"Unconformity: lack of continuity in deposition between rock strata in
contact corresponding to a period of nondeposition, weathering, or
erosion" (page 1284).
"Diastema: a space between teeth in a jaw" (page 351).
"Hiatus: a break in or as if in a material object. [Also] a gap or
passage in an anatomical part or organ" (page 569).
Source: Webster's Ninth New Collegiate Dictionary, Miriam-Webster Inc. (1987)
"Surface separating layers of sedimentary rocks. Each bedding plane
marks termination of one deposit and beginning of another of different
character, such as surface separating a sand bed from a shale layer.
Rock tends to separate, or break, readily along bedding planes."
"Bedding Plane" http://www.webref.org/geology/b/bedding_plane.htm
All four of these terms relate to the presence of a discontinuity
where one type of substance ends and either a gap is present or a
different substance begins. Unconformity and bedding plane share the
additional commonality of being related to geology, specifically rock
strata. However, in the case of an unconformity, the termination of
the rock layer is defined by a gap whereas in the case of a bedding
plane, the termination of the rock layer is defined by the start of a
different type of rock layer, but no gap exists.
Hiatus and diastema are both similar in that they both refer to a gap
in an anatomical part. A diastema is more specific than a hiatus
because it refers to the spaces between teeth, whereas a hiatus can
occur in any anatomical part or organ and can even be more broadly
applied to any material object. A hiatus also does not require for a
break to actually be present in a material object, but can be used to
describe a passage having similar characteristics to a break which is
nonetheless not a break.
Sincerely,
Wonko |
