FIELD ASSIGNMENT

PART 1

By: Brittney Minor

COALINGA, CALIFORNIA

Coalinga, California is located in the Great Valleys of California. Rock deposits are mostly

made up of sediments that have been brought here since the Jurassic, which is about 160 million

years ago, and continue to be deposited. There is a large quantity of oil fields located in the San

Joaquin Valley, and the little town of Coalinga is surrounded by them.• http://www.conservation.ca.gov/cgs/information/publications/cgs_notes/note_36/Documents/note_36.pdf

The Great Valley is composed mostly of Quaternary sedimentary deposits with a few

Tertiary and Quaternary volcanic rocks, and Mesozoic and Paleozoic metamorphic rocks;

including some Precambrian metamorphic rocks. On the west side of the Great Valley, where

Coalinga is located, there are also deposits of Tertiary sedimentary rocks, and Mesozoic

sedimentary rocks. Coalinga, California is located in one of the most diverse rock deposit beds in

the Great Valley. • http://www.conservation.ca.gov/cgs/information/publications/cgs_notes/note_17/Documents/note_17.pdf

IGNEOUS ROCKS

There are two different processes of which Igneous rocks form.

Intrusive igneous rocks-rocks that are formed when lava cools and

crystalizes before it reaches the surface.

• Examples include Granite, Diorite, and Gabbro.

Extrusive igneous rocks-rocks that are formed when lava cools on the

surface, known as molten rock.

• Examples include Rhyolite, Andesite, and Basalt.

Earth an Introduction to Geology 10th Edition- Tarbuck, Lutgens, Tasa

IGNEOUS ROCKS

I believe both samples to be Extrusive igneous rocks. After research

I have concluded that the first sample is Andesite due to the texture

and color. I have also come to the conclusion that the second

sample is Basalt.

Sample #1 Sample #2

METAMORPHIC ROCKS

Metamorphic rocks change form. When the “parent rock” is exposed

to new conditions such as elevated temperatures and pressure that are

extremely different from what the rock is used to. These new elements

change the rock until it finds a new state of equilibrium. Heat can be a

factor, but if the rock completely melt, it would fall under the category of

igneous rock.

Earth an Introduction to Geology 10th Edition- Tarbuck, Lutgens, Tasa

METAMORPHIC ROCK

I believe sample #3 to be Slate because of the shape and texture. I

believe that Sample #4 is Quartzite due to texture and pattern.

Sample #3

Sample #4

SEDIMENTARY ROCK

Sedimentary rocks are rocks that are formed from the weathered products of preexisting

rocks that are transported, deposited, and lithified.

Detrital sedimentary rocks- rocks that are formed by whole particles being transported and

accumulated by chemical and mechanical weathering.

Chemical sedimentary rocks- rocks that are formed of material that was precipitated from

water, whether it be by organic or inorganic means.

Organic sedimentary rocks- rocks that are formed from organic material, such as plants.

They are normally found in the bottom of swamps. The primary example of organic

sedimentary rocks is coal.

Earth an Introduction to Geology 10th Edition- Tarbuck, Lutgens, Tasa

SEDIMENTARY ROCKS

I believe Sample #5 to be a piece of Travertine due to texture and

color patterns.

Sample #5

RESOURCES

http://www.conservation.ca.gov/cgs/information/publications/c

gs_notes/note_36/Documents/note_36.pdf

http://www.conservation.ca.gov/cgs/information/publications/c

gs_notes/note_17/Documents/note_17.pdf

Tarbuck, Lutgens, Tasa (2011) Earth an Introduction to Geology

10th Edition