High-resolution cyclostratigraphy in growth strata are used to reconstruct unsteady folding rates at the regional-scale Pico del Aguila anticline, southern Pyrenees, to evaluate deformation modulation. Magnetic polarity stratigraphy was used to determine absolute time and to calibrate cyclostratigraphy-based anhysteretic remanent magnetization intensity variations to establish precessional frequencies in the growth strata record. Incremental tilting rates were calculated between selected horizons over ~5.24 myr of fold growth. Careful treatment of uncertainties enhances confidence that the results are meaningful and results show significant variability in folding rates over time. The acceleration phase of fold growth was variable, punctuated by a prolonged period of tectonic quiescence, and correlated to sedimentation changes in the wedge-top basin. Shallow-dipping bedding intrinsically modulated the initial rates of folding for the first 25˚ of limb tilt until 38.9 Ma. Then, halotectonics in the Paleogene Jaca Basin extrinsically modulated accelerating folding rates for the next 42˚ of folding, until ~37.5 Ma. Finally, forelimb-steepening leading to geometric strain hardening and blunted folding rates for the last 21˚ of fold tightening and causing a thrust fault to cut the anticline’s core. Folding ended at Pico del Aguila ~35.9 Ma. Calculated folding rates varied between 0°± 5.5˚and 90˚± 19°/myr over 100s kyr time increments. Variations in the folding rate of the Pico del Aguila décollement anticline are attributed to both intrinsic modulation as a result of progressive bedding steepening during folding and extrinsic modulation as a result of variable deltaic sedimentation rates in the wedge-top basin.

The aim of this study is two-fold: (1) measure solid Earth diurnal and semi-diurnal tidal constituents using non-parametric signal analysis, and (2) calculate the time delay of the Earth’s solid tidal response between two land-based geographic locations. For these goals, high-precision tidal signals were collected from borehole strainmeters at Plate Boundary Observatory (PBO) stations in Yellowstone, WY, USA and Sequim, WA, USA. Signals from synchronized microstrain time series sampled at 10 minute intervals from 1 January 2011 to 31 December 2015 were evaluated with power spectra and harmonic analysis with statistical F-testing. The phasing of the Earth’s tidal response for the two stations was also estimated with a solid Earth tidal model. Differences between the observed and modeled phases are investigated.

A comprehensive, but simple-to-use software package for analysis of time-series has been developed for paleoclimate research and education. Acycle runs either in the MATLAB environment or as a stand-alone application on Windows and Macintosh OS X, and is available free of charge. Acycle provides prewhitening procedures with multiple options available to track or remove secular trends, and integrates various power spectral analysis approaches for detection and tracking of periodic signals. Acycle also provides a toolbox that evaluates astronomical signals in paleoclimate series, and estimates the most likely sedimentation rate by maximizing the correlation coefficient between power spectra of an astronomical solution and a paleoclimate series. Sedimentary noise models for sea-level variations are also included. Many of the functions are specific to cyclostratigraphy and astrochronology, and are not found in standard, statistical packages. For a demonstration, Acycle is applied to a paleoclimate series (iron content) from Core BH9/05 in the Paleogene Central Basin of Svalbard that samples the Paleocene-Eocene Thermal Maximum (PETM). Acycle detects significant astronomical forcing of the iron series and demonstrates a relatively stable sedimentation rate during and after the PETM event.