Internal Rb-Sr Age and Initial Sr-87/Sr-86 of a Silicate Inclusion from the Campo Del Cielo Iron MeteoriteThe largest group of iron meteorites, IAB, is distinguished by the presence of diverse silicate inclusions. In principle, Rb-Sr and Sm-Nd radiometric dating of these silicate inclusions by internal isochron techniques can determine both the times of melting and parent/daughter ratios in the precursor materials via initial Sr-87/Sr-86 and Nd-143/Nd-144 ratios. The Sr-87/Sr-86 and Nd-143/Nd-144 ratios could distinguish chondritic precursors from already differentiated silicates. We reported Rb-Sr and Sm-Nd internal ischron ages of 4.52+/-0.03 Ga and 4.50+/-0.04 Ga, respectively, for plagioclase-diopside-rich material in the Caddo County IAB iron meteorite. These results are essentially identical to literature values of its Ar-Ar age of 4.520+/-0.005 Ga and its Sm-Nd age of 4.53+/-0.02 Ga. The purpose of this study is to evaluate the formation and evolution of silicate inclusions in IAB iron meteorites by determination of their initial Sr-87/Sr-86 ratios combined with higher-resolution chronology and mineralogical and geochemical studies.
Document ID
20030111506
Acquisition Source
Headquarters
Document Type
Conference Paper
Authors
Liu, Y. (NASA Johnson Space Center Houston, TX, United States)
Nyquist, L. (NASA Johnson Space Center Houston, TX, United States)
Wiesmann, H. (Lockheed Martin Space Mission Systems and Services Houston, TX, United States)
Shih, C. (Lockheed Martin Space Mission Systems and Services Houston, TX, United States)
Schwandt, C. (Lockheed Martin Space Mission Systems and Services Houston, TX, United States)
Takeda, H. (Chiba Inst. of Tech. Narashino, Japan)