• Get out a small piece of paper and put your
name on it.
• When the bell rings,
the quiz will begin.
• When did the last major eruption of Mt. St.
• What killed most people in the major eruption
of St Helens.
• What causes a major landslide?
2) Lahar, pyroclastic flow, flooding, ash
3) Slope, precipitation, human impact
What killed the dinosaurs?
(Formally called the Cretaceous-Tertiary extinction)
Meteor impact 65.5 million years ago.
Ø Meteor impact in Mexico 65.5 million years ago.
ØKilled 65-70% of all species on Earth.
Ø90% of everything ever alive is now extinct! Extinctions are
ØFive major extinctions in the past and many smaller ones.
ØEarth is 4.6 Billion Years old.
Ø on Earth began in the Paleozoic
(570 million years ago)
ØDinosaurs were present on Earth
around 245 million years ago and lived
for about 180 million years.
ØHumans have only been on Earth for
maybe 10,000 years!
ØSome say fast (few years) some say slow (millions
ØThe fossil record is incomplete, so difficult to
say something is present or not.
What causes this event?
ØMeteor (widely accepted)
ØVolcanism (flood basalts)
ØDeccan Traps (dark purple)
ØAtmospheric changes from other
Ø level change
ØSea level fell after 65 mya
ØDeposits of sea sediments in mountains of Mexico
Who is affected?
ØMarine Invertebrates - 60% species extinct.
ØFish - 80% survived
ØTerrestrial Invertebrates – Not determined
ØPlants - 57% plants extinct
ØAmphibians – Most survived
ØReptiles – Almost all species become extinct.
ØTwo major survivors
Øtestudines - turtles
Ølepidosaurs – lizards and snakes.
Ø current data and theories are based off of fossil evidence.
Ø K-T boundary is identifiable in North America:
Ø lack of ferns before, but abundant after.
ØHell creek, Montana Hells creek formation
ØPollen levels in rocks and ice
Ø5 previous major mass extinctions
ØSome say we are in one now?
ØSea level change
ØLoss of resources