9/22/2011 TOPOGRAPHIC RELIEF MAP of NYS LANDFORMS of NYS Prof. Anthony Grande ©AFG 2011 Physiographic Map of NYS and Landforms vicinity showing Surface Features • The basis of present-day landforms (surface features) is the bedrock geology that has been “worked on” by the forces of nature over the millions of years . • We need to differentiate between the bedrock geology (foundation) and the surficial geology (skin). Edge of continental shelf and Hudson Canyon. Creation of NYS Landforms Detail Physiography of NY, NJ and PA • Taconic Orogeny 450 mya • Creation of the Catskill • Erosion of mountains Delta Central NYS marks the northern 285 edge of the Appalachian • Filling in of shallow • Collision with Africa mya Pla teau. ancitient sea (deposits of salt The Adirondacks are part of the and gypsum) • Alleghanian Orogeny Canadian Shield of N. America. • Acadian Orogeny 375 mya creates the The lowlands of the Lakes Erie • Erosion of mountains Appalachian Mts 250 mya and Ontario are part of the Interior Lowlands of N. America. • Erosion of mountains Long Island is part of the The doming of the Adirondack region occurred Atlantic Coastal Plain. around 50 mya as a hot spot of volcanic activity began to push upward. 1 9/22/2011 Landform Creation Types of Rocks • The landforms were created mainly by forces • Sedimentary – rocks formed by the of folding and faulting during mountain compaction of eroded material from other building periods. rocks and precipitates from dissolved • Volcanic activity was present and led to minerals under pressure of the weight of unique features in the eastern part of the successive layers. state. • They make up 75% of the earth’s surface. • Together the processes were responsible for the creation of the great variety of rocks and minerals found in NYS. Sedimentary Rocks Helderberg Escarpment They are laid down in Catskills horizontal layers. Hudson Valley Cliff face Lowland The layers are deform- ed by folding and fault- ing and displaced by volcanism. Types of Rocks Igneous Rocks Igneous rocks are found at the • Igneous – rocks formed by the cooling and surface in (1) southeastern NYS from Staten Island to solidification of molten material. Rockland County along the • The rate of cooling determines its crystalline Palisades sill (an intrusion of molten rock between layers of structure and creation of minerals. sedimen tary roc k. ) (2) northeastern NYS in the Saratoga Springs area where there are hot springs and pillow lava formations. (Pillow lava is a formation created when molten rock hits cool water.) (3) The Hudson Highlands and Adirondacks contain PreCam- brian igneous rock. 2 9/22/2011 Frontenac Arch Types of Rocks Metamorphic (Thousand Is) Rocks Adirondacks • Metamorphic – rocks formed by the addition of great heat and pressure to Metamorphic rocks are existing sedimentary, igneous and found in eastern NYS (Taconic Mts., Hudson metamorphic rocks. Taconic Mts. Highlands and the • Shale becomes slate; limestone becomes Manhattan Prong), the marble. Adirondack Mts. and in Hudson Highlands the Thousand Island region (Frontenac Arch). Manhattan Prong Resistance of Rocks Setting of Niagara Falls • The composition of the rocks give them The Niagara River drains the ability to resist forces of erosion. Lake Erie. • Igneous and metamorphic rocks are It flows over the generally resistant to erosion and form Niagara Escarp- ment to reach highlands. Lake Ontario. • Sedimentary rock tend to be weaker and In doing so for are found in lowlands. 12,000 yrs, it has created a 7 mile • Together they result in a variety of surface long gorge as the falling water features and slope angles. eroded weak layers of rock. Niagara Escarpment Retreat of Niagara Falls At the present rate of erosion it will take the Niagara River 75,000 years to reach Lake Erie. 3 9/22/2011 Niagara Falls Niagara Falls American Falls 2011 1969 Horseshoe or Canadian Falls Genesee River Letchworth State Park Genesee River in the “Grand Canyon of the East.” High Falls, Genesee River, Age of the Rochester Surface Rocks of NYS Surface rocks are expos- ed by geologic activity and elements of weather. Some surface rocks may be older than surround- ing rocks because of up- lift and other tectonic processes. 4 9/22/2011 Creation of Adirondack Mts. Adirondack Mts. Bedrock Geology and associated Landscape Characteristics Landform Features of NYS Areas of Excessive Slope Cross-sections Appalachian S N Plateau Tug Hill/AdirondacksW E S N Catskills W E 5 9/22/2011 Elevations within NYS Elevation of Landforms in Northeast US The Hudson-Mohawk corridor is the only lowland route to cross the Appalachian Mts. north of Georgia and Alabama. It connects to the Interior Lowlands via the Great Lakes. Physiographic Regions of NYS Landforms and Land use • Physical Characteristics • Influence on People • Elevation – height above sea level • Barrier or Unifier –fosters • Relief –verticaldifference be- isolation or interaction tween a high and low point • Distinction or Assimilation – • Slope – horizontal distance be- separation or mixing tween a high and low point • Transportation/Communicati • Valley Shape and Stream Flow – on – ease and cost work of water and gravity. • Population Density Slope angle + volume of water + geologic • Economic Activities setting = Rate of erosion • Hazards – natural and man- • Vertical Zonation of Climate – made 3.5ºF/1,000 ft. of change in elevation (related to #1 above) Geologic Map of NYS • http://geology.about.com/library/bl/maps/n _statemap_NY3100.htm • Elec tron ic lin k to fo ld ou t map in GlGeology of New York State textbook. 6.