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astrochron (version 0.9)

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

799

Version

0.9

License

GPL-3

Maintainer

Stephen Meyers

Last Published

January 8th, 2019

Functions in astrochron (0.9)

Anchor a floating astrochronology to a radioisotopic age

Generate AR(1) surrogates

Average Spectral Misfit

Track ASM null hypothesis significance level minima in eASM results

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

Generate autoregressive moving-average model

Track eTimeOpt r2 maxima

AR(1) + ETP simulation routine

Generate harmonic model

Apply Gaussian taper to stratigraphic series

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

Combine multiple vectors

Model differential accumulation

Evolutive Harmonic Analysis & Evolutive Power Spectral Analysis

Apply Hann taper to stratigraphic series

Interactively delete points in plot

Arcsine transformation of stratigraphic series

Subtract linear trend from stratigraphic series

Create non-linear response by clipping stratigraphic series

List column numbers for each variable

Generate noise surrogates from a theoretical power spectrum

Generate eccentricity-tilt-precession models

Example stratigraphic model series

Extract record from EHA time-frequency output or eAsm output

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

Adjust spectrum confidence levels for multiple comparisons

Flip stratigraphic series

Apply DPSS taper to stratigraphic series

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

Divide by linear trend in stratigraphic series

Set default plotting parameters for vertical stratigraphic plots

Create color time-frequency plots from eha results.

Hilbert transform of stratigraphic series

Interactively identify points in plot

Create lithofacies rank series from bed thickness data

Read data from file

Evolutive Average Spectral Misfit

Isolate data from a specified stratigraphic interval

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

Query R for color information

Tune stratigraphic series to an astronomical target using graphical interface

Mann and Lees (1996) robust red noise MTM analysis

Multitaper method spectral analysis

Download file from astrochron data server

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

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

Lowpass filter stratigraphic series

Piecewise linear interpolation of stratigraphic series

Log transformation of stratigraphic series

Intermediate spectrum test of Thomson et al. (2001)

Generate power law (1/f) noise surrogates

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

Pad stratigraphic series with zeros

Remove missing entries, sort data, average duplicates

Calculate all possible difference and combinations tones

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

Replace values <= 0 with smallest positive value

Resample stratigraphic series

Synthesize stratigraphy from forcing function

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

Generate cross-plot with kernel density estimates on axes

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

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

Apply Taner bandpass or lowpass filter to stratigraphic series

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

Robust Locally-Weighted Regression Spectral Background Estimation

Imbrie and Imbrie (1980) ice sheet model

Remove Gaussian kernel smoother from stratigraphic series

TimeOptPlot: Generate summary figure for TimeOpt analyses

Fit and remove Lowess smoother from stratigraphic series

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

Write tab-delimited file

Determine the total power within a given bandwidth

Summary statistics for stratigraphic series

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

Monte Carlo simulation for TimeOpt

Adjust spectral p-values for multiple comparisons

timeOptTemplate

TimeOpt analysis using variable sedimentation models

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

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

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

Remove stratigraphic levels that contain one or more NAs

Remove outliers from stratigraphic series

Simple periodogram

Read data matrix from file

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

Replace values < 0 with 0

timeOptTemplatePlot

TimeOptTemplatePlot: Generate summary figure for TimeOptTemplate analyses

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

Standardize variable in stratigraphic series

timeOptTemplateSim

Simulations for timeOptTemplate

Tune stratigraphic series

Integrate sedimentation rate curve to obtain time-space map

Evaluate power spectrum false positive rates via Monte Carlo simulation

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

A tool to interactively trace peak trajectories on plots

Estimate correlation coefficient and significance for serially correlated data

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

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

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

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

Remove outliers from stratigraphic series

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

Bandpass filter stratigraphic series

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

astrochron-package

astrochron: A Computational Tool for Astrochronology

Automatically plot multiple stratigraphic series, with smoothing if desired

Remove mean value from stratigraphic series

constantSedrate

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

Apply cosine taper to stratigraphic series