Week 6 - Geological Interpretations

A visit to Central Coast of California landed me to the complicated Franciscan Rocks that belong to the Marin Headlands Terrane. The geology of the area is complex because of the variety of stones present in the area. There is the sandstone which is a sedimentary rock that is said to be a deposition from submarine landslides that happened at the margins of the continent. The basalt rocks present are said to be the results of the volcanoes that happened under the water. The other type of stone in the area is the chert which is a combination of the shells rich in silica and radiolarian that have single cells. The fourth and last type of stone in the site is the serpentinite that is said to be formed when the earth`s upper mantle alters.

Aside from the given geological map of the area, I would also require aerial photographs, a compass and notes on rock descriptions to complete the geological interpretation.

a)                                     Aerial photographs

Aerial photographs which are pictures taken from the sky are very important in any geological interpretation. Unlike common maps, the pictures give more detailed information of an area making it easier to locate important features. The photograph is also an exact representation of the site hence easier to read.

b)                                    Compass

With a compass I will be able to survey the area in depth and measure the attitudes of the geological features present in the site. A geological compass is called Brunton and it is a combination of the compass, hand level, and the clinometers. Bearings that are taken by a compass will help in giving a better interpretation of the area because they will show the exact point to find a certain material.

c)                                     Rock description notes

The notes that contain all kinds of rocks, where they are found and how they are characterized physically will assist greatly in the geological interpretation of the site. The notes will help confirm the word of the tour guide. It is also via the written notes that we will be able to relate the class teachings to the existing geological structures.