historical geology lecture 25 the pleistocene epoch and human origins

Historical Geology

Lecture 25

The Pleistocene Epoch and

Human Origins

Historical GeologyOutline

I Pleistocene TimelineA. NebraskanB. KansanC. IllinoisanD. Wisconsin

1. Extent2. Great Lakes3. Lake Bonneville4. Lake Missoula

a. Channeled Scablands

II Climate ControlsA. GeographyB. AlbedoC. Milankovitch Cycles

III Glacial Cycles and Sea LevelIV The Origin of Humans

Historical GeologyThe QuaternaryPleistocene Ice Ages

Wisconsin 75,000 – 10,000

Illinoian 265,000 - 125,000

Kansan 435,000 - 300,000

Nebraskan 1,800,000 - 500,000

Historical GeologyThe QuaternaryLast Glacial Maximum

Historical GeologyThe Quaternary

Ice Ages - Wisconsin

Historical GeologyThe QuaternaryIce Age Geology

Glacial Subsidence

Loess Deposits

Pluvial Lakes

Lake Agassiz

Great Lakes

Lake Bonneville

Lake Missoula

Scablands

Drainage System

Historical GeologyThe QuaternaryIce Age Geology - Pluvial Lakes

Historical GeologyThe Quaternary

Ice Ages – Lake Agassiz

Historical GeologyThe Quaternary

Ice Ages – The Great Lakes

Historical GeologyThe Quaternary

Ice Ages – Lake Bonneville

Historical GeologyThe Quaternary

Ice Ages – Lake Missoula

Historical GeologyThe Quaternary

Ice Ages – Lake Missoula

Historical GeologyThe Quaternary

Ice Ages - Wisconsin

BeforeAfter

• Before the ice age rivers drained predominanly to the northeast, but due to the presence of a large continental ice sheet new rivers to the sea were formed.

Historical Geology

Geography

Ocean Currents

Albedo

Earth's Orbit

Climate Controls

Historical Geology

Eccentricity

Obliquity

Precession

Climate ControlsOrbital Forcing

Historical GeologyClimate Controls

Orbital Forcing - Eccentricity

Historical GeologyClimate Controls

Orbital Forcing - Obliquity

Historical GeologyClimate Controls

Orbital Forcing - Precession

Historical GeologyClimate Controls

Orbital Forcing - Cumulative Effect

Historical GeologyThe Cenozoic Era

Sea Level and Glacial Cycles

Historical Geology

10

20

30

40

50

60

CEN

OZ

OIC

Mill

ions

of

years

ago

Present

loss oftree-dwellingexistence

binocular visionopposable digits

tree-dwellingexistence

TREE SHREWS

PROSIMIANS

NEW WORLDMONKEY

OLD WORLDMONKEY

ORANGUTANS

GORILLAS

HUMANS

CHIMPANZEES

Primate Evolution

Historical Geology

Historical GeologyTimeline of Human Evolution

Australopithecus afarensis

Historical GeologyTimeline of Human Evolution

Homo erectus

Historical GeologyTimeline of Human Evolution

Homo neanderthalis

Historical Geology

Brain Size

Erect Posture and Bi-pedalism

Hands

Face and Eyes

Teeth and Jaws

Throat and Larynx

Sexual Dimorphism

Neoteny

Human Characteristics

Historical Geology

Brain Size

L to R: A. afarensisH. erectusH. sapiens sapiens

Human Characteristics

Historical GeologyHuman Characteristics

Bipedalism

Historical GeologyHuman Characteristics

Bipedalism

Historical Geology

Hands

FaceandEyes

TeethandJaws

Throatand

Larynx

Human Characteristics

Historical Geology

Sexual Dimorphism Neoteny

Human Characteristics

FemurA. afarensis3.5 mya

SkullA. robustus

SkullH. habilis2 mya

Historical GeologyHumans Populate the World