Void Areas

VOID AREAS

Voids: Voids occur in four different positions: 1) between (inter) aggregates; 2) within (intra) aggregates; 3)across (trans) aggregates; and 4)within non-aggregated material. See Brewer (1976) for the definitions of the various void classes.

Packing Voids: These are composed of three types:

Simple Packing Voids: Equant to elongate, much interconnected, occurring between single grains.
Compound Packing Voids: Equant to elongate, much interconnected, occurring between peds, the faces of which do not accommodate each other.
Complex Packing Voids: Voids occurring between single grains and small aggregates.
Vughs and Vesicles

Vughs: Relatively large voids other than packing voids, spherical to elongate, irregular, not normally interconnected to voids of comparable size.
Vesicles: Relatively large voids other than packing voids whose walls consist of smooth, simple curves; equant, prolate or oblate. In verticla sections, vesicles are usually characterized by a parallel referred distribution.
Channels and Chambers:

Channels:Elongated, cylindrical or arched, regular conformation, usually smoothed walls; uniform cross section over much of the length.
Chambers: Near spherical, connected by channels, smoothed walls, no cylindrical shape.
Planes: Planar according to the ratio of principal axes.
Micromorphologists often have difficulty in distinguishing planar voids and channels in some materials. Some of the differences are outlined below:

OBSERVABLE DIFFERENCES BETWEEN CHANNELS AND PLANAR VOIDS

Channels Planes

1. Approximately equal diameter throughout length and lacking sharp termination. 1. Variable diameter along length terminating in at least one sharp edge.

2. Coatings may be the same thickness on both sides. 2. Coatings not the same thickness on both sides of the plane.

3. Compaction may occur in adjacent matrix material. 3. No compaction in adjacent matrix material.

4. Opposite walls generally do not accommodate each other. 4. Good accommodation of opposite walls.

5. Changes in direction achieved without angular faces. 5. Changes in direction marked by fairly sharp angles.

6. Often visible only over short distances because of changes in direction in relation to the orientation of the selection. 6. May be visible over long distances.

This page (http://www.ces.ncsu.edu/plymouth/programs/void.html) created by
Vera MacConnell, Research Technician, I on January 27, 1998.
Last Updated on February 4, 1998.


Channels	Planes
1. Approximately equal diameter throughout length and lacking sharp termination.	1. Variable diameter along length terminating in at least one sharp edge.
2. Coatings may be the same thickness on both sides.	2. Coatings not the same thickness on both sides of the plane.
3. Compaction may occur in adjacent matrix material.	3. No compaction in adjacent matrix material.
4. Opposite walls generally do not accommodate each other.	4. Good accommodation of opposite walls.
5. Changes in direction achieved without angular faces.	5. Changes in direction marked by fairly sharp angles.
6. Often visible only over short distances because of changes in direction in relation to the orientation of the selection.	6. May be visible over long distances.