Mount Tallac and the Desolation Wilderness (Lake Tahoe Basin)

Rane PakizProfessor LawlerGeo 103Spring 2015

Table of Contents

• Research methods• Location and access• Geological history• Rock samples• Biotic samples• References

Research Methods

• In late June of 2015, I visited Mount Tallac in the Desolation Wilderness Area.

• All photos, minus aerial, were taken on this trip.

• Satellite photo/maps were provided by Google Maps

• Identification of rocks and living organisms were the result of extensive internet searches.

Site LocationMount Tallac Lies in the Desolation Wilderness in the Sierra Nevada Mountains @ Coordinates: 39.0914759,-120.1585048,11z

Desolation Wilderness

Mount Tallac

Access to Mount Tallac, which lies on the Eastern edge of the Desolation Wilderness area, can be found in the south shore of Lake Tahoe.

Hwy 28Cathedral RdMount Tallac Trail.

Summit lies 5.4 miles from trail head.

Geologic History of Area

• The Sierra Nevada mountain range, including Mount Tallac, are the result of an arc shaped chain of volcanoes, creating a granite mountain chain during the Mesozoic era.

• However, contrary to popular belief, Lake Tahoe itself was not formed by a collapsed crater, but rather from the rise and fall of two landscapes due to faulting.

Rock Sample: Shale

Shale is a sedimentary rock Relatively soft Fissile, splitting into layers

Rock Sample: Granite

Granite is an igneous rock Granite is usually light colored and hard Formed from slow crystalization under

crust Grains are large enough to be seen by

naked eye Most common rock in this area

Rock Sample: Schist

Medium grade (temperature) metomorphic rock

Distinct foliation, representing alternating layers of different minderals

Associated with mountain building episodes

Commonly contain crystals

Rock Sample: Sandstone

Sandstone is a sedimentary rock

Made up of sand-grain sized rock, and cementing agents.

Sand refers to particles between 1/16 mm and 2 mm.

Sandstone is regularly reshaped by wind or water due to its softness.

Rock Sample: Siltstone

Sedimentary rock made of a cross between sand and clay

Can’t see individual grains, but you can feel them

Sometimes contain quartz veins

Plants and animals

Mixed plant life, shrubs, gymnosperms, and angiosperms

Insects were abundant, including ants and bees, but were routinely hard to photograph.

Large organisms, such as bears and deer habitate here, though no evident sign.

Multiple lakes nearby for animal watering

Mariposa Lilly

Scientific name: Calochortus leichtlinii Lives in harsh, rocky terrain Loves water, and has adapted to environment by

storing water in bulbs Have developed color patterning to attract pollinators

Applegate’s Paintbrush Bright colors, suggesting

toxicity, but not actually toxic

Root parasite, tapping into the nutrient and water sources of neighboring host plants

Dispersed amongst relatively dry, high elevation slopes.

Actually used by Native Americans as paint

Lichen

Grow on the roots of plants and trees. Lichen are incapable of making their own food,

and so they have formed symbiotic relationships with both cyanobacteria and algae.

Lichen decompose nutrients which other organisms use

Lichen use the photosynthesis of partner organisms for energy

Aerator Ants

Help decomposition Aerate forest floor Primary Consumers,

provide food for higher consumers.

Underground tunneling improve lake water clarity

References• Alden, Andrew. "Shale - Sedimentary Rock Types." Web. 21 June 2015.

• "Applegate's Paintbrush, Wavy-leaf Paintbrush." : Castilleja Applegatei Var. Pinetorum (Synonyms: Castilleja Applegatei Var. Fragilis, Castilleja Applegatei Ssp. Pinetorum, Castilleja Pinetorum, Castilleja Wherryana). Web. 21 June 2015.

• "Botanical Portrait of Mariposa Lily." Botanical Portrait of Mariposa Lily. Web. 21 June 2015.

• "Castilleja Applegatei | Applegate's Indian Paintbrush." Castilleja Applegatei | Applegate's Indian Paintbrush. Web. 22 June 2015.

• "Desolation Wilderness." Area. Web. 22 June 2015.

• "Granite." : Igneous Rock. Web. 21 June 2015.

• "Lake Tahoe Basin Mgt Unit - Learning Center." Lake Tahoe Basin Mgt Unit - Learning Center. Web. 21 June 2015.

• "Lichen Biology and the Environment." Lichen Biology and the Environment. Web. 22 June 2015.

• "News." Ants of All Things Could Hold Key to Future Lake Tahoe Clarity Efforts: University of Nevada, Reno. Web. 22 June 2015.

• "REFERENCES." Sierra Wild Flowers.org. Web. 21 June 2015.

• "USGS Geology in the Parks." USGS Geology in the Parks. Web. 21 June 2015.

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