Enhanced cosmic-ray production of 10Be coincident with the Mono Lake and Laschamp geomagnetic excursions

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doi: 10.1029/95GL00169
Author(s): McHargue, Lanny Ray; Damon, Paul E.; Donahue, Douglas J.
Author Affiliation(s): Primary:
University of Arizona, AMS Facility, Tucson, AZ, United States
Volume Title: Geophysical Research Letters
Source: Geophysical Research Letters, 22(5), p.659-662. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0094-8276 CODEN: GPRLAJ
Note: In English. 37 refs.; illus.
Summary: The cosmogenic isotope 10Be, total Be, and Al were measured in partly varved sediments from the upper 50 m of core 480, leg 64 (DSDP), Gulf of California. The concentration of 10Be from 1 to 50 kyr is in general agreement with estimates of the geomagnetic dipole moment obtained from archaeomagnetic and marine core research. 10Be anomalies were also found at 32 kyr and 43 kyr, contemporaneous with the Mono Lake and Laschamp excursions, respectively. The production of 10Be required to explain these anomalies is too high, particularly for the Mono Lake excursion, to be produced by a combination of decreased geomagnetic field and unprecedented long-term solar activity. We conclude that the cause is a change in the galactic cosmic-ray flux consistent with a supernova event. The coincidence with the two excursions remains a paradox. Copyright 1995 by the American Geophysical Union.
Year of Publication: 1995
Research Program: DSDP Deep Sea Drilling Project
IPOD International Phase of Ocean Drilling
Key Words: 24 Surficial Geology, Quaternary Geology; Absolute age; Alkaline earth metals; Antarctica; Arctic region; Be-10; Beryllium; C-14; Carbon; Causes; Cenozoic; Correlation; Cosmogenic elements; DSDP Site 480; Dates; Deep Sea Drilling Project; East Pacific; Foraminifera; Greenland; Gulf of California; IPOD; Ice cores; Invertebrata; Isotopes; Laschamp excursion; Leg 64; Marine sediments; Metals; Microfossils; Mono Lake excursion; North Pacific; Northeast Pacific; Pacific Ocean; Paleomagnetism; Planar bedding structures; Pleistocene; Protista; Quaternary; Radioactive isotopes; Relative age; Sedimentary structures; Sedimentation; Sedimentation rates; Sediments; Solar activity; Stars; Summit Greenland; Supernovas; Upper Pleistocene; Variations; Varves; Vostok Station
Coordinates: N275406 N275406 W1103921 W1103921
Record ID: 1995034989
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