Download presentation
Published byNickolas Gibson Modified over 9 years ago
1
Chapter 14 Mesozoic Earth History Million years ago Triassic Jurassic Cretaceous
2
Geologic Time Scale
3
Main Happenings in Mesozoic
Breakup of Pangaea Lots of mountain-building in western North America Appearance + extinction of dinosaurs More detail in the geologic record More climate information!
4
Climate information in the geologic record
Evaporites: precipitation < evaporation = dry Coal = lots of vegetation + lots of moisture Sand dunes = dry
5
The hydrologic cycle and climate
6
Water moves heat from the equator to the poles
When water changes phase, it either releases or takes up energy Evaporation: gaseous water carries energy Humid regions don’t get as hot Precipitation: releases energy as heat Humid regions don’t get as cold Ocean currents are the Earth’s heating and AC ducts, moderating our climate
7
Tectonic drivers of climate
Tectonics influences the hydrologic cycle Mountains can block rainfall Massive continents tend to have hotter, drier cores Coastal regions are more moderate Circumpolar currents prevent heat from reaching poles N/S currents move heat effectively
8
End Permian land and oceans
Panthalassa Pangaea was shaped like a ‘C’ Inside ocean: Tethys Sea Outside ocean: Panthalassa Tethys sea Panthalassa
10
Breakup of Pangea 1: Triple Junctions
Seafloor spreading creates a triple junction: a point where 3 tectonic plates diverge North America split off from S America and Africa
11
Triple Junctions
12
Seafloor spreading raises sea level
Seafloor spreading causes bulges in ocean basins Big enough bulges and/or lots of them lowers the ocean volume This can cause flooding of the continents.
13
Breakup of Pangaea 2: Opening of Gulf of Mexico
In Middle Jurassic, North America and South America separated Gulf of Mexico began to open Restricted basin at first – lots of evaporites deposited
14
Gulf of Mexico Salt
15
Breakup of Pangaea 3: Continued Widening of North Atlantic
In Late Cretaceous, Atlantic widened rapidly Canada and Europe separated
16
Final Breakup In Late Cretaceous, Australia and Antarctica separated
In Cenozoic, Antarctica and South America separated
17
Global Plate Tectonics Jurassic to Present Day
By L.A. Lawver, M.F. Coffin, I.W.D. Dalziel L.M. Gahagan, D.A. Campbell, and R.M. Schmitz 2001, University of Texas Institute for Geophysics February 9, 2001
40
Paleogeography of the World
During the Triassic Period
41
Paleogeography of the World
During the Jurassic Period
42
Paleogeography of the World
During the Late Cretaceous Period
43
Where did most North American mountain-building occur during Paleozoic?
44
Where did most North American mountain-building occur during Paleozoic?
East Coast - Appalachians
45
Cordillera Western margin of North America
Spanish for “mountain range” Rocky Mountains, Sierra Nevadas
46
Cordillera Orogenies General term refering to complex period of mountain-building Jurassic-Cenozoic Farallon plate goes below N American plate Nevadan orogeny – Late Jurassic/Early Cretaceous Orogeny near the current W coast Slope of subducting Farallon plate decreased -> Sevier orogeny – Late Cretaceous Further east (Utah) Laramide orogeny – Late Cretaceous/Cenozoic Even FURTHER east! Rockies
47
Global Sea-Level Rise A global rise in sea level during the Cretaceous
resulted in worldwide transgressions marine deposition was continuous over much of the North American Cordillera
48
Cretaceous Flood Worldwide transgression
1/3 of land area of Earth submerged 100 Ma Cretaceous Interior Seaway in North America
49
Cretaceous Interior Seaway
Paleogeography of North America during the Cretaceous Period
50
Western Interior Seaway
51
Western Interior Seaway
52
The Effects on Global Climates and Ocean Circulation Patterns
At the end of the Permian Period Pangaea extended from pole to pole Covered about one-fourth of Earth's surface Surrounded by a global ocean that encompassed about 300 degrees of longitude Such a configuration exerted tremendous influence on the world's climate resulted in generally arid conditions over large parts of Pangaea's interior
53
Oceanic Circulation Evolved
From a simple pattern in a single ocean (Panthalassa) with a single continent (Pangaea)
54
Oceanic Circulation Evolved
to a more complex pattern in the newly formed oceans of the Cretaceous Period
55
Areas Dominated by Seas Are Warmer
Oceans absorb about 90% of the solar radiation they receive continents absorb only about 50% even less if they are snow covered The rest of the solar radiation is reflected back into space Therefore, areas dominated by seas are warmer than those dominated by continents
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.