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astrochron (version 1.8)

A Computational Tool for Astrochronology

Description

Routines for astrochronologic testing, astronomical time scale construction, and time series analysis . Also included are a range of statistical analysis and modeling routines that are relevant to time scale development and paleoclimate analysis.

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Version

Install

install.packages('astrochron')

Monthly Downloads

697

Version

1.8

License

GPL-3

Maintainer

Stephen Meyers

Last Published

July 17th, 2026

Functions in astrochron (1.8)

Interactively delete points in plot

Wiener Deconvolution through Fast Fourier Transform

Model differential accumulation

Divide by linear trend in stratigraphic series

Apply DPSS taper to stratigraphic series

Evolutive Harmonic Analysis & Evolutive Power Spectral Analysis

Track eTimeOpt r2 maxima

Evolutive Average Spectral Misfit

Remove mean value from stratigraphic series

Extract record from EHA time-frequency output or eAsm output

Subtract linear trend from stratigraphic series

Generate eccentricity-tilt-precession models

Flip stratigraphic series

Convert record of local spatial frequency (from EHA) to sedimentation rate curve

Hilbert transform of stratigraphic series

Track ASM null hypothesis significance level minima in eASM results

eTimeOpt: Evolutive implementation of TimeOpt (Meyers, 2015; Meyers, 2019)

Download file from astrochron data server

Download Laskar et al. (2004, 2011a, 2011b) astronomical solutions

Interactively identify points in plot

Imbrie and Imbrie (1980) ice sheet model

insolation difference map using Laskar et al. (2004) insolation calculations

impulseResponse

Impulse response function calculation

Priors for the fundamental frequencies of the Solar System, using the formulas in Table 2 of Hoang et al. (2021)

Apply Hann taper to stratigraphic series

Apply Gaussian taper to stratigraphic series

List column numbers for each variable

Query R for color information

Tune stratigraphic series to an astronomical target using graphical interface

Log transformation of stratigraphic series

generate an insolation map using Laskar et al. (2004) insolation calculations

Piecewise linear interpolation of stratigraphic series using the approach of Laepple and Huybers (2013)

Piecewise linear interpolation of stratigraphic series

Laskar et al. (2004) insolation calculations

Isolate data from a specified stratigraphic interval

Determine the total power within a given bandwidth

Lowpass filter stratigraphic series

Robust Locally-Weighted Regression Spectral Background Estimation

Multitaper method spectral analysis

Mann and Lees (1996) robust red noise MTM analysis

Calculate moving window correlation coefficient for two stratigraphic series, using a 'dynamic window'

Multitaper Method Spectral Analysis with Power Law (1/f) fit

Generate noise surrogates from a theoretical power spectrum

Example stratigraphic model series

Adjust spectral p-values for multiple comparisons

Intermediate spectrum test of Thomson et al. (2001)

'Dynamic window' moving assessment of maxima and minima in stratigraphic series

'Dynamic window' moving average, median and variance of stratigraphic series

Pad stratigraphic series with zeros

Remove Gaussian kernel smoother from stratigraphic series

'Dynamic window' moving average, median and variance of stratigraphic series, using evenly spaced spatial/temporal grid

Fit and remove Lowess smoother from stratigraphic series

Identify maxima of peaks in series, filter at desired threshold value

Determine 'dynamic moving window' for stratigraphic series, adjusting for changing sample density to maintain a window of constant duration; output on evenly spaced grid

Set default plotting parameters for vertical stratigraphic plots

Determine 'dynamic moving window' for stratigraphic series, adjusting for changing sample density to maintain a window of constant duration

Simple periodogram

Create color time-frequency plots from eha results.

Replace values < 0 with 0

Replace values <= 0 with smallest positive value

Read data matrix from file

Read data from file

Prewhiten stratigraphic series with AR1 filter, using 'standard' or unbiased estimate of rho

Generate power law (1/f) noise surrogates

Remove stratigraphic levels that contain one or more NAs

Resample stratigraphic series

Prewhiten stratigraphic series with autoregressive filter, order selected by Akaike Information Criterion

Apply 'ramping' sedimentation rate model to convert time to stratigraphy

Standardize variable in stratigraphic series

Integrate sedimentation rate curve to obtain time-space map

Identify optimal spatial/temporal shift to maximize correlation between two stratigraphic/time series.

Ar/Ar Geochronology: Generate an Ar/Ar age spectrum and calculate step-heating plateau age.

Remove missing entries, sort data, average duplicates

Estimate power law (1/f) fit to power spectrum

Summary statistics for stratigraphic series

Principal Component Analysis on Stratigraphic Series

Create lithofacies rank series from bed thickness data

Estimate correlation coefficient and significance for serially correlated data

Astrochronologic testing via the precession amplitude modulation approach of Zeeden et al. (2015).

Apply Taner bandpass or lowpass filter to Fourier coefficients

TimeOpt: Evaluation of eccentricity-related amplitude modulation and bundling in paleoclimate data

Synthesize stratigraphy from forcing function

Apply Taner bandpass or lowpass filter to stratigraphic series

Evaluate power spectrum false positive rates via Monte Carlo simulation

TimeOptB: A Bayesian implementation of TimeOpt that calculates posterior PDFs for precession frequency and sedimentation rate

Generate phase-randomized surrogate series as in Ebisuzaki (1997)

Astrochronologic testing via the obliquity amplitude modulation approach of Zeeden et al. (2019).

timeOptTemplate

TimeOpt analysis using variable sedimentation models

TimeOptPlot: Generate summary figure for TimeOpt analyses

TimeOptBSim: Significance testing via Monte Carlo simulation for TimeOptB

timeOptTemplatePlot

TimeOptTemplatePlot: Generate summary figure for TimeOptTemplate analyses

timeOptTemplateSim

Simulations for timeOptTemplate

Monte Carlo simulation for TimeOpt

timeOptSimPwrLaw

Monte Carlo simulation for TimeOpt, using power law (1/f) noise

TimeOptBMCMC: A Bayesian implementation of TimeOpt that calculates posterior PDFs for precession frequency, sedimentation rate, and Solar System g- and s-frequencies, using adaptive MCMC

timeOptBMCMCplot

TimeOptBMCMCplot: Generate summary figures and statistics for TimeOptBMCMC results

TimeOptMCMC: A Bayesian implementation of TimeOpt that evaluates eccentricity-related amplitude modulation and bundling in paleoclimate data, with uncertainties via Markov-Chain Monte Carlo

A tool to interactively select points to track peak trajectories on plots

Frequency-domain minimal tuning: Use interactive graphical interface to trace frequency drift

Tune stratigraphic series

Remove outliers from stratigraphic series

Frequency-domain minimal tuning: Use interactive graphical interface and sorting to track frequency drift

Bioturbation removal function following the approach of Liu et al (2021)

Remove outliers from stratigraphic series

Identify minima of troughs in series, filter at desired threshold value

A tool to interactively trace peak trajectories on plots

Calculate all possible difference and combinations tones

Write tab-delimited file

Generate cross-plot with kernel density estimates on axes

Dynamically explore cross-plot, zoom-in into specified region

Ar/Ar Geochronology: calculate weighted mean age, age uncertainty, and other associated statistics/plots (with interactive graphics for data culling).

Arcsine transformation of stratigraphic series

astrochron-package

astrochron: A Computational Tool for Astrochronology

AR(1) + ETP simulation routine

Generate autoregressive moving-average model

Automatically plot multiple stratigraphic series, with smoothing if desired

Average Spectral Misfit

Calculate geochemical proxy accumulation rates

Compute Earth-Moon distance and length of day from precession frequency

Anchor a floating astrochronology to a radioisotopic age

Generate AR(1) surrogates

Bandpass filter stratigraphic series

Convolution through Fast Fourier Transform

constantSedrate

Apply a constant sedimentation rate model to transform a spatial series to temporal series

Create non-linear response by clipping stratigraphic series

bicoherence: Calculate bispectrum and bicoherence using WOSA method as detailed in Choudhury et al. (2008).

Combine multiple vectors

Bioturbate time series using diffusion model from Guinasso and Schinck (1975), as in Liu et al. (2021)

Calculate eccentricity, obliquity and precession periods in ka, given g, s and k in arcsec/yr

Obliquity and precession periods of Berger et al. (1992)

Adjust spectrum confidence levels for multiple comparisons

Generate harmonic model

Apply cosine taper to stratigraphic series