A re-examination of evidence for the North Atlantic "1500-year cycle" at Site 609

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doi: 10.1016/j.quascirev.2012.08.008
Author(s): Obrochta, Stephen P.; Miyahara, Hiroko; Yokoyama, Yusuke; Crowley, Thomas J.
Author Affiliation(s): Primary:
University of Tokyo, Atmosphere Ocean Research Institute, Kashiwa, Japan
Other:
Braeheads Institute, United Kingdom
Volume Title: Quaternary Science Reviews
Source: Quaternary Science Reviews, Vol.55, p.23-33. Publisher: Elsevier, International. ISSN: 0277-3791
Note: In English. 49 refs.; illus., incl. 3 tables, sketch map
Summary: Ice-rafting evidence for a "1500-year cycle" sparked considerable debate on millennial-scale climate change and the role of solar variability. Here, we reinterpret the last 70,000 years of the subpolar North Atlantic record, focusing on classic DSDP Site 609, in the context of newly available raw data, the latest radiocarbon calibration (Marine09) and ice core chronology (GICC05), and a wider range of statistical methodologies. A 500-year oscillation is primarily limited to the short glacial Stage 4F the age of which is derived solely from an ice flow model (ss09sea), subject to uncertainty, and offset most from the original chronology. Results from the most well-dated, younger interval suggest that the original 1500 ± 500 year cycle may actually be an admixture of the ∼1000 and ∼2000 cycles that are observed within the Holocene at multiple locations. In Holocene sections these variations are coherent with 14C and 10Be estimates of solar variability. Our new results suggest that the "1500-year cycle" may be a transient phenomenon whose origin could be due, for example, to ice sheet boundary conditions for the interval in which it is observed. We therefore question whether it is necessary to invoke such exotic explanations as heterodyne frequencies or combination tones to explain a phenomenon of such fleeting occurrence that is potentially an artifact of arithmetic averaging. Abstract Copyright (2012) Elsevier, B.V.
Year of Publication: 2012
Research Program: DSDP Deep Sea Drilling Project
IODP Integrated Ocean Drilling Program
IPOD International Phase of Ocean Drilling
Key Words: 24 Surficial Geology, Quaternary Geology; Absolute age; Arctic region; Atlantic Ocean; C-14; Carbon; Cenozoic; Chemostratigraphy; Chronostratigraphy; Climate forcing; Cores; Cyclic processes; DSDP Site 609; Dates; Debris; Deep Sea Drilling Project; Expedition 306; Expeditions 303/306; Fourier analysis; GISP2; Greenland; Hematite; IPOD; Ice cores; Ice rafting; Integrated Ocean Drilling Program; Isotope ratios; Isotopes; Leg 94; Marine sediments; Mid-Atlantic Ridge; North Atlantic; Northeast Atlantic; O-18/O-16; Oxides; Oxygen; Paleoclimatology; Quaternary; Radioactive isotopes; Sediments; Solar forcing; Stable isotopes; Upper Quaternary
Coordinates: N495240 N495241 W0241417 W0241418
Record ID: 2014005279
Copyright Information: GeoRef, Copyright 2017 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands