Discriticizes lithologs

Discriticizes lithologs to allow further time-series analysis first the Greatest common divisor/highest common factor is calculated which is then used to discriticize the litholog to an evenly sampled data series. The function is designed to place the boundary at the original depth level of the bed boundaries. The Greatest common divisor/highest common factor can be a very small number as such the discriticized data set can be large which impacts computational performance later on therefore a linear interpolation option is added to downscale the data to allow for computational efficiency later on. This is made to discriticize lithologs created using the 'StratigrapheR' package. as such the same data format for input is used. eg. column 1 is bottom of the bed, column 2 is top of bed, column is depth rank/proxy value

Usage

lithlog_disc(
  litholog = NULL,
  subset_fact = 10,
  lin_interp = FALSE,
  dt = NULL,
  genplot = FALSE,
  x_lab = "rank",
  y_lab = "depth (m)",
  keep_editable = FALSE
)

Arguments

litholog

Litholog as a three-column matrix or data frame (the bed format of 'StratigrapheR'), one row per bed ordered from the base of the section upwards: column 1 the base (bottom) depth of the bed, column 2 the top depth of the bed (larger than column 1, e.g. in metres) and column 3 the depth rank or proxy value of the bed. Required (Default=NULL).

subset_fact

Divisor of the greatest common divisor of the bed thicknesses (numeric, > 0): the litholog is discretised with a step of (greatest common divisor) / subset_fact, so larger values give a finer, larger series. Default=10.

lin_interp

Linearly interpolate the discretised series to the regular step dt, e.g. to reduce a very finely sampled series (logical, TRUE or FALSE). Default=FALSE.

dt

Sampling interval of the interpolated series, in the depth unit of litholog (numeric, > 0); required when lin_interp = TRUE, otherwise ignored. Default=NULL.

genplot

Plot the discretised series, value against depth (logical, TRUE or FALSE). Default=FALSE.

x_lab

Label of the x-axis (rank or proxy value) of the plot (character). Default="rank".

y_lab

Label of the y-axis (depth) of the plot (character). Default="depth (m)".

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

Returns a matrix with 2 columns, the first column is depth the second columns is the depth/rank proxy If genplot is Default=TRUE then a plot of the discriticizes time series is plotted

References

Wouters, S., Da Silva, A.-C., Boulvain, F., and Devleeschouwer, X.. 2021. StratigrapheR: Concepts for Litholog Generation in R. The R Journal. <doi:10.32614/RJ-2021-039>

Examples

# Convert depth rank record to a discrete proxy record to allow for further
# analysis in which discrete time series are needed
depth_rank_example_disc <- lithlog_disc(litholog = depth_rank_example,
           subset_fact = 10,
           genplot = FALSE,
           x_lab = "rank",
           y_lab = "depth (m)",
           keep_editable=FALSE)