GY 112: Earth History

UNIVERSITY OF SOUTH ALABAMA

Lectures 34 and 35: Cenozoic Overview and Tectonics

Instructor: Dr. Douglas W. Haywick Last Time Mesozoic Sedimentation A) Triassic Sedimentation (Breakup of Pangaea) B) Jurassic Sedimentation (Birth of the Atlantic Ocean) C) Cretaceous Sedimentation (Creation of the Coastal Plain Province) D) Mesozoic-Cenozoic climate (Greenhouse-Icehouse Earth Transition)

(web notes 32) Mesozoic Sedimentation

Triassic •Initial opening of Gulf of Mexico

Mesozoic Sedimentation

Triassic •Initial opening of Gulf of Mexico

Mesozoic Sedimentation

Early Jurassic •Initial flooding of Gulf of Mexico and Northern Atlantic Ocean

Mesozoic Sedimentation

Late-Triassic/Early Jurassic

Mesozoic Sedimentation

Late Jurassic …major transgression and flooding of the craton begins

•Sundance Sea

Mesozoic Sedimentation

Late Jurassic …major transgression and flooding of the craton begins

•Sundance Sea •Clastic wedges

Mesozoic Sedimentation

Cretaceous •Southern rifting in the Atlantic Ocean

•Gulf of Mexico stops opening

Mesozoic Sedimentation

Cretaceous •Southern rifting in the Atlantic Ocean

•Gulf of Mexico stops opening

•AL Coastal Plain sedimentation

Mesozoic Sedimentation

North South

Only key formations are labeled (those discussed in GY 112) Mesozoic Climate

• Period of high sea level – Associated with rapid sea floor spreading – Long period without reversal Long Cretaceous Normal Chron Cenozoic Climate

Paleocene-Middle Eocene: •No circumpolar current

Late Eocene-today: •Circumpolar current –Permitted development of glaciers on Antarctica Cenozoic Climate Today’s Agenda

A) Cenozoic Overview B) Cenozoic Tectonics 1. More orogenies (Laramide) 2. Western North American tectonic provinces 3. Plateaus and canyons

(Web notes 34, 35) Cenozoic Time Frame

Era Years

Cenozoic (0 to 65 MA)

Mesozoic (65 to 245 MA)

Paleozoic (245 to 550 MA) Phanerozoic

Cenozoic Time Frame

USA

Period Years The Tertiary and Quaternary Quaternary (1.6 to 0 MA) periods are relicts of an early geological classification of Tertiary (65 to 1.6 MA)

Cenozoic time (Primary, Secondary,

Tertiary, Quaternary). International

Period Years The former divisions were Neogene (24 to 0 MA) soon abandoned. The latter divisions are dropping out of Paleogene (65 to 24 MA) favor. Cenozoic

Cenozoic Time Frame

Introducing the Epochs (the Period Epoch smallest common divisions

Quaternary Holocene (10,000 – 0 years) of geological time) (1.6 - 0 MA) Pleistocene (1,600,000 – 10,000 years) Pliocene (5.0 – 1.6 MA) Tertiary Miocene (24-5.0 MA) (65-1.6Cenozoic Oligocene (37 - 24 MA) MA) Eocene (58- 37 MA) Paleocene (65-58 MA) Key Cenozoic Evolutionary Events Cenozoic Life

• Recovery from Cretaceous extinctions – Modern life forms – New animals • Sharks (Megaladons in Plio-Pleistocene) Cenozoic Life

• Marine life – Miocene ancestral whales • Sperm whale • Baleen whales • Dolphin – Miocene recovery of planktonic foraminifera Cenozoic Life

• Sandy coasts offer new niches – Sand dollars evolved from sea biscuits • Flowering plants expanded – Grasses originated Cenozoic Life • Mammals diversified – Most modern orders present by Early Eocene Cenozoic Life

• Bats present by early Eocene

Cenozoic Life

• Primates evolved in Paleocene – Climbing by Early Eocene Cenozoic Life

• Primates modernized in Oligocene – Monkeys – Apelike primates • Aegyptopithecus

Cenozoic Life

• Mammalian carnivores evolved by mid- Paleogene Cenozoic Life

• And diversified soon after... – Saber tooth tiger – Bearlike dogs – Wolflike animals Cenozoic Life

• Earliest horses by end of Paleocene – Size of small dogs Cenozoic Life

• Early Eocene elephants – Moeritherium • Earliest • Pig sized Cenozoic Life

• Mesonychids – Doglike – Size of small bears • Diatrymas – Huge flightless birds – Clawed feet and slicing beaks Cenozoic Life

• Few birds with flight – Most waded – No songbirds

Cenozoic Life

• Oligocene mammals – A few horses in North America – Rhinoceroses • Paraceratherium • Largest land mammal of all time Cenozoic Life • Terrestrial Life – Grasses – Herbs and weeds – Requires arid climate • Cooler climate linked to Antarctic glaciation Cenozoic Life

• Spread of C4 grasses

– C4 plants • Incorporate more

carbon 13 than C3 grasses • Five times more silica – Wears down teeth of grazers Cenozoic Deep Ocean Currents

Chalk Board Cenozoic Tectonic Events Cenozoic Tectonic Events

•Final breakup of Gondwanna (Australia separated from Antarctica in the Latest Paleocene – earliest Eocene epochs) •India began to collide with Asia forming the Himalayan Mountain Range (Oligocene to Recent) •Africa started to shift northward, gradually sliding under Europe and uplifting the Alps (Oligocene to Recent) •Continued westward movement of North America and South America formed an on again off again land bridge between the two continents. This gave rise to some interesting animal exchanges (see evolutionary events below). •North American orogenies become dominated by strike-slip faulting and uplift. Mountain building in the northern part of the Cordilleran mountains (mostly Canada) slow down stop during the Oligocene. Activity shifts to the southern part of the mountain chain (Colorado, Nevada etc.). •Major late Tertiary flood basalt eruptions occur in Oregon and Washington state. Hot spot volcanism occurs in the area of Yellowstone (Pliocene to present). Composite volcanic eruptions (some incredibly explosive) periodically occurred and still do (e.g., Mt St Helen’s). Cenozoic Tectonic Events

•Final breakup of Gondwanna (Australia separated from Antarctica in the Latest Paleocene – earliest Eocene epochs) •India began to collide with Asia forming the Himalayan Mountain Range (Oligocene to Recent) •Africa started to shift northward, gradually sliding under Europe and uplifting the Alps (Oligocene to Recent) •Continued westward movement of North America and South America formed an on again off again land bridge between the two continents. This gave rise to some interesting animal exchanges . •North American orogenies become dominated by strike-slip faulting and uplift. Mountain building in the northern part of the Cordilleran mountains (mostly Canada) slow down stop during the Oligocene. Activity shifts to the southern part of the mountain chain (Colorado, Nevada etc.). •Major late Tertiary flood basalt eruptions occur in Oregon and Washington state. Hot spot volcanism occurs in the area of Yellowstone (Pliocene to present). Composite volcanic eruptions (some incredibly explosive) periodically occurred and still do (e.g., Mt St Helen’s). Cenozoic Tectonic Events

•Final breakup of Gondwanna (Australia separated from Antarctica in the Latest Paleocene – earliest Eocene epochs) •India began to collide with Asia forming the Himalayan Mountain Range (Oligocene to Recent) •Africa started to shift northward, gradually sliding under Europe and uplifting the Alps (Oligocene to Recent) •Continued westward movement of North America and South America formed an on again off again land bridge between the two continents. This gave rise to some interesting animal exchanges (see evolutionary events below). •North American orogenies become dominated by strike-slip faulting and uplift. Mountain building in the northern part of the Cordilleran mountains (mostly Canada) slows down stop during the Oligocene. Activity shifts to the southern part of the mountain chain (Colorado, Nevada etc.). •Major late Tertiary flood basalt eruptions occur in Oregon and Washington state. Hot spot volcanism occurs in the area of Yellowstone (Pliocene to present). Composite volcanic eruptions (some incredibly explosive) periodically occurred and still do (e.g., Mt St Helen’s). Cenozoic Tectonic Events

•Final breakup of Gondwanna (Australia separated from Antarctica in the Latest Paleocene – earliest Eocene epochs) •India began to collide with Asia forming the Himalayan Mountain Range (Oligocene to Recent) •Africa started to shift northward, gradually sliding under Europe and uplifting the Alps (Oligocene to Recent) •Continued westward movement of North America and South America formed an on again off again land bridge between the two continents. This gave rise to some interesting animal exchanges (see evolutionary events below). •North American orogenies become dominated by strike-slip faulting and uplift. Mountain building in the northern part of the Cordilleran mountains (mostly Canada) slows down stop during the Oligocene. Activity shifts to the southern part of the mountain chain (Colorado, Nevada etc.). •Major late Tertiary flood basalt eruptions occur in Oregon and Washington state. Hot spot volcanism occurs in the area of Yellowstone (Pliocene to present). Composite volcanic eruptions (some incredibly explosive) periodically occurred and still do (e.g., Mt St Helen’s). Tectonic Events

• Cordilleran region – Laramide orogeny – New tectonic style Laramide Orogeny

• Northern segment • Active igneous activity – Active fold and thrust belt inland – Quiescent from Great Valley to Colorado Plateau • Low angle of subduction

Laramide Orogeny

• Thrust sheets exposed in Rockies Laramide Orogeny

• Yellowstone hot spot – Buried trees in lavas • Over 20 successive forests buried Regional Events–Caribbean

• Caribbean plate isolated Land Bridges

• Isthmus of Panama – North and South American mammals developed separately – Pliocene uplift of isthmus allowed for exchange of terrestrial fauna Other US Cenozoic Events

• Scablands – Bare rock scoured by floods – Water-carved channels – 20,000–11,000 years ago – Bretz, 1923

http://www.airphotona.com/image.asp?imageid=16899&catnum=0&keyword=&country=&state= &pagenum=6 Other US Cenozoic Events

• Scablands – Bare rock scoured by floods – Water-carved channels – 20,000–11,000 years ago – Bretz, 1923

http://hugefloods.com/Ellensburg.html Other US Cenozoic Events

• Scablands – Depositional features – Giant ripples • 5 m tall • 100 m apart Other US Cenozoic Events

• Water source – Lake Missoula

(Waitt, 1980) Himalayan Mountains

• Indian craton collided with Eurasia

Himalayan Mountains

• Miocene clastic sediments overlying Eocene limestone • Most uplift during last 15 million years Himalayan Mountains • Broad Tibetan plateau – 3 miles above sea level Himalayan Mountains

• Indian plate subducted • Continental collision – Fold and thrust belt – Modern motion along main boundary fault Cenozoic Tectonic Events • Cordilleran region – Laramide orogeny – New tectonic style Cenozoic Tectonics

First a recap:

The tectonic style in the Mesozoic is best described as “accretionary” Mesozoic Tectonics

Jurassic

Mesozoic Tectonics

Cretaceous

Mesozoic Tectonics

Cretaceous

Mesozoic Tectonics

Cretaceous

Cenozoic Tectonics

But that’s not all. In the southwest during the Cenozoic (Oligocene to Recent), compression is gradually replaced by shear and then by uplift Cenozoic Tectonics

But that’s not all. In the southwest during the Cenozoic, compression is gradually replaced by shear and then by uplift

Uplift Cenozoic Tectonics

Compression is gradually replaced by shear and then by uplift

60 MA Cenozoic Tectonics

Compression is gradually replaced by shear and then by uplift

35 MA Cenozoic Tectonics

Compression is gradually replaced by shear and then by uplift

25 MA Cenozoic Tectonics

Compression is gradually replaced by shear and then by uplift

10 MA Cenozoic Tectonics

Compression is gradually replaced by shear and then by uplift

Uplift

10 MA Cenozoic Tectonics ? Cenozoic Tectonics

Eocene Tectonic elements: