Evaluation of Paleocene‐Eocene Thermal Maximum Carbon Isotope Record Completeness—An Illustration of the Potential of Dynamic Time Warping in Aligning Paleo‐Proxy Records

• Published in: Geochemistry, Geophysics, Geosystems
• Main Authors: Seyi Ajayi, Lee R. Kump, Andy Ridgwell, Sandra Kirtland Turner, Carling C. Hay, Timothy J. Bralower
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2020
• Subjects: dynamic time warping; PETM; correlation; proxy; Geophysics. Cosmic physics; QC801-809; Geology; QE1-996.5; Maud Rise; Southern Ocean
• Online Access: https://doi.org/10.1029/2019GC008620; https://doaj.org/article/82ab73f86fd34119945dfbd36ea28a06

Abstract Variations in sedimentation rate, bioturbation, winnowing, and dissolution modify the deep‐sea sedimentary record, complicating the apparent relationship between stratigraphic depth and time of a geochemical proxy record and confounding the extraction of a clear picture of past climates and environments. Dynamic time warping (DTW) is used to align time series with similar patterns. Here we explore the use of DTW to identify gaps in proxy records of the Paleocene‐Eocene thermal maximum (PETM), aligning bulk sediment carbonate isotope records (δ13C) from various deep‐sea sediment core sections spanning the event. Alignment of PETM δ13C records from the Walvis Ridge, South Atlantic transect of ODP Leg 208 (Sites 1262, 1263, and 1265) was similar to previously published manually established alignments and consistent with the expectation that shallower sites have more complete records. The δ13C record from a Southern Ocean site (Maud Rise; ODP Site 690) was then aligned to ODP Site 1263, the most complete Walvis Ridge site. This alignment identifies a gap in Site 690, indicating that peak excursion δ13C values were not recorded. We conclude that DTW provides an objective way to align climate proxy records and rectify data loss associated with unconformities and other types of distortions, leading to a more complete understanding of the geologic record of past episodes of biotic and environmental change.