Title: Chapter 13 – Mesozoic Events
1Chapter 13 Mesozoic Events
Important events Breakup of Pangaea Begins
200 million years ago Formation of rift
valleys Oceans widen Gulf of Mexico
formation Cretaceous epicontinental
seas Accretionary tectonics add to
continents
2Three Periods
Triassic first dinosaurs Mesozoic first
birds Cretaceous first flowers great
extinction
3Breakup of Pangaea
Stage 1 Rifting and volcanism along normal
faults North America separates from
Gondwana Mexico separates from South
America Eastern border of N.A. separates from
Moroccan bulge of Africa
4Breakup of Pangaea Stage 2
Stage 2 Narrow ocean opening between Africa and
Antarctica An extension of this rift separates
India from Africa
5Breakup of Pangaea Stage 3
Stage 3 Atlantic Ocean begins to unzip from the
south towards the north Starts to rift
Greenland from North America but shifts to
separate Greenland from Baltica
6Breakup of Pangaea Stage 4
Stage 4 North Atlantic rift separates Laurentia
from Baltica Occurred 45 million years
ago Complete breakup took 150 million years!
7Breakup of Pangaea Model
8The Mesozoic in Eastern North America
Appalachian Mountains are eroding and shedding
massive amounts of sediment. Begins to fill in
non-marine continental rifts. Much basaltic
volcanism. Fall Line boundary between
igenous and metamorphic rocks of Appalachian
Mountains and more easily eroded sedimentary
rocks. Location of many water wheels for textile
and grain mills. Philadelphia, Baltimore,
Washington, Richmond, and Augusta.
9Gulf of Mexico
Gulf of Mexico one of worlds great
depositional basins. gt1000 m of rock salt
(halite). Salt Domes low density causes them
to rise producing folded and faulted petroleum
traps. Salt, sulfur and other chemicals also
produced.
10Salt Dome Geology
11Cretaceous (The Chalk Period)
Cretaceous is a period of high sea level.
Why? Continental flooding. The rock chalk is
composed of calcite shells that formerly were
occupied by golden-brown algae.
12Chalk Electron Microscope Picture
13White Cliffs of Dover
14Chunnel
15The Mesozoic in Western North America
North America is overriding the Pacific
Plate Accretionary Tectonics add to western
N.A. Exotic terranes Alien, displaced
landmasses added to continent. Area 51.
16Area 51 Resident
17Abducted Terranes
18Abducted Terranes
19Western United States
20Triassic
Much western volcanism with stream
deposits. Chinle Kayenta formations of
Painted desert. Petrified Forest of Triassic
age. Conifers Uranium deposits of Mt. Taylor
stream channels.
21Triassic
Much western volcanism with stream
deposits. Chinle Kayenta formations of
Painted desert. Petrified Forest of Triassic
age. Conifers Uranium deposits of Mt. Taylor
stream channels.
22Jurassic
Navajo Sandstone (Late Triassic-Early
Jurassic) Cross-bedded sandstone coastal
dunes, windblown sand. Source of sand
Alberta. Sundance Sea (Formation) Marine
reptiles Morrison Formation Floodplain
deposits contain 70 dinosaur species
23Navajo Sandstone
24Sundance Sea
25Morrison Formation
26Seafloor Spreading and Epicontinental Seas
27Mesozoic Volcanism
28Mesozoic Plutonism - Yosemite
29Mesozoic Subduction Complex Franciscan Formation
30Grand StaircaseEscalante National Monument
31Grand StaircaseEscalante Statigraphy
32Deccan Traps Volcanic Eruption