Flashcards in Sedimentary system Deck (36)
Why is sedimentology important?
-origins of life
-mineral and fuel resources
-Impacts of climate change
What is a rock?
Any mass of mineral matter weather consolidated or not which forms part of the earths crust
What is a mineral?
A structurally homogeneous solid of definite chemical composition, formed by the inorganic processes of nature
What is a crystal?
A 3D body with symmetrical bounding surfaces, constant angular relationships, arising from the inherit regular atomic structure of the substance.
Examples of physical weathering? (4)
-Differential expansion of minerals as they heat in the sun
-action of plant roots and micro-organisms
-Abrasion (wind, wave etc)
Examples of natural zones of weakness: (2)
What controls a rocks resistance to weathering in relation to it's chemistry? (2)
What is an ION?
When atoms or molecules gain or loose an electron
What is the formula for the ions halite go to when disolved in water?
NaCl= Na+ +Cl-
What is an ANION?
Atom/molecule gains an electron and so becomes negatively charged i.e Cl-
What is a CATION?
Atom/molecule looses an electron and so becomes positively charged i.e Na+
Calcium carbonate +water + Carbon dioxide
Calcium Cation + bicarbonate anion
State the order in witch the minerals in granite weather
1) biotite mica
2) Plagioclase f'spa (white)
3) Orthoclase f'spa (pink)
What minerals are present in Arkose?
Othoclase feldspar and Quartz
What is there no Plagioclase feldspar in Arkose?
-It reacts with acid in rain water
-some atoms are dissolved and turned to clay
-fine clay particles are washed away large quartz and orthoclase are left behind
What is the relationship between the level a climate supports life and chemical weathering?
the more a climate supports live the higher the weathering
What climate would you expect a)fast b) slow chemical weathering?
a) warm and humid b) cold and dry
what is mass wasting?
Mass wasting is the down slope movement of a mass of sediment and/or rock due mainly to the force of gravity
Mass movement of consolidated rock:
Mass movement of unconsolidated material:
What is a rock slide?
Mass of rock slides down as one unit
What is Rock avalanche? Where do these happen?
Rocks flow downhill, Himalayas
What is creep?
Slow movement of soil or other debris (1-10mm/year)
-Cause issues interperating dip of rocks
What is slump?
Slow slide of unconsolidated material mooving as an unit
what is a mudflow?
Mud flows move very fast and contain large amounts of water
what is debris flow?
Contain material coarser than sand and move at afew tens of km/hour
What makes a slope a) stable b) unsatble?
a) Driving force < /=Resting force
b) driving force > resting force
What are the driving forces of a slope?
Shear stress: Steepness of slope, mass of material