Properties of Features in Thin
Sections
PROPERTIES of FEATURES IN THIN
SECTIONS
(FitzPatrick, 1993)
Color- the color of sample and minerals in thin section
with polarized light.
Prominence- the extent to which the feature is conspicuous
within the field of view. Contrast may be due to transparency,
opacity, color, relief, interference color, size, shape, or
distribution pattern.
Size- it is possible to divide minerals or features into
size classes. Although the exact size is indeterminate because
of the random cut of the thin section, approximations can be
made:
| Very large | >10,000µm
(10mm) |
| Large | 2,000-10,000µm
(2-10mm) |
| Medium | 200-
2000µm |
| Small | 60-
200µm |
| Very small | 2-
60µm |
| Micro | <2µm |
Shape- this inclueds the geometric forms, crystallographic
forms and a number if irregular shapes. About 43 shape forms are
listed in the book (see Bullock et al for some examples).
Frequency of occurrence as determined as percentage of
area. (NOTE - FitzPatrick breaks his frequency distribution into
more divisions than may be feasible without detailed counting of
grains or features)
| Abrupt | <100µm |
| Sharp | 100-
500µm |
| Clear | 500-1000µm
|
| Diffuse | >1000µm
|
Distribution patterns of a feature or the spatial
relationship between individuals. All distribution patterns are
relationship patterns.
Relationship between features includes the relationship
between different features, or how does one feature relate to
another.
Banded - the features occur in alternating
bands.
Clustered - Occurring in clusters - the clusters vary in
closeness of the individuals and may be dense,
even, uneven, or wide.
Coated - Coated with a different material.
Inclined - The feature in inclined to some other
feature.
Intimate - The two or more features present are intimately
associated with each other.
Normal - The feature is arranged at right angles to some
other feature.
Paired - the features occur as pairs (I am not sure how
this differs from intimate)
Parallel - The features are parallel to each other.
Radial - The feature is distributed radially to some other
component.
Unrelated - The feature has no fixed relationship with any
other feature. The relationship may be defined as
haphazard.
Orientation patterns may be due to soil forming processes
or they may be inherited. The orientation should be described in
terms of orientation direction, orientation degree
(strongly to weakly oriented), and orientation
relationships.
This page
(http://www.ces.ncsu.edu/plymouth/programs/properties.html)
created by
Vera MacConnell,
Research Technician, I
on February 6, 1998.
Last Updated on February 20, 1998.