Southern California Geology and Volcanic Hazards Lecture Notes

These flashcards cover key terms and definitions related to Southern California geology, specifically focusing on the Rose Canyon Fault, Mission Trails, and associated volcanic hazards.

Peninsular Ranges

A group of mountain ranges, part of the North American Pacific Coast ranges, that stretch 930 miles from Southern California to the tip of Baja.

Detrital (clastic) sedimentary rocks

Rocks formed from the accumulation of fragments derived from pre-existing rocks.

Plutonic igneous rock

Intrusive igneous rock that forms when magma crystallizes beneath the Earth's surface.

Chaparral

Dense, drought-resistant shrub ecosystem found in arid regions.

Riparian ecosystem

An ecosystem found along water sources such as rivers and streams.

Subduction plate boundary

A tectonic plate boundary where one plate moves under another, leading to volcanic activity.

Spheroidal weathering

A type of weathering where joints develop in response to unloading, with chemical weathering occurring along these fractures.

Mechanical weathering

Physical breakdown of rocks without changing their composition.

Chemical weathering

Altering minerals in rocks through chemical processes.

San Andreas Fault

A right-lateral strike-slip fault forming the plate boundary between the Pacific Plate and the North American Plate.

Lithification

The process by which sediments are turned into rock through compaction and cementation.

Sediment maturity

A measure of how far sediment has been transported from its source, characterized by sorting and rounding of grains.

Weathering

The decomposition and breakdown of materials in the Earth.

Erosion

The removal of weathered rock and soil by water, wind, glaciers, or gravity.

Foliation

A texture in metamorphic rocks where minerals are aligned in planes due to pressure.

Fossils

Preserved remains or traces of ancient organisms found in sedimentary rocks.

Subduction

The process where one tectonic plate moves under another, often leading to volcanic activity.

Mafic minerals

Silicate minerals that are rich in magnesium and iron, and generally weather more quickly than felsic minerals.

Exfoliation

The process where layers of rock peel away from the surface, often due to pressure release.

Volcanic hazards

Potential dangers associated with volcanic eruptions, including lava flows, ash falls, and pyroclastic flows.

Lahars

Volcanic mudflows formed from a mixture of water and volcanic ash.