North American Craton

features in parks on north american craton

very old igneous and metamorphic rocks on continental shield, sedimentary layering covering continental platform, glacial features deposited from continental ice sheet, numerous lakes

what is the craton

nucleus of the continent

continental shield

exposures of old igneous and metamorphic rocks

continental platform

sedimentary deposits from shallow seas

colorado plateau

uplifted part of continental platform

foreland structures

formed as compressional forces deformed the edge of the craton

phanerozoic orogenic belts

young mountain ranges that surround the craton

where is the continental sheild

north middle, mostly canada

where is continental platform

south middle and colorado plateau

coastal plain

young sedimentary layers deposited on edge of continent, gulf and east coast

where are the oldest rocks on the continent

center of continental shield

are we in a glacial or interglacial phase

interglacial

where are caves formed

limestone from warm, shallow seas

domes and arches

places where the rocks have been folded upward and erosion exposes older rocks

basins

places where the rocks have been folded downward and erosion exposes younger rocks

how do cave systems develop

limestone and dolomite layers are dissolved by streams and groundwater, sandstone and shale layers are less soluble and remain intact

features in parks on deformed north american craton

erosional features, stratigraphic layers revealing geologic history, basement uplifts, fold-and-thrust belts, foreland basins

areas of deformed craton

colorado plateau, laramide uplifts, foreland fold-and-thrust belt, alaska

parks in colorado plateau

arches, black canyon of the gunnison, bryce canyon, capitol reef, mesa verde, zion

parks in laramide uplifts

rocky mountains, wind cave

park in foreland fold-and-thrust belt

glacier

national preserve in alaskan deformed craton

yukon-charley

permiain reef complex

developed in interior basins connected to the great panthalassa sea after formation of pangea, uplifted by normal faulting in guadeloupe mountains, some reef remains buried

permian reef complex (front to back)

basin, fore-reef,, reef, back-reef

glass mountains fossils

marine fossils from permian reef complex

parks with ancient passive continental margin strata

grand canyon, petrified forest, canyonlands

how is cross-bedded sandstone formed

wind or water flows over dune and deposits sand on other side

where is cross-bedded sandstone seen

zion, canyon de chelly

what is stair-step erosion

soft rocks erode at gentle slope, hard rocks erode at steep slope

where is stair-step erosion seen

capitol reef national monument

example of slot canyons

glen canyon national recreation area

development of foreland stuctures

normal-angle subduction formed foreland fold-and-thrust belt, low-angle subduction formed foreland basement uplifts

formation of foreland fold-and-thrust belt

sediment eroded from rising mountains was deposited in foreland basin on edge of interior seaway, sedimentary strata scrapped off the precambrian basement and compressed via folding and thrust-faulting

what shape valleys do rivers form

V

what shape valleys do glaciers form?

U

formation of foreland basement uplifts

volcanoes and compressional structures developed, laramide uplifts formed by reverse-faults

laramide uplifts

compressional, reverse-faulted structures, uplift and erosion exposes precambrian crystalline basement rocks

examples of laramide uplifts

flat irons, rocky mountain national park, mount rushmore, dinosaur national monument

what are the foreland basement uplifts (definition)

craton compressed and hard basement rocks deformed and shoved upward

foreland fold-and-thrust belts (definition)

platform strata detached from underlying basement rocks and deformed

foreland basins (definition)

basin that develops adjacent to a mountain belt

greenstone

long, down-warped belts within gneiss, green tinge from chlorite and epidote

outwash gravel

deposit of sand and gravel carried by running water from the melting ice of a glacier and laid down in stratified deposits

till

unsorted material deposited directly by glacial ice and showing no stratification

difference between outwash gravel and till

Glacial till is the collective term for all the material carried by the body of the ice as it flows over land, while glacial outwash is restricted to the particles carried by the water arising from the melting of glacier ice.

glacial erratics

rock fragments embedded in ice and carried a few miles to hundreds of miles, found in many parks

glacial striations

when glacial erratics scrape against underlying bedrock, forming long, parallel grooves

lateral moraine

deposited between glaciers and wallrock

terminal moraine

deposited at the front of glaciers

kettle lakes

lake formed in depressions where ice blocks used to be

dolomite

similar to limestone, forms where groundwater moving through limestone replaces some of the calcium with magnesium

travertine

water contacts air inside a cave and releases carbon dioxide, causes calcium carbonate to precipitate as travertine, a dense form of limestone

speleothems

travertine deposits in caves, include flowstone, stalactites, stalagmites, columns, and helicites

columns

stalactites and stalamites merging over time

flowstone

sheets of water draping over cave walls form these travertine deposits

helicites

small drippings forming “twisted-finger” from ceilings and slanted walls

karst

“stony ground,” features formed by the solution of limestone, include caves, sinkholes, springs, and disappearing streams

sinkhole

funnel-shaped depression in the land, formed as groundwater dissolved underlying limestone

badlands topography

a type of arid terrain with clay-rich soil that has been extensively eroded by wind and water

eolian sandstone

lithified remains of eolian sand dunes, deposited during jurassic period

fins

prominent sets of vertical joints developed in sandstones, erosion in joints produced long grooves and deep valleys, leaving fins behind, like some of the walls in bryce canyon