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NYS TOPOGRAPHY - Why so? 4 GEOLOGIC BASE and PALEOGEOGRAPHY

Landform Creation

Prof. Anthony Grande Geography Dept. Hunter College-CUNY

Spring 2018 Lecture design, content and presentation ©AFG 0118. Individual images and illustrations may be subject to prior copyright.

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USGS Terrain Map Generalized Bedrock Geology Digitally-enhanced

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Complex Geology of NYS Detailed

Generalized Geology Detailed Geology Bedrock Geology

https://www.thoughtco.com/new-york-geological-attractions-4123009 : noteworthy geologic formations of NYS 5 http://www.mappery.com/map-of/New-York-State-Geologic-Map 6 https://mrdata.usgs.gov/geology/state/state.php?state=NY

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NYS is unique in that all 5 Bedrock Geology and Present-day major landform units are Terrain Units Surface Landform Features found within its borders.

1. Mountains 2. Plains 3. Hills 4. Plateaus 5. Coasts

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Landscape Characteristics Elevations within NYS Lake plain Adirondacks

Elevations range from 0 ft (sea level) along the shores of The surface of Lake Ontario is c.240 ft Long Island and the Allegany Plateau above sea level; Hudson River estuary Catskills

Lake Erie to 5,344 ft at Mt. is +570 ft. Marcy in the High Peaks area of the Adirondack Mts. LI South Shore LI North Shore

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Areas of Excessive Slope Climate Regions

Note the correlation between landform Areas with steep slopes and irregular land surface are and climate regions. difficult to use and usually the last areas settled.

From Thompson, Geography of New York State 11 12

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System of Rivers and Lakes Nature of NYS’s Landscapes as part of the physical landscape

• Land + climate provides the basis of lakes, rivers, soil and scenery. It is a finite resource, one that cannot be manufactured by people. >>PHYSICAL LANDSCAPE

• People manage it and reap its harvest: crops, forest products, wildlife and minerals.

• People tend to concentrate their settlement on the best lands: flat with fertile soil, ease of construction, fresh water supply and access to transportation routes. >>CULTURAL LANDSCAPE

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NYS TOPOGRAPHY Paleogeography

 The physical nature of NYS has not always looked the way it does today. Geologic processes and global climate change have combined to create unique combinations of circumstances.  We must differentiate between the bedrock geology (foundation) and the surficial geology (skin).  The subsurface rocks are hundreds of millions of years old but most of the surface topographic features are only thousands of years old! WHY the difference? Can we explain the current distribution of geologic features and various ages of rock found in NYS?

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Paleogeography Plate Tectonics The process by which sections of the lithosphere (plates) move (drift) along the upper  The state’s oldest rocks are part of the continental core mantle, under the influence of interior forces, rearranging the earth’s surface. and are dated at 1.3 billion years old BUT the landform features we see today are only 8,000-12,000 yrs old because of the continental ice sheets.

. About 1.1-1 billion years ago there was the first of many mountain building periods: Grenville Orogeny. . These mountains were then eroded away only to grow again as a result of subsequent continental collisions. . During these periods, a salt water ocean and an inland sea covered areas where there is now land. . These changes are explained by geologists through the theories of plate tectonics and continental drift. SPREADING ZONE: area of youngest crust 17 SUBDUCTION ZONE: area of oldest crust 18

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Geologic Sequence of NYS’s Continental Drift Paleogeographic Landforms The slow lateral movement of the continents across 405 1.1 bil yrs ago now the basement the earth’s surface in response to plate tectonics. million rocks of the years ago Adirondacks About 225 mya North America and Africa are 135 mya 450 mya attached. The Appalachian Mts. are created. 65 mya 420 mya 465 mya 390 mya Catskills present Delta forms 310 mya

180 mya 580 mya (older) 19 present Note the direction of movement as portrayed by the arrows

Creation of NYS Landforms Summary Taconic Orogeny • Catskill Delta rises 450 mya above sea level 300 mya  NYS’s landforms of were created mainly by • Erosion of mountains Alleghanian Orogeny forces of folding and faulting during continental • Filling in of shallow creates the Appalachian collisions and mountain building periods over hundreds of millions of years. ancient sea (deposits of salt Mts 250 mya and gypsum)  Volcanic activity was present and led to unique Acadian Orogeny • Erosion of mountains features in the eastern part of NYS. 390 mya Champlain rift created  The processes are also responsible for the creation of • Erosion of mountains 180 mya as Pangaea splits up the great variety of rocks and minerals found in NYS. Doming of the • Catskill Delta created Adirondacks begins Collision with Africa 20 mya as a hot spot of volcanic activity 310 mya began to push upward.

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Detail Physiography Notice any Physiographic Map of trends in the of NYS and Vicinity orientation NYS and vicinity showing of the 2 landforms? Surface Features 1. Central NYS marks the north 2 edge of the Appalachian Plateau. 2. The Adirondacks and Thous- and Islands are part of the 3 Canadian Shield, the oldest area of North America. 3. The coastal lowlands of lakes 3 1 Erie and Ontario are part of the 4 Interior Lowlands of N.America. 4. The Taconics are part of the New England Upland. They in- clude Westchester, Manhattan 5 Island and northern Staten Is. Edge of continental 5. Long Island and southern shelf and Hudson Staten Island are part of the Canyon. 23 Atlantic Coastal Plain. 24

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Champlain Catskill Delta Lowlands Lake Champlain now oc- cupies a rift zone created EAST as Pangaea split (180 mya). WEST As Africa moved away from North America and pressure lessened, the crust “drop- ped” down in relation to bordering areas, creating a lowland.  HOW? Eventually the lowland Erosion of the Acadian Mts. deposited sediment into the shallow sea in the interior of proto-North American continent. flooded creating the lake. As the mountains grew, erosion increased, filling the sea with sediment. It is thickest on the east and thins toward the west. 25 26

Creation of Adirondack Mts. Adirondack Mts.

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very old rock topped by young rock

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Uplift – a very recent process pushed Radial old rock through younger layers drainage High Tug Hill Champlain patterns Plateau Peaks Lowland 3 indicates a dome

structure. 28

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Tectonic Provinces of Elevation of Adirondack Landforms in Eastern North Mts Northeast US America NYS The Hudson-Mohawk Hundreds of millions of corridor is 1 of 3 routes years of geologic activity across the Appalachian have created the present- Mts. and the only low- day distribution of tectonic land route north of regions of North America. Alabama. Elevation is c.450 ft. at Rome, NY. It connects the Atlantic coast to the Interior Low- lands via the Great Lakes. 29 30

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Physiographic Regions of NYS Physiographic Regions of NYS

NYSGS identifies 12 physiographic regions. – Each has physical characteristics that are unique to it. – Their characteristics have influenced human perception and subsequent land use.

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Landform Analysis How geographers assess the landscape.

Physical Characteristics Influence on People Now on to

• Elevation – height above sea level • Barrier or Unifier –fosters Glaciers ! • Relief – vertical difference 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/Communication – • Valley Shape and Stream Flow – 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)

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