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A (6) | B (6) | C (10) | D (11) | E (7) | F (10) | G (10) | H (1) | I (2) | J (1) | L (7) | M (12) | O (3) | P (11) | Q (3) | R (9) | S (23) | T (5) | U (3) | W (1)

A soil that contains a significant proportion of coarse material; 20 to 80 percent of the particles are greater than coarse sand (0.08 inches or 2 millimeters), with the remainder finer than 0.08 inches or 2 millimeters.

Debris Fan

A deposit of debris-sized material that is known or reasonably inferred to be emplaced by mass wasting processes and has a distinctive lobe, fan, or coalescing fan shape. Debris fan can include colluvial and alluvial components.

Debris Flow

A type of slope movement in which the displaced mass is composed of debris and the water content in the displaced mass is sufficient for the material to liquefy and resemble a viscous fluid.

Debris Slide

A slope movement initiated by slippage along a well-defined failure surface that is usually planar or curvi-planar, in which the displaced mass is composed of debris. Slides are divided into two classes, rotational and translational. Slides usually consist of displaced and deformed blocks of material.


A general term for the process of folding, faulting, shearing, compression, or extension of the rocks as a result of various Earth forces.


The destruction of complex natural environments.


A dark, medium-grained, plutonic igneous rock, consisting mostly of calcium-rich feldspar and mafic minerals, that is chemically similar to basalt.


A tabular igneous intrusion that cuts across the bedding or foliation of the rock surrounding it.


A relatively discrete event in time that disrupts ecosystem, community, or population structure and changes resources, substrate availability, or the physical environment.


A common white or colorless rock-forming mineral, calcium magnesium carbonate; also a rock composed of this mineral; adj.: dolomitic.


An ultramafic igneous intrusive rock composed primarily of the mineral olivine.