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Build a track (depth, sedimentation rate, time) from a tracked period curve, a rate curve or an age model

Source: R/check_agemodel.R
as_wr_track.Rd

The tracking functions return wr_track objects; this builds one from the curves older workflows produce, so that they can be given to analyse_dechirped and check_agemodel: a tracked period curve (track_period_wavelet: depth and the period of one astronomical cycle in depth units), a sedimentation-rate curve (e.g. from an EHA/sedrate workflow) or an age-depth model.

Usage

as_wr_track(
  x,
  type = c("period", "sedrate", "age"),
  cycle = 405,
  rate_factor = 1,
  step = NULL
)

Arguments

x

Curve to convert (data frame or matrix, two columns; further columns are ignored): depth in column 1 and, in column 2, the tracked period (in depth units) for type="period", the sedimentation rate (depth units per kyr after multiplying by rate_factor) for type="sedrate", or the age (kyr after multiplying by rate_factor) for type="age". Rows with non-finite values are dropped, duplicated depths are averaged, and at least two points are needed. Required, no default.

type

What column 2 of x holds (character): "period" (the period of one astronomical cycle in depth units, e.g. from track_period_wavelet; the rate is period / cycle), "sedrate" (a sedimentation rate; must be positive) or "age" (an age-depth model; must be strictly monotonic, and time is counted from the top of the curve). Default=c("period", "sedrate", "age"), i.e. "period".

cycle

Duration of the tracked astronomical cycle in kyr (numeric, > 0), used to turn the tracked period into a sedimentation rate when type="period"; ignored otherwise. Default=405.

rate_factor

Multiplier applied to column 2 of x to bring it to depth units per kyr (type="sedrate") or to kyr (type="age") (numeric); e.g. 0.01 for a rate in cm/kyr with depth in metres, 1000 for an age in Ma. Ignored when type="period". Default=1.

step

Depth step of the output track, in depth units (numeric, > 0); the rate is interpolated (log-linearly) onto a regular grid with this step and the time is recalculated. NULL keeps the depth positions of x. Default=NULL.

Value

A wr_track data frame with depth, sedrate and time (kyr from the top of the curve, increasing with depth).

Examples

curve <- data.frame(depth = 0:100, period = 12 + 3 * sin(0:100 / 10))
tr <- as_wr_track(curve, "period", cycle = 405)
head(tr)
#>   depth    sedrate      time
#> 1     0 0.02962963   0.00000
#> 2     1 0.03036914  33.33908
#> 3     2 0.03110125  65.87969
#> 4     3 0.03181867  97.67026
#> 5     4 0.03251421 128.76219
#> 6     5 0.03318093 159.20898