9/16/2014 TOPOGRAPHIC RELIEF PHYSICAL GEOGRAPHY: An Overview of the Natural Landscape of New York State Prof. Anthony Grande ©AFG 0914 2 Definitions GEOLOGIC PROCESSES TECTONIC (building) GRADATIONAL Geography: Study of people living on the . Folding (wearing down) surface of the earth. Faulting . Weathering (in place): . Volcanism mechanical and chemical Geology: the study of the earth and its processes. Mass wasting (by gravity) . Agents of Erosion (with Geomorphology: the study of landforms. NATURAL PROCESSES movement: take-move-place) Mass movements - Running water Topography: the study of surface features. Earthquakes - Moving ice Volcanic eruptions -Wind Subsidence - Wave action 3 - Long shore currents 4 Folding Faulting Folded rock layer in the Catskills. Lake Champlain, Lake George Forces at work: Forces at work: movement, and Sacandaga Lake are in rift Compression, bending, breaking 5 tension, breaking 6 valleys (also called grabens). 1 9/16/2014 Volcanism New England Seismic Network including NYS Earthquakes occur throughout NE United States and SE Canada. - Two major clusters in eastern NY. - One minor cluster in western NY. Earthquakes are caused by adjustments to the earth’s surface (rebound) Forces at work: melting, movement of molten material; as tension is released. eruption can be explosive or gentle. 7 8 Zones of Seismic Activity in NYS NYS US East Coast Zone 1 1. LAURENTIAN Seismic NYS Zone 3 ZONE Hazard NYS Zone 2 Potential 3. CLARENDON- LINDEN ZONE Greatest 2. RAMAPO ZONE Least Source: NYS Museum 9 Source: USGS 2014 10 Assessing Recorded Earthquakes in NYS Seismic By County 1973-2012 Risk http://www.dhses.ny.gov/oem/mitigation/docu ments/2014-shmp/Section-3-7-Earthquake.pdf 11 http://www.dhses.ny.gov/oem/mitigation/documents/2014-shmp/Section-3-7-Earthquake.pdf 12 2 9/16/2014 Types of Rocks Types of Rocks There are 3 categories • Sedimentary – Rocks of rocks, each formed formed by the compaction differently, each with of eroded material from different resistances other rocks or precipitates to erosion: from dissolved minerals Sedimentary under pressure from the Igneous weight of successive layers. Metamorphic Watkins Glen State Park, Tompkins Co. Exposed rocks, They make up 75% of the Adirondack State Park earth’s surface. 13 14 Sedimentary Helderberg Escarpment Rocks Catskills Sediments are laid down in Hudson Cliff face horizontal layers. Valley Lowland The layers are then often deformed by folding and faulting or displaced by volcanic activity. They are eroded by running water. in Ausable Chasm, Essex Co. 15 16 Igneous Rocks Types of Rocks Igneous rocks are found at the surface in three areas: • Igneous – Rocks formed by the cooling (1) SE NYS from Staten Island to Rockland Co. along the and solidification of molten material. Palisades sill. (2) NE NYS in the Saratoga The rate of cooling determines its crystalline Springs area where there are hot springs and pillow lava structure. formations. The rate of cooling determines the creation of (Pillow lava is a formation created minerals. when molten rock hits cool water.) (3) The Hudson Highlands and Adirondacks contain Pre- Cambrian igneous rock. 17 18 3 9/16/2014 Palisades Sill Igneous Rocks Pillow lava at Stark’s Knob, NY >> Below, recent pillow lava underwater off of Hawaii. Sill: a horizontal underground lava flow <<Volcanic sill, Haverstraw, NY (Rockland Co.) intruded between layers of sedimentary rock. 19 related to the Palisades formation. 20 Frontenac Arch Types of Rocks Metamorphic Rocks (Thousand Is) Metamorphic rocks are found Adirondacks • Metamorphic – Rocks formed by the in eastern NYS (Taconic Mts., addition of great heat and pressure to Hudson Highlands and the Manhat- tan Prong), the Adirondack existing sedimentary, igneous and Mts. and in the Thousand metamorphic rocks. Island region (Frontenac Arch). Taconic Mts. For example, shale (sed.) becomes slate sandstone (sed.) becomes quartzite Hudson limestone (sed.) becomes marble Highlands granite (ign.) becomes gneiss Manhattan Prong basalt (ign.) becomes schist. 21 Banded gneiss in Adirondacks. 22 Resistance of Rocks Setting of Niagara Falls The composition of the rocks give them the The Niagara Lake Erie 22 miles upstream of the ability to resist forces of erosion. River drains Falls. Lake Erie. Igneous and metamorphic rocks are generally It flows over the Moved 7 miles stronger. They are resistant to erosion and form in 12,000 yrs Niagara Escarp- GORGE highlands. ment to reach Sedimentary rocks tend to be weaker. They Lake Ontario. are found in lowlands. In doing so for 12,000 yrs, it has created a 7 mile long gorge as Together they give us a variety of surface 9 miles from escarpment features and slope angles. the falling water 16 miles from the Falls eroded weak 23 layers of rock. 24 4 9/16/2014 Niagara Escarpment Retreat of Niagara Falls At the present rate of erosion it Horseshoe Falls American Falls will take the Niagara River 75,000 years to << Each layer reach Lake Erie. of rock has a different resistance to water erosion. 25 26 Niagara Falls Niagara Falls American Falls 2011 1969 www.dailymail.co.uk/news/article-1338793/Niagara-Falls-ran-dry- Photos-moment-iconic-waterfall-came-standstilll.html - photos of dry 27 Horseshoe or Canadian Falls 28 Niagara Falls in 1969 Genesee River Letchworth State Park Western NYS Genesee River in the “Grand Canyon of the East.” 29 30 5 9/16/2014 High Falls on the Genesee River Landscapes of NYS at Rochester NEXT PALEOGEOGRAPHY 31 32 6.