Earth History, Ch. 16 1 Early Mesozoic of Iowa • No Triassic rocks in Iowa (surface or subsurface) • Jurassic rocks crop out in vicinity of Ft. Dodge (Webster County) – Ft. Dodge Formation is gypsum deposit (evaporite) – Iowa is 2 nd largest gypsum producing state in U.S. (1.65 million tons/year) – Same age as dinosaur-bearing Morrison Formation to the west
Early Mesozoic of Iowa. No Triassic rocks in Iowa (surface or subsurface) Jurassic rocks crop out in vicinity of Ft. Dodge (Webster County) Ft. Dodge Formation is gypsum deposit (evaporite) Iowa is 2 nd largest gypsum producing state in U.S. (1.65 million tons/year) - PowerPoint PPT Presentation
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Earth History, Ch. 16 1
Early Mesozoic of Iowa• No Triassic rocks in Iowa (surface or
subsurface)• Jurassic rocks crop out in vicinity of Ft.
Dodge (Webster County)– Ft. Dodge Formation is gypsum deposit
(evaporite)– Iowa is 2nd largest gypsum producing state in
U.S. (1.65 million tons/year)– Same age as dinosaur-bearing Morrison
Formation to the west
Earth History, Ch. 17 2
MiddleJurassic
Earth History, Ch. 16 3
Ft. Dodge Formation
Earth History, Ch. 16 4
Jurassic rocksof midcontinent
Earth History, Ch. 16 5
Cardiff Giant
• Man-like figure carved from Ft. Dodge gypsum
• 10’ 4.5” long, 3’ wide, 2990 pounds
• Cooked up as a hoax in 1866 by George Hull (visiting his sister in Ackley, Iowa)
• Now preserved in Cooperstown, New York
Earth History, Ch. 17 6
Earth History, Ch. 17 7
Earth History, Ch. 16 8
Cardiff Giant
Sold for $37,500 and then put on display
Earth History, Ch. 17 9P.T. Barnum’s fake of a fake
“There’s a sucker born every minute” (David Hannum)
Earth History, Ch. 17 10
Cretaceous World• Cretaceous System
was named in 1822 for deposits that are “chalky” in many parts of the world
• Duration of Cretaceous Period is longer than any other
142
206
65
251
CretaceousSystem
TriassicSystem
JurassicSystemM
esoz
oic
Era
Earth History, Ch. 17 11
Rise of the angiosperms
• Gymnosperms continued to dominate terrestrial floras in Cretaceous (just as in Triassic and Jurassic)
• Angiosperms initial appearance was in middle Cretaceous time– Double-fertilization and enclosed seeds
– Flowers (for attracting insects)
– Co-evolution wih insects
– Faster reproductive cycles
Earth History, Ch. 17 12
Angiosperm diversification
Earth History, Ch. 17 13
Earth History, Ch. 17 14
Rudist reef
Earth History, Ch. 17 15
Earth History, Ch. 17 16
Tyrannosaurus rex
Earth History, Ch. 17 17
Warm-blooded Dinosaurs?
• Evidence in support of endothermy– Cretaceous dinos lived in high latitudes– Birds are endothermic, and birds are highly
specialized dinosaurs– Dinosaur bone structure resembles that in