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astrochron (version 1.6)

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

516

Version

1.6

License

GPL-3

Maintainer

Stephen Meyers

Last Published

February 25th, 2026

Functions in astrochron (1.6)

Combine multiple vectors

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

constantSedrate

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

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

Convolution through Fast Fourier Transform

Adjust spectrum confidence levels for multiple comparisons

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

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

Create non-linear response by clipping stratigraphic series

Apply cosine taper to stratigraphic series

Track ASM null hypothesis significance level minima in eASM results

Remove mean value from stratigraphic series

Model differential accumulation

Evolutive Average Spectral Misfit

Subtract linear trend from stratigraphic series

Interactively delete points in plot

Generate harmonic model

Apply DPSS taper to stratigraphic series

Wiener Deconvolution through Fast Fourier Transform

Divide by linear trend in stratigraphic series

Generate eccentricity-tilt-precession models

Flip stratigraphic series

Evolutive Harmonic Analysis & Evolutive Power Spectral Analysis

Apply Gaussian taper to stratigraphic series

Extract record from EHA time-frequency output or eAsm output

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

Download file from astrochron data server

Query R for color information

Track eTimeOpt r2 maxima

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

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

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

Hilbert transform of stratigraphic series

List column numbers for each variable

Apply Hann taper to stratigraphic series

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

Laskar et al. (2004) insolation calculations

Imbrie and Imbrie (1980) ice sheet model

Interactively identify points in plot

impulseResponse

Impulse response function calculation

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

Lowpass filter stratigraphic series

Piecewise linear interpolation of stratigraphic series

Log transformation of stratigraphic series

Robust Locally-Weighted Regression Spectral Background Estimation

Isolate data from a specified stratigraphic interval

Example stratigraphic model series

Tune stratigraphic series to an astronomical target using graphical interface

Determine the total power within a given bandwidth

Generate noise surrogates from a theoretical power spectrum

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

Adjust spectral p-values for multiple comparisons

Intermediate spectrum test of Thomson et al. (2001)

Mann and Lees (1996) robust red noise MTM analysis

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

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

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

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

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

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

Pad stratigraphic series with zeros

Multitaper method spectral analysis

Create color time-frequency plots from eha results.

Fit and remove Lowess smoother from stratigraphic series

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; output on evenly spaced grid

Remove Gaussian kernel smoother from stratigraphic series

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

Simple periodogram

Replace values <= 0 with smallest positive value

Replace values < 0 with 0

Resample stratigraphic series

Generate power law (1/f) noise surrogates

Remove stratigraphic levels that contain one or more NAs

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

Read data matrix from file

Read data from file

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

Principal Component Analysis on Stratigraphic Series

Estimate correlation coefficient and significance for serially correlated data

Standardize variable in stratigraphic series

Summary statistics for stratigraphic series

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

Integrate sedimentation rate curve to obtain time-space map

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

Remove missing entries, sort data, average duplicates

Create lithofacies rank series from bed thickness data

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

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

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

timeOptBMCMCplot

TimeOptBMCMCplot: Generate summary figures and statistics for TimeOptBMCMC results

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

Apply Taner bandpass or lowpass filter to Fourier coefficients

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

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

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

Synthesize stratigraphy from forcing function

TimeOptPlot: Generate summary figure for TimeOpt analyses

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

timeOptTemplate

TimeOpt analysis using variable sedimentation models

TimeOptBSim: Significance testing via Monte Carlo simulation for TimeOptB

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

timeOptTemplateSim

Simulations for timeOptTemplate

timeOptSimPwrLaw

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

Calculate all possible difference and combinations tones

timeOptTemplatePlot

TimeOptTemplatePlot: Generate summary figure for TimeOptTemplate analyses

Monte Carlo simulation for TimeOpt

Remove outliers from stratigraphic series

Write tab-delimited file

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

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

Tune stratigraphic series

Remove outliers from stratigraphic series

A tool to interactively trace peak trajectories on plots

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

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

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

Generate cross-plot with kernel density estimates on axes

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

Average Spectral Misfit

Generate autoregressive moving-average model

Bandpass filter stratigraphic series

astrochron-package

astrochron: A Computational Tool for Astrochronology

AR(1) + ETP simulation routine

Automatically plot multiple stratigraphic series, with smoothing if desired

Generate AR(1) surrogates

Anchor a floating astrochronology to a radioisotopic age

Calculate geochemical proxy accumulation rates

Arcsine transformation of stratigraphic series