<xsd:documentation>A single qualifier.
In mudlogging terms, a qualifier is a graphical symbol in the
Interpreted Lithology column of the Formation Evaluation Log (aka "the
mudlog").
In addition to the major lithologies (e.g., sand, shale, etc) existing in the
sample, other minerals (present as accessories or inclusions e.g. chert,
pyrite, glauconite) and fossils (forams, oyster shells, bryozoans, etc)
may exist and their abundance is generally categorized using ranges
such as Trace (less than 10%), Common (10-25%) and
Abundant (greater than 25%). These additional minerals and fossils can be of
disproportionately great diagnostic and descriptive value. For example,
qualifiers can be used to indicate facies changes, marker beds or
something that impacted drilling conditions.
These qualifiers (representing accessories, inclusions and/or fossils)
are used to rapidly and graphically indicate to the recipient of the
mudlog that a significant lithological event was encountered while
drilling the well. </xsd:documentation>