Mass spectrometric study of the lead in carbonaceous chondrites

Journal Article · Tue May 01 04:00:00 EDT 1962 · Journal of Geophysical Research

DOI:https://doi.org/10.1029/JZ067i005p02005· OSTI ID:4830390

Marshall, Royal R.

Measurements of the isotopic ratios of lead from the Indarch, Murray, Mokoia, and Orgueil carbonaceous chondrites show that their leads differ only alightly from the primordial type of lead found in the Canyon Diablo iron meteorite. Formal calculation of the lead-lead ages 4.6 x 10⁹ years, respectively. Empirical justification for these lead-lead ages comes from the agreement of similarly calculated ages for ordinary chondrites with those obtained by completely independent methods. There seems to be an additional small component of the radiogenic lead isotopes. The amount of this excess is comparable to that which was observed in the Holbrook chondrite. Indarch contains an excess of Pb₂₀₇. Either this meteorite is older (about 5.1 x 10⁹ years), or (more likely) some variations in isotopic composition were present at the beginning of the solar system. Carbonaceous chondrites seem to have originated from chondritic material by the addition of certain elements and the loss of others. They acquired of the order of 1 to 4 ppm of primordial lead of the Canyon Diablo type. (auth)

• Research Organization: Universitat, Bern
• Sponsoring Organization: USDOE
• NSA Number: NSA-16-019166
• OSTI ID: 4830390
• Journal Information: Journal of Geophysical Research, Journal Name: Journal of Geophysical Research Journal Issue: 5 Vol. 67; ISSN 0148-0227
• Publisher: American Geophysical Union
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

AGE ESTIMATION
CARBON COMPOUNDS
DISTRIBUTION
GEOLOGY, MINERALOGY, AND METEOROLOGY
GEOPHYSICS
INDARCH METEORITE
LEAD 207
LEAD ISOTOPES
MASS SPECTROMETERS
METEORITES
QUANTITY RATIO
VARIATIONS