1. Behavior of argon gas release from manganese oxide minerals as revealed by [sup40]Ar/[sup39]Ar laser incremental heating analysis.
- Author
-
Li Jianwei, Vasconcelos, P.M., and Zhang Jun
- Subjects
- *
MANGANESE oxides , *PALEOWEATHERING , *PLATEAUS , *ARGON isotopes , *GEOCHRONOMETRY , *DEGASSING of metals - Abstract
Discusses the idea that manganese oxides in association with paleoweathering can offer insight into the factors affecting the formation and evolution of weathering profiles. Finding from laser probe step-heating analysis of supergene hollandite and cryptomelane samples collected from central Queensland, Australia; Indication the plateaus and consistent isochron ages confirm the feasibility dating of supergene manganese oxides by the 40Ar/39Ar technique; Identification of two distinct structural sites hosting Ar isotopes; Mention of degassing behaviors discovered by incremental heating analyses; Assertion there is no significant Ar gas released at laser power higher than 1.0 W, which suggests the breakdown of tunnel sites hosting the radiogenic and nucleogenic components; Suggestion that some isotopes occupy crystallographic sites; Evidence that 39ArK loss from the tunnel site during neutron irradiation and/or bake-out procedure preceding isotopic analysis does not occur; Assertion that neither the overwhelming atmospheric 40Ar nor the very-fined nature of the supergene manganese oxides will be a problem in extracting significant information from the analysis of supergene manganese oxides minerals.
- Published
- 2002
- Full Text
- View/download PDF