A line drawn on a map through points of equal true thickness of a
designated stratigraphic unit or group of stratigraphic units.
CF:isochore
thickness contour. AGI
A map indicating, usually by means of contour lines, the varying thickness
of a designated stratigraphic unit. Also called isopachous map.
AGI
Of, relating to, or having an isopach; e.g., an isopachous contour. Not
recommended usage. AGI
See:isopach
A nonrecommended syn. of isopach map. AGI
British term for isopach. AGI
A series comprising rocks of different chemical composition that were
metamorphosed under identical physical conditions.
Said of sedimentary rocks of the same facies, or said of facies
characterized by identical or closely similar rock types. The rocks may be
formed in different sedimentation areas or at different times or both, but
the lithologies are the same; e.g., a facies repeated in vertical
succession. Also, said of a map depicting isopic facies or rocks.
CF:heteropic
Relating to synchronous deposits that exhibit the same facies.
Constant value of pressure on a surface of the sea. Hy
a. In a strict sense, a line or surface on which some mathematical
function has a constant value. It is sometimes distinguished from a
contour by the fact that an isopleth need not refer to a directly
measurable quantity characteristic of each point in the map area; e.g.,
maximum temperature of a particular point. AGI
b. A general term for a line, on a map or chart, along which all points
have a numerically specified constant or equal value of any given
variable, element, or quantity (such as abundance or magnitude), with
respect to space or time; esp. a contour. Etymol. Greek isos, equal, +
plethos, fullness, quantity, multitude. Syn:isogram; isoline;
isontic line; isometric line. AGI
See:isoporic line
A line drawn through points whose annual change in magnetic declination is
equal. Syn:isopor
A line connecting points of equal density, particularly of ocean water. A
line connecting points of equal atmospheric density may be called an
isostere. Hunt
Lines joining points of equal radioactivity, drawn from geiger- or
scintillation-counter data to form an isorad map. AGI
A plan showing lines of equal resistivity at a certain selected depth. It
is prepared from data obtained by the resistivity method of geophysical
prospecting. Nelson
See:isoseismal line
A line on the surface of the Earth joining points of equal seismic
disturbance due to any single earthquake. Syn:isoseismal line
AGI
A line connecting points on the Earth's surface at which earthquake
intensity is the same. It is usually a closed curve around the epicenter.
Syn:isoseism; isoseismal. AGI
See:kesterite