a.datums: Returns first and last appearance datums

In stratigraph: Toolkit for the plotting and analysis of stratigraphic and palaeontological data

Description

Returns the first and last appearance datums (FADs and LADs) for taxa in a stratigraphic column.

Usage

a.datums(x, depths = NULL, skip = 0, increasing.down = FALSE, ...)

fads(x, depths = NULL, skip = 0, increasing.down = FALSE, ...)

lads(x, depths = NULL, skip = 0, increasing.down = FALSE, ...)

Arguments

x	an object of class strat.column.
depths	depths from which to calculate the datums
skip	a number of depths (levels) to skip, returning NA instead of values for FAD or LAD; defaults to 0.
increasing.down	FALSE (default) returns FADs less than or equal to LADs, as is the case when depths are measured up from the bottom of, e.g. a stratigraphic section; TRUE reverses FADs and LADs, as is the case when depths are measured from the surface in wells or cores.
...	not currently used.

Details

If depths is provided, it will clobber x$depths, should x$depths exist.

Value

a.datums returns a data frame with columns fads and lads, each of which is a numeric vector giving the FAD or LAD of each taxon in the stratigraphic column. fads and lads return respectively just the fads and just the lads in a single named numeric vector.

Note

Currently no other notes.

Author(s)

Walton Green

See Also

plot.strat.column, stratigraph

Examples

data(mohawk)
fads(as.strat.column(mohawk))
# should make mohawk a strat.column without coercion

stratigraph documentation built on May 30, 2017, 12:31 a.m.