Midterm 1 Flashcards
(217 cards)
What is the crust composed of?
Igneous Rocks, Sedimentary Rocks and Metamorphic Rocks
Oxygen (O 46%) and Silicon (Si 28%) are the two most abundant elements in Earth’s crust.
What are the building blocks of minerals?
Naturally occuring
Solid crystalline substance
Inorganic
Specific chemical composition
What are minerals composed of?
Elements,such as carbon (C), oxygen (O), silicon (Si), magnesium (Mg)
What are elements?
Substances which cannot be separated or subdivided into simpler substances by chemical means
Minerals as nutrients
a chemical element required as an essential nutrient by organisms to perform functions necessary for life.
What are the five major minerals in the human body?
Calcium, phosphorus, potassium, sodium, and magnesium.
Trace elements
All of the remaining elements in a human
body are called trace elements. The
trace elements that have a specific
biochemical function in the human body
are sulfur, iron, chlorine, cobalt, copper,
zinc, manganese, molybdenum, iodine
and selenium.
Where is the Loess Plateau
Northwest China
What is the Loess Plateau
An area with dry powdery wind-blown soil.
What causes desertification?
- Overgrazing by sheep and goats, other livestock
- Cutting down trees or other vegetation
What are some methods that have been used at the loess plateau?
- Warping dams to create rich fertile fields in valleys
- Terrace side of ravines
- Fish scale terraces for single trees
- Introduce trees (fruit trees are good)
- Stabilize soil/dunes with grasses, bushes
- Feed livestock in pens rather than herding
Why is it important that the local people be involved in rehabilitating the land?
- Sense of shared responsibility, stewardship
- Get paid for rehabilitation work
- Personal achievement and pride
China has about ____% of the world’s population, but only about _____% of it’s arable land.
22% and 7%
Where does the loess come from
(1) alluvial fans in the central asia orogenic belt
(2) the alluvial fans in the north of the Qilian mountains in the northeastern Tibetan Plateau
(3)North China Craton
What are some of the Loess-forming processes and transport mechanisms?
Strong near surface winds are primarily responsible for transport as well as monsoons
Why is so much dust formed in the Loess plateau?
- Highest known uplift rates in the world in the Himalayas
- Rapid river incision and therefore sediment production
- Unstable slopes
- Glaciation
- Erosion from freeze-thaw fracturing
What is a micron?
1 *10^6 m
What minerals is the loess composed of?
quartz grains (60%), feldspar, mica, carbonate
How thick are the loess deposits?
Up to 500m
What are some physical characteristics of the loess?
low density, soft, high porosity, easily erodible, collapse when wet
Particles smaller than ___ are absorbed into the bloodstream
1um
Particles smaller than ___ will be trapped in the lungs
10um
The size of dust on the loess plateau is ____
5-15um
What is the Occupational Exposure Limit?
0.1mg/m^3