Orphan Arctic Ocean metasediment clasts: Local derivation from Alpha Ridge or pre-2.6 Ma ice rafting?
- 1Department of Geology and Geophysics, University of Wisconsin, Madison, Wisconsin 53706, USA
- 2Department of Geology, Brigham Young University, Provo, Utah 84604, USA
- 3Berkeley Geochronology Center, Berkeley, California 94704, USA
Abstract
Phyllonite and metaquartzite clasts occur in early Pliocene or possibly Miocene sediment at the base of the University of Wisconsin Arctic Ocean core Fl-380. Single-crystal 40Ar/39Ar laser-probe ages derived from feldspars in sediment enclosing the clasts range from Middle and Late Proterozoic to Paleozoic. The clasts occur in sediment deposited 1–2 m.y. earlier than any previously reported central Arctic Ocean ice-rafted debris, and although an ice-rafted origin may be possible, a local source such as adjacent Alpha Ridge bedrock should also be considered.
Footnotes
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- Accepted September 20, 2000.
- Received May 15, 2000.
- Revision received September 15, 2000.
- Geological Society of America
