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astrochron (version 1.3)

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

605

Version

1.3

License

GPL-3

Maintainer

Stephen Meyers

Last Published

May 28th, 2024

Functions in astrochron (1.3)

Create non-linear response by clipping stratigraphic series

Average Spectral Misfit

AR(1) + ETP simulation routine

Wiener Deconvolution through Fast Fourier Transform

Anchor a floating astrochronology to a radioisotopic age

Bandpass filter stratigraphic series

astrochron-package

astrochron: A Computational Tool for Astrochronology

Arcsine transformation of stratigraphic series

Interactively delete points in plot

Automatically plot multiple stratigraphic series, with smoothing if desired

Apply cosine taper to stratigraphic series

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

Adjust spectrum confidence levels for multiple comparisons

constantSedrate

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

Convolution through Fast Fourier Transform

Apply Hann taper to stratigraphic series

Generate AR(1) surrogates

List column numbers for each variable

Multitaper method spectral analysis

Model differential accumulation

Generate harmonic model

Divide by linear trend in stratigraphic series

Generate eccentricity-tilt-precession models

Intermediate spectrum test of Thomson et al. (2001)

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

Extract record from EHA time-frequency output or eAsm output

Remove mean value from stratigraphic series

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

Hilbert transform of stratigraphic series

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

Apply Gaussian taper to stratigraphic series

Query R for color information

Isolate data from a specified stratigraphic interval

Tune stratigraphic series to an astronomical target using graphical interface

Combine multiple vectors

Subtract linear trend from stratigraphic series

Interactively identify points in plot

Piecewise linear interpolation of stratigraphic series

Mann and Lees (1996) robust red noise MTM analysis

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

Track ASM null hypothesis significance level minima in eASM results

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

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

Apply DPSS taper to stratigraphic series

Generate power law (1/f) noise surrogates

Evolutive Average Spectral Misfit

Flip stratigraphic series

Log transformation of stratigraphic series

Standardize variable in stratigraphic series

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

Download file from astrochron data server

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

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

Remove missing entries, sort data, average duplicates

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

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

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

Track eTimeOpt r2 maxima

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

Imbrie and Imbrie (1980) ice sheet model

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

Evolutive Harmonic Analysis & Evolutive Power Spectral Analysis

impulseResponse

Impulse response function calculation

Simple periodogram

Remove Gaussian kernel smoother from stratigraphic series

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

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

Apply Taner bandpass or lowpass filter to Fourier coefficients

Resample stratigraphic series

Remove stratigraphic levels that contain one or more NAs

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

Create color time-frequency plots from eha results.

Laskar et al. (2004) insolation calculations

Generate noise surrogates from a theoretical power spectrum

Evaluate power spectrum false positive rates via Monte Carlo simulation

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

TimeOptPlot: Generate summary figure for TimeOpt analyses

Replace values < 0 with 0

Remove outliers from stratigraphic series

Monte Carlo simulation for TimeOpt

Example stratigraphic model series

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

Fit and remove Lowess smoother from stratigraphic series

Replace values <= 0 with smallest positive value

Pad stratigraphic series with zeros

Determine the total power within a given bandwidth

timeOptTemplatePlot

TimeOptTemplatePlot: Generate summary figure for TimeOptTemplate analyses

Lowpass filter stratigraphic series

Robust Locally-Weighted Regression Spectral Background Estimation

Synthesize stratigraphy from forcing function

timeOptTemplateSim

Simulations for timeOptTemplate

Apply Taner bandpass or lowpass filter to stratigraphic series

Adjust spectral p-values for multiple comparisons

Write tab-delimited file

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

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

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

Set default plotting parameters for vertical stratigraphic plots

Estimate correlation coefficient and significance for serially correlated data

Read data from file

Read data matrix from file

Create lithofacies rank series from bed thickness data

Principal Component Analysis on Stratigraphic Series

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

Summary statistics for stratigraphic series

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

Integrate sedimentation rate curve to obtain time-space map

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

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

timeOptSimPwrLaw

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

A tool to interactively trace peak trajectories on plots

Remove outliers from stratigraphic series

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

Tune stratigraphic series

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

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

timeOptTemplate

TimeOpt analysis using variable sedimentation models

TimeOptMCMC: Evaluation of eccentricity-related amplitude modulation and bundling in paleoclimate data ("TimeOpt"), with uncertainties via Markov-Chain Monte Carlo

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

Calculate all possible difference and combinations tones

Generate cross-plot with kernel density estimates on axes

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

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

Generate autoregressive moving-average model