Lecture 4 - Brief History of Cenzoic Climate

Question 1

structure of the earth

layers of earth

Answer 1

inner core, outer core, mantle, crust

Question 2

structure of the earth

inner core

Answer 2

swirling molten metals that create magnetic field of the earth

Question 3

structure of the earth

mantle

Answer 3

semi liquid-like substance, motion & convection within mantle

Question 4

structure of the earth

crust

Answer 4

fraction of the width than other layers, what we’re on
- up to 100 km thick

Question 5

structure of the earth

tectonic plates

Answer 5

large rock slabs that make up Earth’s crust and upper mantle

Question 6

structure of the earth

types of plate boundaries

Answer 6

divergent - new oceanic crust
convergent - denser plate subducted, mountains form
transform - plates slide horizontally past each other

Question 7

structure of the earth

great rift valley

Answer 7

Eastern Africa, incipient divergent ~ 6-7 mm/year
- eastern part of continent is breaking off the western
- 10 ish million years, red sea will separate east and west Africa

Question 8

evidence for continental drift

Answer 8

• puzzle piece continents
• flora/fauna across continents
• earthquakes and volcanoes
• direct observation of mid-ocean ranges
• direct measurement of continental drift

Question 9

epochs of cenzoic

paleocene characteristics

Answer 9

• 66 - 56 Ma
• NA occasionally connected to Eurasia, similar fauna
• temps lower than K or Eocence
• extensive decidious and coniferous forests
• angiosperms start to evolve
• earliest primate like creatures (plesiadaforms)

Question 10

epochs of cenzoic

eocene characteristics

Answer 10

• 56 - 34 Ma
• almost all present major groups of animals appear
• “Dawn” epoch
• fauna modernizes
• tropical climates and vegetation for large part of globe
• diverse mammalian fauna in Arctic Circle
• diverse set of early primates

Question 11

epochs of cenzoic

Paleocene-Eocene Thermal Maximum (PETM)

Answer 11

• climate gets super hot right in the middle, avg temp rises 5deg. C
• lasts for ~180 Ka
• mass extinction of ocean foraminifera
• caused by CO2

Question 12

epochs of cenzoic

oligocene characteristics

Answer 12

• 24 - 23Ma
• nearly modern continents, no connection btwn NA/SA uet
• India collides with Asia
• SA and Aus break away from Antarctica, currents change
• Eocene primates disappear, early monkeys in Africa/Asia

Question 13

epochs of cenzoic

miocene characteristics

Answer 13

• 23.5 - 5.3 Ma (long)
• slightly warming trend, then cooling, increasing aridity in Africa
• Tethys Sea contracts and dries up @ least once
• Himalayas rise, creates Gobi desert
• Apes diversify

Question 14

epochs of cenzoic

Pliocene

Answer 14

• 5.3 - 2.58 Ma
• lots of early hominins
• climate cooler and drier
• Panama forms, affecting ocean circulation

Question 15

epochs of cenzoic

pleistocene characteristics

Answer 15

• 2.58 Ma - 10 Ka
• ice age
• Homo appears at Plio-Pleistocene boundary
• onset of Northern Hemisphere Glaciation
• massive variability in climate, glacial and interglacial pds on northern continents
• Neanderthals, modern humans appear towards end

Question 16

epochs of cenzoic

holocene characteristics

Answer 16

• 10 Ka - present
• relatively stable climate
• minimal glaciation, habitable zones extensive