Mathematics – Logic
Scientific paper
Oct 2000
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2000e%26psl.182...15h&link_type=abstract
Earth and Planetary Science Letters, Volume 182, Issue 1, p. 15-29.
Mathematics
Logic
24
Scientific paper
The Allende calcium-rich inclusion (CAI) 5241 has been found to contain distinct initial 26Al/27Al in the three consecutive igneous zones that have been identified by extensive petrogenetic studies to have formed in three distinct crystallization events. The zones in order of sequence of formation from the petrologic observations are: (1) spinel-free islands (SFI) included in (2) a pyroxene-spinel-rich core (SRC) which in turn is included in (3) a melilite mantle (MM). The initial (26Al/27Al) values of these zones are respectively (4.6-5.0)×10-5, 4.3×10-5, and 3.3×10-5. It is argued that these distinct (26Al/27Al)0 values are not the result of metamorphism but reflect the relative times of formation by crystallization from melts. Relative to the canonical value of (26Al/27Al)0=5×10-5, we find the following chronology: tSFI~0, tSRC~105 yr and tMM~4×105 yr. The three-layer CAI is inferred to have sampled a reservoir with an initial uniform 26Al/27Al ratio that decreased in value due to radioactive decay. From these observations we conclude that we have resolved time differences of a few hundred thousand years at the very early stages of formation of the solar system. The SFI, SRC, and MM zones reflect sequential addition of molten CAI material which crystallized rapidly without seriously metamorphosing the previously formed material. These additions took place over a time of about 400000 years. We believe that these sequential events are not compatible with condensation in a hot region of the solar nebula. It is proposed that a scenario involving stages of protoplanetary accretion and of melt generation in protoplanetary sites heated by 26Al might provide a possible source for CAIs and chondrules.
Hsu Weibiao
Huss Gary R.
Wasserburg Gerald J.
No associations
LandOfFree
High time resolution by use of the 26Al chronometer in the multistage formation of a CAI does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with High time resolution by use of the 26Al chronometer in the multistage formation of a CAI, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and High time resolution by use of the 26Al chronometer in the multistage formation of a CAI will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-867833