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Cenozoic Earth History

Cenozoic Earth History. The Cenozoic Era. Spans the time from 66 Ma until now Is sub-divided into the periods and epochs Experienced 1 marine transgression, the Tejas Another transgression began ~ 16,000 years ago. Geologic Provinces of North America.

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Cenozoic Earth History

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  1. Cenozoic Earth History

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

  3. Geologic Provinces of North America

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

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

  6. Fall Zone Geologic Provinces of the Southern Appalachians

  7. The Atlantic Coastal Plain • Comprises 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 inland • The ACP strata are progressively younger and thicker toward the coast

  8. 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 located • As sea level receded following maximum transgression: • Erosion began sculpting a stair-step series of • scarps(paleo-shorelines) and • terraces(wave-scoured sea floor) • Acidic groundwater began forming numerous caves and sinkholes in the Santee limestone • Thousands of Carolina Bayswere formed on the Middle and Lower coastal plains

  9. The Atlantic Coastal Plain Scarps and Terraces The ACP Sandhills

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

  11. Santee Limestonewas 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

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

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

  14. Fall Zone 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

  15. 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

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

  17. Accreted CordilleranVolcanic Island Arc Terranes

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

  19. Oregon Trail 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

  20. Centers of Cenozoic CordilleranVolcanism Columbia plateau flood basalts Cascade Range Yellowstone hot spot Snake River Plain San Juan volcanic field Arizona volcanic field

  21. Columbia River Plateau Columbia Plateau, Snake River Plain, and Yellowstone: Products of the Yellowstone Mantle Plume Hot Spot 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

  22. Yellowstone Calderas 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

  23. Comparison of Volumes of Pyroclastic Eruptions

  24. 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 Cenozoic Volcanism in the Cascade Range

  25. 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

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

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

  28. The Alps in Southern Germany The Alpine Orogeny • Is 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 coast • Products of the Alpine Orogeny • Alps (France, Germany, Switzerland) • Pyrenees (Spain and France) • Apennines (Italy)

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

  30. 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

  31. The Circum-Pacific Orogenic Belt • Subduction 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 volcanism • Subduction of the Pacific plate under western Asia is causing mountain-building and volcanism in Japan and the Philippians

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

  33. Global Cooling and Warming Since the Cretaceous

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

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

  36. Two Notable Pleistocene Terminal Moraines End moraines Cape Cod Long Island

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

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

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

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

  41. What is thought to... • ...have caused the Pleistocene Ice Age? • Formation 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 accumulation • ...also cause/contribute to occurrence of ice ages? • Milankovitch cycles, natural periodic changes in • Earth’s orbital eccentricity • Tilt of Earth’s axis • Precession 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.

  42. 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

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