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Astronomical parameters from a tuned record (cycles already in kyr)

Source: R/astro_from_periods.R
astro_from_periods.Rd

Same output as astro_from_peaks(), but the input is cycle periods in kyr and the time scale is set by the tuning target rather than by a sampled sedimentation rate. Give only the terms you actually resolved.

Usage

astro_from_periods(
  cycles,
  age,
  anchor = 405,
  anchor_term = "e405",
  nsim = 2000,
  ptest = c(10000, 28000),
  method = c("angular_momentum", "astrogeo22"),
  s3_uncertainty = c("published", "scaled"),
  seed = NULL,
  verbose = TRUE,
  data_dir = NULL,
  ...
)

Arguments

cycles

Measured period ranges of the cycles you resolved in the tuned record, in kyr (named list; each element a numeric vector c(min, max)). Names are astronomical terms as accepted by constraints in astro_mc (e.g. "e405", "e125", "e95", "k+s3" or "obl", "k+g5", "k+g2", "prec_short", "k+g4|k+g3", "any:k+g5|k+g2"). Passed to astro_mc as constraints. Required, no default.

age

Approximate age of the record in Ma (numeric): c(min, max), or a single value that is widened by age_tol (default 5 Ma, see astro_mc) on either side. Required, no default.

anchor

Period in kyr assumed for the tuning target when the record was tuned (numeric, > 0); every measured period is stretched by (sampled period of anchor_term)/anchor. NULL lets the time scale stretch freely (see scale_range in astro_mc). Default=405.

anchor_term

Astronomical term the record was tuned to (character), any term name accepted by astro_mc, e.g. "e405" (g2-g5). Default="e405".

nsim

Number of accepted Monte Carlo samples to collect (integer, > 0); passed to astro_mc. Default=2000.

ptest

Range of precession constants k to sample, in years (numeric vector c(min, max)); passed to astro_mc. Default=c(10000, 28000).

method

How the sampled precession constants are converted into an Earth-Moon state (distance, length of day) by ctest_earthmoon (character): "angular_momentum" (Earth-Moon angular-momentum conservation) or "astrogeo22" (inversion of the AstroGeo22 curve). Default=c("angular_momentum", "astrogeo22"), i.e. "angular_momentum".

s3_uncertainty

How the uncertainty of s3 is sampled, passed to astro_mc (character): "published" follows the published CTest code, in which the relative uncertainty is applied as an absolute one in years (s3 is effectively fixed); "scaled" applies it relative to the s3 period, as for g2-g5, giving s3 a realistic spread. Default=c("published", "scaled"), i.e. "published".

seed

Seed of the random number generator (integer), passed to astro_mc so that the Monte Carlo results can be reproduced; NULL leaves the current random state unchanged. Default=NULL.

verbose

Print progress messages of the Monte Carlo sampling (logical, TRUE or FALSE). Default=TRUE.

data_dir

Folder that contains the AstroGeo22 table AstroGeo22.txt (character path); NULL uses the copy installed with the package. Passed to ctest_earthmoon and astrogeo22. Default=NULL.

...

Further arguments passed to astro_mc, e.g. age_tol, sampleorb, scale_range, block or max_attempts.

Value

object of class `astro_from_peaks` (see astro_from_peaks())