Pleistocene - Ice Ages
Transcription
Pleistocene - Ice Ages
The Geologic History of New York State The Pleistocene 0 Ma Phanerozoic C M P Pleistocene Paleogene Neogene Cenozoic Tertiary Ma 0 Pliocene Miocene Oligocene Eocene Paleocene Cretaceous Mesozoic Proterozoic 2500 Ma Holocene Quat. 540 Ma Jurassic Triassic Archean 3800 Ma Carb. Paleozoic Permian Pennsylvanian Mississippian Devonian Silurian Ordovician Cambrian .01 Ice Ages 1.6 5 23 35 57 RIP 65 146 208 245 290 323 360 408 439 510 540 Hadean Geologic Time Scale 4600 Ma Pleistocene - Ice Ages • 100 / 40 ka glacial (cold) - interglacial (warm) cycles. • Most recent glacial period = Wisconsin Interval. • Peak glaciation 22,000 years ago. • New York State completely covered by ice. • Up to 1 mile thick ice overwhelmed all topography. • All New York landscapes are glacially modified. • Long Island was created by glacial deposition. Extent of Continental Glaciers Peak of Wisconsin Ice Age App. 22 ka Athabasca Glacier, British Columbia Glacial Features and Deposits • Erosional - carving the bedrock and landscape • glacial striations • chatter marks • U-shaped valleys and tunnel valleys • Depositional - releasing rock, sand, and mud • drumlins • erratic boulders • moraines (till) • outwash • kettle holes and kames Terminal / Recessional Moraines Kame Outwash Kettle Glacial features in New York • Drumlins - tear drop-shaped hills • Finger lakes, kettle ponds • Wide, U-shaped valleys • Bedrock striations, chattermarks • Glacial boulders (erratics) • Long Island (moraines and outwash plain) • Tunnel Valleys (Long Island) (all meltwater) Drumlin fields, Ontario lowlands Finger Lakes Drumlins - Manitoba Glacial Lake Shoreline drumlins flutes Drumlins Finger Lakes Finger Lakes, New York Glaciated Valleys •Trough-shaped •Underfit streams Charlotte Creek Valley, Central New York State Chatter marks and striations, Bear Mountain, Hudson Highlands roche moutonee with striations Shawangunk Ridge, New Paltz, NY N Central Park, Manhattan Moraines of Long Island Cape Cod, Nantucket, Marthas Vineyard (NASA Space Shuttle Image) Harbor Hills moraine, north of Hofstra campus Necks, western Long Island - glacial tunnel valleys Stratified drift (outwash delta), Caumsett State Park, Long Island Loess Glacial till Erratic boulder, Lloyd Neck, New York Glacial polish, erratic boulder Glacial erratics, Smithtown Harbor, Long Island Tunnel Valleys - formed by water flowing beneath the glacier N Eatons Neck Lloyd Neck Little Neck West Neck East Neck Northport Centerport Huntington Port Jefferson Tunnel valley Outwash fan Central Long Island (Hauppauge - Farmingville area) Moraine Lake Ronkonkoma Kettle lake Post glacial stream valley Meltwater channel Meltwater channel North Formation of gaps in Ronkonkoma Moraine South Ronkonkoma Moraine Proglacial Lake Upper Lake, eastern Long Island - Glacial meltwater channel Lake Ronkonkoma Kettle Pond Kame and kettle topography Outwash plain Eastern L.I. - Kettle Ponds Sears Pond Penny Pond Calverton Bellows Pond Lake Panamoka Deep Pond Hampton Bays Swans Pond Eroding terminal moraine, Montauk Point, New York Hyde Park Mastodon locality, Hyde Park, NY Home of Larry and Sheryl Lozier Summer, 2000. Mastodon skeleton Hyde Park, New York http://www.youtube.com/watch?v=ObJgLo0Wa6g