A strontium and neodymium isotopic study of Apollo 17 high-Ti mare basalts: Resolution of ages, evolution of magmas, and origins of source heterogeneities

Journal Article · Mon Jul 01 00:00:00 EDT 1991 · Geochimica et Cosmochimica Acta; (United States)

DOI:https://doi.org/10.1016/0016-7037(91)90040-C· OSTI ID:5749567

Paces, J B; Neal, C R; Taylor, L A ^[1]; Nakai, Shun'ichi; Halliday, A N; Lee, D C ^[2]

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1. Univ. of Tennessee, Knoxville (United States)
2. Univ. of Michigan, Ann Arbor (United States)

A combined Sr and Nd isotopic study of 15 Apollo 17 high-Ti mare basalts was undertaken to investigate geochronological and compositional differences between previously identified magma types (A, B1, B2, and C). Whole-rock and mineral separates for one of the least-evolved Type B1 basalts, 70139, yield Sm-Nd and Rb-Sr isochron ages of 3.71 {plus minus} 0.12 Ga and 3.65 {plus minus} 0.07 Ga and a Rb-Sr isochron age of 3.67 {plus minus} 0.10 Ga. Although these two ages are non-resolvable by themselves, compilation of all available geochronological data allows resolution of Type A and B1/B2 ages at high levels of confidence (> 99%). The most reliably dated samples, classified according to their geochemical type, yield weighted average ages of 3.75 {plus minus} 0.02 Ga for Type A (N = 4) and 3.69 {plus minus} 0.02 Ga for Type B1/B2 (N = 3) basalts. Insufficient geochronological data are available to place the rare, Type C basalts within this stratigraphy. The authors propose that age differences correlate with geochemical magma type, and that early magmatism was dominated by eruption of Type A basalts while later activity was dominated by effusion of Type B1 and B2 basalts.

• OSTI ID: 5749567
• Journal Information: Geochimica et Cosmochimica Acta; (United States), Vol. 55:7; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BASALT
CHEMICAL COMPOSITION
LUNAR MATERIALS
ISOTOPE DATING
GEOCHEMISTRY
ISOTOPE RATIO
MAGMATISM
NEODYMIUM
PETROGENESIS
STRONTIUM
AGE ESTIMATION
ALKALINE EARTH METALS
CHEMISTRY
ELEMENTS
IGNEOUS ROCKS
MATERIALS
METALS
RARE EARTHS
ROCKS
VOLCANIC ROCKS
661300* - Other Aspects of Physical Science- (1992-)