Glacial weathering and the hafnium isotope composition of seawater. Earth (2002).

Content Provider	CiteSeerX
Author	Flierdt, Tina Van De Frank, Martin Lee, Der-Chuen Halliday, Alex N.
Abstract	The Hf isotope composition of seawater does not match that expected from dissolution of bulk continental crust. This mismatch is generally considered to be due to retention of unradiogenic Hf in resistant zircons during incomplete weathering of continental crust. During periods of intense glacial weathering, zircons should break down more efficiently, resulting in the release of highly unradiogenic Hf to the oceans. We test this hypothesis by comparing Nd and Hf isotope time series obtained from NW Atlantic ferromanganese crusts. Both isotope systems show a decrease associated with the onset of northern hemisphere glaciation. The observed changes display distinct trajectories in ONd^ OHf space, which differ from previously reported arrays of bulk terrestrial material and seawater. Such patterns are consistent with the release of highly unradiogenic Hf from very old zircons, facilitated by enhanced mechanical
File Format	PDF
Publisher Date	2002-01-01
Access Restriction	Open
Subject Keyword	Glacial Weathering Hafnium Isotope Composition Unradiogenic Hf Northern Hemisphere Glaciation Hf Isotope Composition Isotope System Bulk Terrestrial Material Time Series Observed Change Distinct Trajectory Nw Atlantic Ferromanganese Crust Ond Ohf Space Incomplete Weathering Old Zircon Bulk Continental Crust Continental Crust Intense Glacial Weathering Resistant Zircon
Content Type	Text