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New M40Ar/39Ar and K/Ar Ages of Dikes in the South Shetland Islands (Antarctic Peninsula)

Open-File Report 2007-1047-SRP-035

By:
, , and
DOI: 10.3133/ofr20071047SRP035

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Abstract

Eighteen plagioclase 40Ar/39Ar and 7 whole rock K/Ar ages suggest that dikes in the South Shetland Islands (Antarctic Peninsula) are of Paleocene to Eocene age. The oldest dikes are exposed on Hurd Peninsula (Livingston Island) and do not yield 40Ar/39Ar plateaux. Our best estimates suggest dike intrusion at about the Cretaceous/Paleogene boundary. An older age limit for the dikes is established by Campanian nannofossil ages from their metasedimentary host. Dike intrusion began earlier and lasted longer on Hurd Peninsula (Danian to Priabonian) than on King George Island (Thanetian to Lutetian). Arc magmatism on King George Island, possibly accompanied also by hypabyssal intrusions, began in the Cretaceous as indicated by ages from the stratiform volcanic sequence. The dikes on King George Island were emplaced beginning in the late Paleocene and ending 47–45 Ma. The youngest arc-related dikes on Hurd Peninsula were emplaced ~37 Ma

Geospatial Extents

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
New M40Ar/39Ar and K/Ar Ages of Dikes in the South Shetland Islands (Antarctic Peninsula)
Series title:
Open-File Report
Series number:
2007-1047-SRP-035
DOI:
10.3133/ofr20071047SRP035
Year Published:
2007
Language:
English
Publisher:
U.S. Geological Survey
Publisher location:
Reston, VA
Description:
3 p.
Larger Work Type:
Report
Larger Work Subtype:
USGS Numbered Series
Larger Work Title:
Antarctica: A Keystone in a Changing World--Online Proceedings for the Tenth International Symposium on Antarctic Earth Sciences. Santa Barbara, California, U.S.A.--August 26 to September 1, 2007
Other Geospatial:
Antarctica
Additional Online Files(Y/N):
N