Create an age model using minimal tuning

Create an age model using the minimal tuning technique. This means that the distance between 2 peaks of an extracted cycle are set to duration of the interpreted astronomical cycle

Usage

minimal_tuning(
  data = NULL,
  pts = 5,
  cycle = 405,
  tune_opt = "max",
  output = 0,
  genplot = FALSE,
  keep_editable = FALSE
)

Arguments

data

Cycle extracted or filtered in the depth domain (e.g. the output of extract_signal or columns 1-2 of the element filtered of gaussian_bandpass): a two-column matrix or data frame with depth in metres in column 1 (in increasing order) and the filtered signal in column 2. Required (Default=NULL).

pts

Number of points to each side that a point is compared with when the maxima and minima of the filtered cycle are detected (integer, >= 2): a point is a maximum (minimum) when it is above (below) the value pts points further on and the value pts - 1 points back. Larger values give more robust extremes but may miss minor ones (see max_detect). Default=5.

cycle

Duration of the filtered/extracted cycle in kyr (numeric, > 0, e.g. 405 for the long eccentricity cycle); the distance between successive extremes divided by this duration gives the sedimentation rate. Default=405.

tune_opt

Which extremes of the cycle are used as tie points of the age model (character): "min" (minima, one cycle apart), "max" (maxima, one cycle apart) or "minmax" (both, half a cycle apart). Default="max".

output

Content of the returned matrix (integer): 0 four columns (depth, proxy, sedimentation rate in cm/kyr, time in kyr); 1 two columns (depth, sedimentation rate); 2 two columns (depth, time). Default=0.

genplot

Plot the result belonging to output (logical, TRUE or FALSE). Default=FALSE.

keep_editable

Keep the graphical parameters (par) of the plot after the function returns, so that features can be added to it (logical, TRUE or FALSE); FALSE restores the previous settings. Default=FALSE.

Value

The output depends on the output setting If output = 0 output is a matrix of with 4 columns being (depth,proxy,sedimentation rate and time) If genplot = TRUE 4 plots are generated; depth vs proxy, depth vs sedimentation rate, depth vs time and time vs proxy If output = 1 output is a matrix of with 2 columns being (depth and sedimentation rate ) If genplot = TRUE a plot of depth vs sedimentation rate is generated If output = 2 output is a matrix of with 2 columns being (depth and time) If genplot = TRUE a plot of depth vs time is generated

References

Routines for astrochronologic testing, astronomical time scale construction, and time series analysis <doi:10.1016/j.earscirev.2018.11.015>

Author

Part of the code is based on the sedrate2time function of the 'astrochron' R package

Examples

# \donttest{
# Extract the 405kyr eccentricity cycle from the wavelet scalogram
# from the magnetic susceptibility record f the Sullivan core
# of Pas et al., (2018) and then create a age model using minimal tuning
# (e.g.) set the distance between peaks to 405 kyr

mag_wt <- analyse_wavelet(data = mag,
dj = 1/100,
lowerPeriod = 0.1,
upperPeriod = 254,
verbose = FALSE,
omega_nr = 10)


mag_405 <- extract_signal_stable_V2(
 wavelet = mag_wt,
 period_max = 4,
 period_min = 2,
 add_mean = FALSE,
 plot_residual = FALSE,
 keep_editable = FALSE
)

mag_405_min_tuning <- minimal_tuning(data = mag_405,
pts = 5,
cycle = 405,
tune_opt = "max",
output = 0,
genplot = FALSE,
keep_editable = FALSE)


# }