ESC 1000 Earth Science Name:_____________

Chapter 3: Rocks Minerals of the Earth

Part K Chapter 3 Key Terms (Updated 13^th edition) 42 Points

Fill in the blanks with the word or words that best fit the definition:

1. Andesitic composition- See Intermediate composition (same definition)

2. Basaltic composition- A compositional group of igneous rocks indicating that the rock contains substantial dark silicate minerals and calcium-rich plagioclase feldspar

3. Bowen’s reaction series- A concept proposed by N.L. Bowen that illustrates the relationships between magma and the minerals crystallizing from it during the formation of igneous rocks

4. Chemical sedimentary rock- Sedimentary rock consisting of material that was precipitated form water by either

5. Coarse-grained texture – An igneous rock texture in which the crystals are roughly equal in size and large enough so that individual minerals can be identified with the unaided eye

6. Contact metamorphism- Changes in rock caused by the heat from a nearby magma body

7. Crystallization – the formation and growth of a crystalline solid from a liquid or gas

8. Crystal settling- During the crystallization of a mineral as determined by its internal arrangement of atoms

9. Detrital sedimentary rock – Rock formed from the accumulation of material that originated and was transported in form of solid particles derived form both mechanical and chemical weathering.

10. Disseminated deposit – Any economic mineral deposits in which the desired mineral occurs as scattered particles in the rock but in the rock but in sufficient quality to make the deposit an ore

11. Evaporate or Evaporite Deposits- A sedimentary rock formed of material deposited from solution by evaporation of the water

12. Extrusive – Igneous activity that occurs outside the crust

13. Felsic- The group of igneous rocks composed primarily of feldspar and quartz

14. Fine-grained texture- A texture if igneous rocks in which the crystals are too small for individual minerals to be distinguished with the unaided eye

15. Fossils- The remains or traces of organisms preserved from the geologic past

16. Foliated texture or foliation– A texture of metamorphic rocks that gives the rock a layered appearance

17. Glassy texture- A term used to describe the texture of certain igneous rocks, such as obsidian, that contain no crystals

18. Granitic composition- A compositional group of igneous rocks that indicates a rock is composed almost entirely of light-colored silicates

19. Hydrothermal solution- The hot, watery solution that escapes from a mass of magma during the later stages of crystallization. Such solutions may alter the surrounding country rock and are frequently the source of significant ore deposits

20. Igneous rock- A rock formed by the crystallization of molten magma

21. Intermediate composition- The composition of igneous rocks lying between felsic and mafic

22. Intrusive rock – Igneous rock that formed below Earth’s surface

23. Lava- Magma that reaches Earth’s surface

24. Lithification- The process, generally cementation and /or compaction, of converting sediments to solid rock

25. Mafic- Igneous rocks with a low silica content and a high iron-magnesium content

26. Magma- A body of molten rock found at depth, including any dissolved gases and crystals

27. Magmatic differentiation- The process of generating more that one rock type form a single magma

28. Metamorphic rock- Rocks formed by the alteration of preexisting rock deep within Earth (but still in the solid state) by heat, pressure, and/or chemically active fluids

29. Metamorphism- The changes in mineral composition and texture of a rock subjected to high temperature and pressure within Earth

30. Nonfoliated texture- Metamorphic rocks that do not exhibit foliation

31. Pegmatite- A very coarse-grained igneous rock (typically granite) commonly found as a dike associated with a large mass of plutonic rock that has smaller crystals. Crystallization in a water-rich environment is believed to be responsible for the very large crystals

32. Porphyritic texture- An igneous texture consisting of large crystals embedded in a matrix of much smaller crystals

33. Regional metamorphism- Metamorphism associated with large scale mountain-building processes

34. Rock cycle- A model that illustrates the origin of the three basic rock types and the interrelatedness of Earth materials and processes

35. Sediment- Unconsolidated particles created by the weathering and erosion of rock, by chemical precipitation from solution in water, or from the secretions of organisms and transported by water, wind, or glaciers

36. Sedimentary rock- Rock formed from the weathered products of preexisting rocks that have been transported, deposited, lithified

37. Strata (beds)- Layer upon layer of sediment accumulation which are the single most characteristic feature of sedimentary rocks

38. Texture- The size, shape, and distribution of the particles that collectively constitute a rock

39. Thermal metamorphism- See Contrast metamorphism (same definition)

40. Ultramafic composition- igneous rocks composed mainly of iron and magnesium-rich minerals

41. Vein deposit- A mineral filling a fracture or fault in a host rock. Such deposits have a sheet like, or tabular, form

42. Vesicular texture – A term applied to igneous rocks that contain small cavities called vesicles, which are formed when gases escape from lava