Tahoe BasinBy: Victoria Luquin

Disclaimer: Unless otherwise specified, all photos are taken by author.

How did the Tahoe Basin Form?“The Lake Tahoe Basin began to form around 670 million years ago and at that time, the area that is now the Basin

was a shallow sea and part of the super continent Pangaea. Sediment slowly deposited on the floor of the shallow sea

for hundreds of millions of years creating a block of sedimentary rock. Nearly 210 million years ago the North

American Continental Plate broke off from Pangaea and began to drift west. At the same time, the Pacific Ocean Plate

beneath the ocean began to drift east. The plates crashed together and the pressure pushed the Pacific Ocean Plate

under the North American Plate. Over the next 130 million years the increased pressure and temperature from the

colliding plates caused rock to melt and form plumes of lava that began rising toward the surface of the earth

thousands of feet below the sedimentary rock. The long, slow cooling process allowed crystals to form and create the

granitic rock seen in the Sierra Nevada. Tops of the lava plumes pushed through the rock leaving outcrops of altered

sedimentary rock, called metamorphic rock. Then, approximately ten million years ago, the Sierra Nevada granitic

rock broke through the surface of the earth after an active fault along its eastern side caused it to rapidly rise. Two

additional active faults on the east and west side of what is now Lake Tahoe created a valley floor that dropped

thousands of feet below the mountain ranges. The last ice age started approximately three million years ago and

ended ten thousand years ago. The Sierra Nevada was not affected by continental ice sheets but did experience

mountain glaciations. Dams were created by glaciers pushing rocks into piles that formed areas like Emerald Bay,

Cascade Lake and Donner Lake in the Lake Tahoe Region” (Hill, M).

Views from Emerald Bay

View from Eagle Falls

RocksThe pictures I have of the rocks were ones that I took as I walked the trails at Emerald Bay and Eagle Falls. I have never actually been up to this area in the whole 17 years I’ve lived in South Lake Tahoe, but I definitely plan on going again soon. The view is amazing!

Rock: Sample 1“The peaks that surround Lake Tahoe

are mountains of granite. Granite is a

light gray, medium to coarse-grained

rock. It is prevalent in the Sierra

Nevada Mountains, along with other

igneous rocks and metamorphic

slate. Granite is composed of two

light-colored minerals, quartz and

feldspar. Some granite appears to be

salt and pepper in appearance due to

the presence of darker colored

minerals such as iron and

magnesium” (The Lake Tahoe Basin).

Rock: Sample 2I believe that these are also

samples of granite. Although the

top right sample seemed to have a

different, and much darker

appearance at first it does have the

“pepper” appearance like the rest.

Igneous rock, what is it?“Igneous Rock is formed when a magma cools underground and crystallizes or when it erupts unto the surface of the ground, cools and crystallizes. Magma that erupts onto the surface is called lava. When magma cools slowly underground the crystals are large enough to see. When it cools quickly on the surface, the crystals are very small and you would need a magnifier or a microscope to see them. Sometimes, when the magma cools very quickly, it forms a kind of black glass that you cannot see through” (Peck, D).

Rock: Sample 3

My best attempt at identifying the

rocks in this picture lead me to believe

that these rocks are the sedimentary

rock sandstone.

Sedimentary rock, what is it?“Sedimentary Rock forms from particles, called sediment, that are worn off other rocks. The particles are sand, silt, and clay. Sand has the largest particles while clay has the smallest. If there are a lot of pebbles mixed with the sand, it is called gravel. The sediment gets turned into rock by being buried and compacted by pressure from the weight above it. Another way it becomes rock is from being cemented together by material that has been dissolved in water. Often, both cementing and compaction take place together” (Peck, D).

FloraThe following pictures of plants are all pictures that I captured on the walk on the trail. I

chose to capture more pictures of flowers because it is obvious that we are surrounded

by trees here in Lake Tahoe, so I figured I’d take advantage of the nice change of view.

While searching for identifications for the plants I took pictures of, I was unable to find

any information on the evolution they have gone through. Some of the other plants that

are common in the area are: “TREES: Alder, Aspen, Cedar, Jeffrey Pine, Lodgepole Pine,

Ponderosa Pine, Sierra Juniper, Sugar Pine, White Fir, Willow. WILDFLOWERS BY COLOR:

Blue & Purple: Dwarf Alpine Aster, Lupine, Meadow Penstemon; Pink & Red: Columbine,

Indian Paintbrush, Shooting Star, Snow Plant, Thistle; White: California Corn Lily, Common

Yarrow, Cow Parsnip, Mariposa Lily, Ranger Buttons; Yellow: Buttercup, Mountain Mule

Ears, Sulphur Flowers” (The Lake Tahoe Basin).

Plant: Sample 1

The identification I have

found for this plant is that it

is mountain spiraea. It is a

pink plant that looks kind of

fuzzy. It is a dense branching

shrub.

Plant: Sample 2This flower is called mountain

pride. It took me forever to find

what this flower was. It is a really

beautiful flower. It is also known

as, “Penstemon newberryi and it is

a bushy perennial subshrub that

reaches a height between 12 to 30

centimeters” (Mathews, L).

Plant: Sample 3

This flower, I think, is the

Sulphur flower. This is the

name I found for the closest

resembling flower to this.

Plant: Sample 4This is a sagebush.

“Common Name: Sagebrush,

Big Sagebrush

Genus: Artemisia

Species: tridentata” (K., E).

FaunaI wasn’t lucky enough to see any animals on the larger scale, or on the small scale

for that matter. I heard the birds, but couldn’t spot where they were. Therefore, I

researched the common animals of the area and they are: “BIRDS: American

Robin, Bald Eagle, California Gull, Canada Goose, Dark-eyed Junco, Hairy

Woodpecker, Mallard, Mountain Chickadee, Red-tailed Hawk, Steller's Jay,

Western Tanager, Yellow-Headed Blackbird. MAMMALS: Black Bear, Coyote,

Douglas Squirrel (Chikaree), Golden-mantled Ground Squirrel, Mule Deer, Pine

Martin, Yellow-bellied Marmot” (The Lake Tahoe Basin).

Animal: Sample 1I believe this butterfly is the

Spring Azure. It is also known as

the Celastrina ladon. “Family:

Lycaenidae; Subfamily:

Polyommatinae” (Butterflies and

Moths of North America).

Unfortunately I couldn’t find any

information on the evolution of

this butterfly.

Animal: Sample 2“The Steller’s jay is a bold and

aggressive species frequently found

scavenging in campgrounds, picnic

areas, and feeding stations in the

West. It’s identification is a nearly

unmistakable dark blue, black-

crested jay with variable white or

blue markings on the head. The

wings and tail are a vivid blue, with

fine black barring. The head,

including the crest; back; and throat

are blackish (Stellar’s Jays). It is also

known as Cyanocitta stelleri. I

couldn’t find evolution for this either.

(Stellar’s Jay Photo)

Animal: Sample 3The Brown Bear. They are the

most common bear seen in the

area. They are most fun to see

when they are mom and baby,

although, it isn’t safe to get

close to baby even if you don’t

see mom because she is closer

than you think. The brown bear

is also known as Ursus arctos.

Brown bears are thought to

evolve from Ursus etruscus.

They remain from the

Pleistocene, where it is

believed that they outcompeted

cave bears.

(brown bear of south lake tahoe)

(The Lake Tahoe Basin)

References

Butterflies and Moths of North America | collecting and sharing data about Lepidoptera. (n.d.). Butterflies and Moths of North America |

collecting and sharing data about Lepidoptera. Retrieved June 17, 2013, from http://www.butterfliesandmoths.org/species/Celastrina-

ladon

Hill, M. (n.d.). Lake Tahoe Geology. eh2o.saic.com Home Page. Retrieved June 6, 2013, from

http://eh2o.saic.com/tiimsWebsite/Content/BasinTopics/geology/default.html

K., E. (n.d.). Common Sagebrush - Artemisia tridentata. Blue Planet Biomes. Retrieved June 12, 2013, from

http://www.blueplanetbiomes.org/common_sagebrush.htm

Mathews, L. (n.d.). California Phenology Project. CPP. Retrieved June 10, 2013, from https://www.usanpn.org/cpp/PENE

Peck, D. (n.d.). Rock Key. Bob's Rock Shop: The First 'Zine for Mineral Collectors and Rockhounds. Retrieved June 10, 2013, from

http://www.rockhounds.com/rockshop/rockkey/

Steller's Jay Photo - Photograph - Picture. (n.d.). South Dakota Birds and Birding - By Terry Sohl. Retrieved June 18, 2013, from

http://sdakotabirds.com/species_photos/stellers_jay_1.htm

Steller’s Jays, Steller’s Jay Pictures, Steller’s Jay Facts - National Geographic. (n.d.). Animals - Animal Pictures - Wild Animal Facts - Nat

Geo Wild - National Geographic. Retrieved June 19, 2013, from http://animals.nationalgeographic.com/animals/birding/stellers-jay/

The Lake Tahoe Basin | Lake Tahoe Vacation Rentals | Lake Tahoe Cabins. (n.d.). Lake Tahoe Vacation Rentals | Lake Tahoe Cabins. Retrieved June

6, 2013, from http://www.tahoevacationguide.com/laketahoe.html

brown bear of south lake tahoe - Google Search. (n.d.). Google. Retrieved June 19, 2013, from http://www.google.com/search?

q=brown+bear+of+south+lake+tahoe&bav=on.2,or.r_qf.&bvm=bv.47883778,d.cGE&biw=12 42&bih=542&um=1&ie=UTF-

8&hl=en&tbm=isch&source=og&sa=N&tab=wi&ei=sEjBUcOtKIrAigKnq4DICg#imgrc=_