Lindsay Patrick Emily Howson Lizz Echard

Draw a line around the world, starting mid-center between Joshua Tree and Death Valley, and you will touch or come close to many of the world’s great deserts: Mojave, Great Basin, Sahara, Arabian, Iranian, Gobi. Most deserts occur between the latitudes of 15 and 40 degrees on either side of the equator.Draw a line around the world, starting mid-center between Joshua Tree and Death Valley, and you will touch or come close to many of the world’s great deserts: Mojave, Great Basin, Sahara, Arabian, Iranian, Gobi. Most deserts occur between the latitudes of 15 and 40 degrees on either side of the equator.

For a first time visitor the desert only hints at it’s vitality and may appear uninviting or bleak; but surreal geologic features add to the attraction of this place.For a first time visitor the desert only hints at it’s vitality and may appear uninviting or bleak; but surreal geologic features add to the attraction of this place.

One Of A Kind Nearly 800,000 acres Southern California Is a land shaped by strong winds, sudden torrents of rain, and climatic extremes. Rain Shadow desert Junction of 3 ecosystems: –2 deserts (mainly determined by elevation), & 1 oasis

–The Colorado Desert ( a western extension of the vast Sonoran Desert) –“Low”: 3000 ft above –Eastern & Southern –Creosote bush, Spidery Ocotillo & “jumping” Cholla Cactus

Mojave Desert “High” (cooler & wetter) Northern part of park Joshua Tree (Western part) Lowest absolute elevation & the highest maximum temperature 134°F “Basin and Range Province”: A landscape of alternating mt ranges & their bordering basins –Explorer John Fremont- “The most repulsive tree in the vegetable Kingdom”. Rain Shadow effect –Created when mountains lie parallel to moist, coastal areas.

–Oases: Dramatic compared to arid surroundings Western 4000 feet –6 Fan Palm Oases Water occurs naturally along fault lines 80 to 90 years 75 feet Shaped like a fan and folded like an accordion The presence of beetles is actually a sign of a healthy oasis.

“As old as the desert may look, it is but a temporary phenomenon in the incomprehensible time-scale of geology” –Ranger plate tectonics, volcanism, mountain-building, & stark erosion ft above Sand dunes, dry lakes, flat valleys, rugged mountains, granitic monoliths, and oases Queen Valley & Lost Horse Valley Pleasant Valley-basins 6 Mt ranges –Little San Bernardino Mountains (southwestern) –Cottonwood –Hexie –Pinto Mountains (center) –Eagle & Coxcomb Mts (eastern)

oJoshua Tree is crisscrossed with 100’s of faults oCan see raw rocks & effects of earthquakes. oSan Andreas Fault on south side of park (Keys View) oBlue Cut Fault (center) oFault zones = localized natural springs oPinto Mountain fault (Maria Oasis-visitor center) plus 4 other fault oases

100 mil yrs ago, molten liquid, heated by the movement of Earth’s crust, oozed upward & cooled while still below the surface. granitic rock called monzogranite. –system of rectangular joints –1 ST : Horizontal set, removal by erosion of overlying rock, called gneiss –2 ND : Vertical set, contact of the monzogranite with its surrounding rocks –3 RD : Vertical set, develop rectangular blocks. Rock Piles= As ground water filtered down through the monzogranite’s joint fractures, transform soft clay, the eroded boulders settled one on top of another.

Daytime: Birds, lizards, roadrunners, & ground squirrels Nocturnal: snakes, bighorn sheep, kangaroo rats, coyotes, & black- tailed jack rabbits. Burrows Reptiles vs. mammals in storing water Desert Plants National Park: 700 species Cryptobiotic crusts- hold the place in place

Wilderness is an area “…where the earth and its community of life are untrammeled by man, where man himself is a visitor who does not remain…”

Can see the Mexican border/ Mount San Jacinto/ Los Angeles from the mile-high Keys View. Over 12 million ppl in LA= smog/pollution

Man-made lake 20 miles outside park, scientists claimed that it’s messing with the rain shadow effect.

Admired By Many Clear skies & clean air Peaceful and tranquil An adventure Extremely fragile, carelessness may leave lasting scars or disrupt a system of life that has existed for eons.

n.html Our Geology book under “Rain Shadow Deserts”

Where do oases occur? What is the name for the granitic rock found in the rock piles at the park? What famous fault is on the south side of the park? Which of the two deserts (ecosystems) is considered the “low” desert? Why is it a rain shadow desert?