NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
The Initial W-182/W-183 and Hf-182/Hf-180 of the Solar System and a Consistent Chronology with Pb-Pb AgesThe utility of the Hf-182 (bar-tau ==13 x 10(exp 6) yr) -W-182 chronometer for early solar system processes is now well established. At the 2002 LPSC meeting we first reported new Hf-W data for chondritic meteorites showing that some crucial data as well as interpretations of Lee and Halliday for chondrites were incorrect. Our results were confirmed by reports of two other groups. This new data imply a much-shorter timescale for the early Solar System evolution and the formation of the Earth s core more consistent with the original conclusions of Harper and Jacobsen. Thus, the chondritic Hf-W evolution is now well established as beginning with epsilon(sub W)(0) = -3.45 +/- 0.25 at the time of origin of the solar system and evolving to -2.2 by 20 Myr and -1.9 +/- 0.20 at present. However, there are a number of iron meteorite data that suggest the existence of initial W lower than those measured for chondrites. If the low epsilon(sub W)(0) of -4 to -5 are correct then we face an embarrassing dilemma of differentiated iron meteorites being older than the primitive chondrites, or we would have to conclude that there is an additional pre-history of 5-10 Myr in primitive chondritic meteorites prior to the closure of the Hf-182 - W-182 system. Such a prolonged early time does not seem reasonable to us. We have therefore initiated a study to resolve this issue.
Document ID
20030111293
Document Type
Conference Paper
Authors
Yin, Qingzhu (Harvard Univ. Cambridge, MA, United States)
Jacobsen, Stein B. (Harvard Univ. Cambridge, MA, United States)
Date Acquired
August 21, 2013
Publication Date
January 1, 2003
Publication Information
Publication: Lunar and Planetary Science XXXIV
Subject Category
Lunar and Planetary Science and Exploration
Distribution Limits
Public
Copyright
Public Use Permitted.

Related Records

IDRelationTitle20030110578Analytic PrimaryLunar and Planetary Science XXXIV
Document Inquiry