreats inland by mass wasting as wave erosion undercuts it.
  377. nm Bonding due to the sharing of electrons by adjacent atoms.
  378. nn The transformation of preexisting rock into texturally or mineralogically distinct new rock as a result of high temperature, high pressure, or both, but without the rock melting in the process.
  379. no Forces generated from within Earth that result in uplift, movement, or deformation of part of Earth's crust.
  380. np A gently sloping erosional surface cut into the solid rock of a mountain range in a dry region; usually covered with a thin veneer of gravel.
  381. nq A large discordant pluton with an outcropping area greater than 100 square kilometers.
  382. nr Cracks that develop parallel to the outer surface of a large mass of expanding rock, as pressure is released during unloading.
  383. ns A soil layer characterized by the accumulation of material leached downward from the A horizon above; also called zone of accumulation.
  384. nt The sudden release of progressively stored strain in rocks results in movement along a fault.
  385. nu Ridge of sand paralleling the shoreline and extending above sea level.
  386. nv A basinlike depression over a vent at the summit of a volcanic cone.
  387. nw Fine-grained igneous rock of intermediate composition. Up to half of the rock is plagioclase feldspar with the rest being ferromagnesian minerals. (Begin Chapter 3)
  388. nx Terrane that did not form at its present site on a continent.
  389. ny Arrangement of various faces on a crystal in a definite geometric relationship to one another.
  390. nz Movement of sediment parallel to shore when waves strike a shoreline at an angle.
  391. oa The lengthening of a valley in an uphill direction above its original source by gullying, mass wasting, and sheet erosion.
  392. ob See rock-basin lake.
  393. oc Igneous rock formed at great depth.
  394. od An ultramafic rock composed primarily of the mineral olivine.
  395. oe A terrane that may not have formed at its present site.
  396. of A fine-grained, felsic, igneous rock made up mostly of feldspar and quartz.
  397. og Portion of a fold shared by an anticline and a syncline.
  398. oh A fold in which the limbs are parallel to one another.
  399. oi A river let down onto a buried geologic structure by erosion of overlying layers.
  400. oj An earthquake magnitude calculated from the strength of the rock, surface area of the fault rupture, and the amount of rock displacement along the fault.
  401. ok A rock composed of sand-sized grains of quartz that have been welded together during metamorphism.
  402. ol Collective term for several clay minerals.
  403. om The balance or equilibrium between adjacent blocks of crust resting on a plastic mantle.
  404. on A stream bar (see definition) deposited on the inside of a curve in the stream, where the water velocity is low.
  405. oo Each period of the standard geologic time scale is divided into epochs (e.g., Pleistocene Epoch of the Quaternary Period).
  406. op A shallow temporary lake (following a rainstorm) on a flat valley floor in a dry region.
  407. oq Ground that remains permanently frozen for many years.
  408. or A hill or mountain constructed by the extrusion of lava or rock fragments from a vent. (End Chapter 4)
  409. os A type of frost action in which the expansion of freezing water pries a rock apart.
  410. ot Each era of the standard geologic time scale is subdivided into periods (e.g., the Cretaceous Period).
  411. ou A compressional wave (seismic wave) in which rock vibrates parallel to the direction of wave propagation.
  412. ov A vertical angle measured downward from the horizontal plane to an inclined plane. (Begin Chapter 15)
  413. ow A subsurface zone in which rock openings are generally unsaturated and filled partly with air and partly with water; above the saturated zone.
  414. ox A boundary between two plates that are moving toward each other.
  415. oy A margin consisting of a continental shelf, a continental slope, and an oceanic trench.
  416. oz The physical removal of rock by an agent such as running water, glacial ice, or wind.
  417. pa Surface mines in which valuable mineral grains are extracted from stream bar or beach deposits.
  418. pb Movement, caused by gravity, in which bedrock, rock debris, or soil moves downslope in bulk.
  419. pc Total area drained by a stream and its tributaries.
  420. pd Mechanical weathering of rock by freezing water.
  421. pe For igneous rocks, refers to the size of mineral crystals in the rock.
  422. pf A measure of the energy released during an earthquake.
  423. pg The steep, downwind slope of a dune; formed from loose, cascading sand that generally keeps the slope at the angle of repose (about 34°).
  424. ph Atoms (of the same element) that have different numbers of neutrons but the same number of protons.
  425. pi Observations or measurements used by scientists to test hypotheses.
  426. pj An arrangement of relatively thin layers of rock inclined at an angle to the more nearly horizontal bedding planes of the larger rock unit.
  427. pk A curved line of islands.
  428. pl Naturally occurring material that can be profitably mined.
  429. pm Depression eroded into the hard rock of a stream bed by the abrasive action of the stream's sediment load.
  430. pn Luster giving a substance the appearance of being made of metal.
  431. po A broad, gently sloping platform that may be exposed at low tide.
  432. pp The point within Earth from which seismic waves originate in an earthquake.
  433. pq An igneous body that crystallized deep underground.
  434. pr A substance that cannot be broken down to other substances by ordinary chemical methods. Each atom of an element possesses the same number of protons.
  435. ps Rock composed entirely or almost entirely of ferromagnesian minerals.
  436. pt Movement within a glacier in which the ice is not fractured.
  437. pu Iron/magnesium bearing mica.
  438. pv The land near the sea, including the beach and a strip of land inland from the beach.
  439. pw Two thin layers of sediment, one dark and the other light in color, representing one year's deposition in a lake.
  440. px A rock containing organic matter that is converted to petroleum by burial and other postdepositional changes.
  441. py An igneous rock in which large crystals are enclosed in a matrix (or ground mass) of much finer-grained minerals or obsidian.
  442. pz A crescent-shaped dune with the horns of the crescent pointing downwind.
  443. qa A blanket of till deposited by a glacier or released as glacier ice melted.
  444. qb A coastal inlet that is a glacially carved valley, the base of which is submerged.
  445. qc Change in size (volume) or shape of a body (or rock unit) in response to stress.
  446. qd Block of glacier-derived ice floating in water.
  447. qe A very slow circulation of a substance driven by differences in temperature and density within that substance.
  448. qf Separation of different ingredients from an originally homogeneous mixture.
  449. qg A significant type of mechanical weathering that causes rocks to crack when overburden is removed.
  450. qh A tensional valley bounded by normal faults. Rift valleys are found at diverging plate boundaries on continents and along the crest of the mid-oceanic ridge.
  451. qi Traces of plants or animals preserved in rock.
  452. qj The horizontal distance between two wave crests (or two troughs).
  453. qk Being able to physically follow a rock unit between two places.
  454. ql A seismic wave that travels on Earth's surface.
  455. qm Huge ocean wave produced by displacement of the sea floor; also called seismic sea wave.
  456. qn The arrangement in map view of a river and its tributaries.
  457. qo A nearly flat surface separating two beds of sedimentary rock.
  458. qp The solid material that precipitates in the pore space of sediments, binding the grains together to form solid rock.
  459. qq A fracture in bedrock along which movement has taken place.
  460. qr Conical mountain rising 1,000 meters or more above the sea floor.
  461. qs A theoretical concept relating tectonism, erosion, and various rock-forming processes to the common rock types.
  462. qt The physical disintegration of rock into smaller pieces.
  463. qu An instrument that measures the strength of Earth's magnetic field.
  464. qv Greater than normal gravitational attraction.
  465. qw A relatively steep slope extending from a depth of 100 to 200 meters at the edge of the continental shelf down to oceanic depths.
  466. qx A soil layer composed of incompletely weathered parent material.
  467. qy A drainage pattern in which streams diverge outward like spokes of a wheel.
  468. qz A strike-slip fault in which the block seen across the fault appears displaced to the left.
  469. ra A relatively straight, elongate dune oriented perpendicular to the wind.
  470. rb An explanation for observed phenomena that has a high possibility of being true.
  471. rc A surface that represents a break in the geologic record, with the rock unit immediately above it being considerably younger than the rock beneath.
  472. rd A fault in which the hanging-wall block moved down relative to the footwall block.
  473. re Parallel alignment of textural and structural features of a rock.
  474. rf Iron/magnesium-bearing mineral, such as augite, hornblende, olivine, or biotite.
  475. rg Fracture in rock usually filled with late stage magmatic minerals and often containing metal ore. (End Chapter 7)
  476. rh Color of a pulverized substance; a useful property for mineral identification.
  477. ri The covering of a large region of a continent by a sheet of glacial ice.
  478. rj A sedimentary rock composed of fragments of preexisting rock.
  479. rk A line of batholiths or volcanoes. Generally the line, as seen from above, is curved.
  480. rl A body of till either being carried on a glacier or left behind after a glacier has receded.
  481. rm Luster that gives a substance the appearance of being made of something other than metal (e.g., glassy).
  482. rn A complex of old Precambrian metamorphic and plutonic rocks exposed over a large area.
  483. ro The discovered deposits of a geologic material that are economically and legally feasible to recover under present circumstances.
  484. rp The most recent of the eras; followed the Mesozoic Era.
  485. rq The return of part of the energy of seismic waves to Earth's surface after the waves bounce off a rock boundary.
  486. rr A force acting on a body, or rock unit, that tends to change the size or shape of that body, or rock unit. Force per unit area within a body.
  487. rs A type of hot spring that periodically erupts hot water and steam.
  488. rt Elongate region in which subduction takes place.
  489. ru A worldwide relative scale of geologic time divisions.
  490. rv A new, shorter channel across the narrow neck of a meander.
  491. rw A fold in which both limbs dip in the same direction.
  492. rx Crystal development and growth.
  493. ry The percentage of a rock's volume that is taken up by openings.
  494. rz The vertical distance between points on Earth's surface.
  495. sa A fault in which movement is parallel to the strike of the fault surface.
  496. sb A fine-grained sedimentary rock (grains finer than 1/16 mm in diameter) formed by the cementation of silt and clay (mud). Shale has thin layers (laminations) and an ability to split (fissility) into small chips.
  497. sc Volcanic rock in parallel, usually vertical columns, mostly six-sided; also called columnar jointing.
  498. sd A fold in which the hinge line (or axis) is not horizontal.
  499. se Any of the layers of soil that are distinguishable by characteristic physical or chemical properties.
  500. sf The texture of a rock in which visible platy or needle-shaped minerals have grown essentially parallel to each other under the influence of directed pressure.
  501. sg A body of sediment deposited at the mouth of a river when the river velocity decreases as it flows into a standing body of water.
  502. sh A principle or law stating that a disrupted pattern is older than the cause of disruption.
  503. si A plot of seismic-wave arrival times against distance.
  504. sj A hydrous aluminum-silicate that occurs as a platy grain of microscopic size with a sheet silicate structure.
  505. sk Greater than average strength of the earth's magnetic field.
  506. sl A feldspar containing sodium and/or calcium in addition to aluminum, silicon, and oxygen.
  507. sm The oldest eon of Earth's history.
  508. sn A trembling or shaking of the ground caused by the sudden release of energy stored in the rocks beneath the surface.
  509. so An eruption in which lava erupts out of a vent on the side of a volcano.
  510. sp A narrow pinnacle of resistant rock with a flat top and very steep sides.
  511. sq A flowing mixture of debris and water, usually moving down a channel.
  512. sr Usually slow but effective process of weathering and erosion in which rocks are dissolved by water.
  513. ss Determining the age of a rock or mineral through its radioactive elements and decay products (previously and somewhat inaccurately called radiometric or radioactive dating).
  514. st The lower edge of a glacier.
  515. su A depression on the land surface caused by wind erosion.
  516. sv Less than average strength of Earth's magnetic field.
  517. sw A structure in which the beds dip toward a central point.
  518. sx Attachment of an atom to one or more adjacent atoms.
  519. sy Group of most common minerals of Earth's crust. All feldspars contain silicon, aluminum, and oxygen and may contain potassium, calcium, and sodium.
  520. sz A fold in which the layered rock usually dips toward an axis.
  521. ta The grinding away of sharp edges and corners of rock fragments during transportation.
  522. tb Pressure applied equally on all surfaces of a body; also called geostatic or lithostatic pressure.
  523. tc Highly leached soil that forms in regions of tropical climate with high temperatures and very abundant rainfall.
  524. td An arrangement of rock fragments bound into a rigid network by cement.
  525. te The rigid outer shell of Earth, 70 to 125 or more kilometers thick.
  526. tf The way a substance breaks where not controlled by cleavage.
  527. tg A gaseous mixture of naturally occurring hydrocarbons.
  528. th The location in which deposition occurs, usually marked by characteristic physical, chemical, or biological conditions.
  529. ti An arched fold in which the rock layers usually dip away from the axis of the fold.
  530. tj Paper record of earth vibration.
  531. tk Soil that develops directly from weathering of the rock below.
  532. tl The process whereby the minerals that crystallize at a high temperature in a cooling magma move downward in the magma chamber because they are denser than the magma.
  533. tm The deposition of most water-laid sediment in horizontal or near-horizontal layers that are essentially parallel to Earth's surface.
  534. tn Breaking waves.
  535. to Rock that forms from crystals precipitating during evaporation of water.
  536. tp A fault in which the hanging-wall block moved up relative to the footwall block.
  537. tq A hole, generally cylindrical and usually walled or lined with pipe, that is dug or drilled into the ground to penetrate an aquifer below the zone of saturation. (End Chapter 11)
  538. tr A metamorphic rock in which clay minerals have recrystallized into microscopic micas, giving the rock a silky sheen.
  539. ts A moving body of water, confined in a channel and running downhill under the influence of gravity.
  540. tt Rounded by weathering from an initial blocky shape.
  541. tu A ridge of sediment that cuts a bay off from the ocean.
  542. tv A representation of a portion of Earth in a vertical plane.
  543. tw Mineral with the formula SiO2.
  544. tx Cracking or rupturing of a body under stress.
  545. ty Lithified till.
  546. tz The lifting of rock or soil by the expansion of freezing water.
  547. ua Broad, flat-topped area elevated above the surrounding land and bounded, at least in part, by cliffs.
  548. ub A resource that forms at extremely slow rates compared to its rate of consumption.
  549. uc A glacier covering a large area (more than 50,000 square kilometers) of land.
  550. ud Strip of sediment, usually sand but sometimes pebbles, boulders, or mud, that extends from the low-water line inland to a cliff or zone of permanent vegetation.
  551. ue A material that forms as the organic matter of buried wood is either filled in or replaced by inorganic silica carried in by ground water.
  552. uf The total number of protons in an atom.
  553. ug Major belt around the edge of the Pacific Ocean on which most composite volcanoes are located and where many earthquakes occur.
  554. uh A broad strip of land built up by sedimentation on either side of a stream channel.
  555. ui An ice-transported boulder that does not derive from bedrock near its present site.
  556. uj Layers of basalt flows that have built up to great thicknesses.
  557. uk The underlying surface of an inclined fault plane.
  558. ul The total number of neutrons and protons in an atom.
  559. um A glacier with a negative budget, which causes the glacier to grow smaller as its edges melt back.
  560. un The speed at which water in a stream travels.
  561. uo A principle or law stating that within a sequence of undisturbed sedimentary rocks, the oldest layers are on the bottom, the youngest on the top.
  562. up A fault in which movement is parallel to the dip of the fault surface.
  563. uq Any unconsolidated material at Earth's surface.
  564. ur Coarse-grained igneous rock of intermediate composition. Up to half of the rock is plagioclase feldspar and the rest is ferromagnesian minerals.
  565. us Less than normal gravitational attraction.
  566. ut Dark-colored soil layer that is rich in organic material and forms just below surface vegetation.
  567. uu A tabular intrusive structure concordant with the country rock. (End Chapter 6)
  568. uv The upper surface of the zone of saturation.
  569. uw The gradual straightening of an irregular shoreline by wave erosion of headlands and wave deposition in bays.
  570. ux Naturally formed, consolidated material composed of grains of one or more minerals. (There are a few exceptions to this definition.
  571. uy Major line of weakness in Earth's crust that crosses the mid-oceanic ridge at approximately right angles.
  572. uz Crystal structure in which each silica tetrahedron shares three oxygen ions.
  573. va and interrelationships of rock units.
  574. vb A single, negative electric charge that contributes virtually no mass to an atom.
  575. vc An area with many sinkholes and a cave system beneath the land surface and usually lacking a surface stream.
  576. vd A set of conditions that hold petroleum in a reservoir rock and prevent its escape by migration.
  577. ve Portion of a continent that has been structurally stable for a prolonged period of time.
  578. vf A very rapidly moving, turbulent mass of broken-up bedrock.
  579. vg A long, sinuous ridge of sediment deposited by glacial meltwater.
  580. vh A fine-grained rock that splits easily along flat, parallel planes.
  581. vi A principle or law stating that fossil species succeed one another in a definite and recognizable order; in general, fossils in progressively older rock show increasingly greater differences from species living at present.
  582. vj In mass wasting, movement along a curved surface in which the upper part moves vertically downward while the lower part moves outward. Also called a slump.
  583. vk Large, symmetrical ridge of sand parallel to the wind direction.
  584. vl There is no definition for this term in the glossary.
  585. vm A wave that has become so steep that the crest of the wave topples forward, moving faster than the main body of the wave.
  586. vn A sharp ridge that separates adjacent glacially carved valleys.
  587. vo A crescent-shaped lake occupying the abandoned channel of a stream meander that is isolated from the present channel by a meander cutoff and sedimentation.
  588. vp A cavity in volcanic rock caused by gas in a lava.
  589. vq Hard, rounded mass that develops when a considerable amount of cementing material precipitates locally in a rock, often around an organic nucleus.
  590. vr Region of magnetic force that surrounds Earth.
  591. vs A ferromagnesian mineral with the formula (Fe, Mg)2SiO4.
  592. vt A stream that exhibits a delicate balance between its transporting capacity and the sediment load available to it.
  593. vu An instrument that measures the gravitational attraction between Earth and a mass within the instrument.
  594. vv A volcano constructed of alternating layers of pyroclastics and rock solidified from lava flows.
  595. vw A fold with gently dipping limbs.
  596. vx A sedimentary rock formed from the consolidation of plant material. It is rich in carbon, usually black, and burns readily.