NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
U-Th-Pb, Rb-Sr, and Sm-Nd isotopic systematics of lunar troctolitic cumulate 76535 - Implications on the age and origin of this early lunar, deep-seated cumulateThe U-Th-Pb, Rb-Sr, and Sm-Nd isotopic systematics of four lightly leached residues of pristine, high-Mg, troctolitic cumulate 76535 were analyzed in order to determine their ages and magma sources. The data indicate that the cumulate was in isotopic equilibrium with a fluid or magma characterized by a high U-238/Pb-204 (mu) value of 600 at 4.236 Ga. Two and three stage Pb evolution calculations define even greater source mu values of about 1000, assuming low lunar initial mu values between 5 and 40 prior to about 4.43 Ga. These results are similar to mu values for KREEP sources and are also consistent with values from 78235, suggesting that at least some high-Mg suite rocks were derived from magma sources with high-mu values similar to KREEP, and support that idea that these rocks postdate primary lunar differentiation and formation of ferroan anorthosites.
Document ID
19920048260
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Premo, Wayne R.
(NASA Lyndon B. Johnson Space Center Houston, TX, United States)
Tatsumoto, M.
(USGS Denver, CO, United States)
Date Acquired
August 15, 2013
Publication Date
January 1, 1992
Subject Category
Lunar And Planetary Exploration
Meeting Information
Meeting: Lunar and Planetary Science Conference
Location: Houston, TX
Country: United States
Start Date: March 18, 1991
End Date: March 22, 1991
Sponsors: American Association of Petroleum Geologists, NASA, Lunar and Planetary Institute
Accession Number
92A30884
Funding Number(s)
CONTRACT_GRANT: NASA ORDER T-783-H
Distribution Limits
Public
Copyright
Other

Available Downloads

There are no available downloads for this record.
No Preview Available