Cenozoic Earth History

The Cenozoic Era Spans the time from 66 Ma until nowSpans the time from 66 Ma until now Is sub-divided into the periods and epochsIs sub-divided into the periods and epochs Experienced 1 marine transgression, the TejasExperienced 1 marine transgression, the Tejas Another transgression began ~ 16,000 years agoAnother transgression began ~ 16,000 years ago

Geologic Provinces of North America

Rift Basins and Magnetic Highs along the East Coast of North America What do the two ridges of magnetic highs represent?

The eastern margin of North America is presently a passive continental margin What geologic events would suggest subduction has begun? But ultimately oceanic crust will break along the continental margin and subduction of Atlantic basin crust will begin

Geologic Provinces of the Southern Appalachians Fall Zone

Comprises a thick sequence of sediments deposited on top of the Appalachian crystalline rocks by the Zuni (Cretaceous) and Tejas (Eocene) transgressionsComprises a thick sequence of sediments deposited on top of the Appalachian crystalline rocks by the Zuni (Cretaceous) and Tejas (Eocene) transgressions The Cretaceous and Eocene strata crop out the farthest inlandThe Cretaceous and Eocene strata crop out the farthest inland The ACP strata are progressively younger and thicker toward the coastThe ACP strata are progressively younger and thicker toward the coast The Atlantic Coastal Plain

Evolution of the Atlantic Coastal Plain Following Maximum Advance of the Tejas Transgression The Tejas Transgression began in the Paleocene, peaked in the Eocene, having advanced as far inland as where Augusta, Columbia, Raleigh, Richmond, and Philadelphia are now locatedThe Tejas Transgression began in the Paleocene, peaked in the Eocene, having advanced as far inland as where Augusta, Columbia, Raleigh, Richmond, and Philadelphia are now located As sea level receded following maximum transgression:As sea level receded following maximum transgression: –Erosion began sculpting a stair-step series of scarps (paleo-shorelines) andscarps (paleo-shorelines) and terraces (wave-scoured sea floor)terraces (wave-scoured sea floor) –Acidic groundwater began forming numerous caves and sinkholes in the Santee limestone –Thousands of Carolina Bays were formed on the Middle and Lower coastal plains

The Atlantic Coastal Plain Scarps and Terraces The ACP Sandhills

Peachtree Rock A remnant of tidal inlet sands deposited near Columbia during maximum advance of the Tejas Transgression

Santee Limestone was deposited in deeper water on the continental shelf as sands that formed Peachtree Rock were deposited at the coast The core (a) Was drilled at Pregnall

Sinkholes (irregularly-shaped depressions) formed in Santee Limestone near Eutaw Springs, SC

Sinkhole and Cave at Santee State Park, SC A cavecidic water slowly dissolves limestone A cave forms as acidic water slowly dissolves limestone A sinkhole forms when the roof of the cave collapses

Atlantic Coastal Plain Arches and Embayments The eastern margin of North America has been folded into a series of NW-SE-trending arches and embayments by tectonism associated with formation of the Caribbean plate and persistent northward movement of Cuba Fall Zone

Carolina Bays near Orangeburg, SC Carolina Bays are NW-trending oval depressions surrounded by a sand rim. They are found only on the Middle and Lower Coastal Atlantic Plain

The Western Margin of North America Continued subduction of the Farallon Plate yielded the: Juan de Fuca and Cocos plates (its Cenozoic remnants) Juan de Fuca and Cocos plates (its Cenozoic remnants) San Andreas fault system San Andreas fault system Numerous Cordilleran accreted terranes Numerous Cordilleran accreted terranes

Accreted Cordilleran Volcanic Island Arc Terranes

An eastward-advancing wave of hot mantle caused... Cretaceous-Tertiary Laramide uplift of Archean crust that formed the Rocky Mountains Uplift of the Colorado Plateau Wind River Range, a Laramide uplift Extension that formed the Basin and Range

E-dipping Permian (left), Triassic (red) and Jurassic (tan) sandstone beds (right) on the E Flank of the Wind River Range (a Laramide Archean basement uplift). View toward the NW from Red Canyon Overlook near Lander, Wyoming Oregon Trail

Centers of Cenozoic Cordilleran Volcanism Yellowstone hot spot Columbia plateau flood basalts San Juan volcanicfieldCascadeRangeArizonavolcanicfield Snake River Plain

Columbia Plateau, Snake River Plain, and Yellowstone: Products of the Yellowstone Mantle Plume Hot Spot Columbia River Plateau Northwestward movement of N. A. over the hot spot in the Mid Tertiary caused eruption of the Columbia Plateau flood basalts. Then N. A. began moving toward the SW, forming the hook-like shape of the Snake River Plain flood basalts

Island Park Caldera Erupted the Huckleberry Ridge tuff 2 Ma Henry’s Fork Caldera Erupted the Mesa Falls tuff 1.3 Ma Yellowstone Caldera Erupted the Lava Creek tuff 0.6 Ma Yellowstone Calderas

Comparison of Volumes of Pyroclastic Eruptions

Subduction of the Juan de Fuca plate along the Cascadia subduction zone is responsible for the Late Tertiary to recent volcanism of the Cascade Range volcanoes CenozoicVolcanism in the CascadeRange

San Francisco Mountains, Arizona Late Cenozoic volcanism formed the San Francisco Mountains Volcanism ceased ~ 1200 years ago They are remnants of a stratovolcano that blew its top

The Circum-Pacific and Alpine-Himalayan orogenic belts, Earth’s present-day major mountain building belts Earth’s Major Orogenic Belts

Volcanism, seismicity, and deformation in the Alpine- Himalayan orogenic belt extends eastward from Spain through the Mediterranean region into Southeast AsiaVolcanism, seismicity, and deformation in the Alpine- Himalayan orogenic belt extends eastward from Spain through the Mediterranean region into Southeast Asia The tectonism, due to,The tectonism, due to collision of the Arabian, African and Indo-Australian plates with the Eurasian plate, The Alpine-Himalayan Orogenic Belt Eocene (50–40 Ma Miocene (25–15 Ma caused closure of the Tethys sea

Is occurring in response to northward movement of the African and Arabian plates toward southern EuropeIs occurring in response to northward movement of the African and Arabian plates toward southern Europe The convergence is causing deformation along a linear zone from Spain eastward through Greece and Turkey and along Africa's northwest coastThe convergence is causing deformation along a linear zone from Spain eastward through Greece and Turkey and along Africa's northwest coast The Alpine Orogeny Products of the Alpine Orogeny Alps (France, Germany, Switzerland) Alps (France, Germany, Switzerland) Pyrenees (Spain and France) Pyrenees (Spain and France) Apennines (Italy) Apennines (Italy) The Alps in Southern Germany

Subduction of Mediterranean crust under Italy, Greece, and Turkey continues to cause volcanism and seismicitySubduction of Mediterranean crust under Italy, Greece, and Turkey continues to cause volcanism and seismicity In 1999 an earthquake killed 17,000 people in TurkeyIn 1999 an earthquake killed 17,000 people in Turkey Italy and Greece Mount Vesuvius, Italy, has erupted 80 times since it destroyed Pompeii in A.D. 79 Mount Etna, Sicily, is Earth’s most active volcano

The Mediterranean Basin Most of the water flows into the Mediterranean Sea from the Atlantic Ocean through the Strait of Gibraltar Northward advance of the African plate ~ 6 Ma closed the Strait of Gibraltar, caused the Sea to dry up When the dam broke, a colossal flood from the Atlantic ocean rushed into the basin and re-filled the sea

Subduction of the Cocos plate under western Central America is causing mountain-building and volcanismSubduction of the Cocos plate under western Central America is causing mountain-building and volcanism Subduction of the Nazca plate under western South America is causing mountain-building and volcanismSubduction of the Nazca plate under western South America is causing mountain-building and volcanism Subduction of the Pacific plate under western Asia is causing mountain-building and volcanism in Japan and the PhilippiansSubduction of the Pacific plate under western Asia is causing mountain-building and volcanism in Japan and the Philippians The Circum-Pacific Orogenic Belt

Global Cooling and Warming Since the Archean Paleogeography during the Permian Ice Age

Global Cooling and Warming Since the Cretaceous

Changes in Sea Surface Temperatures Since the Eocene High The Pleistocene “Ice Age”

Pleistocene Ice Ages and Interglacial Intervals The Pleistocene began 1.6 Ma, ended 10,000 years agoThe Pleistocene began 1.6 Ma, ended 10,000 years ago Four major periods of widespread glaciation occurred, were separated by warmer interglacial periodsFour major periods of widespread glaciation occurred, were separated by warmer interglacial periods

Two Notable Pleistocene Terminal Moraines End moraines Long Island Cape Cod

Glacial and Pluvial Lakes Pluvial Lake Bonneville Glacial Lake Missoula Wave-cut shore lines cut by Glacial Lake Missoula Channeled Scablands formed by the Missoula flood Great Salt Lake

Pleistocene Glaciation of the Northern Hemisphere Climate Belts Maximum Extent of glaciation in the Northern Hemisphere

Sea Level Change during the Past 20,000 Years Global warming has been occurring for 17,000 years

Positions of the coastline of North America during the Ice Age and if the ice sheets melt

What is thought to......have caused the Pleistocene Ice Age? Formation of Central America deflected the Gulf Stream and moist air northward, produce more snowFormation of Central America deflected the Gulf Stream and moist air northward, produce more snow Northward movement of North America and Eurasia provided more surface for snow accumulationNorthward movement of North America and Eurasia provided more surface for snow accumulation...also cause/contribute to occurrence of ice ages? Milankovitch cycles, natural periodic changes inMilankovitch cycles, natural periodic changes in Earth’s orbital eccentricityEarth’s orbital eccentricity Tilt of Earth’s axisTilt of Earth’s axis Precession of Earth’s axis, of the equinoxesPrecession of Earth’s axis, of the equinoxes –Cause periodic changes in the amount of sunlight at high latitudes –Lead to natural periods of global cooling and warming Excessive volcanism, etc.Excessive volcanism, etc.

Milankovitch Cycles A change in Earth’s orbital eccentricity occurs every 100,000 years A 2° change in tilt of Earth’s axis occurs every 41,000 years A precession of Earth’s axis occurs every 23,000 years