REQUIRED ROCKS & FAMOUS ROCK FORMATIONS
IGNEOUS ROCKS
Formed when magma or lava cools & crystallizes
INTRUSIVE (Plutonic): magma cools underground slowly large,visible crystals
GRANITE Feldspar, quartz, mica & hornblende
PEGMATITE Quartz, feldspar, mica & muscovite
Intrusive Igneous Rocks
GRANITE PEGMATITE
Yosemite – El Capitan
3,600 feet granite exposed by glaciers
Yosemite – Half Dome
8,900 feet of granite Other ½ carved away? 93% grade
Joshua Tree– skull rock
granite
Joshua Tree– granite marbles
Shasta– Castle Crags
Granite from remnant of plug dome volcano.
Intrusive Igneous Rock
magma can penetrate rock Horizontally SILLS Vertically DIKE
INTRUSION ROCKS are rocks that have been “disturbed” magma
Devil’s Tower, WY
Igneous intrusive rock in sedimentary rock
Thought to be a volcanic neck or plug, exposed by erosion
Devil’s Pipes– CA
Los Arcos, Cabo San Lucas
intrusive igneous rock worn away by waves
IGNEOUS ROCKS
EXTRUSIVE (Volcanic): lava cools above ground rapidly no visible crystals
OBSIDIAN Silicon & oxygen
BASALT Feldspar,pyroxene, & olivine
PUMICE Silica & feldspar
Extrusive Igneous Rocks
OBSIDIAN PUMICEBASALT
“glassy”
black & forms
bedrock
gas trapped as it cools
Columbia River Flood Basalts, OR
Shiprock, New Mexico
Basalt volcanic neck erosion
SEDIMENTARY ROCKS
Rock form from sediments or organic material
CLASTIC: formed of large or small sediments cemented together
CONGLOMERATE - particles cemented SANDSTONE- quartz, feldspar, & calcite SHALE - feldspar, quartz, mica LIMESTONE- calcite (coral, shells) DIATOMACEOUS EARTH – calcite (diatoms)
Clastic Sedimentary Rocks
CONGLOMERATE SHALESANDSTONE
2 mm or larger
mudless than 1/256
mm
sand1/16 – 2
mm
Clastic Sedimentary Rocks
LIMESTONE DIATOMACEOUS EARTH
Arches, Utah
Sandstone built above salt beds combined with wind erosion arches
Beehive, Utah
Chimney Rock, Colorado
Sandstone worn by erosion
“Finger to God”, Africa
Mono Lake Tufa
river carries calcium into lake which reacts with carbonates in lake limestone
“Diatomaceous Earth”, Hat Creek
“chalk like“rock that crumbles into powder.
fossilized diatoms (algae)
used in tooth fillings, pool filters, cat litter
SEDIMENTARY ROCKS
NON-CLASTIC: made from minerals or living things “ORGANIC”
CAVE DEPOSITS “dripping” limestone
PETRIFIED WOOD Fossilized wood – manganese, iron & copper
COPROLITE Fossilized animal dung – calcium, phosphorous
& quartz
Non-Clastic Sedimentary Rocks
PETRIFIED WOOD
COPROLITECAVE DEPOSITS
Shasta Caverns
METAMORPHIC ROCKS
Rocks changed by heat or pressure
MARBLE - changed from limestone SLATE - changed from shale MICA SCHIST - changed from pegmatite QUARTZITE - changed from sandstone GNIESS- changed from granite
Metamorphic Rocks
MARBLE MICA SCHISTSLATE
QUARTZITE
GNEISS
Sierra Nevada Mtns
Marble Canyon, Death Valley