Transcript Ch6.1 Sedimentary Rocks

Ch6.1 Sedimentary Rocks
Vocab Exercise and Notes
CEMENTATION
CHEMICAL WEATHERING
CLASTIC SEDIMENTS
DEPOSITION
LITHIFICATION
PHYSICAL WEATHERING
SEDIMENTARY ROCK
SORTED DEPOSITS
SEDIMENT
UNSORTED DEPOSITS
1. ________________________consists of solid material that has been deposited on Earth’s
surface by wind, water, ice, gravity, or chemical precipitation.
2. Glaciers and landslides tend to create __________________________in which sediments of
different sizes are mixed together.
3. During _______________________ , the minerals in a rock are dissolved or otherwise
chemically changed.
4. The process by which mineral growth binds sediment grains together into solid
rock is ______________________ .
5. Weathering produces__________________ , which are rock and mineral fragments.
6. When sediments become cemented together, they form _____________________ .
7. As a result of _________________________, sediments are laid down on the ground or on the
bottom of bodies of water.
8. The physical and chemical process called _________________________ transforms sediments
into sedimentary rocks.
9. During _________________________, minerals remain chemically unchanged, and rock
fragments simply break off of the solid rock along fractures or grain boundaries.
10. Sediments tend to form ___________________________when transported by water and
wind.
Ch6.1 Notes
Sediments
• _____________are
pieces of solid material that
have been deposited on Earth’s surface by:
– Wind
– Water
– Ice
– Gravity
– Chemical Precipitation
Ch6.1 Notes
• Weathering –
– Chemical – when minerals are dissolved or
changed by chemical means
– Physical – no change chemically, just break of
fragments.
•
•
•
•
Clastic Sediment –
Weathering produces clasts of varying sizes.
Table 6-1
Clastic sediment exhibit worn surfaces and rounded
corners due to abrasion
Ch6.1 Notes
• Erosion and Transport
– Erosion – the removal and movement of surface
materials from one place to another.
– 4 Main Agents of Erosion
•
•
•
•
Wind
Moving Water
Gravity
Glaciers
– Downhill movement
Ch6.1 Notes
• Deposition – when sediment comes to a rest on
the ground or at the bottom of a water body
• Sorted Deposits – usually caused by wind and
water. Faster wind and water moves bigger
sediment. Deposits can be sorted into like sizes.
• Lakes, point bars, turbidity currents
• Glaciers do not sort sediment. They leave all
sizes together at end and side of glacier
• Lanslides do likewise.
Ch6.1 Notes
• Burial – sediments end up in sedimentary
basins.
– Sediments can be more >8km thick
– P and T increase with depth in basin
– Lithification – physical and chemical process that
changes sediment to sedimentary rock.
Ch6.1 Notes
• Lithification –
– Compaction – squeezes sediment into layers
• Mud can be 60 % water and shrink tremendously
– No pore space / low porosity
• Sand will resist additional compaction –
– Larger pore space / high porosity
– Good for groundwater, gas, and petroleum
– Temperature gradient = 30 C per km
– 3-4 km deep = T for cementation
– Cementation – chemical and mineral changes that
cements the sediment grains toghether.
• New mineral grows between grains (CaCO3) or (Fe2O3)
• Same mineral precipitates from groundwater and crystallizes
around them.
Ch6.1 Notes
• Features of Sedimentary Rocks
– Bedding – horizontal layering
– Graded bedding – progressively coarser grains
towards the bottom – Underwater landslides
– Cross-bedding – inclined layers of sediment
progress forward leaving tilted layers of bedding
– Sandy beaches, Sandbars, Sand Dunes
– Ripple marks – wind, wave, river current
• Symmetrical = waves
• Asymmetrical = current or wind
Ch6.1 Notes
• Fossils – preserved remains, impressions, or
any other evidence of once-living organisms.
– Death, Burial without decomposition, Fossil
– Parts replaced by minerals and turned to rock
– Great value – evidence of types of organisms from
the distant past.