Eps 80 - Quiz 2

Front 1

What is neoglaciation?

Back 1

New "ice age" during the holocene era

Front 2

How long ago did neoglaciation occur?

Back 2

4500 - 2000 YA

Front 3

What happened to Earth's temperature and glaciers during neoglaciation?

Back 3

The global climate cooled

Glaciers expanded

Front 4

What did pollen found in Sierran lake sediment cores show?

Back 4

Reduced levels of charcoal

A shift to trees adapted to cooler climate (fir and pine)

Front 5

How long ago did the bay reach its present size?

Back 5

5,000 YA

(also earliest evidence of human occupation at this time)

Front 6

What as found in SF shell mounds?

Back 6

shells, mud, sand, fish/ bird remains, artifacts, human burials

Front 7

Why is the Bay saltier during a drought?

Back 7

There is less river flow entering, so the bay consists of more sea water

Front 8

How much of the Sacramento river flows into the SF bay?

Back 8

80%

Front 9

How much of the San Joaquin River flows into the SF bay?

Back 9

15%

Front 10

What is an estuary?

Back 10

mixture of salt and freshwater

Front 11

Does O16 or O18 evaporate more easily?

Back 11

O16 evaporates more easily

Front 12

Does O16 or O18 precipitate more easily?

Back 12

O18 precipitates more easily

Front 13

Water enriched in O16 has what level of salinity?

Back 13

low salinity levels

Front 14

What can be used to measure Oxygen isotopes to determine past water salinity levels?

Back 14

shell chemistry (microfossils/ forminifera)

Front 15

What information does sediment analysis tell us?

Back 15

fossil/pollen informaiton, mineralogy/bedding, chemistry of fossil shells, radiocarbon dating

Front 16

Where was Lake Bonneville?

Back 16

Utah

Front 17

What remains of Lake Bonneville?

Back 17

The Great Salt Lake

Front 18

What can be used as evidence for large ice age lakes?

Back 18

Evaporated lake bottom (evaporites) and ancient shorelines

Front 19

Where was Lake Lahontan?

Back 19

NW Nevada

Front 20

What caused large ice age lakes to occur?

Back 20

Cooler temperatures, so less evaporation

and increased precipitation (storms shift downwards due to high sheets of ice

Front 21

What is deglaciation

Back 21

thawing of ice

Front 22

What causes deglaciation?

Back 22

temperature and CO2 begin rising

Front 23

What happens during deglaciation?

Back 23

ice sheets begin melting and filling the ocean, sea level rises, large lakes shrink

Front 24

What compound levels tend to correlate with temperature?

Back 24

CO2

Front 25

When did the early Holocene occur?

Back 25

10,000 to 7,000 YA

Front 26

What happened during the early Holocene?

Back 26

The climate in CA and the west warmed and dried

Front 27

What evidence indicated warmer and drier summers in Sierran lake sediments?

Back 27

abundant large charcoal fragments indicated frequent fires, and open forests with oaks replaced dense pine forests

Front 28

When did the "climate optimum" period of global warmth occur?

Back 28

Mid Holocene, 7000 to 4500 YA

Front 29

What did CA Bristlecone pines moving upslope indicate?

Back 29

warmer climates in CA

Front 30

What do submerged trees indicate?

Back 30

prolonged drought caused lake level to drop at one point in time

Front 31

What is an ROV?

Back 31

Remotely operated vehicle (deployed to locate submerged tree stumps)

Front 32

Why did people move to the coast during the mid Holocene?

Back 32

The coast had more resources

Front 33

Why were there more resources along the coast during the mid holocene?

Back 33

Upwelling was strengthened, so cold, nutrient-rich water was brought to the surface -- high nutrient levels lead to high biological productivity (ex. fisheries, shellfish)

Front 34

Why was there an abundance of coastal fog in northern CA?

Back 34

Upwelling strengthened, and cold water was brought to the surface. The wind would then blow this cold air to the north

Front 35

When/where did CA water development begin?

Back 35

LA, 1900s

Front 36

Where does San Diego get its water from?

Back 36

the Colorado river

Front 37

Where does the bay get its water from?

Back 37

Mokelumne

Front 38

Where does south bay get its water?

Back 38

hetch hetchy

Front 39

Where does LA get its water from?

Back 39

LA aqueduct

Front 40

Originally, where did LA get its water?

Back 40

the LA river

Front 41

When did LAs population grow too large for its water source (LA river)?

Back 41

the early 1900s

Front 42

What is the result of the dried lakebed in the owens valley?

Back 42

dust storms and poor air quality

Front 43

What reservoir held water from the owens river?

Back 43

St. Francis dam

Front 44

When did the St. Francis Dam burst?

Back 44

1928, 600 people died

Front 45

What prompted SF to build another major water project?

Back 45

SF earthquake in 1906... fires caused 90% of damage, lacked water supply!

Front 46

Where is hetch hetchy (tuolumne river) valley located?

Back 46

yosemite

Front 47

What did the CA aqueduct do?

Back 47

transport water from N CA to the central valley and S CA

Front 48

What is eccentricity?

Back 48

shape of earth's orbit around the sun, affects amount of solar radiation received on earth

Front 49

How long is an eccentricity cycle?

Back 49

100,000 yrs

Front 50

What does the tilt of the earths axis affect?

Back 50

the amount of solar radiation received

Front 51

What is precession?

Back 51

the wobble of the earth's axis

Front 52

how long is a precession cycle?

Back 52

23,000 years

Front 53

How does water temp change during an el nino?

Back 53

warmer

Front 54

how does water temp change during a la nina?

Back 54

cooler

Front 55

During medieval warm periods, what is more common?

Back 55

La Ninas (drier climate in CA and south west)

Front 56

During a little ice age, what is more common?

Back 56

el nino, wetter climate in CA and the southwest

Front 57

How long are sunspot cycles?

Back 57

11 years, 208, 2300

Front 58

What happens during a solar max?

Back 58

more solar radiation is given off, more sunspots, and more solar energy is received by earth

Front 59

What happens during 2300 yr climate cycles?

Back 59

mountain glaciers advance and retreat, and the treeline of bristlecone pines shift up and down

Front 60

How do volcano eruptions affect climate?

Back 60

cause cooling

Front 61

What time period had an increase in large volcanic eruptions?

Back 61

little ice age

Front 62

How much $$ is the central valley agricultural industry?

Back 62

$44 billion

Front 63

How much has the central valley subsided due to groundwater extraction?

Back 63

30 ft

Front 64

How much has the temp risen since 1970, what does this mean?

Back 64

2F, larger atmospheric river storms and floods

Front 65

Name 2 major periods of global warmth w/ megadroughts:

Back 65

middle holocene, midieval warm period

Front 66

Name 2 periods of global cooling w/ wetter climate

Back 66

neoglaciation, little ice age

Front 67

When was the little ice age?

Back 67

1300 ad

Front 68

Evidence for past megafloods?

Back 68

sacramento valley, mono lake, sb basin

Front 69

What are delta layers like in the summer?

Back 69

diatom-rich sediments

Front 70

what are delta layers like in the winter?

Back 70

land sediments from rains

Front 71

what are delta layers like during large floods?

Back 71

thicker layers

Front 72

When was the last megaflood?

Back 72

1605 AD

Front 73

What civilization in arizona developed dams and canals?

Back 73

hohokam

Front 74

which civilization built pueblos and agriculture?

Back 74

anasazi

Front 75

Who built kivas (round ceremonial structures), check dams, canals, and pueblos?

Back 75

chaco canyon