Vein mineral ages of old oceanic crust

Online Access: Get full text
doi: 10.1029/JB085iB12p07195
Author(s): Richardson, Stephen H.; Hart, Stanley R.; Staudigel, Hubert
Author Affiliation(s): Primary:
Mass. Inst. Technol., Cent. Geoalchemy, Dep. Earth Planet. Sci, Cambridge, MA, United States
Volume Title: Journal of Geophysical Research
Source: Journal of Geophysical Research, 85(B12), p.7195-7200. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0148-0227
Note: In English. 26 refs.; illus. incl. tables
Summary: Vein smectites with large Rb/Sr enrichments from extensively altered basaltic oceanic crust in Deep Sea Drilling Project hole 417A in the western Atlantic define a highly constrained Rb/Sr isochron age of 108 ± 3 m.y. This age is identical to a less well constrained age of 108 ± 17 m.y. for vein smectites with lower Rb/Sr enrichments from adjacent hole 418A and to the 108 m.y. age of crust formation derived by paleontological and magnetic anomaly correlation. Reasonable agreement exists between the 87Sr/86Sr ratio of vein calcites from both sites and the seawater 87Sr/86Sr ratio at the time. Pervasive low-temperature alteration in the contrasting environments of sites 417 and 418 appears to be coeval and essentially coincident with basement formation. Alteration may be used to advantage in determining ages of old oceanic crust.
Year of Publication: 1980
Research Program: DSDP Deep Sea Drilling Project
Key Words: 02 Geochemistry; 03 Geochronology; Absolute age; Age; Alkaline earth metals; Alteration; Atlantic Ocean; Calcite; Carbonates; Clay minerals; Cretaceous; Crust; Dates; Deep Sea Drilling Project; Geochronology; Halmyrolysis; Isochrons; Isotopes; Lava; Lower Cretaceous; Mesozoic; Metabasalt; Metaigneous rocks; Metals; Metamorphic rocks; Minerals; Oceanic type; Ratios; Rb/Sr; Sheet silicates; Silicates; Site 417; Site 418; Smectite; Sr-87/Sr-86; Stable isotopes; Strontium; Tectonophysics; Veins
Coordinates: N250000 N350000 W0600000 W0700000
Record ID: 1981043919
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute.