Transcript Slide 1
Landscapes of New York Virtual Field Trip By Nick D’Anna Photos courtesy of Gail & Bret Bennington, A. Orgonik, & myself What are landscapes? 3 Major Classifications: •Mountains •Plains / Lowlands •Plateaus / Uplands New York has all three! Notice the Catskills are part of a plateau, and are not really mountains Mountains / Highlands • At least 300 meters above the surrounding land. • Created by a tectonic collision between two landmasses (Orogeny). • Characterized by distorted rock structures (metamorphic bedrock): a result of the pressures applied during collision. Plains / Lowlands • Large areas of flat land at low elevations. • Lots of gravel, sand and clay. • HOME SWEET HOME! Plateau / Uplands • Large areas of flat land at high elevation. • Usually flat, horizontal, sedimentary rock structures. Check your note sheet now Landscapes Mountains Plateaus Plains Stop Here! The rocks around the room are from all over NY. Describe them as best you can. What are the clues in the rock that we can use to answer: Igneous, Sedimentary, Metamorphic? Environment of formation? Fossils? Mineral Composition? Landforms are the result of the interaction of tectonic forces and the processes of weathering, erosion, and deposition. What tectonic events and surface processes were occurring during these times? Adirondack High Peaks Correlate page 2 to page 3 of your ESRT What was happening in NY during the Middle Proterozoic? Correlate pages 2 & 3 to pages 8 & 9. No horizontal layering – blocky, chunky, jointed metamorphic rock. Isolated garnet crystals like this one, tell us the rock has been subjected to a lot of heat and pressure (metamorphism). Anorthosite; composed of large crystals of labradorite feldspar (another clue of metamorphism). Distorted bedrock structure – result of compression forces during the collision of landmasses that created the supercontinent that came before Pangea. Letchworth Gorge Correlate page 2 to page 3 of your ESRT What was happening in NY during the Devonian? Correlate pages 2 & 3 to pages 8 & 9. During the Devonian the western parts of NY are underwater. The Acadian orogeny occurs mostly to the North (Maine, Newfoundland, Greenland, etc…). The rising of those mountains produced a lot of erosion of the softer surface sedimentary rocks and the Catskill delta was formed. Is this a true mountainous region? Elevated sedimentary rocks being worn down by running water Watkins Glen These and other marine fossils tell us that the area was once covered by a shallow sea. Sedimentary rocks, at fairly high elevations, being worn down by running water Shawangunk Ridge Notice the layering in the rocks Conglomerate rock from the Catskills. The Catskills are made of sedimentary rocks, not metamorphic rocks! Take us home, Mr. D Correlate page 2 to page 3 of your ESRT Correlate pages 2 & 3 to pages 8 & 9. Caumsett State Park, Lloyd’s Neck, LI Pleistocene Sands & Gravels Cretaceous Clay Loess Glacial till Thank you for your cooperation, We’re almost done Write one thing about a rock you observed that is a clue to the landform it is found in.