Transcript Provinces of Virginia Presentation

Provinces of Virginia
Differences Among Provinces
Physiography: landforms change and the
countryside has a different appearance
Rock Type: igneous, sedimentary and/or
metamorphic
Rock Structure: flat or folded & faulted
Geologic Ages of the rocks
Coastal Plain
Location
from Atlantic Ocean on
east to fall line at west
continues underwater
to continental slope
Physiography
Flat & often marshy
Low slopes, barrier
islands & salt marshes
Coastal Plain
Rock Type: Sedimentary
Layered by sediments left
when area was flooded &
by sediments eroded from
Appalachian Mtns
transgression: when sea
level rises & floods the
land
regression: when sea level
drops, exposing the land
All sedimentary rocks at
surface
Many oceanic fossils
Oblique aerial view of Passmore Creek
and
marsh, Jamestown Island, James City
County
Coastal Plain
Structure
Fairly low-relief, but
dips slightly toward
ocean
Geologic Age
Youngest of VA
provinces
Started forming when
Atlantic Ocean opened
in late Triassic
Coastal Plain Fossils
Whale fossil from Miocene
Eastover Fm., New Kent County
Common seashell fossils
Coastal Plain – Chesapeake Bay
The Chesapeake Bay was
created about 5000 to
6000 years ago when the
area was flooded as
meltwater from glaciers
raised sea level.
Continuing sea level rise
and shoreline erosion
caused the bay to grow
further.
Piedmont
Location
from fall line at east to
mountains (Blue Ridge
province) on west
Physiography
Outer Piedmont (Eastern)
gently rolling upland
erosion flattened the
surface of the folded
bedrock beneath
Inner Piedmont (Western)
rugged terrain
erosion hasn’t smoothed
the folded metamorphic
rock
small broken belt of
mountains
Piedmont
Rock Type: Metamorphic
Metamorphic rocks (from
Precambrian) folded during
the Paleozoic when North
America and Africa hit
Igneous intrusions (granite
& basalt) from rifting when
Pangaea broke apart
Soil at surface is red &
clayey from oxidation of
rocks below
Montpelier anorthosite exposed
in the Virginia Piedmont
Piedmont
Structure
Deeply weathered
folded bedrock
More resistant outcrops
are seen nearer the
Blue Ridge
Scattered old volcanic
arcs, faults &
intrusions
Geologic Age
late Proterozoic
through Paleozoic
Piedmont Resources
Virginia Slate(above)
and Gold (below)
Dinosaur
footprint (left)
found in
Culpeper Basin
sandstone
quarry, above
Blue Ridge
Location
thin province
extending from Piedmont to
east, Valley & Ridge to
west
Physiography
Average height of area
~3000ft above sea level
VA’s two highest peaks in
southwest corner of Blue
Ridge
Blue Ridge
Rock Type: Igneous &
Metamorphic
Complexly folded & faulted
granite & metamorphic rock
dating from Precambrian
age – original North
American basement rock
(Grenville)
Thrust upward during
collision between N Amer
& Africa in late Paleozoic
The northern Blue Ridge of Virginia, as
seen from Shenandoah National Park
Blue Ridge
Structure
Folded & faulted
Steep mountains, high
relief
Geologic Age
Mid-Proterozoic
through Cambrian
Blue Ridge Resources
Beautiful views which
draw tourists
Catoctin Greenstone – Skyline Drive
Valley & Ridge
Location
Extends from Blue
Ridge to east,
Appalachian Plateau to
west
Physiography
Folded mountains,
which have been
eroded leaving valleys
& ridges
Valley & Ridge
Rock Type:
Sedimentary
Thick folded
sedimentary rock
deposited during
Paleozoic
Resistant sandstone
caps the ridges;
limestone is eroded to
form valleys
(differential erosion)
Valley & Ridge
Structure
Folded bedrock
Steep mountains, high
relief
Geologic Age
Paleozoic
Valley & Ridge Resources
Well-developed Karst topography
Luray Caverns
Appalachian Plateau
Location
Smallest, southwestern
corner of Virginia
Continues into WV
Physiography
High plateau
Somewhat flat, but
eroded by many rivers
Appalachian Plateau
Rock Type:
Sedimentary
Thick folded
sedimentary rock
deposited during
Paleozoic
Deeply cut by many
rivers
Appalachian Plateau
Structure
Similar rocks to Valley
& Ridge, but weren’t
folded – still horizontal
Geologic Age
Pennsylvanian (late
Paleozoic)
Appalachian Plateau Resources
Coal seams exposed along Keen
Mountain, Buchanan County. Each
seam is approximately 0.5 m.
Petroleum
Virginia Relief
Bibliography
http://www.wm.edu/geology/virginia/
http://www.baydreaming.com/images/baymap.gif
http://www.cliffsnaturalstone.net/Wallston%20Template.htm
www.ldeo.columbia.edu
http://pubs.usgs.gov/of/2002/of02-437/image_files/photogallery/frd-s32_l.jpg
http://www.terragalleria.com/america/south-east/virginia/picture.usnc4107.html
http://www.pineyhillbandb.com/attractions.html
http://content.answers.com/main/content/wp/en-commons/thumb/9/9c/500px-Virginia_topographic.jpg
http://www.mme.state.va.us/Dmr/PUB/Brochures/gold.html