Impacts 3

Question 1

What went extinct in K/Pg extinction

Answer 1

over 50% extinct

• 80-90% of marine life
• half plants
• ammonites
• non avian dinos extinct

Question 2

Evidence used to support impact theory of K/PG?

Answer 2

1. Alvarez
   - Iridium anomoly
2. soot
   - black carbon when burning organic stuff, suggest forest fires
3. fern spores
   - dominate burned landscapes
4. tektites
   -natural melted rock / glass stuff, cool shape cuz fall thru air
5. shocked quartz
   - lots of internal fractures / lamellae only produced in high pressure
6. crater in Mexico
   - when drilled found suevite

Question 3

Describe location and nature of K/PG impactor

Answer 3

Chicxulub Impact Crater
- peninsula in Mexico
- asteroid 10km wide (size of mt Everest!)
- probably from outer asteroid belt

• 200km diameter
• thick layers of shocked quartz and tektites
• tsunami deposits

Question 4

Describe initial effects of K/PG impact

Answer 4

• vaporize
• blast wave (broken ear drums, can shatter glass)
• fires
• freezing temperatures for years (-5 to -50 degrees)
• rain of tektites
• 1% light cuz so much dust
• tsunami waves 100m high
• disrupted rainfall = desert

Question 5

When did dinosaurs first appear, and go extinct?

Answer 5

first appeared 240 Ma on Pangea

extinct at 66 Ma, end of cretaceous period

Question 6

Technically, which Dinos went extinct in K/PG?

Answer 6

the non avian ones

Question 7

The K/PG affected ____ more than ____

Answer 7

the oceans // the land

Question 8

Earth science building Dino is

Answer 8

Elasmosaurus

Question 9

Alvarez Hypothesis

Answer 9

asteroid impact in K/PG, discovered iridium anomaly in 1980

rare on earth, common in space
- clay layer at top that is rich in iridium and soot
- suggested 10km+ impact

Question 10

Crater structure

Answer 10

concentric ring
central peak

Question 11

What happened after the K/PG impact?

Answer 11

• impact winter: lots of dust in atmosphere cooled planet
• photosynthesis stopped cuz no sun
• food chains collapsed

At site of impact asteroid hit limestones, releasing CO2
- temp rose

Question 12

What was at Yucutan Peninsula (site of impact)?

Answer 12

• limestones = CO2
• Evaporites = rain salts
• ex/ gypsum = acid rain cuz SO2

Question 13

what did acid rain devastate

Answer 13

primary producers
like phytoplankton

Question 14

What was stressing the biosphere before the K/PG impact?

Answer 14

1. Deccan Traps erupted in India
   - flood basalt lava, releasing gases
   - after impact, volcanic activity doubled
2. Break up of pangea
   - changing environments

Question 15

main cause of K/PG extinction

Answer 15

asteroid impact

Question 16

Who survived the K/PG?

Answer 16

• MAMMALS
• small creatures who could burrow and hibernate
• birds
• crocs + alligators