4.7.15 eTimeOpt

evolutive TimeOpt method (Meyers, 2019).

• Step 0: Select a time series in depth domain (interpolation may be needed if the sampling rate is un-even).

For an example, select “Basic Series” --> “Examples” --> “Late Triassic Newark Depth Rank” --> select generated text file entitled “Example-LateTriassicNewarkDepthRank.txt” in the Acycle main window.

• Step 1: In the pop-up window, set the test sedimentation rate:

linear or log model?

Minimum, maximum, and the step of sedimentation rates.

• Step 2: Set the middle age of data OR type frequencies of eccentricity and precession.

You’ll only need to give the middle age of the data; the frequencies will be calculated automatically from an astronomical solution of La2004.

If the middle age is > 249 Ma, you may type the frequencies.

• Step 3: Set filter.

Fit to precession modulations (default), and short-eccentricity modulation may not be reliable.

The Taner bandpass cut-off frequencies are also adjusted automatically.

• Step 4: Set the sliding window and step.

Default window size is 35% of total range of depth. This should be adjusted, a window size of 1.5 - 2 x (405-kyr related wavelength) is usually good enough. Default step size usually generate ~200 sliding window, this is sufficient to generate a publication quality eTimeOpt result.

• Step 5: You may select to normalize each sliding window (forcing the maxima values of each window to 1). Ticking “Flip Y-axis” checkbox will flip y-axis.

• Step 6: Click OK button to run the eTimeOpt.

You will have following two new MatLab figure file, and eTimeOpt plot.