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Porphyritic texture : large crystals that were removed from a

Window for Test 1 will start today (January 30) at 2:00 pm and end Sunday evening, February 5. All lecture material from First Lecture through Igneous Rocks (today)– Chapters 1-4. Porphyritic texture : large crystals that were removed from a

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Porphyritic texture : large crystals that were removed from a

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  1. Window for Test 1 will starttoday(January 30) at 2:00 pmand end Sunday evening,February 5.All lecture material from First Lecture through IgneousRocks (today)– Chapters 1-4

  2. Porphyritic texture: large crystals that were removed from a fine-grained matrix. Usually the result of a two-stage cooling history (slow cooling [big crystals] followed by rapid cooling [fine matrix]).

  3. No two magmas are exactly alike….

  4. What leads to melting of rock and generation of magmas, rising or sinking?

  5. Magmas can form where: 1) rocks are heated; 2) rocks move into zones of lower pressure; 3) water is added (dehydration melting). Pressure drops where material rises at divergent margins and mantle plumes. Water is added to mantle rocks when the minerals in subducting slabs heat up and lose their water.

  6. dikes

  7. dikes pipe or neck dikes Satellite view Ship Rock, NM

  8. pipe or neck

  9. central France

  10. sill

  11. South-central Utah

  12. Glacier National Park, Montana

  13. Is this (dark) basalt a sill or a flow??? Look for vesicles (gas bubbles)! Or basalt pebbles in sedimentary rock above the contact. If either of these are present, the basalt is a buried lava flow, not a sill.

  14. laccolith

  15. Henry Mountains, Utah See text, p. 104

  16. Compared to a batholith or laccolith, the size of crystals in a basaltic dike is likely to be: Small (due to rapid heat loss to surrounding rock) Large (due to rapid heat loss to surrounding rock) Small (due to slow heat loss to surrounding rock) Large (due to slow heat loss to surrounding rock)

  17. Most of the surface of the continents is covered by sedimentary rocks.

  18. Sedimentary rocks contain: Nearly all of Earth’s fossil fuels. A majority of Earth’s ore deposits. Nearly all of Earth’s fossils. Nearly all the info on the history of Earth’s rapidly changing surface. Most of the surface of the continents is covered by sedimentary rocks. 21

  19. Clastic Sedimentary Rocks are composed of fragments of older rocks. Examples are sandstone, conglomerate, mudrock Biochemical and Chemical Sedimentary Rocks are produced when ions dissolved in water come together to form solid particles. Examples are limestones, chert, and rock salt. 22

  20. Naming of clastic sedimentary rocks looks simple, and it is. Why? 23

  21. The process of sorting segregates sedimentary particles and puts them in distinct, separate places. 24

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