0 a fossil that is found in many places and comes from the same time in history, so that scientists can use it to decide how old certain rocks are --
1 a fossil that is found in many places and comes from the same time in history, so that scientists can use it to decide how old certain rocks are --
They have been recorded from every continent and many are used as zonal or index fossils.
Index fossils are more helpful in providing geologic references or reference markers.
Fossils are often dated by their proximity to strata containing index fossils whose age has been determined by its location on the geologic column.
Some flood geologists dispute geology's assembled global geologic column since index fossils are used to link geographically isolated strata to other strata across the map.
They are excellent index fossils, and it is often possible to link the rock layer in which they are found to specific geological time periods.
Misleading results are produced if the index fossils are incorrectly dated.
Such index fossils must be distinctive, be globally distributed and occupy a short time range to be useful.
Such index fossils must be distinctive, be globally distributed and have a short time range to be useful.
