Bowens Reaction Series

1
Bowens Reaction Series
Ca-Plagioclase
Olivine
Pyroxene
Na/Ca- Plagioclase
Amphibole
Biotite
Na- Plagioclase
K- Feldspar
Muscovite
Quartz
2
Sedimentary Rocks(part 2 of 3)
3
Starts with the Weather

• Weathering breaks rocks down at the Earths
  surface
• Chemical minerals are altered or dissolved
• Physical rocks broken w/o changing composition
  (frost wedging, tree roots)
• Erosion carries away loose material (grain by
  grain) exposing new, fresh surface to weathering

4
Physical vs. Chemical Weathering
5
Its All Downhill From Here

• Rocks fall from a cliff
• Sand carried by a river to ocean
• Glacial ice bulldozering downslope
• Ash blown about and dropped by wind
• Most sediment carried by water
• rivers carry annually 27 billion tons

6
Lithification

• Sediment eventually is deposited
• But transportation and deposition is always
  occurring
• So the particles that get there first are
  progressively buried
• Compaction (loss of water, empty space)
• Cementation (filling in spaces)

7
Compaction
Cementation
8
Recall

• Sedimentary rocks form from loose sediment
  compacted and cemented together into dense rock

9
Types of Sedimentary Rocks

• Clastic sedimentary rocks
• solid fragments of pre-existing rock
• Organic sedimentary rocks
• remains of plants and animals
• Chemical sedimentary rocks
• dissolved ions in water eventually get
  concentrated and form solid minerals (salt!)
• Bioclastic sedimentary rocks
• biologically formed solid minerals (e.g. shells)

10
Clastic Sedimentary Rocks
11
Organic Sedimentary Rocks

• Coal
• Buried, heated, compressed, dead things

12
Chemical Sedimentary Rocks

• Sediments formed through evaporation
• Very small proportion of sedimentary rocks

13
Bioclastic Sedimentary Rocks

• Limestone and dolostone formed by lithification
  of shells of dead organisms

Coquina
Chalk
14
Sedimentary Structures

• Book covers many major ones include
• Bedding, cross-bedding, ripple marks, mud cracks,
  bioturbation (fossil animal activity)

15
Homework

• Read pgs. 47-60
• Due Wednesday
• 13 pts Review Questions (pg 71) 5, 7, 8, 10,
  13, 14
• 8 pts For Discussion (pg 71-2) 2, 6 (THINK)