K/Ar and Rb/Sr ages of celadonites from the Troodos ophiolite, Cyprus
K/Ar dating and Rb/Sr isochrons of two celadonite veins from the Troodos ophiolite, Cyprus, consistently yield precipitation ages of 77-80 and 87-92 Ma, respectively. Their K/Ar bulk-rock age data (84.7 +/- 2.3 Ma), combined with the oldest celadonite age and recently published radiolarian ages, suggest that the Troodos ophiolite was formed between 85 and 92 Ma, providing an estimate for the duration of celadonite formation of at least 7 m.y., but possibly up to 15 m.y. These data are consistent with data from Deep Sea Drilling Project holes, suggesting that precipitation of the most significant portion of vein minerals in the oceanic crust occurs within about 12 m.y., but possibly up to 19 m.y. after crustal formation. Leaching experiments suggest that K, Ar, Rb, and Sr in exchangeable and nonexchangeable sites of the structure of stoichiometric celadonite maintain their isotope characteristics and are resistant to change from diagenetic processes or surface alteration.
- Research Organization:
- Univ. of California, San Diego, La Jolla
- OSTI ID:
- 5393116
- Journal Information:
- Geology; (United States), Vol. 14:1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CYPRUS
GEOLOGIC DEPOSITS
AGE ESTIMATION
ISOTOPE DATING
ABSORPTION SPECTROSCOPY
ARGON ISOTOPES
GEOCHEMISTRY
GEOLOGIC HISTORY
LEACHING
OCEANIC CRUST
POTASSIUM ISOTOPES
RUBIDIUM ISOTOPES
STRONTIUM ISOTOPES
ALKALI METAL ISOTOPES
ALKALINE EARTH ISOTOPES
CHEMISTRY
DISSOLUTION
EARTH CRUST
ISOTOPES
MIDDLE EAST
SEPARATION PROCESSES
SPECTROSCOPY
580100* - Geology & Hydrology- (-1989)
580400 - Geochemistry- (-1989)